Diagnostic help?

[ORCGuide]

TL/DR distributor or timing belt?

 

1988 Pathfinder SE- V6 auto

 

176606 km on the odometer. (that'd be about 110 000 miles)

Has a new throttle body (from the Dealership before I bought it), new starter (also from the dealership before I bought it).

 

Previous owner was a little old Italian grandma. This was her grocery getter. It lived a very comfortable indoor life, scrupulously maintained at the dealership until she went into "the home" and her husband decided to get rid of it. That's the story I heard and I'm inclined to believe it. Low miles, little rust around the wheel wells and no evidence of collision damage or abuse. No mickey mouse wiring, everything was pretty much as it came from the factory. Factory Clarion deck, amp and speakers. . . sweet!

 

The only problem to be corrected during the insurance inspection in . . .June? was the horn relay needed replacement. Ran great for the summer, got 20mpg (12L/km IIRC). And then two of the blades on my fan went missing. . . $75 later I had a used fan and fan clutch. . . no big deal.

 

Then winter came and ruined my fun.

 

When it's cold it runs like crap.

It starts fine, idles up idles down just like it should. Get the temp gauge up to operating temperature and roll out of the driveway no problem. Stick your foot into it and between 2500 and 3000 RPM it bucks and stumbles. Both during acceleration and just cruising. . . srsly wtf? Every 5-10 seconds it feels like the motor will die, the RPMs drop below 2500 and everything is fine again for a few seconds.

 

After 20 minutes or so of driving the symptoms would disappear and it would run just fine like it did all summer for me.

After 15 minutes of driving and then sitting in a parking lot for half or three quarters of an hour, no symptoms on the way home. wtf?

 

So I checked the codes.

Had a code 11 - crank angle sensor. A little bit or reading in the FSM, found the CAS in the distributor. Tore the top part of the distributor down and cleaned the CAS with a little isopropanol and a kimwipe, blew some little flakes of schmutz out with compressed air. Yay no more code 11. But, it started throwing . . .

Code 21 - ignition.

Well, the cap and rotor were pretty manky so I replaced them. Symptoms and code 21 persisted.

So, I replaced the plugs and wires. Symptoms and codes persisted. . . srsly?

Changed the power transistor (AKA ignition control module) and coil.

 

NO more codes. . .

 

But the symptoms persisted. . .

 

It feels like a fuel starvation issue but all of the codes pointed to the ignition. . . wtf?

 

So I was thinking maybe a clogged fuel filter. . . changed that, no difference.

Water in the gas? Half a liter of 99% isopropyl alcohol in a quarter tank of gas works so much better than the little bottles of gas line antifreeze (methanol). . . burned through that and filled up with regular.

 

Next morning. . . same symptoms, buck and stumble until it warms up completely. . . srsly? wtf?

 

So I asked the mechanic at work about it. He says ignition timing.

I haven't touched the timing since I got the truck and that doesn't seem like the kind of adjustment that just goes out on its own. And how would that be affected by how warm the motor is anyway? So he says, "distributor". . . Now, when I had the cap and rotor off to change them, I did notice some play. . . a few degrees in the distributor shaft. Side to side, front to back, up and down are nice and tight but there's maybe 5 degrees of rotational slop . . . "Yeah," he says, " you get randomly variable ignition timing until things warm up and expand enough that it tightens up and things run great again."

 

Hmmm, makes sense. . . so I'm sourcing a new (reman) distributor.

Local stealership wants $7-800. Not so local stealership will get me one for $626 + $90 core charge + tax and shipping.

Local Nissan/Infinity (only, thats all they do!) wants $125 for a used one.

Local Pick-a-part might have one used for $50. They open back up in a couple of days, I may have to go for a walk. . .

I even found reman dizzys all over the interwebs for as little as $162 (CDN even. . . but after taxes shipping and a $20 core charge I'm still looking at $235).

