Another Ignition Problem Thread

[rtboy02]

I've been scouring all of the misfire, ignition problem, and car running rough threads on this forum for weeks and have also been keeping my eye on the Supraforums for ideas on what to do. I haven't come up with the right answer yet, so I am posting my own thread for my own symptoms and hopefully someone can help bounce ideas.

Here is the general info on the car:

• 1JZGTE engine swapped in over 2 years ago and car has been running fine with 0 problems until about a month ago
• Engine is bone stock except for new, aluminum front-mount intercooler and piping (due to damage to the stock intercooler on the front clip I received)
• Replaced spark plugs at the time of the engine swap (can't remember the plugs used but they were ones that a lot of people on here used)
• Plug gap is fairly wide (bigger than the .028 that a lot of people on here are running) due to the stock nature of the engine
• Wiring harness was done by my buddy who has a Masters degree in Electrical Engineering and we have had 0 problems with any wiring on the car in the 2 years I have been driving it
• Battery is relocated to behind the passenger seat (with 2 guage wiring with gold connectors)
• 3" exhaust with high flow catalytic converter (stock downpipe)

Here is the symptoms of the problem:

• Intermittently, the exhaust will pop in rapid succession between shifts upon throttle changes (letting off of the throttle and easing back into throttle)
• When this occurs, the problem will persist until the car sits for a while (i.e., when the popping issue arises it will remain until the car has been parked and cooled down for several hours)
• Not always, but sometimes during this problem situation the engine will stall at a stoplight or stop sign
• Not always, but sometimes the car will buck like the ignition has cut to all or some of the cylinders briefly
• During this problem, I can smell a sulphrous smell from the exhaust strongly inside the car as I drive
• Sometimes, but not always, the problem will occur immediately upon startup. Since the car is not up to operating temperature and the cat is not yet hot enough, I can smell raw fuel through the exhaust and the car will struggle to hold an idle
• Never has the car been hard to start, even when the problem occurs. Starts up every time I turn the key, no exceptions
• Exhaust popping and hesitations do not happen under any sort of load or boost (only tried boost a few times gingerly), only part throttle, steady-state cruising, or throttle transitions
• Problem may not occur every time I drive the car. It has gone away for 3-4 days before resurfacing again
• Problem occurs during the heat of the day and the cool of the night, nor is it affected by temperature of the engine/engine bay
• No check engine light or codes have ever been displayed (just the all clear flashing when I check)

Here is what I have checked/done so far:

• Pulled the plugs and they are not overly dirty, do not show signs of detonation, and have virtually no wear
• Checked coil wiring and plugs for damage or corrosion
• Checked 1 of the cam sensors (the easier one to reach) and it was dirty so I cleaned it (no change in the problem)
• Checked the coils for cracks and found cracks on every one. Sealed with 3-4 coats of nail polish and cleaned the blue boots
• Pulled the ECU and checked for obvious damage. Did not notice any and the internals of the ECU are very clean (no dust or grime)
• Alternator checks out and voltage is good under driving conditions
• Replaced oxygen sensor with direct replacement Denso unit (no splicing, re-wiring involved; no change in problem)

There may be more that I can't remember right now, but I think that hits the most important details. I will be checking the electrical grounds next, but if it were a problem with grounds I would think the problem would show up more under boost. It is also possible that a coil or two are going bad and the nail polish isn't enough. I do not have a second set of coils to test out, nor do I have another ECU to try out. I am in Utah and I do not know of any other 1JZ owners in the state to borrow parts from. Any help would be appreciated.

 

[tissimo]

try a new ignitor

 

[rakkasan]

Sounds a lot like the problem I'm having. I spoke to Aaron about it & he recommended swapping out ignitors with someone local to see if that's the source, but there isn't anyone around.

I'm going to swap the coils around to see if one or two of them are bad. If not, I'm sure that a new ignitor is in order......

 

[rtboy02]

Yeah, I'll have to ask some of the 2JZ guys if they have an extra one I could try.

Barring that, does anyone know if there is a way to test the igniter?

 

[tlo86]

Yeah, I'll have to ask some of the 2JZ guys if they have an extra one I could try.

Barring that, does anyone know if there is a way to test the igniter?

check the mkiv tsrm

 

[rtboy02]

Awesome, thanks for the links in your sig. I'll check the resistances on my coils and igniter this weekend and report back.

 

[Machineica]

Are you using any kind of fuel controller or modded ecu? no vaccumm leaks near the map sensor?

 

[rtboy02]

I haven't found any vacuum leaks. I'll keep that in mind when I am testing the coil and igniter tonight to check those, as well.

100% stock fuel system. In other words, there is still a 7m n/a fuel pump in the tank, which I have not upgraded because the engine is stock and the A/F ratios checked out perfectly fine with my wideband O2 sensor under all driving conditions when I installed the engine. I'd much rather the problem be with fuel, but I don't see how it can be given the symptoms :icon_cry:

ECU is stock for a j-spec JZA70 Supra and came with the clip.

 

[rtboy02]

OK, I just got done checking all the ignition grounds, the spark plugs, coils, and igniter.

I cleaned all the grounds (just to make sure I had a good clean ground) in the engine bay except for the ones off the tranny under the car.

I pulled all the plugs and 4 of the 6 were pretty dirty, covered in jet-black soot. The ones that were not were #2 (from the front of the engine, looking at it from in front of the car) and #6. They weren't exactly clean, but they were about the same as when I pulled them about a week ago. #1, 4, and 5 were all covered in flaky, black soot so I cleaned them off. #3 was the same as #1,4, and 5 but was still wet with fuel somehow (strong fuel scent from the plug)! I had not driven the car in about 48 hours at that point.

Also, I checked the spark plug gap and they are all .034. I forgot to look at what brand and part number they were, though.

The coils all checked out perfectly on their resistances of about 0.7 ohms. So those are definitely not the culprit and the clips that plug into the coils look fine, too.

So at this point, I know the car is running pig rich when this problem occurs based on the spark plugs and the fuel smell present in the exhaust when the problem occurs at start-up. I have contacted some 2JZ guys in the area and cannot find a spare stock igniter to test with (since I would need to test for several days to be sure, I cannot simply borrow the one they have on their car). I will look into getting a used stock igniter if I can find one that someone knows for sure works fine.

Any other ideas? Someone mentioned in another thread that they had similar behavior when their gas pickup filter/sock got clogged up in the fuel tank? I would think that would lean things out due to a lack of fuel, though, instead of make things rich enough to be hard to ignite.