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92 RS Camaro Fuel Pump Problem


WhiteRS209
07-25-2008, 02:05 AM
I have a 92 RS Camaro 3.1 V6 auto. The problem is there is no power at the fuel pump and the fuel pump is brand new. Fuses are new, relays are new, all wiring and connections are all fine. I've heard that theres a oil pressure switch thats inline with the power for the fuel pump. Is that true? Would that might be the problem? Also Before this problem I took it in to get smoged, everything passed but the Fuel EVAP test and the 25mph test. Anyone have any idea on fixing that? The day after that the car didn't want to run right, rough idle and would die if at a stop in drive. Then the day after that the car wouldn't start at all, after a few weeks of messing with it I figured it out, well at least I thought I did. So heres a list of parts I replaced: plugs, wires, cap, rotor, coil, map sensor, 1 fuel injector, all injector o-rings, fuel line o-rings, fuel pump, top intake plenum gaskets, TB gasket, EGR gasket, fuel pressure reg., both battery cables and ends, and a few relays. After all that the car did start but really rough idle, almost like it had a miss. But when I would try to give it gas it would die. So then I started it and let it idle on its own but still rough for like a half hour, I then pushed on the pedal and it died again. It wouldn't start after that, just crank. Thats when I found out about no power at the fuel pump, went thru and checked everything again but everything still good. Please help me out if you can, I've spent a ton of money and time on this damn car and still nothing. Thanks :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead:

Morley
07-25-2008, 03:17 AM
I have a 92 RS Camaro 3.1 V6 auto. The problem is there is no power at the fuel pump and the fuel pump is brand new. Fuses are new, relays are new, all wiring and connections are all fine. I've heard that theres a oil pressure switch thats inline with the power for the fuel pump. Is that true? Would that might be the problem?
Yes, there is an oil pressure switch in the fuel pump circuit...but no, it won't cause your problem. The pressure switch is there as a failsafe incase the relay gives out. What it does is as you are cranking and oil pressure reaches around 7 PSI, it closes and allows voltage to go to the pump, effectivly bypassing the relay.
Now with the questions..do you have voltage at the pump relay? Next check for voltage at the oil pressure switch. If you DO have power there (check power to a good ground, not the ground wire) then you have a bad ECM. The ECM provides the ground for the pump circuit. The ECM turns on and off grounds since doing it with voltage takes heavier duty components.
To verify the ECM is at fault you'd need to find the pump ground wire at the ECM, pull the connector off and probe into the pin and to the other end of the wire and check for continuity, If it is good, bad ECM. If it checks bad, replace the wire or find the break and splice it. A bad ECM could also explain your rough idle and stalling when you give it gas.

The emissions things...What part of the evap failed? There is a relay on top of the cannister that may be malfunctioning...There is also a filter under the bottom side of it (a couple bucks at the parts store).
By 25 MPH test I assume they ran the IM 240 test? Did it fail on acceleration or deceleration? For that one you may be looking at an A.I.R. pump (AKA smog pump)
You had one bad injector and repalced it? At this car's age if one goes bad, the others probably aren't far behind. Ohm them out, they should be between 15-17 ohms and there should not be more than .5 ohms difference between any of them.
That ought to give you something to do this weekend.

WhiteRS209
07-25-2008, 10:40 AM
Thanks Morley for all the advice. I will definitely check all that today and will reply back in a few hours with all your answers. Thanks again.

WhiteRS209
07-25-2008, 01:50 PM
Ok so I checked everything you said and theres power at relay, oil pressure switch and ECM also grounds are good. I decided to jump the fuel pump relay and now there is power at the fuel pump but pump not turning on. Pulled the pump and plugged in another new one and it worked when i turned on key, I then put the relay back on and it still worked. So the pump was a faulty one. Replaced pump. Ok so now that I have fuel at the fuel rail, I try to start it and it started but ran really rough and I gas it, it revved up, then i let off and it died. Now it won't start back up and gas is coming out of the #2 exhaust port. What do you think it is now. I'm so confused, it's like I'm chasing something that never ends. Damn this car. :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead: :banghead:

Morley
07-25-2008, 03:33 PM
Now it won't start back up and gas is coming out of the #2 exhaust port. What do you think it is now.
Simple. The #2 injector is stuck wide open. Like I said; if one injector has already gone bad, the others aren't far behind. Unless the injectors are new, if one goes bad it is a good idea to just replace the whole set.

