GTA91

iTrader: (1)

Well, its really starting to **** me off now. Finally got it running again by bypassing that starter enable relay. Car starts, but is driving like ****. We redid the chip and only changed VATS, EGR, and the injector constant to 24#. Its still running very ****ty. It seems to drive ok, until you get going. Then it hits a dead spot and stumbles or misses. You can hear it thru the tailpipe even. DEAD miss. I've already put new plugs in also. Coil,wires,ignition module, and all that **** aren't even a year old. When it does this, the O2 volts are dropping down to like .01V-.10V and it of course then reads LEAN on the scanner. WTF??? I'm not sure, but I'm thinking it might not be getting spark or timing is messed up. I did change the o2 sensor out last night also. Tried two other different ones I had and neither of them made a difference. Any ideas? Vaccum leak I guess could cause a lean condition. Possibly a header leak causing extra air into exhaust system b4 O2 sensor?? Anyone??? I need help. It HAS to be running for the Bowling Green event next weekend. Man, I'm sooo pissed. Sometimes EFI is just plain gay! Well, sorry for venting gotta run. Oh yeah, I had driven this motor for a month or so on the hypertech 305 chip and it ran fine... just rich. Then my VATS went haywire causing me to have a friend do me a chip. Oh yeah, when it stumbled I finally just kinda punched it and it seemed to run decent (not 100% strong) but then after I let off and was coasting it fu(king backfired thru the pipes? WTF? Also, my BLM's are very low... like around 100. Less than 100 when its really showing low O2 volts. Can anyone help? Is there something easy I'm forgetting to look at? Thanks!

Scott 88 GTA

It sounds to me like you corrupted the EPROM and forced the ECM into the limp home mode. (I know this, because I just did it recently ) Try this, take the EPROM completely out of the MEMCAL and try starting and driving the car that way, if it's driving the same way it is now, then that's your problem.

EDIT: Let me clarify a little, the actual EPROM chip is fine, you just programmed it using a corrupted file. Erasing it and uploading a normal one will work.

GTA91

iTrader: (1)

Yeah, but isn't there some way to tell if its in limp-home mode?? I guess I could try that though.

I don't think its a corrupted file though. The first chip we did was a '92 350 car chip with VATS and EGR disabled, and it had the 24# constant with a 8* base timing set. Then we reflashed (reburned it) and went back to my stock Hypertech file and just changed VATS and the 24# constant I believe. The friend helping me is somewhat new to burning, but we thought everything was going ok. Any other way to tell limp home mode or if the file is/was corrupted???? Thanks!

Scott 88 GTA

The way that I corrupted mine was when I was reading the file off the chip with the burner. I'm using an Atmel 29c256 chip, so when I read the file I ended up with a 32k file, but Tunercat only recognizes a 16k file for the MAF cars. So I tried deleting the preceding spaces using Notepad, and Tunercat recognized it fine, but when I burned it my ECM wouldn't take it. I ended up downloading a free hex editor, and deleting the extra space with that program, and it worked fine.

Since your car is SD, you should be getting a 32k file when you read your Hypertech chip too, but IIRC the SD programming doesn't take up the whole chip, so you should have some extra space too. If you tried deleting any of this like I did, you probably did the same thing.

Also, when my car was in limp-home mode there was no way that I could tell, other than it was driving like crap. And removing the EPROM from the Memcal won't hurt anything either, especially if you're already in limp-home mode anyway.

GTA91

iTrader: (1)

Thanks! The ECm wouldn't be throwing a prom code or anything though??? As for my car, I'm not sure if thats whats wrong or not. I'll have to show my buddy this post (he burned my chips) Thanks again!

u r sofa king we tah did

he is telling you the prom may very well be THE problem.

GTA91

iTrader: (1)

I understand that, but I was just talking with my friend who did the chip. He said that the SD file he burned for me used the whole chip. Hell I don't know. I'm gonna go and get my Hypertech chip back from him and see if that cures it. I'll be amazed if it does... even though I wish thats all it is! I just hate spending a ton of money on this new motor and now having it run like total $HIT! Oh well, I'll let ya know what I figure out. Thanks again. Later