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Another Fuel pump related issue???


hschwartz3
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My 87 starion learned a new trick. Twice in the past three weeks it wouldn't start. Both times the fuel pump wouldn't come on. Both days were very humid. The car would run until it bled off the remaining fuel pressure in the line then sputter and die. I have a fuel pressure gauge mounted to my hood to monitor fuel pressure and both times there was none. I also have a MSD-2222 adj. fuel pressure regulator installed. Both times I left the car at work (@ 4:30p) and came back (@10:30p) and the car fired up and ran great all the way home. The diagnostic light stayed on solid all the way home and the fuel pressure stayed constant at 39lbs idling and 52lbs boosting at 10 lbs. My a/f meter stayed stoich/rich under boost and hunted when not. Both times I used a jumper wire and applied 12v to the fuel pump test terminal and the fuel pump did not come on. I haven't checked for power back at the tank yet. I have a multimeter with me for the next time it happens.

 

I was looking for some more info on the test terminal. Does the test terminal pass thru the fuel pump/eci relay. I'm trying to determine if I have a bad relay, igniter box, fuel pump, or broken wire.

 

Thanks for any help.

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From Mike C :

 

StarQuest fuel pumps will NOT run if you just turn the key to the ON position. They run when the key is in START, and the ECU keeps the pump on as long as the engine is running. To test your fuel pump you can do the following:

 

1: by the air filter assembly you'll see a beefy wiring harness; hanging from it (or taped to it) are two small test connectors - connectors not plugged into anything; just capped off. One will have a single wire - that's the power feed to the fuel pump. Find it.

 

2: Hook a voltmeter to that single wire test connector and to ground. Turn the ignition key to START. Do you get +12volts on that wire? If so, the ECI relay is basically working - that's the relay that sends power to the pump. If the pump isn't running at this point (pop the cover plate off the floor of the trunk, driver's side, then you can see/touch the pump) it's bad.

 

3: For testing the pump, you can also run a beefy jumper wire from the battery "+" post to that test connector - now the pump should be running even with the keys in your pocket.

 

StarQuest fuel and ignition systems are really electronic carburetors and stand-alone electronic ignitions - not like more recent cars where everything is all ECU controlled. The ignition system is independent of the ECU on StarQuests... so you can check for spark while trying to start. If you don't have spark, you've got to find out why: pick-up coil inside distributor, ignitor (aka knock box, it's the electronic ignition module), bad coil, or lousy electrical connections on the ECI fusible link. The ECU won't command fuel, nor will it keep the ECI relay and fuel pump ON, until it sees pulses from the ignition system.

 

mike c.

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I never thought to put a voltmeter on that line. I have one with me for next time it happens. I'm still driving the car and waiting for the problem to re-occur. Do fuel pumps usually act this way when they fail?
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10-4, I'll let you know what I find. I'm sure it'll happen again sometime this week. thanks
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Yes, I do still have the plastic box. I'm still trying to rule that out as well. When the problem occurs the car will start and run until it bleeds off the remaining fuel pressure in the line. Could that still be the ignitor box?

 

I hope thats not it, just did a price look-up on the 88&up ignitor p/n MD125748 from mitsubishi is over $700, and aftermarket p/n LX658 can be found between $275 -$550.

Edited by hschwartz3
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no no you just get a used one and the pigtail and slice that into your harness or remove both plugs and hard wire it in, the wiring colors are even the same I think you add in one power or ground or something but its easy, its in the FAQ how to do that
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MAN, wish you guts talked about this 2 days ago :kowtow: I've been tryin to get my 87 that we just bought runnin. Would fire on ether but wouldn't run. Cleaned both screens, changed filter, wouldn't run. Checked fuel pump with key on, not runnin, checked wire, no power???? pulled line off throttle body, cranked motor, had fuel pumpin????? Gas was old, drained tank put in fresh and car would idle, but wouldn't rev???? Checked injectors, one clip had wires pulled out. stuffed them back in and it runs till wires fall out. Guess I'll replace both clips. I was REALLY puzzled with fuel pump not running with key on. Where's the best place to get the new injector clips?
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  • 1 month later...

Just wanted to write back and add the resolution to my problem in case someone performed a search and needed answers. It took two more weeks for the problem to reoccur, but I was armed with the approiate tools when it did. I was able to confirm the fuel pump was failing by using a multimeter and probing the fuel pump connector under the access panel in the trunk. It had voltage at the connector, but the pump was not running. I was also able to figure out that using two screwdrivers you can bump start the pump, use the tip of one and the handle of the other and tap lightly. You will here it spin up again. That is not the resolution. The problem does and will get progressively worse. I ordered the parts needed, but was holding off replacing them. The issue surfaced as a non-restart, but progressed into dies while driving...(not good).

 

As for the replacement, it went suprisingly easy. I upgraded to the walbro pump and used the following link as a resource.link The tank came out the easiest of any car I've ever owned. I was expecting a nightmare, but it was tollerable.

 

 

Thanks for your help.

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