Need Help - Car Wouldn't Start This Morning

[RKHiPerformance]

My wife went out to the T-Type this morning to go to work and the car wouldn't start. She made several attempts and the engine would crank easily, catch for a moment and then stall. She gave up and took her Monte today. The weather was cool (40's) and damp this morning, but we've started the car in worse conditions without issue.
A few moments ago I attempted to start the car. It would crank for a few seconds, run very roughly, and then immediately stall. After numerous attempts, I was able to get the car to stay running by gently opening and closing the throttle. The car's rough idle smoothed somewhat as the temp came up but the engine continued to chug to some degree.
Nothing appears amiss on the Scanmaster. Disconnecting the MAF connector had no impact on the engine's behavior. I let the car idle at temperature for a while, hoping to set a code but none appeared. I did notice a miss when I raised the engine speed above 2000 RPM, as if the car was hitting a rev limiter. This occurred when the MAF was both connected or disconnected.
The coil pack, ignition module, and ignition wires were recently replaced in my on-going attempt to locate a popping/backfiring problem that occurs under boost. O2's seem normal, with good cross counts.
I really need to get this issue resolved. What should I look at next?

 

[strikeeagle]

Is the ECM wet???

 

[RUQWKNF27]

Maybe this will help!!

Got a friend with a miss at high boost, with the car cutting out. Also good coil, plugs an such. Turns out the fault lies in one of his plug wires having hi resistance an the spark getting blown out at hi boost. Not sure if this is your problem but you could try out some different wires. Also I have had this problem before with fouled plugs where on a cold start the motor would start but then I would have to romance the throttle to keep it going an then it would eventually quit. An would not imediately restart for a while. Just think if the scanmaster is not showing a code then it may be something mechanical. Plug,plug wires, maybe even fuel pump but doubt it. Let us know what you find out!!!!

 

[RUQWKNF27]

Ooppss

Just saw that you replaced the wires. Well then hum, replace the plugs cheap easy to do that MAY be it. Good Luck!!!!

 

[GN SBS]

Try this great resource:

I'd start here:

http://www.gnttype.org/techarea/maintenance/nostart.html

Note there are 3 pages.

good luck!
Scott

 

[RKHiPerformance]

The latest...

Strikeeagle...I checked and there is no evidence that the ECM is wet.

I started the car a few minutes ago and it started right up. The temp gauge still read 121 from my testing earlier this morning. The idle seemed normal, so I took the car for a ride. My test drive did not include any heavy throttle due to the wet roads and my desire to keep the car out of the woods. I noticed nothing out of the ordinary while driving.
Back in my driveway and in park, I did confirm the presence of the miss that occurs at about 3300 RPM. The engine rarely sees this engine speed in 'normal' usage so I can't confirm exactly when this problem appeared.
I'm frustrated, although relieved that the car appears usable.

I wonder if this problem is related to my popping/backfire problem under boost.

I'll guess we'll see how she starts tomorrow morning.

 

[Granny 2]

Cam Sensor

 

[RKHiPerformance]

cam sensor?

 

[JDSfastGN]

umm, maybe cam sensor, crank sensor, bad grounds? How old is the timing chain? One time I had the pin that holds gear on the cam sensor break and it caused a no start and a no oil pressure. Just a few ideas. Good luck.

 

[RKHiPerformance]

Almost everything under the hood is new. We recently installed a professionally-built long block with good parts, and at the same time we replaced both battery cables with GM pieces and anything else we could unbolt and replace. The charging system (and grounds) always seemed very healthy.
The timing chain is a Cloyes Tru-Roller, and oil pressure is unchanged (35 psi @ idle).

 

[fitz3820]

I had one of the pins on the ECU corrode off due to a leaky t-top dripping water in the kick pannel. Check to see if all the pins are there.

Mark F. 87 GN 11.9 @ 115

 

[TurboDave]

Did I miss something, or did you say that you unplugged the MAF and nothing changed with the way the engine was running?

I would assume that with a heatlthy MAF, unplugging it should have a dramatic affect on how the engine is running.

 

[RKHiPerformance]

The car was running like crap with the MAF plugged in and continued running like crap once I unplugged it. However, I can't say for certain that I trust that MAF sensor. It did pass the 'tap' test. The MAF is also under suspicion for causing my popping/backfiring problem under throttle. I plan to swap it with a known good one at first opportunity.

BTW,
My wife started the car this morning and drove to work without any hassles.

 

[JDSfastGN]

i think turbodave may be onto something, i misunderstood when you said it didn't change anything when it was unplugged, sure sounds like it could be the problem though. I had a similar problem when mine went out.

 

[TR Custom Parts]

Think TurboDave nailed it. My bet is on the MAF.

 

[RKHiPerformance]

I'll swap the MAF at first opportunity, which will probably be tomorrow afternoon. I'll post the results.

I'm grateful for all the help - This board is the best.

 

[machinegun]

I would wait for all of the above. First try to start the car. Does it start to run and then die? If so then all of the above is null except maybe the maf sensor. I would first try to start the car by stepping on the gas a very little amount. I mean little. If the car starts and runs then simply remove the IAC. Clean IAC and TB with sensor safe carb cleaner. Reinstall and reset your IAC counts using a scan tool. I almost always have to to this on my daily driver this time every year. Let me know what you find.

 

[RKHiPerformance]

Thanks for the input, machinegun. The problem seems intermittent, because the car started normally this morning and the conditions were similar. If the IAC had failed or was malfunctioning, wouldn't I see a consistently rough idle? IAC numbers on the Scanmaster are below 15 at idle, I think.
The IAC was replaced about 6K ago, and the throttle body was thoroughly cleaned when the engine was installed (5K) ago. Could the IAC need servicing again after such a short period of time?

 

[Blown&Injected]

MAF

 

[RKHiPerformance]

Update...

The car wouldn't start again this morning for my wife. I went outside shortly afterwards and attempted to start the car myself and noted the same behavior as the day before yesterday. The car cranked easily, started and proceeded to run like crap - chugging and popping. I retrieved the MAF from another car, installed it and re-tested - no change. Bummer.
I looked at the IAC and realized that it had not been changed in some time. In my response to machinegun I was thinking I'd changed it recently, but that was another car (too many Buicks?).
A swap to a new IAC from Advance Auto yielded a perfect start-up and a normal idle - even cold. Whaddaya know...Machinegun was on the money.

I'm gonna leave the other MAF on the car to see if it improves my popping problem under boost. But it appears that the car will now be usable once again. Thanks to everyone for their help with this problem.