Weird issue Stalling Sputtering when warm

[84ttype]

Hey guys, I need some direction here I don't really know what to look at on this one. Having an issue where once the car is fully warmed up (driven for about 20-30 minutes to where the oil pressure drops down at idle) it will start stalling out at cruise and idle. Its seems like a power loss issue not so much a "miss" the check engine light comes on and the engine goes silent for a bit, then it starts firing again CEL turns off. this occurs a couple times per second and happens in spurts where it will do this for about 30 seconds and then it will stop. if I let off the gas the CEL will flicker and the engine stumbles really bad. once this starts happening it idles rough and dies every few seconds as well. what I dont get is that the car runs flawless when it cold, idles awesome runs smooth all the way through the rpm range. this has happened the last three times i've driven it now. everything starts out great then once its warm the stalling starts.

I've checked all the engine grounds are tight as well as the one on the coilpack, pulled the conduit off didnt find any broken or shorted wires. change some vacuum line(not really related was already planning to)

scanmaster at idle when its running ok
int 140
af 6
l8 27
ats 160
iac 28
cc slowly climbing (takes about 30 seconds to get to 250 and reset)
tps .40

when its stalling at idle I did notice the tps will flash to 0.0, other numbers do fluctuate aswell but the engine is also struggling to idle.

I think I 'll try to get ahold of bob bailey tommorow and ask if this has come up as an issue with the TR6 ign. other than that im not sure where to look? coilpack, o2 sensor, cam or crank sensor?

any advice or insight would help if you've got it. thanks in advance

 

[whitehot1]

My guess would be the ignition module or coil pack. If you were running the stock type.

But it seems you are running the tr6 ignition module and newer coils. I have read about this setup giving some that run it problems, nothing major but seems the sensors have to be set perfect for it to function properly. Looks to be a great product though. Your best answer like you said would be to contact turbobob and see what he suggests to check for.

 

[TurboBob]

Try retensioning the pins in the flat connector that plugs into the unit.

when the ECM loses the ignition reference pulses, it does an internal reset, this will cause the data in the datastream to blip to zero momentarily.

Bob

 

[84ttype]

I got chance to to look at the flat connector to the ignition module, some of the pins do move around a little bit. how do I go about tightening that up? I cranked down the center bolt as tight as I felt comfortable turning it. car still has the same symptoms though.

 

[Boxcars]

Could be your positive cable. Sounds like your losing electrical power momentarily causing power loss and everything to reset.

 

[84ttype]

Update: No good news though. I did double check and re tighten the positive cable at both ends. checked basically the whole engine harness and the ecm for loose wires, found nothing. bought a new Oxygen Sensor which made it idle better until it warms up and the issue starts anyway. still no change in symptoms. I have a new coil pack on the way, we'll try that next...

 

[84ttype]

Update: Well its not the coil pack either but I did notice when I was pulling back into the garage that the IAC counts were over 60. I did the full reset on it jumping that ALDL pins, and got it to around 22 with the tps at .42. drove it around the block, after about ten mintues while at a stop light the idle shot up to around 1500 rpm and wouldnt go back down. TPS stayed at .42 but the iac went up to 160 then it started the stalling issue again. got it back in the garage and the idle slowly dropped back down to ~700rpm but my iac was back up around 45 now and every once in a while it would stumble and the iac would shoot up to 160 and then slowly come back down, but never below 45. is this an issue with the IAC or is it just reacting to the car stalling out?

 

[Boxcars]

Try re-seating your chip. Or, do you have another chip to try? Or maybe a different ECM?

 

[GNRick]

Try taking out the iac and give it a good spritz with throttle body cleaner. Also take off the up pipe and spray/wipe the throttle body. My iac was black with carbon when I cleaned mine.

 

[84ttype]

Update: I've actually made progress on this issue. I found my old stock ign. module and coilpack and put it in, it didnt fix the problem but it made it less severe. after this i noticed that when ever I hit a good bump in the road that the issue was popping up. I got the car back in the garage and started pulling and tapping the wiring connectors, nothing in the engine compartment but then i noticed if knock on the kick panel with ECM in it, thats whats starting the symptoms. it will idle fine, i hit the kick panel and it starts dying out, hit it again and the idle jumps up like before. Its got to be a short somewhere near the ECM. I've checked the connections a few times nothing seams loose. the ECM itself has some wiggle room to move around in the kick panel I think I'll get some packing foam and wrap it up so its wedged in there. I did reseat the chips and powerlogger at the bottom just in case. im hoping that fixes it cause I definitely didnt find any loose wires.

 

[84ttype]

Update: I Fixed it.

I really wish I could say for sure what it was or that I found the so called "smoking gun" but I didnt... What I did was double and triple checked all of the pins on the ECM and harness pushed the connectors in as hard as I could, then I re-seated the chip the cal-pack and the powerlogger module. After all that I wrapped the ecm in packing foam so that its wedged tightly into the kick panel now, and the issue went away. I've probably put 200 miles on it now with no hiccups.

Thanks to everyone who chimed in on the thread!