More 3100 problems. Any ideas?

[jeffreylane]

I hope someone in this forum has some ideas. Thanks in advance. I have a 99 malibu, has a 2000 model engine. cone style filter, pcm tuned by MP Racing. I had problems for while with it stuttering and dieing after the engine warmed up. It would always start back up, but wout lack power (20 - 30 mph tops at times), and backfire throught the intake. Problem normally only happend after driving the car over about 10 miles. I was able to drive to work and back everyday withouth problems (most of the times), but if I tried to drive it farther, the problems would start. It would also die if you turned the air conditioner on. I guess it couldn't handle the extra load of the engine while not getting a good spark. Finally fixed the problem by replacing the coil pack. It has been about 4 months or so without any problems. Even ran great with the air conditioner on. About 2 weeks ago I drove it to the store, about a half mile, and parked it at home. My wife got in it to drive it about 30 min later and it would not start. I could not hear the fuel pump prime when turning the key on. Out of about 30 times turning the key on, I heard the fuel pump maybe twice, in which it would crank and turn for about 5 seconds and die. I checked the hot wire going to the pump with a test light and it was hot with the key on. (Just a note, the pass lock theft system has been disabled by cutting the yellow wire). I figured the fuel pump must be dead. Went through the fun of dropping the tank on a cold day and replacing the pump. I replaced it with a used unit. Tested the fuel pump I got and worked fine. Got it all put together, and it finally pulled the gas up and started. Drove it around the block and ran fine. Pulled back into the house and it died. Tank was pretty low on gas, so went and got gas in a jug and put it in the car. It still would not crank. The next morning I came out and it cranked fine on the first time. Figured it just had needed to pull the gas up better? We drove it to run several errands that day, and to go eat, all withing about a mile range. Then that evening, we went about 3 miles away, and when we came out of the store it would not crank. Called the tow truck.
Switched the relays around (since there are several the same as the fuel pump relay). Still nothing.
I could not hear the fuel pump come on. Sometimes it would start and then die within 3 seconds like it was not getting fuel.
Yesterday I was thinking and read that the passlock can reset after cutting the wire if the battery is disconnected. I had disconnected the battery while chaning the coil. I hooked the wire back up (theft light went out), the re-cut the wire again. Car cranked and ran fine, but I was not so sure and not about to drive out again and have to wait on the tow truk again, went through that enought during the coil pack episode.
The next morning, came out and tried it, and it cranked fine and ran great.
Today, I cranked it and went back and forth in the driveway a few times, cutting it on and off. Then I let it run and get up to operating temp. After a while it died. I cranked it back up, which it did, then drove back and forth in the drive way for a little bit. I could fill it start to stutter a little bit. Finally it got worse like it was not getting gas. Then it died. cranked up and ran, but would start stuttering after a little while and falling on its face while ideling. I would give it gas, and it would backfire a couple times out the intake, then bog down and die. Changed the fuel relay around again with a different, and still no better. Then it would not crank. I could not hear the fuel pump kicking on anymore. (I also burnt my finger on the negative battery terminal when checking to see if it was tight). It was a little loose, but did not help anything when tighting it. Still would not crank.
I'm sure it will crank fine tomorrow, but it doesn't help me if I can't drive it. I'm determined to not let this car beat me. I think it's doing this to me because I said I had won against the car after fixing the coil pack.
Does anyone think it may be the coil pack again? Acting different than it did the last time. The coil pack was a used one that I put on. I plan on changing it out this weekend to see if it helps. I just hate throwing money at it over and over. Engine code is MAP (which I changed) or vacuum leak. But it showed this code even while it was running fine. I think there may be a small vacuum leak somewhere from the engine swap.
Here is what all I have changed that may be relevent:
coil pack (ran great after doing this)
spark plugs
intake gasket
pass lock bypassed
cam sensor
crank sensor
crank sensor wires
pcm (from MP Racing)
map
maf
throttle position sensor
ERG
fuel filter
fuel pump
run fuel system cleaner through it
fyi: no water at all in the oil
Any help would be appreciated. I already had to buy another vehicle for my wife so she would have a way back and forth to work (that money was supposed to be for me an extra vehicle so I could work on my bmw project car which is currently my daily driver ...which has not heat right now. So I have incentive to get this one fixed).
Sorry for the long post.

[pocket-rocket]

Is there any chance of the gas freezing? Normally the consensus says to keep the tank topped off as much as possible in cold weather because all of the bare surface in the tank being exposed gives condensation a place to form on, causing water in your gas which can and will freeze in cold weather. If it is in the fuel pump and frozen, I can see why you aren't hearing the pump run. You could also have a bad ground to the tank. How well does your gas gauge work?

[jeffreylane]

It hasn't gotten cold enough here to freeze the gas (I'm in Memphis, TN). The gas guage seems to work fine, but the same day that this started, we did realize that the low level light by the guage was not coming on anymore. It had always worked up to that point.

[pocket-rocket]

Ah, ok. When I read "cold day" I think about our weather up here and think snow blowing all around, lol. Trade you weather? Ours looks nice I take it Malibu's don't have an access port under the rear seat to get to the gas tank? Then again, I think most GM's don't. I would at least try to check out the ground for it to see if that could be your problem. It's worth a shot.

[jeffreylane]

mid 30's and people are freezing stiff in the streets around here. We occassionally get down in the teens, but not yet this year.

[jeffreylane]

I'll give it a look. It looked ok when I glanced at it while changing out the pump, but I'll double check it since I didn't pay that much attention to it. Of course the malibu dont have the access under the seat. I changed one out in my e36 a few months ago, it has the access under the seat, took about 20 min total. Thanks for the advice. I'll give the ground another look tomorrow when I get off work.

[pocket-rocket]

It might check out visually, so take a multimeter under the car with you. If the Malibus are like the GA's, I remember unplugging the harness going to the tank before even undoing the straps, so at least the tank doesn't have to come down to check the ground. I would also look at the pins in the sockets as well.

[bszopi]

Its not a cheap part to throw at it, but it may be your ignition switch starting to go bad. I had an Alero that was having starting (and sometimes dying) issues, and I had the same issue with no always hearing the fuel pump. Turned out to be the ignition switch was heading south...

[pocket-rocket]

Good call, I had forgotten completely about that

[60dgrzbelow0]

I noticed that "New Spark Plug Wires" were not listed...and just in case they were not part of all those other things...I was wondering whether the intermittent nature of the stuttering might be a wire burned through that only acts up when the engine demand is increased. You would not think it possible that improved compression would cause a spark to leak... but more years ago than I care to think about... I was trained on the Wright R-1820 Radial Engines that we had the USCG SU-16 Grumman Albatross Search and Rescue Airplanes. They came equipped with a dual "High Tension" coil and ignition system sufficient to contain the spark energy inside the wire harness to the nine radial cylinders and resist bleeding off in some path of least resistance at higher altitudes when the supercharger had to be used...and be able to drive energetic spark plugs inside cylinders. The idea applies here that after your engine warms up and the compression improves...it might reveal the spark plug wires leaking out through manifold burns, insulation breaks, cracks... carbon dust and dirt on the outside under those conditions, too. It might be easy to discover these "Wire Weaklings" by covering the the outside of the open engine with several blankets around the edges of the raised hood in "no light" conditions and look for any spark leaks as flashes of blue lightning under there as someone raises and lowers the engine RPMs.

[draco587]

codes?

what codes are showing up ?

[natehale88]

That sounds just like a crank sensor... But you replaced it so thats a tuffy.. Just swap in an LS1..