Having major issues with new setup!!!!!

A

AntiVtec

Member
I finished my setup yesterday SR, 20G, DW 740cc, Z32 MAF, and Enthalpy tune and everytihing was fine. The car idled perfect, pulled hard and stayed pretty steady A/F readings. Today i change the oil and put in a new battery and take the car out for a spin. First off i notice a slight hesitation taking off. Then as i near 2700rpm accelerating slowly there is a bad stutter and the A/F gauge goes completely lean until 3200rpm where it smooths out and A/F goes almost completely rich. Under hard accel it stutters all the thru 2200-3400rpm then goes rich and pulls hard. Any one know why the car would go Jekle and Hyde on me over night? Im thinking bad maf but it was working great yesterday and idles fine at 800 RPM. Maybe daughter board came loose?
Thanks for any help.
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I asked Scott at Enthalpy and he said thats impossible. But thats the first thing i thought also.
Thanks though,
Laz
 
My car has teh same hesitation around that rpm range... I was thinkin it could be some kinda vac? idk.. :D lmk when u fix it :D
 
I'm trying to find a good write up w/ pictures but I'm having trouble. There used to be a really nice one KA-T.org but idk what happened to it. Basically you're hard wiring the fuel pump to a relay. I found this pretty descriptive write up on tampa racing:

cyanide said:
cut white/purple and blue/red on tank side of connector. send blue/red to ground. connect white/purple coming from connector to turn on the relay. attach other end of relay to ground at same spot you ground blue/red. run 12ga. cable with an inline 30A fuse from battery to the relay, and then connect the opposite end (that connects when the relay turns on) to white/purple at the tank.
if you want to do it cheap and reliable, www.partsexpress.com get a bosch 30A 12V relay, the bosch harness, and a pioneer (if they still carry this) 12ga. cable with built in 30A fuse, should come to $6-7 total.
Click to expand...

That's the double relay method.
 
My FP is hard wired, but i havent even taken the motor near redline. The issue is under slow or steady throttle application. Under hard accel it hesitates a little then hits boost and goes rich but pulls steady and hard. And it was running fine till redline with the stock setup. Thats why im so lost!
 
AntiVtec said:
My FP is hard wired, but i havent even taken the motor near redline. The issue is under slow or steady throttle application. Under hard accel it hesitates a little then hits boost and goes rich but pulls steady and hard. And it was running fine till redline with the stock setup. Thats why im so lost!
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Well you have changed a lot since then and I think you ought to check for boost leaks. Go over every hose and clam and vac line at least as a start. You did change your battery...are all your grounds hooked up?
 
AntiVtec said:
I finished my setup yesterday SR, 20G, DW 740cc, Z32 MAF, and Enthalpy tune and everytihing was fine. The car idled perfect, pulled hard and stayed pretty steady A/F readings. """""Today i change the oil and put in a new battery"""""" and take the car out for a spin. First off i notice a slight hesitation taking off. Then as i near 2700rpm accelerating slowly there is a bad stutter and the A/F gauge goes completely lean until 3200rpm where it smooths out and A/F goes almost completely rich. Under hard accel it stutters all the thru 2200-3400rpm then goes rich and pulls hard. Any one know why the car would go Jekle and Hyde on me over night? Im thinking bad maf but it was working great yesterday and idles fine at 800 RPM. Maybe daughter board came loose?
Thanks for any help.
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Click to expand...

quoted

well it makes no sense to happen its as if the power going to the ecu's memory had complety gone out but it seams to be the most likely cause aside from boost leaks

and to be offical every electrical load on the car like a fule pump should have its own relay unless its a factory pump

then it still has one but its a gay one
 
Devil Man said:
thats what i thought.. but the ninja said other wise.
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ROM chips stand for Read Only Memory - meaning they cannot be written to unless they're "flashed." They don't need power to hold their data either. I've had shorted out ROM chips (from a static shock most likely) - if they were, the ecu would ignore them and with a z32 maf and 740's, that would mean it basically wouldn't run the car at all.
 
Just got home and turned on the car and it seems to be getting slightly worse. Idles fine still, but what is weird is if i gas it hard it goes thru the RPM's flawlessly and pulls like a champ, but if i give it light throttle it breaks up terribly. What affects the motor at light throttle that dosnt play a part in heavy throttle applications? Thanks and let me know if you get any other ideas.
 
What are your air fuel ratios when the engine stumbles? Dose it happen at a specific rpm while you are easing into the throttle? Can you check to see if your tps voltage is linear from .5volts to around 3.5?


ROM is the common abbreviation for EPROM, which is Erasable Programmable Read Only Memory which is non volatile (it is able to retain its information if all power is disconnected.)

Considering the car was running fine before, I do not believe that its the ecu. How do you have your egr disconnected \ sealed off? How many inches of vacuum are you pulling at idle ?
 
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240SicknessX said:
What are your air fuel ratios when the engine stumbles? Dose it happen at a specific rpm while you are easing into the throttle? Can you check to see if your tps voltage is linear from .5volts to around 3.5?


ROM is the common abbreviation for EPROM, which is Erasable Programmable Read Only Memory which is non volatile (it is able to retain its information if all power is disconnected.)

Considering the car was running fine before, I do not believe that its the ecu. How do you have your egr disconnected \ sealed off? How many inches of vacuum are you pulling at idle ?
Click to expand...

Vacuum is steady as its always been and theres no idle issues, the a/f i read from an a/f gauge not a wideband so its not perfect but gives me a general idea. The stuttering only occurs at light or steady throttle at RPM's from about 2K thru 4K during which the a/f gauge goes completely lean. Im thinking maybe o2 sensor since it usually only affects performance during light throttle or cruising. How do i check the TPS voltage meaning at idle or during accel.
Thanks alot to all of you for taking some time to help, :bigthumbu
Laz
 
When the car's warm and ignition is turned to the on position (right before starting), you can check the voltages at the TPS. I think .45~.49 is factory spec for completely closed.
 
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