CATDIESEL

Ok here is the deal , mods are in sig . After tune under heavy accel the engine will start breaking up at about 2700 rpm to about 4500rpm.It will smooth out at 5000 but seems to be lazy. I have a snap on scanner and have been trying to narrow things down. When I accelerate both o2s go to about 35 mv , tps goes to 100% , maf gradualy rises to about 100 to 110 gm/sec. , and the injector pulse width is 11.6 - 12.0 . What do you guys think ? The fuel psi will stat at 58 psi the entire time. During normal driving the car seems fine and the o2s switch quickly. no codes .

MeentSS02

iTrader: (11)

You can't judge WOT performance by the narrow band O2 sensors...you need to get a wideband on there to make sure. My car runs sluggish if it is too rich, and also runs sluggish if it is too lean. Injector pulse width doesn't mean much unless you tell us what size injectors you are running.

MeentSS02

iTrader: (11)

FWIW, with my stock 28.8 lb/hr injectors, I see about 18.6 max injector pulse width at WOT (but my fuel pressure drops to about 52 psi)...I've since gone to new injectors, but don't have any log files handy to give you an idea on what those look like for pulse width at WOT.

foff667

iTrader: (2)

did this just start happening out of the blue or did it start happening after a certain mod like a mail order tune maybe?

MeentSS02

iTrader: (11)

I'm gonna guess it was the mail order tune...if he's running different injectors and they didn't tune for it properly, it could be the problem.

Doc99SS

iTrader: (2)

It sounds like you are going lean when you tip into the accel pedal. But, again, another horror story concerning a mail-order tune. You can not tune a car thru the mail.

CATDIESEL

Yes , after the tune. I know the horror storys from this board but I wanted to be able to drive the car get a dyno tune , There are no reputable ls1 shop in the area so I thought this would be the best course of action. Believe me I am kicking myself in the a#@ for doing it now . The injectors are stock , I believe 26lb . The wife is buying me the FAST dual sensor wide band for xmas , but I think I will put the car on a rollback and take it to one of the sponsors on this board for a real tune ,

MeentSS02

iTrader: (11)

Wow...26 lb/hr injectors on that setup can't be good. You need bigger injectors...

CATDIESEL

The thing ran like a beast before tune , just idled like crap . shouldnt the pulse width go higher , as yours did , before the injectors need to be upgraded ? I know I am trying to fix something without the right tools . Thanks for your help . Any injectors better than the rest?

MeentSS02

iTrader: (11)

Your pulse width should be higher than my 28.8 lb/hr numbers, that's for sure. My car is a bolt-ons only car, so you should be putting down way more power (and require more fuel) than me. As for injectors, most people just get the Ford SVO injectors. I went with some flow-matched Bosch injectors.

SSpdDmon

iTrader: (10)

I wonder if your mail order tuner gave you the injector tables from a car with 28.8lb injectors on accident???? If the car is breaking up and your NBO2's are less than 100mV, then you are pushing a 15:1+ AFR. Yes, the NBO2's aren't to be used for tuning, but they at least know when you're above or below stoich. I wouldn't drive it if I were you until I got bigger injectors and a good tune. If you have to drive it, stay out of the throttle to keep it in closed loop so the computer can at least keep you in a safe place.

The other issue it could be is he could have screwed up your MAF table. At WOT, my bolt-ons Z28 hits roughly 300grams/sec of airflow according to my MAF logs. Also, check the intake/lid to make sure there aren't any obstructions affecting airflow. I've heard of shop rags actually being left in some weird places....

Either way, you need to have a real tuner look at that car or pick up EFILive/HPtuners and take care of it yourself.

CATDIESEL

Thanks for the info guys . SSpdDmon-- That was my thought with the o2s , they are at least pointing in the right direction. I think I will get some 42#rs and a real dyno tune and see what happens. I just wanted to eliminate a problem before I got on the dyno and found out I needed injectors , or a new MAF , because it will be a long trip to the dyno. Do you think I should buy another PCM and install that to save the fastchip tune ? It is probly no good but it was $450 .

SSpdDmon

iTrader: (10)

I'd call 'em back and see if they can help you out before you get to the dyno. If they charged you $450 and it's not right, they should do something about it.

CATDIESEL

I have talked with them. He wants me to run it on a dyno with wide band. clean the MAF , change the plugs. The problem is I changed the plugs , no change. I realy think a dyno pull with this issue is not a good idea. On the street it is pulling 4deg of timing because of knock(WOT). Like you guys say you cant tune a car thru the mail and I am sick of paying $50 each way for next day air. This is not a daily driver and it is off the road for the winter anyway so no big hurry but test driving will be impossible when we get snow up here.

SSpdDmon

iTrader: (10)

I'd demand a refund...partial or full. He was hired to get your car running right. He didn't do that. Did he plan on paying for your dyno time or paying for someone local to make some adjustments to your PCM? If it's not a DD, why the $50 to ship? It seems like there's a whole lot of money being spent here....but you're not exactly seeing a whole lot of results.

CATDIESEL

I overnighted to reduce the risk of loss or damage.(my headers came in and I watched the UPS guy pull the box out , look at it , and put it backin , and drive away. Tracked package DAMAGED IN DELIVERY. 1 week later I got them , same banged up box. I was also hoping to get it back for the nationals . I had a difficult time making the decision to send it out. The original plan was to buy heads , cam , intake and headers from slp , have them tune it and then I would have a tune by the people who sold me the parts. It turned out that they stopped tuning by the time I installed the heads ect... They said , after begging them to do it , to send it to fastchip "he has done lots of them and can set it up right for me" . I have not asked them for any type of refund because I wanted to rule out any other issue before I went down that road. I have changed a new set of plugs with another new set of plugs , I have ran all (6month)old gas out and filled with fresh sunoco 93 , repaired slight exhaust leak at header to cat . Now it still runs the same , Like crap. Fastchip says check afr on a dyno . Well if I had a dyno down the street I would not have sent my pcm half way across the country now would I. And If I had a wideband , a dyno I would have been $500 away from tuning it myself , I have never tuned so it would probly run the same and I could only blame myself. Sorry for the rant just starting to agrivate me