Sparatically runs...

Andrew7dg · 04-22-2008

Getting very fustrated and don't know where to turn. Please help!

Problem is that the car will be running and then all of a sudden will stop running like I turned the key off or something. I have to pull to the side of the road and then I try to start it up and it fires over for 2 seconds and kills on me. If I sit and wait around long enough it wiill start up without the 2 second hesitation. Then I can drive it home without a problem, and it runs JUST FINE like nothing happened. Even took it to WOT to see if I get a hesitation or something. Runs just fine.

I have been fighting this for a while

I thought first that this was a fuel pump issue and so I just got done rewiring my pump with heavy guage wire and putting the pump on a relay
(255 warbro HP) Works really well. Battery was relocated to the back and so it was pretty easy to rewire it (except wiring it down to the pump). I can hear the relay that I installed click on and off and also I can hear the fuel pump itself. I took it out after I did the rewire and was hoping this would fix the problem. Did the same thing and I listened to the fuel pump to see if it was cutting out, it wasn't and sounded strong. Even when the car died on me again. So that didn't fix the problem.

So I am kind of at a loss where to go from here...

Check engine light doesn't come on and I even checked all the codes to see if any fault comes up and doesn't.

So where do I turn to next? Does it sound like it is still in the fuel system? I have an Aeromotive FPR. Could that be going out? The guage reads normal.

What happens when O ring start going out? I should have checked those when the pump was out but too late.. Plus I think they are new because of the new 255.

Spark problem with coil packs?

ECU problems? I have some cap sitting around that I could install but I don't think my ECU is giving me problems.

Fuel rail, injectors? Something injector related?

MAF-T? but wouldn't I get a check engine light? Putting on stock MAS soon to see if that fixes the problem.

I am at a loss right now so any help is appreciated.

DSM making normal people in to insane mechanics since 1989

**Shane@DBPerformance** · 04-22-2008

Could be a lot of things, like you listed. But I have had 2 bad ECUs do the same thing.

**scheides** · 04-23-2008

You said you have your battery relocated to the trunk. How do you have it grounded? When this studdering occurs, does the car go electrically dead? I had this same problem with my 1G, and the ground going to the battery was on tight, but corroded. The car would randomly go electrically dead until I wiggled it back and forth and then re-tightened it. Check your wiring!

Andrew7dg · 04-23-2008

Quote:

Originally Posted by scheides

You said you have your battery relocated to the trunk. How do you have it grounded? When this studdering occurs, does the car go electrically dead? I had this same problem with my 1G, and the ground going to the battery was on tight, but corroded. The car would randomly go electrically dead until I wiggled it back and forth and then re-tightened it. Check your wiring!

The radio still plays and dome lights work. I also thought for a while it was because relocated the battery to the back but I have to come to the conclusion that isn't causing the problem.

I have the negative terminal grounded to two strong locations, one to the frame underneith and one to the spare tire screw. I took a drill and removed all of the paint at both locations so that it was down to bare metal. Also I made a grounding kit for my engine so to be sure that it was grounded when I did the relocation. I don't have to worry about the corrosion on the terminals because it is a sealed battery. All the connections are clean (I love this battery!) Positive is being run through a 0 or a 1 guage wire to the engine bay (inbetween there is a 150A fuse) and I though that was acting up on me and so I connected it straight onto the battery... no luck... then while the engine was running and I was checking the fuse I found out the car doesn't need the positive cable to run... kind of weird...

Just to help out maybe, the car isn't really studdering. It just goes dead like someone shut the key off but everything electical still works. Then when I am stopped I turn the key to start it, fires right over without hesitation (and starter turns over at normal speed) and runs for a second or two before shutting off. I have tried to rev the engine during this time to keep it running but that does nothing. I wait for bit (couple of minutes) and turn the key, car starts and it stays running like nothing happened. Then I drive it home and park it in my drive way.

Thanks for the suggestion, again I need all the help I can get. Anyone near AV?

I hate to think it is the ECU but it is looking more and more like it, however I didn't think that ECUs go bad like this.

I am going to be putting in my standalone soon and see if I can get it running consistantly on that. Or at least to fire up and idle...

Andrew7dg · 04-25-2008

ok I think I figured out what is causing my problems.

I think what is happening is that the fuel cut activates before it should.

I took the car out for a drive and while driving it kind of agressive I hit fuel cut. After it started to have the same symptoms that I described where it would start but only run for like a second. I am assuming this device is causing the problem.

But I was wondering what controls fuel cut? and what does it do to cut fuel (relay?) Also I know there is a fuel cut block out in the MAF-T but how effective is it and could that be causing my problems?

I am going to be installing my standalone pretty soon so hopefully that will take over the system. However if it is a relay that is giving me problems perhaps I could change that.

Getting closer to the solution!!!