When warm backfire, shuts off, goes lean

[Clipsoe]

Ok, so here is what happens. The longer the car sits the longer I can drive it. I'll start the car let it warm for a sec, and start driving. After about 10-15 min the car will start backfire, the rpm gauge will jump all over the place, the a/f gauge will show it go lean, and the car will shut off. The more I try to restart it and get back to my driveway the more it does it. Once it starts doing this, the a/f guage will pretty much stay lean the whole time. Keep in mind it happens slowly at first. ill be driving the rpm gauge will stutter and then back fire but keep going, then it starts happening more and more closer together till I have to start it every minute or so. Well after its first signs of starting the other day, and I turned the ac on and it started doing it immidiately, and when I shut off the ac it stopped. It does do it regardless, but for some reason its like the ac made it do it on que. As far as what I have done to fix it I have changed timing belt, tensioner, pulley, water pump, ignition coil, wires, plugs, transistor, vc gasket, tb gaskets, battery, alternator, 400lph fuel pump, front 02 sensor (aftermarket), maf, tps, icv, ecu, and fpr. All oem except the O2. Any help would be greatly appreciated.

 

[pauleyman]

Have you ran a boost leak test? How are you running such a large fuel pump on a stock regulator?

 

[Clipsoe]

I have not done a boost leak test, and will be doing one this weekend. As far as the fuel pump I had just put it in and plan on getting a regulator as well. Just been trying to get the car to stop cutting off non stop for the moment.

 

[IdleSurge]

Check your coolant temperature sensor. Also backfire and going lean can be caused if your ignition system is not operating correctly such as having the wrong firing order.

 

[TunedUp]

Check your coolant temperature sensor. Also backfire and going lean can be caused if your ignition system is not operating correctly such as having the wrong firing order.

If it were firing order you would have a misfire as soon as you start it up.

I haven't ever paid enough attention to see if there are A/C wires running by the coil packs just throwing it out there that what if the was a short from the A/C wires to the coils? Don't quote me on this maybe someone with more knowledge of our cars could chime in on this?

 

[Clipsoe]

OK, did a boost leak test, and found that my bov gasket had a huge leak, boost controller and fpr hoses had a leak. Fixed those and the car hits boost like its nothing now. Drives amazing....until it warms and does that same thing again. Now when I did the BLT I opened the oil cap and could hear it spraying out inside. Think the vavles need seals? Also, firing order is definitely good. As for the ac wiring it does go down that side I don't see problems with it though. I'll check to coolant temp sensor now. Is there anything that regulates the voltage of the ignition?

 

[Maes]

Just a long shot but do you have a spare ecu by any chance?

 

[Clipsoe]

Well the original ecu which I have, I had fried the ground strap in it. I fixed it and it worked till I had this problem, then I bought a used one from someone and put it in and still had the same problem. Unless both ecus are bad.

 

[Maes]

It's possible but I highly doubt it. Just sounds like something is getting hot and failing.

 

[Clipsoe]

This is exactly what I am thinking, cause the longer the car sits the longer and farther I can drive it till it starts doing it again. Worst part is no check engine light.

 

[oneslowwdsm]

Odd issue. Make sure all your grounds are tight and clean. A few you can check: ground off the battery, off the coil pack, off the alternator. Also, make sure the ECU is bolted down and tight.

 

[Clipsoe]

Ok, so I have tried a few things with no results. I tested my coils resistance seems well, also cleaned them out. I tested my alternator it was at 13.30 volt and notice it would drop fairly low during rev or turning the ac on. So I tried disconnecting the white wire to force maximum voltage, it went up to 13.80, but still same thing. Checked inside my new ecu looks good. Tried bypassing the Mpi/Fuel pump relays to see if a relay was bad. Tried disconnecting the iac to see if maybe something was going on there. Tried disconnecting the coolant temp sensor, ac plug compressor connector, checked all the grounds in the engine bay and everything is tight and clean, all fuses are good. I tried doing multiple searches for any other kind of vehicle that might have similar issues and what it could be with no avail. I really am not sure what else to do at this point this problem came outta nowhere and has me stumped. I am at the point where I am ready to take it to Mitsu and really don't wanna do that cause you know the kinda shit that's gonna come out of there mouth, but I don't know if I really have any other choice.

 

[Clipsoe]

Heres a question, I do have an srs light on from deleting the driver air bag. Would anything in the srs system cause this?