# Beat to death: Weber conversion on B12 Sentra



## fairlanephantom (Feb 3, 2010)

Been looking through the archives and questions on fitting a Weber carb kit on an 87 Sentra have been beat to death. I have the kit on it's way right now and I have questions that I need answered all in one place and for a five-speed, seems like most were about automatics. Other things I just need confirmed.

- Can I still use the stock mechanical fuel pump with a fitted fuel pressure regulator? Or do I really need to get a generic electric pump.

- Seems that I need to swap my stock distributor for one from an 84, so the computer doesn't reset timing.

- Is the jetting right out of the box have decent performance? I'm not aiming to race with the car, just reliable. Is acceleration at least how the car already performs?

Any other things I should know about fitting the carburetor on my car with a five-speed. Post pictures of your setups if you've done it.

I just need to have everything simplified and ready for the carburetor, I don't have a spare car, so I may not get to work if I miss something.


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## fairlanephantom (Feb 3, 2010)

Got the carburetor in the mail today and looked over all the parts in the kit. I'm not sure why some seemed to have made a big deal about the coolant passage not being covered on the plate, seems like an easy fix. 

Is it really necessary to reverse the carburetor and have the throttle linkage on the passenger side? Does it mess with the fuel bowl if the throttle is kept on the driver side?


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## fairlanephantom (Feb 3, 2010)

Had the carburetor on the car for about two weeks, but I can't get it started. I'm apparently not getting spark. Is there something I'm missing in how the distributor and coil should be setup? I have power to the vacuum advance distributor IC.


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## fairlanephantom (Feb 3, 2010)

Still not getting spark.


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## fairlanephantom (Feb 3, 2010)

Now that I'm not freezing outside I can elaborate more. Tested the coil, and it tested good. in range on secondary, 1.2k on primary. Same as one from my parts car. I ordered a new ignition module, the one on the car, the new one, and the parts car all come with the same reading of continuity. 
I'm not sure if I understand how Haynes describes it, but they state pins 1 and 3 on the connector should not have continuity with pin 4, but on all three part harnesses, one of the pins does have continuity. Same on each individual part. Not sure if their representation is correct, as one of their Toyota books had a Honda engine pictured. 
When the engine is cranked it looks like I have 10v to the harness. This is when using the stock coil that was already in the car, I got the same when I had the canister type coil hooked up. I still had the same result when I tried using that kind. 
The only thing I haven't actually tested is the new distributor, though I know voltage is going to it, I haven't tested it any other way.

Since the beginning of the project, here's what's actually different. 
- Carburetor has been bolted on.
- All vacuum lines have been capped. EVAP lines are still routed, EGR and vacuum advance are connected to the carburetor on the designated ports.
- Vacuum advance distributor from an 84 to 87 California emissions Sentra. As stated, routed to the vacuum advance port on the carburetor. Power from the IC is routed directly to the battery for now, was at first wired to the lines from the coil until I decided to keep the original. 
- Electric choke is wired directly to battery for now. 

Been a few weeks, I really need to get this car running again. Looks like a stupid project when the car ran before I started.


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## 19sentra88 (Oct 24, 2009)

it seems like a high resistance problem. you said you're getting 10 volts when cranked and i see 2 problems with that: A-it's a 12 volt system and B-you should see around 14-15 volts when cranked. it seem like you're getting a voltage drop across something


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## fairlanephantom (Feb 3, 2010)

Well, I guess I would attribute that to drawing from the battery while cranking it for a few days at a time before charging it again at work. Though I'm not too sure past that.


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## fairlanephantom (Feb 3, 2010)

How would i go about testing the wires from the harness back?


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## fairlanephantom (Feb 3, 2010)

Or what I meant to ask is if anyone has a wiring diagram more in-depth than the Haynes manual. They show just one vague line leading to the coil.


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## fairlanephantom (Feb 3, 2010)

Should I get anything if I hook up the original electronic distributor? Was wondering if I could put it back in for a test to see if it really is a serious problem or not. From what I read is that I may get spark, but the timing won't advance with that type distributor missing the carburetor.


