major power loss

[choppester]

ok heres the mods

95 pontiac gtp 3.4l dohc
light weight lifters
6/6 cam timing
ported heads
ported to match up and low intake manifolds
msd ignition
magnecore wires
ac delco plugs
38lb injectors
p1sc procharger 7psi
bf intercooler
3inch exhaust
alky control kit (not installed)


ok heres my problem. last year it started to hesitate when on full throttle, Mind you didn't have any of the supercharger stuff hooked up. than I noticed the vacuum line to the fpr was burnt through, so I parked it for the winter. this year I put a new fpr on and the supercharger kit. I went and started it and everything seemed to be running fine. I went and drove it and it hesitated. so I took off the supercharger and was going to wait to get it to the tuning shop first. I drove it without the supercharger on and it was worse by that point. it wouldn't go at 3/4 to full throttle from a stop and when rolling it would just rev high with no power. we checked all sensors and they tested fine. we checked spark and cylinder order and everything is ok there. we rest the prom chip and check the maf sensor and still the same. I can't figure it out. I was going to do a compression check but haven't got to it yet, also checked the fuel rail from a stop and fuel pressure is good, but didn't check it from a load on the car or check the fuel pump. please somebody give me good advice, not even my computer guy could figure out what was wrong.

[jmgtp]

I'm having a tough time interpretting the state of your car. It is currently normally aspirated? What injectors are in it? Fuel pressure?

If you are running 38lb injectors while it is normally aspirated that is a huge problem and you are probably drowning it in fuel.

[HayesPerformance]

yep......

[Dave96z34]

Ran 42s n/a for a year with no change in power or fuel economy. Its all in how you tune it. Are you running a 96 harness for obd2? If you haven't yet do so asp and get a dhp tunner. Why don't you have a wideband o2 sensor? Thats such a critical part for doing tunning cant live with out it. I recommend ngk afx. Bypass the msd no point to having it any way.

[SofaKingWeToddDid]

maybe your transmission is toast!!

[SappySE107]

42s and no change in fuel economy? Granted the DOHC blows for fuel economy, but usually you run into a min ms open time issue with larger injectors and see some sort of mpg loss running that large. Wideband is not critical by any definition of the word. Its nice to have to fine tune, but but not even close to necessary at this point for what his issues are. DHP is dead. HPTuner works for 97 DOHC and at least has a shot at support and updates. Either way, tuning is the critical part.

[Dave96z34]

Agreed tuning and making shure your other gear is working is importent. My boost bypass has jamed on me a few times. Irritating when it hapends.
Can tune with out it but its a pita and not worth the time. Spend 300 and never look back. Took 2-3 hours to get it tunned in spent most of the time with the maf. Thats why a wide band and a/d is so importent. makes life so easy. The the narow band data is useless at low rpm range. Thats why my mpg never changed. I was able to get it dead on what it needs to be. Im geting 27 highway now boosted with the 42s and havnt retuned for summer air yet.
With the Dohc always go dhp it just makes more scense. You can tune 96 and 97 not just 97. Can tune as many cars as you want from 96-04 gm fwd and not have to buy credits. They are cheap to get becuse alot of guys are selling the cars. Dhp the last version is 100% stable and works great. Just cant use the analog to digital. If you want to you use an older viersion.

[choppester]

I did change back to the stock injectors and no my transmission isn't toasted. Its a running condition problem. It still hesitates bad after 3k and won't go no where when I gun it, or even go 3/4 throttle. I wiped the computer, and all sensors check out.

[RedZMonte]

what is the general consensus of the Timing mods on a boosted car? it kinda sounds like a timing problem to me... normally at ~3000 is where mine kinda starts to take off, so if yours is falling on its face then i would double check your timing settings and even go back to stock settings... As long as everything else checks out (ie. fuel pressure, fuel filter new, plugs, plug wires, ignition module and could all working properly). it also could be starving for fuel... replace fuel filter... after sitting for a while could be plugged up bad.

S