2000 Malibu problems, electricaly/fuel delivery?

[codyturner]

I have a 2000 Malibu. The fuel pump went out on it a few weeks ago. Put a new one in. Then the car started stalling out a lot and then not starting. Found some wires under the hood that I could jiggle to get the car to start back up after stalling. Figured they ran to the crankshaft sensor, so I replaced that and the problem went away. Noticed that for a few days the car would almost stall out on start up, but the RPMs would go back up and there would be a slightly rough idle. Well, one day it started and then died, but after a few tries it started and ran just fine, but with a rough idle again. It does it again later that night and started when I gave it some gas. The next day it ran fine, just had the rough idle again. Took it by advance auto parts and they read a few codes. something about an engine stalling, computer error and egr, insufficient flow. The only pending code was the EGR code. So, I assumed that's what was causing the rough idle and figured I'd get around to cleaning it or replacing it on Sunday. Well, I get up this morning to drive to work and the car starts and runs fine. I get off work and turn the key to on before starting the car so I could roll down the windows and notice that my fuel gauge didn't move off the E. I had driven about 70 miles up until that point since I last filled the tank all the way up and that morning my gauge was reading around 7/8 of a tank. So I try to start the car and it starts and dies immediately and that's all it would do. It was too noisy for me to check to hear if the fuel pump was working, but I'm assuming since the car would start, just immediately die that it was engaging, but being shut off? I'm wondering if the crankshaft position sensor has a short in a wire somewhere and it could be throwing everything off (gauges, shutting off fuel pump). I'm really lost here and can't think of anything other than that or maybe a bad ground or connection or something in the fuel pump.

[rkvons]

Was the crank position sensor you replaced the one on the back side of the engine? If jiggling wires made it work for you then it was probably the wires that were bad and not the sensor. I would remove wire and look at it. As you are removing it, notice how it is routed. It will be going close to your exhaust manifold. If it touches it, it will melt the insulation off and cause a short.

[codyturner]

The sensor was at the front, bottom-side of the engine. Right up around the oil pan. I went back to the car yesterday after work and my gas gauge read the proper amount of fuel and the car started right up. Cleaned my air intake and checked for air leaks out of curiosity and no vacuum leaks. Car had a slightly rough idle and was going between 650 - 700rpms. Also checked my MAF sensor and I don't think it was that. One thing I noticed is that with my MAF unplugged my CEL didn't come on while the car was running. I thought it was supposed to? But after a little bit of messing around with the car that involved starting it the car had a bit of a rough time starting. It would start and then die sometimes, but other times it would start right up. Had fuel pressure at the rail. I'm thinking it's gotta be an electrical issue, especially after the gas gauge reading empty randomly and not letting the car stay running issue.

[codyturner]

Also, rvkons, the wires I could jiggle were to the right of the coil pack.

[rkvons]

I'm pretty sure that wire on the coil pack (ICM) does not go to the crank position sensor you replaced. It actually goes to the back of the engine to a cam position sensor. That pair of wires is on the driver's side of the ICM towards the firewall. You can actually pull the connector for it out of the ICM while the engine is running and the car will die. That wire runs down the back of the engine and can get damaged if it touches the exhaust manifold. You should check it out. I had a mysterious stalling issue on a 1998 Malibu and it ended up being a loose fitting connector into the ICM like I'm talking about. If that wire is not intact, the car will not start. I'm not sure about your type of engine. The 1998 I'm talking about had a 3.1 in it.

[Tech II]

The cam sensor is on top of the engine......the second crank sensor goes down to the back of the engine, from the ICM....

[ChevMali99]

I think I'm facing the same problem with my 1999 Malibu 3.1. I began to notice some rough idling. I wasn't too concerned because the rough idling comes and goes for a while and occasional hesitation while accelerating. Didn't think much of it and blamed bad 89 octane gas. Today while sitting on a red light the car simply would not accelerate... it shut down... it died. I would try to crank it and it would sort of start but die soon after. Intuitively I ruled out the the started and alternator because of that so I moved over to the fuel pump. I hear no buzzing noise from the fuel pump. This all happened 30 minutes after filling up in NJ.

I'm concerned that even if the fuel pump is replaced the hesitation problem will remain as well as the shut downs. Has anyone figured out decisively what the problem is? I hope to find out before taking it to Pep Boys. Any advise?

[Tech II]

First, why are you paying more for 89 octane? It runs on 87....

Some times it is hard to hear the pump......remove the gas cap....have someone turn the key on.....pump should run for just two seconds.....cycle the key 3X's with 10 seconds between off and on.....this should max your fuel pressure......now go over to the fuel rail on top of the engine(located at the end of the rail just behind the P/S pump).....remove the black cap....using a rag to catch fuel, depress the schraeder valve.....should get a good flow of fuel with pressure....if it drips or trickles out, no pressure(need around 40psi).....

Can verify a fuel problem, by having someone crank the vehicle while you spray carb cleaner into the intake.....if car starts and runs as long as you spray, it's a fuel delivery problem....either injectors are not firing or no fuel pressure.....

If fuel comes out, but not sure of pressure, need a gage.....if too low, need to verify power to pump....if ok, then need pump.....

If you have good fuel pressure then you need to check if the injectors are firing.....

Have you scanned for codes yet? Do you have spark?

[ChevMali99]

Tech II - thanks for the reply.

I checked the codes and other than the standard issue 00410 & 01404 (I say standard because I've had them since I bought the car 6 years ago), there were none. At any rate I changed the fuel pump for a little less than $700. So far problem solved - wish me luck.

With regards to the octane issue, I know is not a popular thing to admit but I gotta say while 87 octane works just fine on most cars including mine, I like how higher octane improves the way my cars run. The improved performance is noticeable and on the malibu 91 octane + other additives makes the check engine light disappear.