Thread: Fuel Trim trouble

Originally Posted by Reptile

That looks like a vacuum leak somewhere......I'm not gonna get back up on my soapbox about ZZP PCM's.

aw come on it's hard to resist isn't it?

Were your fueltrims ok before and it just started doing this? If your fuel trims sit positive like that too long it will throw the lean code. Positive trims means the pcm is adding fuel either to compensate for an improper tune an engine/parts problem like a vacuum leak mentioned above. A dirty maf can cause this also but if your trims were always +16.4 then something was never right as they should always sit as close to zero as possible

Brian you know whats funny and scary at the same time? I was going to put that smiley at the start of my thread lol

Well Brian, I'll have to get you to explain the problems with the ZZP PCM cause I have one, LOL.

Brian I completely understand your frustration here and completely agree. I have had my share of encounters with their bad pcms also. 38Special on here, Ryan, has an 04 Monte SS and he got a custom pcm from them for an XP cam, 42lb hr injectors, and 3.29 gears. It even said all of this on the sticker on the pcm. They also told him that they couldnt change the fan turn-on temps to match his 160 or 180 stat because it doesnt work on his car. Well I get the car put back together and go for a drive..... Second shift cycle I feel max line pressure which is extremely BAD with one of my transmissions at part throttle! I blew up!!!! I had my laptop and scanner with me to watch data and well to no suprise there was an incorrect gear ratio code. Because of this we were both in a bad position, the car needed to drive correctly and he needed the car. I cant drive a car to break things in if it isnt drivable. We opted it be best for me to add support for his car to my HPTuners and I then tuned the car on my own. Looking at their file they didnt change everything that needed to be changed for the gear swap so I had to fix that. The fuel trims were good and i was happy with some of the tune in that aspect. For an off the shelf pcm it really did pretty well other than the trans and the fan turn on, which I fixed as well and the fans turn on when the customer wanted them to now. In the end, sure we could have sent back his pcm and waited two more days and may end up with more problems and lose more time which seems to be all I have gotten out of them the last year that I used their stuff, so rather than gamble again we took care of the problem ourselves. I check out the KC and STL boards daily and I always see complaints of these pcms, its a wonder they still sell them with all the problems that everyone mentions with them. Sure they will give you a different pcm or multiple new pcms, but if they are all bad then all you have done is lost a lot of time, shipping fees, and built up agrevation.

First, Brian and Dave I dont take what you are saying as bashing ZZP. You're okay there, you both have posted your dissent with their pcm's in a respectable manner, so no issues there.

That said, what should I be looking at in mine? I have a DHP but havent really used it to get a good tune yet. But I can get in there and check things out. I also have my bin file with me.

Originally Posted by Reptile

Every single last one that I've seen in the KC and STL area have had some kind of issue. Fuel and timing being the main ones. I'm not trying to throw punches here, but they just are horrible. A local member has to have an engine rebuilt because the one he got from ZZP was still in the read/write mode 4 times when he recieved it. Being a newb and not knowing any better, he blew a piston. Looking at the timing tables and fuel, it ran about 20* with an AFR of around 12.1 IIRC. All that coupled with something else that might have not been right. Others have idle issues, surging, poor mileage like in the low teens, IAC tables off. One other thing is that most of the trouble codes are turned off for some reason, and it makes it very difficult to diagnose if a single cylinder is misfiring, if you have an evap problem...which if you can't find a code for it, makes it a nightmare to figure out why your fuel trims are fluctuating....I can go on and on with the dozen or so that we've seen. And then you see the people in other areas that don't have any problems. And on a side note, when this guy locally told them that he wanted a full refund, the customer service guy got really crappy with him. Don't remember the guy's name, but that right there just turned me completely off of them.

While I never bought a ZZP PCM, I have had the chance to look one over and check out some things. And I must say that I agree with all that is said. There were codes turned off, tables not set right, etc. While these PCMs may work well for some people, they can cause nightmares in others. ZZP is a good company, but if they intend to continue to offer custom PCMs, they need to perfect their methods.

Ohh Scotty where to start! Im not sure exactly what you have done and what pcm you have or what has been done to it. I always like to start with a 100% STOCK file so I know I am not trying to tune around a "built-in" problem. What is wrong with your car or do you just want to do a tune on it and dont know where to start? I could write a book on this stuff and Im sure there is a LOT more than I know about and am still learning, and I have probably tuned over 100 cars since HPT came out with support for these cars 4 years ago.

Originally Posted by Reptile

Every single last one that I've seen in the KC and STL area have had some kind of issue. Fuel and timing being the main ones. I'm not trying to throw punches here, but they just are horrible. A local member has to have an engine rebuilt because the one he got from ZZP was still in the read/write mode 4 times when he recieved it. Being a newb and not knowing any better, he blew a piston. Looking at the timing tables and fuel, it ran about 20* with an AFR of around 12.1 IIRC. All that coupled with something else that might have not been right. Others have idle issues, surging, poor mileage like in the low teens, IAC tables off. One other thing is that most of the trouble codes are turned off for some reason, and it makes it very difficult to diagnose if a single cylinder is misfiring, if you have an evap problem...which if you can't find a code for it, makes it a nightmare to figure out why your fuel trims are fluctuating....I can go on and on with the dozen or so that we've seen. And then you see the people in other areas that don't have any problems. And on a side note, when this guy locally told them that he wanted a full refund, the customer service guy got really crappy with him. Don't remember the guy's name, but that right there just turned me completely off of them.

I'm sure that Lee may chime in and also ChrisGTP if he sees this.

My car wasn't drivable with the PCM ZZP sent me. Well not more than about 2 miles anyway. I was afraid to drive it back home it was shifting and running so bad. My radio also display "CAL ERROR"...I was pissed.

Originally Posted by Trannyman95

Ohh Scotty where to start! Im not sure exactly what you have done and what pcm you have or what has been done to it. I always like to start with a 100% STOCK file so I know I am not trying to tune around a "built-in" problem. What is wrong with your car or do you just want to do a tune on it and dont know where to start? I could write a book on this stuff and Im sure there is a LOT more than I know about and am still learning, and I have probably tuned over 100 cars since HPT came out with support for these cars 4 years ago.

Theres another instructional DVD to occupy the little spare time you have

Basic mods thus far. PCM, Intake, Exhaust (DP, No res, no cat), MSD Wires, AL605's, 180* tstat. I think that is about it. But I got a lot planned when the tranny comes out. Valve train upgrades, ported blower, ported TB, Timing Chain, maintenance stuff and so on.

I want to get it tuned but you are correct in I dont know where to really start. I have wanted to follow Jerrys Tuning Notebook but Im wondering if a stock bin would be a better starting point. I know the last time I was at the track, the scan indicated (10.7 AFR), though I think my O2's were in the low 900 high 800 range when I crossed the line, Id have to check the scan again to be certain, and I trapped at 95 or 96 mph.

So I know that isnt all that good. I do remember the fuel trim locked in a -4.7, maf ran around 9900 or so. The good news was I did spank the Camaro I was up against