car pulls harder at less than WOT...confused

[cjmatt]

Is there any sensor that I should start messing with that would cause the car to feel slower at wot then partial? tonight I unhooked the o2 sensor and reset the battery to see how itd idle and the car felt alot stronger driving around, especially at like half-3/4 throttle, but it felt somewhat slower once the throttle was mashed down. Am I getting into another table in the pcm that would be less performance oriented?

 

[BOP4ever]

mine felt like this too... what is the boost ?
mine was 19 and after turning it back to 15 it feels better... I think

 

[cjmatt]

mine felt like this too... what is the boost ?
mine was 19 and after turning it back to 15 it feels better... I think

Its the same boost. At less than full throttle and 13 lbs it feels better than full throttle and 13 lbs. Thats what the boost seems to be around, at least on the crappy gauge, ill have my real one on tomorrow

 

[Dave]

Check your fuel pressure @ WOT

 

[QUIP'6']

do you have a scan tool you are probably getting knock retard which the computor cuts timming way back if its running lean. thats probably why it is pulling back on power. it can also be valve springs that are getting weak

 

[ijames]

Most likely is that you are getting knock at full throttle and it is pulling timing. Could also be way rich and it leans out a little when you don't go quite wot (depends on exactly which chip you have). Start with a scan tool and check for esc counts and knock retard and look at the O2 volts, and you will know.

 

[BlackMetal]

Doesn't really make sense that you'd be at the same boost at part throttle as at full throttle so definitely install a more reliable gauge to monitor your boost level.

Could be a number of things, could be detonation like someone already mentioned, possibly a slipping trans that can handle the power under gradual throttle but at WOT starts to slip and feel sluggish (slipping bands or a seal that's allowing fluid past it), could be coming up short on fuel at WOT, or the opposite, might be too rich at WOT so you need to watch your 02s and try to diagnose.

 

[VadersV6]

If you have a scanmaster, go to the AF screen (MAF reading), and go WOT in 3rd gear for 3 or 4 seconds and see what it says. That will tell you if the MAF is going bad. Do it several times and see if teh number keeps changing by a large number. Mine has always run better at part throttle than full throttle...and I even have the same boost at 2/3rds throttle that I do at WOT. Its usually the MAF not giving the right air reading.

 

[cjmatt]

If you have a scanmaster, go to the AF screen (MAF reading), and go WOT in 3rd gear for 3 or 4 seconds and see what it says. That will tell you if the MAF is going bad. Do it several times and see if teh number keeps changing by a large number. Mine has always run better at part throttle than full throttle...and I even have the same boost at 2/3rds throttle that I do at WOT. Its usually the MAF not giving the right air reading.

I dont have a scanmaster yet, but one of my good friends has an IROC Camaro with the same bosch maf on it and I know his is good. Ill swap them tonight and see if it feels any better

 

[cjmatt]

Well i was talking with a guy who builds 200-4rs about my late shifting issue and he said its probably weak valve springs as well, so thats the next thing im going to replace, im guessing my lack of power is a case of valve float. My tach is showing double so i really dont know how high im revving, scanmaster here i come

 

[QUIP'6']

:biggrin:

Well i was talking with a guy who builds 200-4rs about my late shifting issue and he said its probably weak valve springs as well, so thats the next thing im going to replace, im guessing my lack of power is a case of valve float. My tach is showing double so i really dont know how high im revving, scanmaster here i come

 

[strikeeagle]

Valve float, huh? Well, that's got to rank near the last of about a million reasons anyone could cite, but if you say so? Better to follow the good advice appearing above.

strike