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## fairlanephantom (Feb 3, 2010)

Messed around with it for awhile and still didn't get anything, I put the original distributor in and it started on the first turn of the key. I looked into it, and it may have been an issue with a bad IC module in the distributor. Obviously I can't keep it like that, so I have another module on the may and I'l be trying it again. 
The Weber sounds really nice on there, already ran smooth on just base settings. Right now my accelerator cable is held on by a heavy gauge copper wire, I'm working on grinding half my original throttle cable mount so it will clear the throttle shaft nut on the Weber.
Someone said before they tapped the holes in the intake for the coolant passage. I just put Loctite on the threaded hole in the adaptor, and it never leaked. So pretty much, pay attention to the instructions when it tells you to put Loctite on everything. 
I drove it around the block just to move the car, it did eventually stall out and back fire when I turned it off, but I'm sure that's just because of the distributor. 

Anyone know where i can find a salvage two wire Distributor harness? For the year and California emissions, scrap yards around CT and MA just gave me a big 'fuck you' and hung up. For now it'll be soldered and crimped until I find one.


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## fairlanephantom (Feb 3, 2010)

Swapped out the IC and had the distributor tested at a custom shop, it's now good and sparked strong during the test, but I have to figure out the wiring to the control module still. I tried it a few different ways and it didn't work out. I'm going to ditch that module and get a GM ignition module that can pretty much work for all ignition applications when connected right. 
I tried one earlier today, but it may have been faulty or wired wrong, didn't have time to test it at work, so I just ordered a new one. Instead of using the early stock coil, I may get one with hotter spark for better performance. Whichever is ultimately cheaper. Either way I have the new bracket for the coil. 
To be safe I ordered a new power transistor and bracket, and someone at Nissan will get back to me on wiring. That part was about $120, so I hope I can get the generic setup to work first.


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## TOOQIKK (Jul 11, 2009)

got some pics of your set up? and doog luck with your lil project!


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## fairlanephantom (Feb 3, 2010)

TOOQIKK said:


> got some pics of your set up? and doog luck with your lil project!


Not yet, I wanted to do a before and after, but I forgot to take a picture before I started. But I do still have a bag of the ridiculous vacuum lines I ditched. It's weird to actually be able to see my intake now. There's also going be so much extra space after removing the rest of the electrical emissions parts. Some of this process annoys me because of some not being that old, when I was doing my best to get through emissions last year. Like the $400 VCM I had to order directly from Nissan because my idle was crazy in idle, or $50 for an air temp sensor that didn't change how the car ran anyway. I may try to sell some of it to make my money back on the project.


I'll have to take pictures of what I have left, and anything in particular anyone wants for smaller details. I haven't seen anyone post GOOD pictures of this project, so I hope to do that. I have more plans for the engine after, so I may post those as I can afford them. My camshaft is apparently split in the middle and only held together because it's an offset split, I'm deciding if I want to replace it stock or with the Euro cam.


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## fairlanephantom (Feb 3, 2010)

Finally have spark with the vacuum distributor. 

Though '82 and '83 use a different distributor than '84 to CA '87, the IC module inside both models in the same part number. The later transistor modules also require a line back to the ECM. The two pin connector on those is for 12v and ECM line to detect pulse. So because I have a Federal computer, that wouldn't necessarily work. So I decided to go the early route and just ad a condenser to the line, like the original model Sentras. Condensers are generic, and go for about $5, mine was $3.50 after my discount. I now have spark, though just a little weak until I mount the condenser better, still strong enough to hurt like a bitch when it got my hand. The car only started twice out of my many attempts, but nice for a few seconds before stalling out. My guess is fouled plugs after so my tries. 
Didn't have a chance to try the stronger V8 coil, the positive terminal snapped twice on two different coils, so even aftermarket Dodge parts are garbage. I bought a universal performance coil, but haven't had a chance to hook it up before it got dark and started to rain. I may stick with the stock coil anyway.

Attempts for tomorrow are swapping out the plugs to eliminate chance of fouled plugs with ignition. If it still doesn't start, play with my timing and do a routine check of the carburetor.


