# 86 nissan d21 v6 cranks but no start, please help



## 240sx90 (Feb 23, 2010)

i have read up about my problems but cant find any help. Heres the situation, i have no pics, sorry, but i went mudding on wednesday night and went through some mud/water. i was in the middle of the water and shut the truck down in fear of sucking up water and hydrolocking my engine. i went back to the truck on thursday morning and still wouldnt crank and battery was dying but used jumpers for juice. so i changed my plugs thinking they were bad and nothing. got triple a and got the truck home for free. now its on to friday and i let it dry for that day. went out to start it saturday and nothing so i got a new cap, rotor, ignition coil, plugs and wires....sadly it still cranks but no start

sorry for the long post but im out of ideas, for some reason im leaning towards starter solenoid, distributor, or crank/cam position sensors are shot...i know im getting but theres no spark to kick the engine over, just cranks and cranks and cranks...........also theres no water inside that i know of as i used a vac to suc through the spark plug holes but i could be wrong............any help is greatly appreciated!!!!! 

truck is 86 nissan hardbody pickup d21 v6 4wheel drive 5spd....i still have interior/exterior lights and everything:wtf::wtf:


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## rogoman (Dec 16, 2004)

Go through the engine harness connectors; disconnecting each one to clean and dry the pins.


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## 240sx90 (Feb 23, 2010)

correct me if wrong, but using a hair drying to help dry is encouraged right?


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## jemtec (Jan 22, 2005)

Try to run a test on your main engine computer located under your passenger seat (this is an old school OBD-1 System, but one of the best ones out there because you can test things yourself!
Its possible you may have blown a coil switching transistor which is located IN the computer (causes ground to work on your coil to discharge sparks) for the distributor IF your distributor itself isnt bad, but this is VERY rare. 
Provided the computer wasnt under water. 
The test can be done through a good service manual, as I dont know all the codes to tell you for sure what is what, although I believe, your system used a "toggle switch" mounted on the side of the computer, along with a site "window" that has 2 leds in it.(the newer models post 1990 used a "turn screw").
Go into Diagnostic mode.(called mode III) turn igntion on, DO NOT TURN OVER just turn the switch on so your dash lights (oil light, alternator etc, illuminate) you will see the site window begin flashing when you flip the switch. 
It begins with 1 red flash, then after a second, 2 red flashes, then at the THIRD red led flash, immediately turn the toggle switch back and the codes will begin to post visually.
You will want to take out the passenger seat for more access, but it IS possible to do with it in.
Note: if you take the seat out.. be careful not to strip the bolts out when you put the seat back in! 
Another motivator to take the seat out.. you will probably find alot of change in and around the computer.. LOL 
Anyway to read the Leds:
There are 2 LEDS.. the first one is for 10s (in green I believe).. and the second is for ones (red).
So.. one flash on the Green LED is 10.. followed by a short pause.. then 1 flash in the ones (red) is "Code 11".
Code 11 is a bad crankshaft position sensor, and that is located IN the distributor.
I have replaced a distributor myself, and so have 2 other friends due to a bad "optic sensor", which is mounted in the distributor.
They usually show up with a rough idle for a time before they fail.
The other possiblity is a shot coil.. and that can be measured with a Ohm meter.
The coil also has a important item called a signal ampifier (little box mounted on the coil) the computer sends to trigger ground (hence spark). (procedure in a service manual too).
Id test the coil and Ohm out the amplifier too.
There have been MANY failures here too.. Id say there is a 50/50 chance you have a bad amplifier, or a bad Optical sensor in your distributor.
There are 5 main parts for the Ignition system..Ignition switch power, Distributor, Computer, Coil and finally the Amplifier.
Now back to the computer for a moment:
If you get no codes, (I believe it will show a code 45 or 55) or there is no power to the engine computer when you turn your ignition on, then look a little closer to wiring connections, and battery terminal leads. 
The postitive side has a main power harness that can get corroded and not work properly causing partial power operation.
Additionally, there IS a main computer power relay (Brown I believe located on the passenger side in a rectangular box by the fender clearly marked on what each relay does) that sometimes fails if you have a no "computer" operation, so keep that in mind.
There is a way to test for power at the Computer if there is none, but you need to be very very careful not to short any test leads, as this can blow the computer rendering it partially operational, or totally gone.
The test procedure I mentioned is safe to do, just dont jam any metal into the port where the switch is, as you may short it.
I use a piece of plastic, such as a pen, or even a pen lid with the little shirt holding tab on it to activate the switch.
One last thing, if you DO have to replace your distributor, there is a OEM # on the side of it.. Get that #, as Nissan had made them with 2 different designs, some were "shallow" depth connectors, and others were "deep" depth.
I hope this can at least steer you in a good direction on where to look for things.
If I were a betting man, Id say, after you check for trouble codes and dont get a code 11, check your coil amplifier.
I have seen those fail completely with no warning.. But the distributor typically fails over time with misfires and may take years to actually "quit".


