Need Immediate Help Please!

[Blackwidow6p]

Ok my car was not starting all the time and when it would start it would just shut off suddenly, even when I was driving. Everyone said it might be my fuel pump, so I checked the pressure and sure enough there was none. Needless to say I put a new fuel pump in. Well the car still does it. There is pressure now so I know I needed a fuel pump but why would the car just shut off while I was driving it and why is it so hard to start? Some people say it could be a bad filter but would that actually make the car shut off? If anyone has any idea of ANYTHING it might be let me know. Thank you and thanks for the space.

 

[92awddsm]

Could be the ecu. Have you pulled it out and checked the caps yet?

 

[Blackwidow6p]

no I havent, to be honest, I dont know what that it is

 

[luv2rallye]

Another possiblilty (if you still think it may be fuel related) along with a clogged fuel filter is a bad fuel pressure regulator. You asked for ANYTHING.

 

[turboholic]

no I havent, to be honest, I dont know what that it is

http://www.tmo.com/howto/ecu1g/caps.htm

 

[Blackwidow6p]

Ok but where is the ecu to check it?

 

[bobcatnn]

Alright, i could be way off on this one, but on most other cars i've worked on, mostly domestics, there is a oil pressure switch hooked into the supply voltage of the fuel pump via the relay. Basicly, if there is oil pressure it activates the relay and the fuel pump works. When you start it, however, the computer will activate the relay to allow the pump to run for a little while before starting to prime the lines--when the car is off there is no pressure and you'd never get the darn thing to start. I would suggest to check both the fuel pump relay and, if these cars have them--correct me if I'm wrong, the oil pressure switch--where it plugs into I don't know, be it the ECU or straight to the relay, i'm not sure. Worth a shot anyway.

 

[92awddsm]

Alright, i could be way off on this one, but on most other cars i've worked on, mostly domestics, there is a oil pressure switch hooked into the supply voltage of the fuel pump via the relay. Basicly, if there is oil pressure it activates the relay and the fuel pump works. When you start it, however, the computer will activate the relay to allow the pump to run for a little while before starting to prime the lines--when the car is off there is no pressure and you'd never get the darn thing to start. I would suggest to check both the fuel pump relay and, if these cars have them--correct me if I'm wrong, the oil pressure switch--where it plugs into I don't know, be it the ECU or straight to the relay, i'm not sure. Worth a shot anyway.

Youve worked on too many GM's. Our cars arent like that. You can pull both wires from the oil pressure sending units and the car runs fine. All we have is a wire for the idiot lite and one for the gauge. Also, the ecu is in the center behind the radio. Pull both carpeted panels off the side of the console and you will se it.

 

[bobcatnn]

So what runs the fuel pump relay then? Every electric fuel pump i've ever worked on has a oil pressure switch or something along that line to drive the relay--no pressure it turns off the pump to prevent too much damage--correct me if i'm wrong, i'm trying to learn about these cars too.

 

[luv2rallye]

So what runs the fuel pump relay then? Every electric fuel pump i've ever worked on has a oil pressure switch or something along that line to drive the relay--no pressure it turns off the pump to prevent too much damage--correct me if i'm wrong, i'm trying to learn about these cars too.

The Engine Control Module runs the fuel pump relay (which I'm sure uses a lot more conditions than just oil pressure to turn it on/off).

 

[92awddsm]

The Engine Control Module runs the fuel pump relay (which I'm sure uses a lot more conditions than just oil pressure to turn it on/off).

Actually, the cam angle sensor energizes the fuel pump relay.

 

[luv2rallye]

Actually, the cam angle sensor energizes the fuel pump relay.

Well my 99 Mitsu schmatics show the fuel pump relay wire goes only to the ECM (pin 8 on connector B-53) - so the ECM is the actual thing that turns it on in the 2g. The ECM probably makes sure many signals are there before turning it on, one of which may be the cam angle sensor. Or are you saying the 1g models are different? I'm only looking at a 2g.

 

[92awddsm]

Actually, on a 1g, the ecu takes the signal from the cas and activates the fuel pump. Im not sure it is the same on a 2 g but I thinks so. Im just saying that oil pressure has nothing to do with the fuel pump. Maybe on a 92 grand am but not a 92 dsm.

 

[bobcatnn]

Yes it may take it from the cas, but happens if you all of a sudden have no oil pressure. Do you want to have to manually turn off the car or wouldn't it be great to have the fuel get cut off for you? And what the hell does a 92 grand am have anything to do with it. I'm simply offering up knowledge I have, I don't wish to be put down, made fun of, or anything like that. I would guarantee you oil pressure DOES have something to do with your fuel pump being on or off. I'm just not sure how. Like I said, I'm new to the whole DSM world.

 

[92awddsm]

I wasnt putting you down or talking s@it but now that you "guarantee" that you know, I will prove you wrong in front of everyone. And you asked for it since you think you "know" Go outside to your dsm. Look on the driver side under the harmonic balancer. You will see 2 wires going to 2 differant sensors on the oil filter housing. Those are the only 2 sensors that monitor oil pressure on a 4g63 turbo, or non/turbo. Pull both wires from the sensors and crank you car up. The only thing that wil change is your oil pressure idiot light will be on and your gauge will read zero, but the car will run. I have serviced, repaired, owned, and scrapped many of cars and a dsm doesnt work like that. Gms do, thats why I mentioned a 92 grand am. If I was putting you down, I would have said an 87 fiero or something worthless like that.

 

[bobcatnn]

Hey now, you were the one to first take a cheap shot, maybe I took it wrong, you know it's hard to portray sarcasm on a post but what you said sounded pretty threatening. Anyways, if a DSM doesn't take oil pressure into account for the fuel pump, then it's the first electric fuel pump I've ever seen that wired that way. And if it is, great, I learned something new. Until I see evidence of that, then I guess I'll go with the knowledge I have from every other vehicle I've worked on and they all take oil pressure into account. It makes sense to me to have some sort of backup like that, that's what electronic devices are for in these new cars.

 

[92awddsm]

Like I said, a 4g63 has only 2 devices that monitor oil pressure. Both are located on the oil filter housing. Beleive what you want or you cant take it from an experienced mechanic that knows. If the fuel pump relied on oil pressure, noone would ever get their jdm engines to crank up. I am not trying to be an ass, but I do know how it works. Im trying to teach you something but you seem to stubborn to listen so beleive what you want.