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Post by nemolovich on Mar 30, 2006 23:31:45 GMT -5
I have a 91 mpfi justy that always starts fine on the first try. It's just when I drive it for a bit and shut it off and restart again is when I have problems. It turns over but doesn't catch. I have to keep starting it and pressing the gas, where it then starts to catch a bit then nothing. It takes a while, but I finally get it to go. Very hard on my starter. I end up smelling a heavy gas smell once I get it going.
I replaced the fuel filter recently, didn't really help. I also used fuel injector cleaner as well, didn't really help. It has no problems driving once it's started, doesn't die out or anything. I am thinking something to do with fuel pump, relays to fuel pump, etc during startup. Anybody have any suggestions? Thanks.
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Post by Esteban on Mar 31, 2006 6:31:05 GMT -5
A coil going bad can act like this. When first started they are fine, but after driving, they overheat. Then when trying to restart, they produce only a small spark.Try a 12v coil from another car & see if that helps. I have replaced these with $15 universal coils from parts shops.
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Post by nemolovich on Apr 3, 2006 21:27:53 GMT -5
Sounds like that could be it. I was thinking of low gas pressure as I know one of my rubber gas lines running from my gas filter is cracked a bit on the end. But I don't think that would affect anything as the crack is right on the end after the clamp to the gas filter anyways. This makes sense because I only have the problem on start up and the ignition coil is used for spark. Thanks alot I will try that out.
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Post by nemolovich on Apr 16, 2006 20:05:45 GMT -5
It's not the ignition coil, I went to the scrapyard and picked up a similar one and installed it and same problem. I am thinking more fuel pump which was my original guess. The reason being is when I try starting and almost get the engine going, pressing the accelerator helps alot. Low fuel pressure. The higher revs, the greater the fuel pressure.
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Post by SUBIEJIM on Apr 16, 2006 23:26:36 GMT -5
nemoiovich, Your 91 MPFI Justy has an in-tank fuel pump that operates anytime the ignition switch is in the on, start, or run position. It is designed to provide a constant fuel pressure to the tip of the fuel injectors. The proper fuel pressure (PSI) is controlled by a fuel pressure regulator located on the fuel rail. All excess fuel is returned to the tank via the return line. The fuel pressure regulator is tied into manifold vacuum which senses engine load (High Vac=Light load) (Low Vac=Heavy load) The Fuel Injector pulse width or "On Time" is controlled by the engine control module, which calculates the injector ON Time based on input from several other sensors. With that said, lets look at the problem. You mention that the car runs well when cold and even when hot. The problem occurs only on hot restarts. Pumping the gas pedal while cranking the engine will give the engine control module fits because it sees a changing throttle position from the throttle position sensor. Try this...Do not pump the gas pedal, just crank the engine over. If it does not start push the gas pedal to the floor and hold it there while cranking. (This is known as clear flood mode) This prevents the injectors from delivering fuel. You mention a heavy gas smell when it finally does get going..This indicates too much fuel being delivered not too little. You may have a coolant temp sensor that is slightly out of range. (Telling the ECM the engine is cold when in fact it is hot..Remember...A cold engine requires a richer air/fuel mixture to run. If the same rich mixture is used in a hot engine it may not start.) Is the check engine light on?? Any codes? I don't think its a bad fuel pump but, It is easy to check fuel pressure if you have access to a fuel pressure gage. Just tee it into the supply line under the hood where it changes from the solid steel line to the flexible rubber line near the firewall. Good luck! Jim
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Post by pricanteo on May 21, 2007 13:50:18 GMT -5
I had the exact same problem and I did all the thing you guys mentiond and it helped. I changed the fuel filter sparkplugs&wires put a new coil on cleaned out my fuel injectors, cleaned off my temp sensor because it was gunked up. The car starts and runs now but i have a rough Idle with poping like the timing is Off. I don't think that the valves have been properly adjusted for a looooooooong time like they supposed to be. But could that be my problem, or should I look into the base timing?
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