 

Enter the squealing belt. . . as if I don't have enough symptoms to deal with. . . So, down to NAPA for new power steering and alternator belts. But they still squeal? Replace the broken alternator tensioning bolt (that the head sheared off?). Still squealing! A little bit of bar soap (regular bar of hand soap, you know. . . applied to the sides of the belt). Still squealing. . .

 

Hey wait a minute. . . what if its not the belts? What if its the timing belt tensioner? And if the tensioner is going south, how is the belt?

 

So, long story short: Is it the distributor? the timing belt? or is there something else that I am overlooking?

 

Anyone have any insight?

 

[ORCGuide]

More information and video.

 

I picked up a timing light. Timing is set where the sticker on the hood indicates it should be, mostly between the second large mark on the crank pulley and the next small tick to the right of it. But it jumps randomly between the second and third large mark on the crank pulley intermittently . . .

 

I am inclined to hope that simply changing the distributor will fix it. Getting tired of throwing money at it and hoping I fix it by chance.

 

Anyway, couldn't sleep this morning so I stuck my GoPro on the drivers side window pointing at the tach and went for a little drive. Apologies for the poor video quality, low light performance is not the Hero 1080's strong point. . .

 

Miss occurs at 4:28. and intermittently until I shut cruise off and turned off the highway.Under 2500 RPM, no problem. Cruising between 2500 and 3000 RPM misfire or detonation?

 

Just for laughs I checked the codes when I got home. . . 55 all good.

 

IIRC RF600 had a similar issue. Would be interest to know if it had been resolved and how?

 

Anybody else have any input?

[krmiller07]

Since you like to diagnose your car problems at night! I'd peek under the hood when it's dark, and see if you are getting any 'cross firing' between plug wires or anything associated with the ignition system. It's not unlikely that small cracks in the cap or plug wires 'grounding' to them selves or anything they rest on could cause a misfire!

 

If you feel bold, try moving the plug wires around by hand, and see if you get 'sparked' !

[ahardb0dy]

What brand spark plug wires did you use? I had cheap auto parts store wires on my sentra and it ran like crap, would stumble from a stop, put OEM wires on it and it ran perfect. never had another problem. I now have NGK wires and it still runs the same as the OEM wires. You may want to try that.

[ORCGuide]

Plugs are NGK. Plug wires are ProSpark Platinum 8mm hi-temp silicon from NAPA. Coil, Cap and Rotor are Intermotor. Power transistor/ignition control module is BDW (? I think).

 

The local Nissan dealership doesn't seem to want my money They don't carry any parts for my truck and are reluctant to order parts for me. If its older than their showroom, they can't be bothered.

So, I'm stuck with aftermarket.

 

I still have the Yazaki wires that came with the truck. I might try them out and see if there is any improvement.

 

The miss or detonation was the reason for my changing plugs, wires, cap and rotor in the first place. It wasn't until I changed the coil and power transistor/ignition module that I finally cured the code 21. . . but the symptoms persist. . . It's no worse with the new parts so I think I might be barking up the wrong tree. . .

 

Since you like to diagnose your car problems at night! I'd peek under the hood when it's dark, and see if you are getting any 'cross firing' between plug wires or anything associated with the ignition system. It's not unlikely that small cracks in the cap or plug wires 'grounding' to them selves or anything they rest on could cause a misfire!

 

If you feel bold, try moving the plug wires around by hand, and see if you get 'sparked' !

krmiller: It's not so much that I like to twist wrenches and bash knuckles at night, more like the wife and kids were still asleep and I could not sleep (every time I lay down I cough my lungs out. . . thanks to my little plague monkeys. . .) so I went for a drive under conditions that I knew would result in the symptoms being apparent.

I will fire it up again this evening and look for sparks though.

 

It's an intermittent problem. It only does it when it's cold out. If the temperature is below freezing it runs like crap (in the video it's not too bad really; it's been a lot worse) for the first 20-30 minutes and then it will clear up. Or run it for 15-20 minutes and then let it sit for a while. . . then it's fine.

