05 cavi with m62 S/Ced eco and GM crapflash. The last 3 times I've driven it, it occasionally falls flat on its face when I push the throttle to any position from 0. It does it in and out of gear. If I play with it long enough it cleans up and starts running smooth again. If I turn the car off then restart it goes away and drives fine again as well. It almost feels like it's running out of fuel; but then I wonder if it's loaded up because the gm flash runs so rich. I don't see any black smoke coming out the back but who knows for sure unless I'm behind it. I've been reading A LOT of threads about the problems people had with the GM flash and so I'm always suspect of it and quick to blame it for any issues like this. I didn't say anything that was JUST like this issue though, and it seems that the auto's have a lot more trouble than the 5-speeds like mine.
After a little thinking I'm wondering if my fuel pump is going bad. I don't have any trouble starting up and never run out of fuel on the top end when it's running well. Then again, I don't have a wideband or a FP gauge so I wouldn't really know anyway. These things are all shortly down the road. I actually ordered new plugs before this happened so I'll be putting those in soon, NGK LTR7IX-11's. I almost hope it is the pump so I have an excuse to upgrade to the racetronix pump. Anyway, anyone have any ideas as to what I may be experiencing?
"In Oldskool we trust"
Another thought, maybe I should just pull the positive cable for a few minutes when I get home and see if that fixes it.
"In Oldskool we trust"
My cav(5-speed) did the exact same thing on the crapflash. After i swapped ECUs(custom HPT) and injectors(63#) i never had it happen again. I wont completely rule out a dyeing injector, but since the car was fine after i restarted i figured it had to be something 100% electrical/ECU. I would think that if it was an injector(s) that restarting the car wouldnt "correct" it. If you truly want to diagnose it then i would 1st have the injectors checked out then i would ditch the crapflash. If you just want the car to run, then it is the perfect time for a set of 42s or 60s and a fresh ECU. Whatever you do, you need to ditch the crapflash.
It isnt the fuel pump, but if your cav is nearing 100k miles on the odometer then i suggest replacing the fuel pump as a preventive maintenance item. I know mine was ready to give up when i pulled it after ~95k miles.
Edited 1 time(s). Last edited Wednesday, August 29, 2012 11:05 AM
Ya, and I agree, pulling the battery cable off will do nothing, as this PCM uses retaind memory.
Tinkles(KGM) wrote:Whatever you do, you need to ditch the crapflash.
I want too in the WORST way. I'll have to pay someone so I'm trying to hold off as long as possible. That way I can get the rest of the mods I want to do completed before I tune (h/e, wideband, 60# injectors, 3.0 pulley, racetronix pump). I'll also have to find someone in the Boston area to help me out, which is unlikely. Figure I'll have to make a trip to backside NY or to NJ on the way home to central PA sometime.
I am almost to 100k, another reason the fuel pump is really on my mind. I'm really wanting to get a racetronix pump in there. Like you said, the fact that it runs fine after a restart leads me to believe the injectors are functioning properly. I'm glad this is likely a crapflash issue so I know it's not about to leave me sit in the interim before I get all this work done.
"In Oldskool we trust"
if you're in PA, I'd HIGHLY recommend talking to oldskool for a custom tune. he does great work.
Addicted to meth wrote:Could be a bad TPS sensor as well.
I tired that, no luck. Still ran like @!#$ with a known good TPS in it.
strat81 wrote:if you're in PA, I'd HIGHLY recommend talking to oldskool for a custom tune. he does great work.
PA is a big state... And unfortunately I moved to Boston so I only go to PA every once in awhile to see family and all that jazz. Wish I still lived there. As for the tps thing, I have an extra so ill give it a shot, but I'm pretty sure Tinks has it right.
"In Oldskool we trust"
But luckily, he is 20 minutes from my home town. Wow.
"In Oldskool we trust"
+1 for Oldskool tuning.
He's the only person I'd ever trust tuning my car.
EVILution (KGM Godfather) wrote:+1 for Oldskool tuning.
Already contacted, wideband purchased. Anyone have a spare stock PCM? 03-05 5-speed. PM me!
"In Oldskool we trust"
Ok I inadvertently got some more data on this issue today. I installed a wideband and took it for a test drive. Everything was working properly, AEM AFR gauge reading flawlessly. I had to make a quick 3-point turn, and it did it. It doesn't like when you feather the throttle. I looked at the AFR and it was pegged at 10.0 during idle; confirms the theory of it being loaded up. But here's the scary part: As soon as I started driving again, the AFR's went way lean, anywhere between 15-17 but mostly on the higher end and even once gave me the --- like when decelerating in gear (fuel cut). I pulled over, turned the car off, restarted, and boom right back to 13.5-15at idle and 11s and 12s while under half throttle.
So,
1. This is definitely a PCM issue and likely a GM flash issue.
2. If you are experiencing this problem with the GM flash, D
O NOT ATTEMPT TO DRIVE THROUGH IT. Turn your car off, wait a minute, and restart ASAP>
"In Oldskool we trust"
We'll get you fixed up!
And thanks for the props/recommendations guys, much appreciated!