WhiteRS209
07-25-2008, 04:22 PM
I checked the injectors again and they are all good, cleaned all connections and put it back together. Still won't start but no gas coming out anymore that I can see. I checked the oil and it seems to be like a qt too high and smells like fuel. I'm thinking that thats from before I changed the injector cause I never checked the oil then. I notice sometimes when I try to start it, the security light stays on and it won't even turn over. I checked the timing by putting it on TDC and use a welding rod down the spark plug hole to make sure the #1 piston is all the way up and that was good, so timing is not an issue. But when I did get it started it would only run for like 10 seconds and it was popping out of the intake pipe to the air filter. Do you think that maybe I should change the IAC valve or any other sensors? I'm going crazy with this car. I think it's beer thirty. LOL

Morley
07-25-2008, 11:48 PM
I checked the injectors again and they are all good, cleaned all connections and put it back together. Still won't start but no gas coming out anymore that I can see. I checked the oil and it seems to be like a qt too high and smells like fuel. I'm thinking that thats from before I changed the injector cause I never checked the oil then. I notice sometimes when I try to start it, the security light stays on and it won't even turn over. I checked the timing by putting it on TDC and use a welding rod down the spark plug hole to make sure the #1 piston is all the way up and that was good, so timing is not an issue. But when I did get it started it would only run for like 10 seconds and it was popping out of the intake pipe to the air filter. Do you think that maybe I should change the IAC valve or any other sensors? I'm going crazy with this car. I think it's beer thirty. LOL
Ohming the injectors won't tell you if it is stuck open or closed, just if the windings are good.
Your oil smells like gas ahd is a qt high is probably because a lot of the gas that you didn't see pouring out of #2 actually ran down past the rings (it can do that easily) and diluted your oil. Change that oil and filter now. Pull the #2 spark plug and crank the engine over and watch for lots of gas coming out. If there is lots, change ALL of the injectors. I know its expensive but you'll thank yourself later.
Once all of that is done, pull ALL of the spark plugs and let all cylinders dry out. Pour a couple tablespoons of oil in each cylinder and crank the engine over by hand several times. Gas in the cylinders like you described is a very bad thing. It washes down the cylinder walls and can let the rings scrape them or even possibly break a ring.
The security light and no crank is not a big thing. It means that the "box" is having a hard time reading the resistor chip in your ignition key. Clean it off with some alcohol or use another key.
Poping out of the intake could be another sign that you have one or more injectors stuck open. Be careful with that, if you hydro lock a cylinder with gas you could do serious damage to the engine.
I wouldn't change any sensors just yet, you needto get the thing to start and run for a while first, even running badly would be ok at this point.
What you really need to do is run an injector balance check or even simpler do a fuel pressure check.
Hook a pressure gauge to the fuel rail at the test point. Have someone turn the key on while you watch the gauge. I assume this is a 6 cyl MPFI engine (as in it has 6 injectors)? The pressure should read "around" 36 PSI and HOLD. If it immediately starts to drop, you have a problem. To isolate it do this.. Key off for 10 seconds or more. Pinch off the fuel return hose. Key on and watch the pressure, should be above 45. If it still won't hold, either the regulator is bad or you have leaking injectors. To check the regulator pull the vacuum hose off of it and see if any gas comes out. If it does, you need a new regulator. The next thing to do would be to pull the injectors up out of the intake with them STILL hooked to the fuel rail. turn the key on and look at their tips...Any injector that forms a drop of fuel on it is considered to be leaking. An injector balance check requires a specialized tester that Sun used to make but they have since discontinued it (I got one from them on clearance :) )

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