Above freezing it's not an issue.

When it's really cold out it's really bad. Like fear and loathing . . . bad. And the symptoms do not get better. . .

[Trogdor636]

The local Nissan dealership doesn't seem to want my money They don't carry any parts for my truck and are reluctant to order parts for me. If its older than their showroom, they can't be bothered.

So, I'm stuck with aftermarket.

Contact Alkorahil....he's a board member who works at a Nissan dealership. Better prices than your local dealer can give you and his shipping is cheap.

[ORCGuide]

When I figure out what parts I actually need, I may just have to order from him. Hope customs doesn't sit on my package forever. . . again.

[Alkorahil]

I heard my name mentioned......

 

 

The symptoms you are describing sort of sound a little like distributor and a little like MAF harness, but neither totally seem to fit either 100% to me.

 

And you keep mentioning low temperatures outside.

I am thinking the Engine Coolant Temperature Sensor is the culprit. Keep in mind these trucks have two sensors, one for the gauge and one that feeds info to the ECU.

Without proper info the ECU doesnt know what to do and can/will stumble like you are describing.

Edited January 3, 2013 by Alkorahil

[ORCGuide]

Heh, I've had just about every connector under the hood apart and they all look like they haven't seen the sun since 1987. Surprisingly clean, no evidence of corrosion. Will check the MAF connector tomorrow. Actually, screw that, I'll pull the MAF and clean it tonight. . .

 

I'm leaning towards a worn distributor drive gear. The paranoid part of my lizard brain says check the timing belt. . . even if the teeth on the belt aren't worn enough to slip, they could be allowing enough play in the camshaft that I can turn my rotor a couple of degrees back and forth when its cold. . . haven't checked it hot... hmmm

 

Then again, I was going through the papers in the glove box. . . new starter in April, 2012. . . $105 receipt for pulling codes and checking fuel pressure in February with a $2200 quote to R&R the MPFI??? um, I might be a little slow but I'm pretty sure it has a throttle body. But that points me toward fuel issues. . .

 

And this is why I'm asking for other people's experiences and knowledge. . . It might just keep my wallet from becoming bulemic, . .

[krmiller07]

Your truck is TBI, not MPFI. Before you pull the timing cover off and all the stuff needed to get into it that far, I would be more inclined to replace the coolant temp sensor on the top side of the drivers side cylinder head...and or the connections. There a 'pig tail' connector on there that can throw some wierd running symptoms. I wouldn't be to concerned about a distributor, given the mileage of the truck. It doesn't make sense that it would be that worn. Unless of course, you can move the rotor and shaft side to side, or up and down by a fair amount. Some rotational play would make sense, given the fact that there will be some 'play' in the dist gear and the cam gear. Enough to maybe cause 2 degree's of rotational play. Try the sensor, clear the codes and see what happens.

[ORCGuide]

Hasn't thrown a code since the new coil and power transistor/ignition module was replaced. I checked this morning when I got home from my little trip. 55, everything is fine.

 

Distributor shaft has no perceptible play front to back, side to side or up and down. Rotational. . . not sure, a few degrees at least. I can estimate from the crank sensor but I would have to tear it apart again.

 

Cylinder Head Temp Sensor. that would be the one hiding behind the timing belt cover directly below the distributor . . .yes? Looks like a PITA to change.

 

Cleaned my MAF. Got my nipples crossed. . .

[ORCGuide]

I'll know for sure when it gets cold again but I think cleaning the MAF cured it.

[Alkorahil]

I dont think it is the distributor. If it was the outside temp wouldnt be symptomatic, and it would stall on you when you decelerate, say at a stop light, or floor it suddenly.

It would also not want to start randomly either with the engine cold or warmed up.

[ORCGuide]

It'll be below freezing again on Saturday. I'll have to go for a drive then and see. Then I can move on to the fun stuff like reindexing my torsion bars and replacing broken exhaust manifold studs. . . whee!

 

Thanks much for pointing me in the right direction.