timing/tuning question--91 5.7
08-26-2011, 11:44 AM
#1
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
timing/tuning question--91 5.7
I have a 91 z28 5.7 tpi. stock internals but lots of bolt ons.
--
The other day i took off my jet stage 2 chip and went back to stock chip while changing my timing from 6* to 10*. after doing so i drove it for a few days and after a while of driving it and warming it up, it would stall at a stop or stall while i was driving and put in nutreul my self. never did that before i change the chip and timing. I put it back(jet chip and 6*) and seems like its back to normal.
ANY IDEAS ON WHAT I SHOULD DO TO TIMING AND COMPUTER to get my best performance??
I HAVE GAUGES IN MY CAR, FUEL PRESSURE AND AIR/FUEL WIDEBAND--so i can get tuning close.
It seems to run rich and im thinking about going back to stock injectors or putting a small cam in it to make up for too much fuel.
THANKS FOR YOUR GUYS HELP!
my mods-
MSD ignition
ram air, k&ns
slightly bigger injectors (27lbs)
full exhaust (headers back)
jet stage 2 chip
underdrive pullies
plentum is ported
adj fuel pressure reg
160* therm
and fans on full time
few othe small things
--
The other day i took off my jet stage 2 chip and went back to stock chip while changing my timing from 6* to 10*. after doing so i drove it for a few days and after a while of driving it and warming it up, it would stall at a stop or stall while i was driving and put in nutreul my self. never did that before i change the chip and timing. I put it back(jet chip and 6*) and seems like its back to normal.
ANY IDEAS ON WHAT I SHOULD DO TO TIMING AND COMPUTER to get my best performance??
I HAVE GAUGES IN MY CAR, FUEL PRESSURE AND AIR/FUEL WIDEBAND--so i can get tuning close.
It seems to run rich and im thinking about going back to stock injectors or putting a small cam in it to make up for too much fuel.
THANKS FOR YOUR GUYS HELP!
my mods-
MSD ignition
ram air, k&ns
slightly bigger injectors (27lbs)
full exhaust (headers back)
jet stage 2 chip
underdrive pullies
plentum is ported
adj fuel pressure reg
160* therm
and fans on full time
few othe small things
08-27-2011, 07:52 PM
#2
Registered User
Join Date: Jul 2003
Location: usa
Posts: 1,025
Re: timing/tuning question--91 5.7
Id put the stock chip back in. Set fuel pressure at 48ish, 12deg timing. My old 92 350 loved that set up. Used to run mid to low 13's at 100-102 depending on weather w/ 3.73's and 3200 stall converter on drag radials
08-28-2011, 10:11 AM
#3
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
Re: timing/tuning question--91 5.7
ok, ill give that a try.
I drove it yesterday and it was acting up again, like it was wanting to stall every now and then at a stop. Im starting to think that the timing and stuff are not connected.
It drives fine for about 20 mins and then SometimeS it idles high at a stop and then wants to stall on me.
Do you guys think it could have something to do with my trans or drivetrain? or a sensor? NO Check engine lights are on.
The car has 75,000 miles.
I drove it yesterday and it was acting up again, like it was wanting to stall every now and then at a stop. Im starting to think that the timing and stuff are not connected.
It drives fine for about 20 mins and then SometimeS it idles high at a stop and then wants to stall on me.
Do you guys think it could have something to do with my trans or drivetrain? or a sensor? NO Check engine lights are on.
The car has 75,000 miles.
08-28-2011, 08:09 PM
#4
Registered User
Join Date: Jul 2003
Location: usa
Posts: 1,025
Re: timing/tuning question--91 5.7
I dont think that problem is drivetrain related or timing. Whats you timing set to now and fuel pressure? Have you tried the basics? Sounds crazy but Id star by pulling the TB off and giving it a good cleaning. They can get stuck in a slight open position when leting off the gas, carbon and what gets built up behind the blades and makes it stick
08-28-2011, 09:05 PM
#5
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
Re: timing/tuning question--91 5.7
6* base timing and the jet stage 2 chip (runs at 10.0-19 A/F)WAY TO RICH!. To be honest it seemed to run alot better when it was at 10* with the stock chip, it was running a bit leaner about 11.2ish. I know its running rich as hell and thats why i want to put the factory injectors, but when it stall on me i went back and it still did it, so I Dont Know
Ill pull the TB off and clean it tomorrow, anything else you can think of that will effect it??
THANKs
Ill pull the TB off and clean it tomorrow, anything else you can think of that will effect it??
THANKs
08-28-2011, 09:11 PM
#6
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
Re: timing/tuning question--91 5.7
It made not too bad power for the stock tpi and internals, about 250hp and 330lb-tq, I think i can squeeze a little more power out of it by putting the old injectors in,adjusting the A/F and timing.
08-31-2011, 08:38 PM
#7
Registered User
Join Date: Jun 2004
Location: Austin, TX
Posts: 151
Re: timing/tuning question--91 5.7
If it's too rich (AFR 10:1 is WAY too much), you can just turn down the fuel pressure. The 27lb injectors are an overkill for this engine. But if they are newer than the stock injectors, I would recommend keeping these because the stockers might be way out of balance by now.
And the 160-degree thermostat and hardwired fans are not helping either because your ECM might never get into closed loop at this temperature and won't be able to control the mixture.
Let us know how it goes.
Lou
And the 160-degree thermostat and hardwired fans are not helping either because your ECM might never get into closed loop at this temperature and won't be able to control the mixture.
Let us know how it goes.
Lou
09-06-2011, 02:13 PM
#8
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
Re: timing/tuning question--91 5.7
update**
i took off the TB and cleand it.
ok i put the stock chip in and its currently running on 12* base timing. after driving it for a little bit the RPMs started to idle a bit high in drive about 1100rpm and when i put in nutruel it goes up to 1500rpm. so it acks like there is a gasket leak but it only does it for a little bit then goes back to normal. it hasn't stalled or anything since cleaning the TB.
I looked around for a leak where it would be sucking in air and i didnt find anything.
FYI it did the RPM jump around before i cleaned the TB but it stalled also.
i took off the TB and cleand it.
ok i put the stock chip in and its currently running on 12* base timing. after driving it for a little bit the RPMs started to idle a bit high in drive about 1100rpm and when i put in nutruel it goes up to 1500rpm. so it acks like there is a gasket leak but it only does it for a little bit then goes back to normal. it hasn't stalled or anything since cleaning the TB.
I looked around for a leak where it would be sucking in air and i didnt find anything.
FYI it did the RPM jump around before i cleaned the TB but it stalled also.
09-06-2011, 05:32 PM
#9
Registered User
Thread Starter
Join Date: Apr 2009
Posts: 110
Re: timing/tuning question--91 5.7
Iv been messing with it all day and my air fuel is now between 11:2 and 12:3 through the RPMs, so its running alot better. but still a little rich.
so as of now; the only thing it does weird is, idle high at when it feels like doing it like it has a intake leak, just not all the time.
could it be a sensor or something like that going bad?
I have already cleaned and checked for a gasket leak and i dont think that is the problem. or could it be that the car isnt liking the timing???
so as of now; the only thing it does weird is, idle high at when it feels like doing it like it has a intake leak, just not all the time.
could it be a sensor or something like that going bad?
I have already cleaned and checked for a gasket leak and i dont think that is the problem. or could it be that the car isnt liking the timing???
Thread
Thread Starter
Forum
Replies
Last Post
karpetcm
Parts For Sale
2
09-29-2015 10:08 AM