numerous problems

[OmahaKnight]

I've been having a problem for a while with my car dying on me and not restarting for a while. When I drive it for more then 10 minutes, turn it off, then try to restart, it wont' start. It'll constantly turn over but not start. After anywhere from 10-20 minutes, it'll start back up. Well, I thought it might be the MAF and IAC motor so I replaced both those from NAPA. Now it runs worse!! Now when I'm driving, the engine will cut out on me, not die, but cut out and sputter really bad like it's getting no fuel, and I have to really ease into the throttle in order to accelerate. I replaced the MAF on tues, and noticed my IAC #s were in the 70-90 range so i replaced that thinking it would fix it, it didn't. The only thing I've noticed is when it starts to sputter and cut out, my MAF readings will go from 25 to 250+. These are the scan master readings I took while it was idling at 800 RPM after lunch today.

AF 05
L8 37
INT 128
BL 111
ATS 91-97
RPM 800
TPS .44
IAC 21
cc 137

O2 was from 400-875

Any ideas? As of right now it's my daily driver so I need it fixed asap!

 

[Hacksaw]

Did you clear out the ECM after changing these? I don't think that's the stalling cause, but it is a good idea when up change any emissions parts.

OK, for the engine to run you need fuel, spark, and compression. I don't think it's a compression issue, because it restarts. I doubt if it's the EGR stuck open because that should be constant.

So, next time it quits, get some one to help you & run a spark check. I just pull a sparkplug wire, stick a screwdriver in the boot, hold the shaft of the screwdriver near a metal area underhood, using the insulation to keep from getting shocked, & have someone crank it.

Do you always hear the fuel pump come on for a second or 2 when you turn the key on? It could be getting flakey. Yes, my mother's turbo V6 had this problem before the fuel pump totally quit.

A bad wastegate solenoid will cause stumbling under throttle, but I don't think it would affect idle.

If you get clouds of black smoke when you do restart, then something is causing the mixture to go way rich. Be careful about holding the petal all the way to the floor when restarting, because it will signal that you have a flooded condition on some ECM systems. A little throttle is ok at start.

-Mike H.

 

[OmahaKnight]

i'm running really rich right now, some black smoke and black crap coming from the exhaust. I'm starting to suspect that the MAF i bought is not correct. My chip is set for a stock MAF.

 

[TurboBuckeye]

I'm starting to suspect that the MAF i bought is not correct.

Or just junk right out of the box...as many are

 

[Hacksaw]

Yes, replacement parts are sometimes a gamble.

2 other things come to mind:

1. Your fuel pressure regulator. DON'T remove the vacuum line from it, it needs it. Leaving it off will richen the mixture at idle & part throttle. Do you have an adjustable (aftermarket) one? If it's set too high idle & part throttle richness will be a problem.

2. The vacuum line to your Manifold Air Pressure (MAP) sensor may be leaking or disconnected.

How does it run at highway speed?

-Mike H.