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## TOOQIKK (Jul 11, 2009)

yeah im in the process of removing the egr stuff off my wagon....
have to make a block of plate for the manifold and then weld shut the pipe from the catalytic converter and the two pipes in the exhaust manifold....sure cleans up the engine bay! 
i laugh as i have passed emissions in my 91 sentra with a hollowed out cat and zero egr parts on the car(had a jdm motor swapped into)....ran so clean they ran it twice they were amazed at how clean the motor ran....lol wish i would have saved the paper work when i sold it....lol


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## TOOQIKK (Jul 11, 2009)

i miss my old skool cars with carbs....had a 67 f100 with a 352fe motor, 69 mustang with a stroked 315w , 74 ford courier(had a mazda motor in it!!), 78 chevy 1/2 ton hi po 350
could rebuild the carbs with my eyes closed! life was so much simpler!!LOL


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## fairlanephantom (Feb 3, 2010)

That's part of the reason I'm going through this process, there will be only so many things it can be when something fails. It's mostly because when emissions started up again a few years ago, I couldn't get the car to pass. The original out of factory carb was still on the car and dumping fuel. The limit on the test was 1 for CO, I was up at 5. I swapped out the carburetor and it passed, then not much later the rebuilt failed. I swapped it again... then it eventually failed again. Then I put another on and it seemed like it was starting to fail again. After I did the head gasket on the car and put it back together, the CO even jumped to 6 the second to last time I went through. I can't deal with the Hitachi anymore or it's shit rebuilts. Guy at the local Nissan dealer told me he swapped at least 12 a week out up to the early 90s. 

I want to keep my EGR, but I want to get rid of the second pipe that leads up up to the air cleaner. I've considered just buying a new exhaust manifold and leaving the plugs in it for the air line and the oxygen sensor, but it would likely take forever to transplant the EGR pipe. When doing the head gasket, I had to take off the manifold, pipes, and EGR all out in one piece, weaving them through the engine compartment to move. 

Shame will be that I won't be able to easily use my AC anymore. Though I haven't been able to get the system to stop leaking for a long time.

Think right now on the car I may have killed my fuel pump, I cranked it for maybe a half hour with no luck, and it didn't smell of gas at all under my hood. Every once in a while I swear I hear clanging and buzzing from somewhere on the engine, so my first guess is the pump on the cam. The pump on these is cheap enough, $25 and easy to do. So I may even just toss it in without doing a complete test. Also debating if I should keep the regulator I added as the pump already operates about what the Weber is rated for, maybe a half pound difference.


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## TOOQIKK (Jul 11, 2009)

regulator is a nice safety catch


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## TOOQIKK (Jul 11, 2009)

get one of the UV dye kits so you can track the leak down and go from there...they arent that much at the local parts store...i know auto zone and walmart and meijers carry them to name a few


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## fairlanephantom (Feb 3, 2010)

Tested my fuel pump when I had some time, and I apparently blew the one on the car when forcing it to pick up parts. Took the twenty minutes or so to do the new one and the car started back up. Now it's just back to adjusting the carburetor.


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## fairlanephantom (Feb 3, 2010)

TOOQIKK said:


> get one of the UV dye kits so you can track the leak down and go from there...they arent that much at the local parts store...i know auto zone and walmart and meijers carry them to name a few


I know where it leaks from, just never could get it to stop. It leaks on the receiving end of my condenser at the fitting. I replaced the o-ring, and made sure it was flush and it still leaked. Also tried a sealant and it still leaked. The air conditioning does still work, it just leaks out the same day I add new frion.


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## TOOQIKK (Jul 11, 2009)

j b cold weld ftw! lol
other than that you either need a new line or condenser....


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## fairlanephantom (Feb 3, 2010)

TOOQIKK said:


> j b cold weld ftw! lol
> other than that you either need a new line or condenser....


Tried it, it actually still leaked. I almost changed the condenser, but it seamed like I was going to strip the other fittings so I stopped. 

Did more work on the car. Everything is wired, including the coil in the ignition circuit so it's still under the same system, also mounted the coil and condenser. I'm almost done, but once in awhile it diesels for a second before shutting off. I haven't gotten it to the best timing spec and idle, one of the two I'm sure it doing it. Drives nice besides though. Once I get that straightened out and clean everything else up, I'll be taking pictures and a better write up on the project so it's easier for anyone else for anyone else after.


