95SE Starts, then dies after a few seconds Mark it fixed

[crzydmnd72]

At a loss here.

Car refused to start up one night, so we had it towed home. I finally got a fuel pressure gauge, and ran the tests, had 20psi of fuel pressure. I thought, slam dunk, fuel pump. Got that changed out, and now have 40psi when the key is cycled, however the problem remains the same. It will start right up, run for about 3 seconds, then stutter out and die. Fuel pressure does not drop much when this occurs. It does not miss or shake upon start up. Here is whats new

Fuel Pump
Fuel Filter
FPR (several months ago)

I have pulled the rail and flushed it out, it did have some rust particles in it.
I pulled a sparkplug, my son thought it smelled rich, and it is sooted/carboned. Sparkplugs have less than 5k miles on them.
I can hold the throttle just barely above idle, and it will run for maybe 10 seconds, but even the dies out. It will always restart promptly, but dies every time. Its very consistent.

What am I overlooking here?

ETA, MAF arrived today and fixed the problem. Thanks!

[willwren]

What you're missing is a scan.

[crzydmnd72]

I'd love to scan it. The scantool I have access to will not connect, I guess because its not OBDII. So that might be tough. I'm open to suggestions there

Tools I do own are, Fluke DVM and analog meter, fuel pressure gauge.

ETA, on Actrons website now looking for what may work. Wish the paper clip worked for this one.

[J Wikoff]

Clean the MAF recently?

[crzydmnd72]

yes. And also makes no difference plugged in or unplugged

[J Wikoff]

Isn't that the sign of a dead MAF?

[crzydmnd72]

I'm not sure. Can't ever remember one failing.
Also update, cheapest scantool I've found is around 300.
Mighty pricey for me, but I guess it can be used on newer cars also lol

[willwren]

We can sit here and guess all week. By the time you fix this, it's going to be far more expensive as that if you have to throw parts at it.

[crzydmnd72]

I agree with your point Bill. I don't feel too bad about the fuel pump, the gas gauge didn't work either so we just got the whole assy. Now the gauge works, so that's handled. I understand, the intent to get to the problem and not shovel parts at it.

I went out to the 99 with the intent of swapping MAF's to see. I was greeted by tamper resistant Torx screws. Yet more tools to get. Won't be able to try that tonight.

Interesting note that may or may not be relavant. None of the pins on the old MAF have any continuity with one another. Total open it appears.

[00Beast]

Make sure the MAF's have the same # on them, it should be AFMxxx-xx. The part after the dash needs to match.

[reb]

I agree with your point Bill. I don't feel too bad about the fuel pump, the gas gauge didn't work either so we just got the whole assy. Now the gauge works, so that's handled. I understand, the intent to get to the problem and not shovel parts at it.

I went out to the 99 with the intent of swapping MAF's to see. I was greeted by tamper resistant Torx screws. Yet more tools to get. Won't be able to try that tonight.

Interesting note that may or may not be relavant. None of the pins on the old MAF have any continuity with one another. Total open it appears.

All you need to do is cut a slot in the screw with your dremel tool and then use a slotted screw driver to remove that torx screw.

[willwren]

All you need to do is buy a $5 set of the correct bits. You'll need them again.

[00Beast]

And then replace them with allen-head cap-screws. M1-2.5 is the thread. I got stainless ones with SS washers, adds a nice little flash to the TB.

[Boss455]

Definately a scan is in order. Since I believe the 94-95's are all OBD 1.5, only a few scan tools will work. My Actron CP9145 was only $100 from Amazon. Worked great, showed enhanced codes. I'm thinking the computer is bad. That's what cured my 94.

[crzydmnd72]

Ed, thanks for that heads up. They are indeed different numbers. Won't be trying that one

Reb, Not too sure I'd want a good MAF subject to the vibrations of a dremel cutting the screw.

Bill, I picked up the correct set of tamper Torx today, but won't be needing them for this lol.

Boss, are you pretty happy with that scanner? Amazon came up dry, so its off to ebay and craigs for me. If I have to get a scanner, I sure want one thats good for more than just 94-95 GM

[willwren]

I've heard good things about the 9145 myself. That may be my next scanner.

[Boss455]

As a scanner for the 94-95's, it's pretty darn good. It'll scan all the enhanced parameters like tranny temps and such but on 96 and up (like my van and Regal), it'll scan the basics, coolant temp, speed, fuel trims (but no voltage!), no extras. It'll clear codes and such too. I've tried it on my 92 GP with no luck, I guess I had the wrong cable. Overall, I'm pretty happy.

[crzydmnd72]

update, had it scanned with a Snapon scanner by a friend. He showed the MAF output to be zero, with a code 101, which he said later models would report as a P101.

Then we took a DVM, had 12v, 5v ref also, so he felt pretty sure it was a bad MAF.

Based on earlier replies, I guess I coulda threw a MAF at it, but knowing my luck it would have been something else.

[Jrs3800]

Will it start with the MAF unplugged?

[crzydmnd72]

Don, it does start either way, plugged or unplugged. It acts the same either way. I've had a few minutes to fiddle with it lately, if I KEEP restarting it, and letting it idle, it idles a LITTLE longer each time. after 10 repeats (warmup I guess?) it will idle on its own, but has no throttle response at all.
I've ordered the MAF, should be here Friday, guess we will see.

ETA, I had to order for a 96, the 95MAF mounts with 3 screws and has a 90 degree connector. This one is a straight connector and mounts with 2 screws. Maybe the engine isnt original?