Car starts but wont stay running...

[NicksTurbo6]

OK, car is now running after a year and a half of sitting. Once it start, will only run for 5 to 10 seconds and wants to die. Car ran and drive fine before sitting. It was completely stock. Here is what I did in the downtime:

Racetronix HW kit, Walbo, NOS4GN sending unit
Caspers ground kit, and positive battery kit, heated 02
NGK UR5's gaped at 0.32, MSD wires
T/A race headers, PTE 5857, RJC 3" DP, Cottons 3" cat back
PTE upper plenum with RJC PP
PTE FM IC
Scanmaster, AEM WB


I still have the stock chip, injectors, and MAF in the car. I have a Turbo Tweak chip, 60's, Translator, and Z06 MAF waiting to go in. I wanted to get the car running first on the stock stuff before going further. The car starts and runs for a few seconds, then it wants to die like its not getting enough fuel. If I tap the gas a few times, I can keep it running, but its not smooth. I have an AEM WB hooked up, and you can see the gauge start off around 14:1 AFR, then go leaner like 15...16...17..18 then according to the WB it goes so lean its off the gauge. If I give it some gas, it will bounce down for a second to around 15 or 16:1, then back to super lean where it wants to sputter and die. I checked everywhere for vacuum leaks and cant find or hear anything. I had an oil pump prime issue where I pulled the cam sensor out to prime the system. I Reinstalled the cam sensor, and set it using Casper's Cam setting tool. I triple checked it, and that's all good too. One thing I will check later is fuel pressure and verify it with a gauge. Other than that, I don't know what else it could be. Any suggestions?


Nick

 

[87GNSteve]

What are the MAF readings? Any why wait for the upgraded Maf and translator?

 

[TurboBuRick]

If it starts the cam sensor is set.

Does it sound like it's misfiring or just lean out and dying?

See what fuel pressure is doing.


RL

 

[NicksTurbo6]

OK, I verified the fuel pressure at 38 psi, vacuum line off, stock regulator. Pressure is steady when running, so fuel is good. I did find a vacuum leak on one line at the block on the throttle body. Replaced that, and its better, but not cured. It will stay running and idle on its own now. Hard to say if its a misfire. When giving it gas from idle, I get an occasional light "pop". Here are some numbers off the Scanmaster at idle:


MAF: 06
L8: 43
BAT: 13.7
INT: 142 - 150
BL: 150
CT: 184
AT: 85
RPM: 875
TPS: .42
IAC: 17
CC: start at 16, gradually go up to 252 then back to 16 and repeat.

AEM wideband readings: Idle: 15.5 to 16:1. As I give it gas it goes up to 18:1 and, then right back down to 12:1 to 13:1 as I let off the gas. Then at idle it settles back to 15.5 to 16:1. Not sure where to look next.




Nick

 

[TurboBuRick]

It's way lean. Go over all the cooler couplings. Check maf pipe. Sounds like your getting un metered air.

RL

 

[NicksTurbo6]

Steve, I am waiting to put that in because I want the car to run well with the stock stuff as it did before. I don't want to change anything else yet and add more variables. The stock MAF is reading correctly.

Rick, I will go over all of the cooler couplings again, as well as all of the vacuum lines. Could the probelm be with the mods I have done the stock chip is trying to compenstae by adding fuel but it can't add anymore? I was thinking of putting on my AFPR (Accufab) and setting the FP to 42 with the line off to see if that helps?


Nick

 

[87GNSteve]

Nick, to me it it doesnt seem like those are radical modifications, and putting the upgrades on and solving the problem will end there. If you solve the problem then you do the mods then you need to tune again.
Like Rick said seems like you have some pirate air getting in..lots of it.

 

[NicksTurbo6]

Steve, I agree, the modifications are not radical. That's what bothers me, is that the car should idle fine and not go super lean when you tap the gas. Keep in mind I am not driving the car, this is all done while in park. I think it should still drive fine at cruise/light boost. As for the tuning, I plan to do that once the TT chip, 60's and Z06 MAF are in. Are you suggesting that I should put those in now? The car can idle fine now, and reving in neutral or park its very sluggish and breaks up. I am going to keep searching for this "pirate air" making its way in.


Nick

 

[87GNSteve]

I think if you can change a sensor to eliminate a suspect problem its keeping with good diagnostic practices. And it is easily put back if needed. If it was my personal car I would put in the new MAF and translator in because it isnt going to be any worse off. and if it fixes the problem you know what it was. MAFs can die slowly yours is reading on the max of its range.

 

[TurboBuRick]

The mods should not effect it down low. Increasing fuel pressure would help.

 

[NicksTurbo6]

OK, I figured it out! First I went over all of the hose connections, and vacuum lines. All were OK. I fired it up, still sounded the same. As it was running, I sprayed water on each primary tube to see if they were all firing. Turns out cylinder #2 was cold. I pull that plug out to find that the tip was slightly wet. So I rechecked the spark plug wires to find that I had cylinders 2 and 4 swapped! So I corrected that and fired it up.... ran smoother than my Caddy! Wideband was reading between 14:1 and 15:1 at idle, going to around 12:1 when I gave it gas. Scanmaster INT and BLM came right down and started to settle around 128 to 130. The GN is running as it should! Now later this week....chip, 60's, Z06 MAF Thanks again everyone!


Nick