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## 240sx90 (Feb 23, 2010)

thanks, im going to go out and work on the truck, will post my findings sometime later, thanks again for the advice, seems very helpful to me right now


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## 240sx90 (Feb 23, 2010)

well it was raining off and on yesterday and had no time to check anything out and its raining again today, but yesterday i had 5minutes and was able to take out the pass seat and the computer, opened the cover and inside was some light mud and water, time to hit a junkyard in the coming week for new dizzy, and comp


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## dentedsub (Oct 23, 2007)

just try spraying wd-40 on your electronics( it cleans repells the water) you might not need all those new parts.


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## 240sx90 (Feb 23, 2010)

ill see what happens tomorrow


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## jemtec (Jan 22, 2005)

Typically, an energized circuit will take damage with randomly travelling electrons in water.
The engine computer has hundreds of individual circuits and although spraying wd-40 works ok if you aren't worried if the petroleum base won't damage the circuitboard laminate or remove resist from resistors, or soften any silicone sealants or actually force more contamination further into sensitive areas, then yes use wd-40.
No.
If anything, use isopropyl alcohol (also disperses moisture) but be aware that you can clean circuitboards with water IF they aren't energized and alowed to air dry.
I used to work at agilent technologies building circuitboards.
I'm not being an ass, but chances are the board is too damaged to even bother repairing. It's scrap in this case.
As far as the distributor, it's probably fine, and your amplifier is propably good too.
Just get another engine computer. 
Should be set.


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## 240sx90 (Feb 23, 2010)

jemtec said:


> Typically, an energized circuit will take damage with randomly travelling electrons in water.
> The engine computer has hundreds of individual circuits and although spraying wd-40 works ok if you aren't worried if the petroleum base won't damage the circuitboard laminate or remove resist from resistors, or soften any silicone sealants or actually force more contamination further into sensitive areas, then yes use wd-40.
> No.
> If anything, use isopropyl alcohol (also disperses moisture) but be aware that you can clean circuitboards with water IF they aren't energized and alowed to air dry.
> ...


well, took a journey to a junkyard today and no luck finding a comp, they are all gone from the trucks already so im gonna keep checking, unless someone knows a place to get one.........also i was thinking of extending the wires so i could relocate the comp to a higher area, would this be a good or bad move on my part?


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## 240sx90 (Feb 23, 2010)

would a push button start serve any purpose in this?


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## jemtec (Jan 22, 2005)

You may check online and see if there are any computer relocator kits. The harness is pretty packed with wires and if you have the time and skill, you could try fabricating your own, but remember it could take several hours wiring it up. 
Anyway, my .02 cents there.
As far as an engine computer, you could try eBay, or any other auto salvage yard.
eBay is pretty good most times.
If I remember correctly, there were 6 engine computers.. 2 4cyl manual..2 6cyl manual.. And 2 6cyl automatic.
Good luck dude!


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## 240sx90 (Feb 23, 2010)

just an update, it was the ecu, i think, but after replacing all the parts and a junkyard ecu, the truck is back up and running and i also added a homemade snorkel, and went to the woods today and broke a front right axle


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## jemtec (Jan 22, 2005)

Crap dude, I'm sorry to hear that. 
at least she runs good again.
How much was the ecu?
Half shaft won't cost too much, and is pretty easy to repair. Just take your time. Check your wheel bearings, use a good high temp wheel bearing greaseand don't forget to replace the inner wheel seal. (mudding messes them up) and it's cheap insurance for the bearings.
Best of luck man.


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## 240sx90 (Feb 23, 2010)

i got the ecu from a pathfinder in a junkyard for 26 bucks plus fuse relays just in case, the computer was clean and intact and there was sitting there for a little while with all windows up and no leaks and it about 75k on it from the dash


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## jemtec (Jan 22, 2005)

Wow.. Smokin good price man!
Good thinking ahead about the relays too.
With only 75K on that Pathfinder donor, you can be sure the computer should give you alot more time before it even comes close to going out.
Typically though, Nissan ECU's last a very long time and rarely fail.
They were built pretty tough, but cant hold up to submersion in water when powered.
LOL 
Might even consider picking up the coil/amplifier out of the same Pathfinder (they are mounted together) just to have one on hand.
Who knows when yours was replaced (if ever).
They sometimes just "fail". 
So if you have a ton of miles on your D21, you might seriously consider getting a spare.
Glad you are getting things situated.
:thumbup:


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## 240sx90 (Feb 23, 2010)

yea im going back to the junkyard in the next few days for some more parts, possibly a drivers door due to rust as well as a bed if in good condition...gotta start a new thread tomorrow for updated progress of my truck and the mods im doing, i also painted my snorkel and hood today to a black since the snorkel was pvc white and the hood was silverish:givebeer:


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