2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Need help...fuel problem

Old Oct 16, 2003 | 10:38 PM
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Need help...fuel problem

My car has a lot of trouble getting started and when it does get started it usually wont idle. And when I rev it the rpm's go up very slowly. I have checked everything else and the only thing I can find is the gas. There is ALOT of gas coming back out of the fuel pressure regulator (which goes out the return line, right?) We noticed that when we crimped the hose that the fuel is coming back out of the car idled well. I can drive the car but its INCREDIBLY slow and runs like crap. Oh yea, BTW just got all my injectors checked and serviced today, they are all good. Someone please help me get my 7 running!
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Old Oct 16, 2003 | 11:31 PM
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And btw...im not sure, but I dont think all of my injectors are working, my front secondary was dry. But the injector itself is good. not sure though.
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Old Oct 17, 2003 | 12:13 AM
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I would re-inspect my work if I was in your shoes. Quite possible you missed something.

And I hope the secondaries are dry, they only come on after 3800...
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Old Oct 17, 2003 | 01:02 AM
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yea but the car will rev all the way to redline with the clutch in but if i drive it it wont go much above 3000 rpm. And my rear secondary i know was working, but not the front. And like I said, there is ALOT of fuel going back through the return line.

Last edited by Crush; Oct 17, 2003 at 01:14 AM.
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Old Oct 17, 2003 | 02:04 AM
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Originally posted by Crush
yea but the car will rev all the way to redline with the clutch in but if i drive it it wont go much above 3000 rpm. And my rear secondary i know was working, but not the front. And like I said, there is ALOT of fuel going back through the return line.
There should be a lot of fuel going back through the return line. Your pump outputs pretty much the same flow rate all the time, and the rail keeps whatever amount it needs to maintain the rail pressure (39-42 psi at 0 manifold), and then bleeds the rest back to the tank. at idle, the rail pressure drops to around 30-32 psi, so the flow rate increases even more. If the injectors used everythign that the pump was pumping, you car would use a full tank of gas in around 15 minutes (and thats at idle).

So, flow in the return line is normal under ALL operating conditions.

Your problems sounds like no compression in one rotor. Straight fuel out the back, hard to start, won't idle, lack of power... Do a compression test. Take out your two lower spark plugs, remove your EGI fus, put your finger in the spark plug holes, one at a time, and get someone to crank the engine. You should feel three even pulses on eaqch rotor. If any are extremely weak or missing, your motor is popped.

Let us know.
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Old Oct 17, 2003 | 05:04 PM
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Nah, the motor has excellent compression. That was my first guess so I tested it. Im pretty sure it has something to do with the fuel. I believe that my front rotor is not getting any fuel for some reason, I just dont know why.
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Old Oct 17, 2003 | 08:39 PM
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Ok, I narrowed it down a bit. Took off all of the accesories to find that ONLY my REAR injector on the primary rail is injecting fuel. My front one is not, and neither are my secondaries, but those dont inject until 3800 rpms, right? Like I said all injectors checked out, I checked resistance to the resistor pack, all good. Any ideas?
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Old Oct 18, 2003 | 12:01 AM
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Could it be that I dont have enough fuel pressure to make all the injectors spray? I disconnected the fuel hose and cranked it and it didnt seem to have much. I mean the fuel had pressure, it sprayed out like 2 feet, but maybe not as much as needed. Im thinking something to do with my fuel pressure?
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Old Oct 18, 2003 | 12:02 AM
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Because it doesnt hold pressure after I turn it off either. I can disconnect the hose and a little bit sprays out but not much.
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Old Oct 18, 2003 | 10:17 AM
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Swap the primaries into the secondaries and vice versa. Do both primaries now work? Sounds like a toasted injector or harness problem. Can you measure 12V at the non-working injector (with the car on)?
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Old Oct 18, 2003 | 05:42 PM
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Alright Ill give it a shot and see what happens.
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Old Oct 18, 2003 | 06:16 PM
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Nope, still the same thing. Only my rear primary works and it doesnt even do a good job at that. Seems a little weak.
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Old Oct 19, 2003 | 10:10 AM
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Wiring harness or ECU problem. Have you checked for proper voltage at the connector? If you have a scope, you should see a square wave that varies with the RPM and load on the engine.
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