# 2002 Xterra 3.3 troubles



## davidklintworth6 (11 mo ago)

I have a 2002 Xterra. I literally just finished putting new injectors in due to it limiting the Rpms to 2500. I have already put several new parts into it and still got no where. I installed new parts as follows;
2 Distributors, caps
Plugs, wires (year ago less than 1000 miles)
Injectors
Fuel pump
Throttle body
Exhaust from second cats and back ( not for same reason)

After all this I still have to change the Crank sensor and pig tail. I'm curious if I need to replace the fuel regulator because I still get a solid miss and popping when at all rpm ranges and yes maxed 2500 Rpms. 

When I first got the vehicle I had to replace the distributor because of the bearings and did the plugs and wires at the same time. Well every once in a while mostly only when driving in wet conditions it would drop power for a second or a few. Then it just stopped running good all together. Can someone help me before I drop more money into it, please?


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## davidklintworth6 (11 mo ago)

Ok so after a little messing around with my scanner all codes are for MAF which my connector has a crack in it. Had a P0505 as well which I did a half as job resetting the idle air control. I did happen to get mixed results... I still have the trouble of it idling on its own without me having some pressure on the throttle otherwise it dies. It did go above 2500 and sometimes it smoothed out then right back to missing and popping. I do have to pump the throttle or hold it to the floor to the floor to get it to start. So I have to conclude it is the air mixture problem. I know that once I can get it to idle on its own I can reset the idle air sensor. 

Question I guess now is, could my timing be off and/or just the crank sensor and pig tail and MAF connector be my problem?


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## VStar650CL (Nov 12, 2020)

Try unplugging the MAF and see if it stabilizes. It does sound like a MAF or vacuum issue. Timing won't cause a misfire like that unless it's _way_ out, normally a little retard causes sluggishness and possibly running hot, too much advance causes pinging and possibly hard warm-starts.


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## VStar650CL (Nov 12, 2020)

PS - I wouldn't sweat the crank sensor, I'm pretty sure all the VG33's only used it for tachometry and diagnosis.


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## davidklintworth6 (11 mo ago)

I'll play with it some more tomorrow. I will send an update with those test ran. I did have to replace a vacuum line on the intake plenum manifold. Line was old and broken. What about the sensors on the bottom of that plenum any thoughts there?


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## rogoman (Dec 16, 2004)

davidklintworth6 said:


> Ok so after a little messing around with my scanner all codes are for MAF which my connector has a crack in it. Had a P0505 as well which I did a half as job resetting the idle air control. I did happen to get mixed results... I still have the trouble of it idling on its own without me having some pressure on the throttle otherwise it dies. It did go above 2500 and sometimes it smoothed out then right back to missing and popping. I do have to pump the throttle or hold it to the floor to the floor to get it to start. So I have to conclude it is the air mixture problem. I know that once I can get it to idle on its own I can reset the idle air sensor.
> 
> Question I guess now is, could my timing be off and/or just the crank sensor and pig tail and MAF connector be my problem?


If you're unable to go above 2,500 rpm, then the ECU has set the system to run in fail-safe mode due most likely to a bad MAF circuit. Fix your MAF connector, then clear all the DTCs and see if any come back.
Several things that could cause misfires:

What brand of spark plugs are you using? You should be using OEM NGK plugs; other brands such as Champion or Bosch many times cause driveability problems in Nissan engines.
The camshaft position sensor may be marginal. A common problem with random engine shutdowns, difficult startups, rough running is a marginal camshaft position sensor. Most of the time when this happens, the "check engine light" never comes on; subsequently when performing an ECU code readout, there was no fault code set. However to replace the camshaft position sensor which is inside the distributor, the distributor needs to be replaced; buy a re-man distributor, not a new aftermarket type; aftermarket distributors generally are not reliable, don't last long, and many times are DOA.
Incorrect fuel pressure. Tee-in a temporary fuel pressure gauge between the fuel feed hose and the fuel rail. The readings at idle should be as follows: with vacuum hose connected to the fuel pressure regulator: 34 psi. With vacuum hose disconnected from the fuel pressure regulator: 43 psi.
There may be a major intake system vacuum leak. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
Dirty fuel injector(s). Run some good injection cleaner, like BG products 44K, through the system; give the cleaner about a week or two to do it's job.


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## VStar650CL (Nov 12, 2020)

davidklintworth6 said:


> What about the sensors on the bottom of that plenum any thoughts there?


Of you mean the knocks, they won't cause the kind of symptoms you're seeing. Rogo is right, get your MAF straightened away before you go hunting for other stuff.