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## 19sentra88 (Oct 24, 2009)

is it true that you can use the carb from a nissan hardbodyon the e16? if so, what'll it take to do the swap? i dont quite have funds for the weber swap


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## fairlanephantom (Feb 3, 2010)

19sentra88 said:


> is it true that you can use the carb from a nissan hardbodyon the e16? if so, what'll it take to do the swap? i dont quite have funds for the weber swap


I don't know anything about the original carburetor on those, so I couldn't say for sure. If it isn't an electronic carburetor, pretty much any will work if you can get it bolted and sealed to the intake. From there it's all adjustments, so you're better off just waiting until you can afford the Weber kit, so just buy a used one and a rebuild kit for $20. 

Shop around for price, the Weber kit is a K662 and comes with the adaptors needed. I got mine off eBay for $260, while others wanted close to $400 for the kit. Keep in mind the additional parts you'll need after like I had to, though not really that much, besides having to eat the core price. When I do the write up I'll have a list of part numbers and prices so you have a better idea of how much you really need to save. I paid for everything with my tax return.


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## TOOQIKK (Jul 11, 2009)

wish i would have known i scraped mine....damn i would have sent it to you....
i was goin crzy pullling stuff out of the engine bay.....lol


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## fairlanephantom (Feb 3, 2010)

Still making adjustments to make it run at it's best. I've been getting at least stock mileage with the Weber, it may be a little better. Only things I have to take care of are the car not going over 55 on the highway and random dieseling. It can go a week before doing it again, but it eventually does. I'll have to see what I can do in my next free time.


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## TOOQIKK (Jul 11, 2009)

make a vid of it running....


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## fairlanephantom (Feb 3, 2010)

I can do one tomorrow if it the rain around here stops.


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## fairlanephantom (Feb 3, 2010)

Tried to do a video, but my camera doesn't do video, so it's pretty much just me silently playing with my throttle cable. That'll have to wait until I use someone else's camera, but I did did some quick pictures. 


























I still haven't had enough time to finalize a few things, but it's pretty close.


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## TOOQIKK (Jul 11, 2009)

might as well remove the egr stuff as its not being used....lol
clean up the engine bay a little by doing that too....
looking good would love to hear it runnig....


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## fairlanephantom (Feb 3, 2010)

Don't think the cylinders would get too hot? 

I tried to take a video and I ended up just getting blamed for supposedly breaking her camera, so I'll have to ask around to use someone elses. 


Weber just told me that I have to back off my throttle and play with my timing to get the dieseling to go away, as well as go over 55 on the highway, so I'll be working on that now.

Edit: throttle response improved, but it still can't go over 55.


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## fairlanephantom (Feb 3, 2010)

Still chasing the same issues. I found oil in my distributor so I swapped it out, but it didn't change any of the performance issues. While doing that I checked my coil and it apparently cracked open. I'm wondering if this is because I should add a ballast resistor to the ignition, not just the condenser. I could try that $120 early Sentra ignition module again, but I wasn't too sure what both pins were before. One person told me, but I'll have to check back and reference that if the resistor doesn't help.


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## 19sentra88 (Oct 24, 2009)

the coil is prolly from the way you mounted it, the coil has oil in it along with an air gap, both the small terminals must be submerged in oil therefore both small terminals have to be as low as you can get them, in other words, completely sideways, you way you have it mounted looks like one of the terminals is at the top of the coil and prolly overheated


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## fairlanephantom (Feb 3, 2010)

So are you saying I should rotate the terminals so they're both horizontal, or turn the entire coil upright?


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## 19sentra88 (Oct 24, 2009)

fairlanephantom said:


> So are you saying I should rotate the terminals so they're both horizontal, or turn the entire coil upright?


sorry, i didnt make it very clear what i was saying. the coil should be horizontal as you have it, but when looking at the terminals, they too should be horizontal. sorry for the mix up


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## fairlanephantom (Feb 3, 2010)

The conversion is on going, technically done, I'm just cleaning up the grime and simplifying everything to look more streamline. 

