timmJ

Ok so over the last few months every blue moon I have this scary issue where I am accelerating in either 2nd or 3rd (manual) and my motor all the sudden basically stalls out but kinda continues to run and then dies. There is a really strong odor like burning something (doesnt really smell like fuel) and it will not turn back over. However I can wait for a few minutes and then it will struggle to restart but finally gets up and starts going. It mainly happens in second but it has also happened in 3rd a couple of times. Luckily I have been able to get to the side of the road everytime. I am worried though that my 4runner will do this in not such a lucky spot in the future and cause a major accident.

I have a converted 95 4runner with a 1997 3.4 engine. Running a S/C with the walbro 190 fuel pump and the URD 7th and 2.2 pulley. I also have always had backfire issue ever since I completed the swap. Invested lots of time to figure it out but have never fixed it. I am assuming I have a sensor somewhere that is going out and is causing all of the issues i have seen but not sure which one. (have lowered fuel mileage in comparison to other rigs, the backfire problem, slight hesitation from a stop).

Any thoughts on how to track this issue down? Or has anyone had a similiar issue? I just replaced my fuel flter thinking that I had sediment breaking free and clogging an injector somehow because it seems so much like something getting through the fuel or intake and just stopping everything so quickly. Wish I could give a better description of the smell when the stall happens. It is very strong odor like almost something burning. Very weird. Oh yeah, no cel at all. Both when the stall occurs and just normal driving i have no pending or trouble codes at all..

Thoughts?

timmJ

Any thoughts on this guys?

maachine

sounds like an ignition issue to me. i'd check for codes anyway. you may have some pending codes that havent set of the CEL yet, or possibly, the bulb for the CEL is burned out.

timmJ

I tried to pull any pending codes but no dice. I have a scangauge hooked into the obd11 port. I was thinking it might be something do to with ignition as well. I changed the igniter and watching to see if the issue resurfaces. It is hard to diagnose because it happens so infrequently. Maybe one every ten days.

I have also been wondering if my wiring done for the swap is a bit off as I have always been plagued with an ongoing issue of a backfire and lowered fuel performance. Even before I added all the mods for the SC and the SC itself. Just thinking maybe its all related somehow.

What else should be checked in ignition (coils, plugs, wires, etc.)?

Any other guiding words? I really don't want to throw parts at it but have been tempted.

timmJ

Real quick one other item that I noticed recently is a problem when speeding up in 2nd or 3rd sometimes my car goes lean on the wideband gauge. Only above 3200 rpms and it is very brief. It happens when not in boost. The wideband will instantaneously jump from the 14.8 range up to over 16 and then settles back down. Really strange and i looked over the fuel maps and nothing sticks out as problamatic. I don't have anything loaded in the maps in the range that the issue comes in.

Thought this might be information that could point to the culprit.

It could be that I am leaning way out and the car dumps fuel like crazy to compensate and then kills it. Just a thought. Not sure why the car would be doing this.

maachine

ohm out the plug wires. easiest way to check them and you'll know they are fine. honestly i dont have much advice other than throwing parts at it. maybe check the cam/ crank sensor to make sure they are good

timmJ

Well I ohmed out the wires and one was out of spec. The wires were made by denso so I assumed they were same as OEM and switched to these about 6 months ago from OEM. I also found that one of my coil packs was not correct ending part number. So I swapped that out as well. With the new OEM wires and the original coil packs it sounds much better and I believe the issue is gone. I will keep watchining it and report back if anything changes. Thanks for responses!

maachine

glad to hear

timmJ

So the intermittent issue came back on saturday this weekend. Happened 4 times that day and then again this morning. I am wondering if my URD controller is starting to act up on my supercharger.

I am trying to do some more literature searches and see where to start looking now. My runner is perfect when I go maybe half throttle to 3/4 but when I pound on it is where it will basically shut off the fuel. Luckily the car hasn't died when it happens but it is close.

Does anyone have any ideas to trace back and start looking? It could be a dangerous situation and I really need it fixed.

wyoming9

iTrader: (1)

This whole time the Mil has not tripped??

Perhaps you have a loose ecm ground ??Which would wipe all the codes.

Are the other system tests running like they should??

For some reason the fuel pressure drops off have you checked what it is ??

timmJ

No MIL - I know it works but not getting any codes.

Could be a loose or missing ecm ground. I checked the ground out on the side of the SC and they ohmed out at 1 ohm with the car off and 6 ohms with the car on but not running. I am pretty sure that they should be lower but cant find the answer.

I am going to do a bunch of testing throughout the week and this weekend on other sensors but right now everything else is checking in ok. At least nothing clear out of the blue. I have always had terrible milage and I also get kindof a backfire sometimes when shifting but they have been there since I did the swap.

I have not cracked into the fuel line to measure the pressure but I thing that is a must do and it is on the list to do.

I will keep doing some checking. I did replace all the vacuum lines this afternoon to silicone and that helped out my trim values and now down to a level that is good.