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## davidklintworth6 (11 mo ago)

I only use NGK plugs in all my engines from the smallest to largest ( except my diesel lol). I do believe the plug wires were not NGK I cheapest out after getting the good plugs lol.. I just ordered the MAF pigtail I did replace the MAF sensor and housing last year and that is when the crack happened on the pig tail. Hard to believe a crack would cause a malfunction, but hey.

I do believe I do need to retard the distributor a little bit to help with the starting. As far as the distributor it is aftermarket only because I could not find a remanufactured original, everywhere did not have any. And when I found one it was after a month or so of searching, and no I don't still have the Original one to get new internals. 

As far as getting outside today to tinker around is a wet and icy one so no work today...


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## davidklintworth6 (11 mo ago)

Ok so I was wrong on the plugs I guess I bought shit Bosch. Probably because ngks were sold out at the time and they had them handy. I am about to get a reman distributor because I can't get any starting and if I do it don't run long. Anyone know of where to get a good reman distributor?


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## rogoman (Dec 16, 2004)

davidklintworth6 said:


> Ok so I was wrong on the plugs I guess I bought shit Bosch. Probably because ngks were sold out at the time and they had them handy. I am about to get a reman distributor because I can't get any starting and if I do it don't run long. Anyone know of where to get a good reman distributor?


You can get a re-man distributor here:






2002 NISSAN XTERRA 3.3L V6 Distributor | RockAuto


RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.



www.rockauto.com


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## davidklintworth6 (11 mo ago)

I bought one off eBay out of an old parts Xterra. $79 sum. Even if it last a couple month at least it will benefit with not buying parts for it a quick minute. And I had a few seconds today of run time above 2500rpm. I had to readjust a couple teeth on the distributor from timing marks to get that run time. Yesterday I changed out the coil and cam sensor disk. 

So I'm also thinking I need more grounding in hopes that would help. I noticed for a couple days now that there was a grounding strap that fastens to the passenger wheel well. That strap was broken and the other half I don't see anywhere. By chance might anyone know where that ground connects too? _I'll send a picture tomorrow_


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## rogoman (Dec 16, 2004)

davidklintworth6 said:


> So I'm also thinking I need more grounding in hopes that would help. I noticed for a couple days now that there was a grounding strap that fastens to the passenger wheel well. That strap was broken and the other half I don't see anywhere. By chance might anyone know where that ground connects too? _I'll send a picture tomorrow_


It might connect to the exhaust pipe heat shield or engine/transmission case or engine head.


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## davidklintworth6 (11 mo ago)

Ok... I'll see about adding a couple of them just for the heck of it. I will also go thru all the grounds and clean them and spray them with battery terminal spray


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## davidklintworth6 (11 mo ago)

So after fixing the MAF pigtail I cleared my codes and still get the code P0505. It is the idle air control valve. I did not have the code before I changed the injectors. I just double checked the plug-in's and ordered another which is still on its way. I've tried all the throttle relearning steps with no luck at all. Still only getting 2500rpm limit. The Xterra will start cold fine with a little pedal, but when it warms up it will not restart. I've burned up 2 starters and working on the 3rd. I have checked vacuum lines and seen nothing that stands out. 

I'm thinking I should replace every hose when I change the IAC valve and the fuel pressure regulator. If all this don't work I have in mind to either part it out or take it to the dealership and have them mess with it.

Oh... Also it have roughly 240k I believe and a friend mentioned about be possibly having to Eplace the timing belt or chain. Any thoughts if that is more my problem??


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## VStar650CL (Nov 12, 2020)

P0505 on your ride is pretty much always an electrical issue. The valve is PWM-controlled and there are only 2 wires. YEL/BLK is always hot through fuse #15, ORG/BLU is grounded at a ~500 Hz rate by the ECM. The percentage of time the ECM grounds the wire controls how wide the valve opens. So the lower the voltage on ORG/BLU, the wider the valve is open. 


















If the IACV coil is shorted, it's possible for the drive transistor in the ECM to be damaged. So first, ohm the coil. It should read around 10 ohms. Anything much above 14 ohms means a weak coil. Anything much below 6 ohms is dangerous to the ECM, and a short below 2 ohms will definitely damage it. If you read infinity, the coil is open.

Next, make sure you have 12V on YEL/BLK _while running_. If you don't see battery voltage, the valve can't function. If you see 0V, check fuse #15. If fuse #15 has power on both sides but you see no-or-low voltage, you have a wiring or connector problem on YEL/BLK.

If YEL/BLK is good, measure voltage on ORG/BLU at idle. You should see what the chart shows, 10.5~11.5V. If you see battery voltage then either ORG/BLU has a wire or connector problem, or the ECM drive transistor is damaged. In that case, ohm ORG/BLU back to the ECM connector. If it reads near 0 ohms then your ECM is shot, otherwise it's a problem in the wire.


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## michellent (24 d ago)

Adjust the black screw on the side of the IAC valve.


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