I'll be buying a salvage intake for $25 locally, and will be drilling new holes so the Weber will be a direct bolt on. No more adaptor plates.

All the vacuum tees on the engine have been replaced with brass plugs, The line to the brake booster is a single barb fitting. Only vacuum lines now are for the vacuum advance, egr, and crankcase ventilation.

Mounted a ballast resistor under the bottom bot for my coil mount. It can't be seen unless you really stick your head down there. The condenser will be mounted to the distributor soon. It will be soldered directly to the positive in the distributor, then routed through the slot in the side of the cap, and mounted where the wires bolt to the side of the distributor. 

I ordered a parts distributor just so I could get the harness. It was beat to shit, so I had to make a new one using the grommet that came with it. Keep in mind that one from a Federal emissions may also fit, I'm not sure where mine went. 

I got the throttle cable to fit in the bracket supplied with the carburetor. Just stuck a screwdriver in it sideways until it became large enough to fit the cable threads through. I was using a paperclip before. 

I cut unused wires out of the engine compartment. I used my parts car to trace back the lines to their original harnesses, then removed them all the way back. I cut the wires recessed, then filled to the top and smoothed out with hot glue. The only lines going to my engine now are coolant sensor, alternator, oil switch, and transmission. The choke is wired from one of the vacuum sensor lines that run along with the brake level sensor. 

I'm still looking into doing a header and dual exhaust, but I'm out of money and the body work will be priority as soon as I find the money to do so. 

I'll take updated pictures and a video sometime soon. If anyone needs some of the harnesses I'm not using, let me know, I have no use for some of them.


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## fairlanephantom (Feb 3, 2010)

Still working on this when I get time. Finally got it to stop dieseling without adding a solenoid. I had it running just a little too lean, I turned the mixture screw in a half turn from where I had it and every few days leaning it back out til it did it again, then back in just a little bit. That was really the part of the entire project that has been pure frustration. Timing and idle are set at 5 degrees, 700 RPM.

I bought the spare intake from a local junkyard, wasn't expensive at all. Going to plug up the spare intake like the one on the car, but going to drill the carburetor mounting face so the Weber will be a direct bolt on. Then I'll just have to invest the $10 in a phenolic spacer. After that the transition will be complete and everything else I do from there will only be cosmetics.

I'm charging my camera now to take more pictures, and finally a video of it running. If anyone else needs an intake to do the same thing, the junkyard did have about three more of the intakes in stock.


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## TOOQIKK (Jul 11, 2009)

cant wait to see some pics......sounds like you are close to have it all done!


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## fairlanephantom (Feb 3, 2010)

Then body work will be my only concern. Seriously need to at least do the bottom of my car before snow. The rest in the spring with a change in color. 

On this intake, any ideas what the three bolt bracket is that bolts to the underside of the intake? I was confused when I first saw it today, the original one on the car never had one, never saw it when I did the head gasket. At the very least, it apparently wasn't important.


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## TOOQIKK (Jul 11, 2009)

eastwood company makes a frame/interior spray for rust proofin the insides of the frames and nocks and crannys...it has a long hose with a cool head on it that helps dispense it...I would recommend that along with their clear coating for the lower areas of the car....its like a stone protection spray you can paint over....some cars have it....

post up a pic of the manifold ill see if it triggers anything in my rusty brain!


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## fairlanephantom (Feb 3, 2010)

So it comes out looking like that rubber looking paint they have on the bottom trims of VWs?

The bracket pretty much looks like the one that supports the carbon canister.


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## blownb310 (Jun 10, 2002)

I've run the '82-'83 vacuum advance distributor in my '86 B11 for years. There was no fuss with any wiring. As you know, there are only two wires. Just connect the white with a black tracer wire to the positive side of the coil and the other wire to the negative side of the coil. It's that easy.

Mike


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## fairlanephantom (Feb 3, 2010)

blownb310 said:


> I've run the '82-'83 vacuum advance distributor in my '86 B11 for years. There was no fuss with any wiring. As you know, there are only two wires. Just connect the white with a black tracer wire to the positive side of the coil and the other wire to the negative side of the coil. It's that easy.
> 
> Mike


Yeah, it looks like really the only difference between the original Sentra distributor and the one that came after was the advance, same distributor besides. My original starting issues were because I forgot the condenser, started right up after I put one in. 

