Strange starting issue. Intermittently misfiring and dying on startup.

[JamesFoster]

Hey guys, quick question. My GVR4 has been doing this thing where it starts fine in the morning, but if I've been driving it, say I go to the store for 20 minutes, I come out and start it, and it starts, but misfires and idles like crap and dies. It's very frustrating. Other that the intermittent misfiring and dying on startup it runs good. My GVR4 does not have link so I can't post a log. It also has new plugs.

Could It need a new coil pack? that's the only thing I can think of. Any help is greatly appreciated.

 

[Andy_S]

Might be a CAS pooping out.

 

I am having the same issue.... Did you ever figure it out.
I had mine scanned and 3 codes came back

O2 sensor relay
MAF sensor relay
Or injector relay

 

[gramkrakr89]

...so when you park it to go into the store it's perfectly fine... idles fine after you've stopped and parked.

So you shut it off and go in... but 20 minutes later when you come out, you go to start it and it idles rough, misses, and dies?

Mine used to do that a lot, but in ECMlink V3, I have enabled something called "hot start enrichment"... it doesn't do it nearly as much anymore...

 

I haven't had it plugged into anything at all to change any settings

I popped the hood and messed with the fuel injector , there isn't anyway to really diag a fuel injector other then unplug it

When I unplug it; it doesn't make any difference.

I am gonna clean my MAF with some rubbing alcohol
And see what happens.

 

I wish I was a better mechanic...
Because I am not I will have to buy a new everything
Just to get my car to run now that I got it back .
Whatever

 

[gramkrakr89]

please give the OP a chance to respond here...

 

Sorry guys... I am thinking out loud.

 

Sorry guys... I am thinking out loud. /ubbthreads/images/graemlins/confused.gif

 

[656of1000]

Quoting gramkrakr89:
Mine used to do that a lot, but in ECMlink V3, I have enabled something called "hot start enrichment"... it doesn't do it nearly as much anymore...



Along those lines, do you still have the fuel pressure solenoid hooked up? It is the solenoid in the back corner of the engine bay near the factory alarm horn. It has two vacuum lines- one coming from the intake manifold and the other going to the pressure regulator. If that is not hooked up it can make the car run bad on hot starts.

 

Way back in the day when I had my Talon, I had an interesting issue that had similiar symptoms. It turned out that I had a bad injector. I could always start the car cold with no issues, and it would run fine as long as I didn't shut it off. Same scenario though, I would kill it for a short period of time and come back to it and it would miss badly. It took quite a while to figure it out, but once I did, it was obvious. I would do an ohms check across the terminals of each injector and look for a variance. When they were checked cold, they were even. But when hot, one had less resistance. Realizing that an injector is basically just a valve that is electromagnetically operated, it occured that the likely fault of the injector was in the coil of wire that acts as the magnet. Metal expands when it heats up. Everyone knows that. The insulation inside the injector must have weakened over time, and once the injector was heat soaked from a hot engine bay, and was no longer being cooled by the fuel flowing through it, the coil of wire would expand and short itself out. The proof in the pudding, as it were, was the fact that I could take a cup of ice water and pour it over the faulty injector (engine running, with the misfire), and the car would smooth out and run normally again.

 

My issue is indeed the injector

Now I just have to find one....

Anybody have one?

 

I have injectors. PM me.

 

Done!!

I hope we can work something out

 

[mitsuturbo]

I had this happen to 161/2000 (RIP)

Turned out to be the ECU. Caps were fried. This is not typical behaviour of an ECU going south. Usually the car starts cutting out under power over ~3k when the caps are going, but your issue sounds exactly how mine was, in one particular instance. Swapped in a known good ecu, and the problem went away. Had the ECU fixed and now keep it as a spare.

Of course it's always a good idea to try a known good ecu and see if the problem goes away. However, i understand that most people don't have 2-3 spares lying around. In my experience, it doesn't take up a lot of room, and is always handy to have at least one spare of the following: CAS, Power TR unit, ECU, coilpack, knock sensor. It makes diagnosing things like this a LOT easier.

 

So my issue was the fuel injector.

I changed it this morning....

It was 19 degrees outside....

Brrrr!!

Runs so much better.

Thanks to 1517....

Justin thank you very much!!!!

 

[gramkrakr89]

good to hear!

now how about a status update from OP? /ubbthreads/images/graemlins/dunno.gif /ubbthreads/images/graemlins/grin.gif