Most of the conversion just to get it working is pretty straight forward, and you really could do it all in one day if you're prepared. I've been getting cosmetic things out of the way, but I'm pretty sure I have to change the jetting on the carburetor. It seems like as it is it needs different jets, and more so after I put the header on.


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## blownb310 (Jun 10, 2002)

fairlanephantom said:


> Yeah, it looks like really the only difference between the original Sentra distributor and the one that came after was the advance, same distributor besides.


Actually, no that's incorrect. The '82 & '83 E15 and E16 ditributors use a simple reluctor setup and were designed to work as a simple electronic ignition [without an ecu]. They use engine vacuum for advance and/or retard. The '84 to '88 E-series distributors contain a crank angle sensor unit that will not work without the ecu. The ecu controls the ignition advance curve in the '84 and up models.

Mike


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## fairlanephantom (Feb 3, 2010)

Well, I really meant between the original 82 distributor, and the California emissions models. The first year had two vacuum lines on the advance, and the others just had one. My car is a Federal emission model, so it originally had the ECU controlled spark advance. I cut that four pin connection back and sealed it where it can't be seen.

I'm just using individual condenser and ballast so I didn't have to shell out over a hundred for the actual module. It looked bulky anyway being part of the bracket.


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## fairlanephantom (Feb 3, 2010)

Made a little more progress. Cut back the pipe that originally led from the exhaust to the air cleaner. The metal section originally ended right behind the distributor, getting in the way of adjusting my timing. I cut it back a few inches from the exhaust manifold with just a decent hacksaw and capped it.
The line from the EGR I haven't cut yet. I cut a piece of gasket to block the EGR passage, and now driving it to see any difference in performance and mileage, so far nothing different. I'll cut that back also, also get a block off plate so I can completely remove the EGR. It looks like one from an '86 300ZX will fit and readily available online. 

Haven't rejetted the carburetor yet, but will be getting to it. The jets that come in the kit are apparently too small. I read a general Weber tuning guide on a Datsun forum, and it said that if you have to turn the mixture more than two completely turns to make it run well at idle, then the main jet is too small. I had to go over two turns.


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## fairlanephantom (Feb 3, 2010)

Finally found a charger for the camera, now I can finally post updated pictures of what I’ve done.

I cut the EGR tube back and capped it. The EGR valve gasket for a 300zx fits the 1.6 Sentra, bought two for twelve dollars off eBay.

Use the delay valve, originally connected to the vacuum sensor mounted to the firewall, for the distributor. The engine will diesel if you don't. It hasn't done it since I put it on there a few weeks ago. 


Also included a picture of the resistor I put in when I removed my third brake light. It’s a 50w resistor, soldered and heat shrinked, tucked into one of the openings. It’s stable, and the warning light still comes on when the other lights go out. 

Also posted a video on YouTube of the car running. Sorry if it seems dark, they were all in my garage. 

Here are the pictures.


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## blownb310 (Jun 10, 2002)

Thanks for posting the pics. Looks nice!

Mike


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## fairlanephantom (Feb 3, 2010)

Thanks. Only things left are blocking what's left on the intake, bringing it to a shop to fabricate a plate to make the Weber a direct bolt on, and relocating the new FPR to the firewall where the vacuum sensor was. I was almost going to modify a Pinto intake as I've seen, but it didn't sound beneficial enough. Though someone in town is selling one for $20.


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## leagalmadness (Jun 26, 2010)

hi, did you do any more work to the car.


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## jaysonbarn (Jan 4, 2011)

I did washing and waxing today and what about you????


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## fairlanephantom (Feb 3, 2010)

The only thing really left in this project is properly jetting the carburetor for this engine, but I have a few other priorities with the car first before I go into that. One being that I really need to do my camshaft, pretty sure I mentioned before that it split in a half a few years ago. I've been pushing my luck for awhile. 

I also need to bring the car in to get the under side welded up before there isn't a car left to work on. Had it priced at about a grand, I have the money, just haven't had time to make the appointment. The camshaft I'll tackle after I get my tax refund.


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