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88 Bronco fuel problems

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  #1  
Old 12-26-2014, 12:23 PM
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88 Bronco fuel problems

So I have an 88 Bronco that has old gas that I suspect is causing it not to run. I started it up after putting the trans in and it idled for maybe 20 seconds and died. It has 40-45psi fuel pressure.
When I crank it it coughs a little then nothing. So I go to drain the old gas out of the tank and was draining pretty well then decided to unplug the high pressure pump so its not pumping air and now I'm hardly getting anything maybe a few ounces.
How much should an in tank pump put out?
If the High pressure pump is working but not the low pressure will it pump to pressure specs but not supply enough to run?
 
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Old 12-26-2014, 11:26 PM
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Siphoned out old gas and put fresh in, after purging the system it fired up idled kinda lopey then slowly died. Cranks really fast like it's about to start and when holding TB open it starts sputters then dies.
Put out a bunch of white smoke but then again its about 30-35 degrees.


Any Suggestions?
 
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Old 12-27-2014, 08:22 AM
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check for fuel pressure before the high pressure pump. it sounds like the in tank low pressure pump died.
 
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Old 12-27-2014, 10:40 AM
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Will check for pressure today before I drop the tank, luckily the pump is still under warranty because it has 0 miles on it just been sitting a year and a half.
 
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Old 12-27-2014, 03:18 PM
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Checked pressure before HP pump, its 7 with key on then bleeds up to about 20 psi after the one second pump time. With engine on pressure is a steady 5psi.


My manual doesn't give a pressure spec for the low pressure pump, is 5psi normal?
 
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Old 12-29-2014, 06:54 PM
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New pump, new gas, clean tank. Still idles rough and usually dies when the throttle is touched. Cant get it to rev past about 1800 rpm. Unhooked exhaust at manifolds thinking maybe the cats were clogged and its backfiring out of the manifolds.


Would the timing being off allow it to start easily but not idle very long? I can go back out in a half hour and it will start on the first try but not want to rev past idle.
 
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Old 12-29-2014, 09:23 PM
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Timing is on at 10 before TDC. Ruled out coil, had spark at plugs while cranking even started on seven cylinders. guess I'll check TFI and if that doesn't fix it, new distributor. Thanks for the reply TJC didn't think those would be that rare
 
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Old 12-30-2014, 07:10 AM
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i am kind of at a loss other than fuel problems, i am mainly a diesel mechanic and don't know a lot about the newer EFI gas engines.
sorry i could not be more helpful to you.
 
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Old 12-30-2014, 11:02 AM
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turned the key on and put the battery charger on because I forgot to turn the key off last night. And the fuel pumps turned on running non-stop and I had some weird buzzing from the distributor with the tach reading 2000rpm. Looks like a new distributor to me. Not sure what to make of the fuel pump relay though
 
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Old 12-30-2014, 11:29 AM
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Originally Posted by PlumCrazy7
turned the key on and put the battery charger on because I forgot to turn the key off last night. And the fuel pumps turned on running non-stop and I had some weird buzzing from the distributor with the tach reading 2000rpm. Looks like a new distributor to me. Not sure what to make of the fuel pump relay though

If the stator (PIP) inside the distributor has failed in some weird manner, aka the tach is showing 2000 RPM, then the computer is interpreting that the engine is running therefore the fuel pump relay is energized 100% of the time.

On the other hand continuously running fuel pump and a no start condition are symptoms of a bad computer (PCM).
 
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Old 12-30-2014, 04:30 PM
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Thanks rla, makes me feel less like I'm throwing money/parts at it. 9 times out of 10 the pumps just cycle the normal 1 second so hopefully not PCM.


Some fortuitous information, ordered the distributor with the steel gear (its about $30 cheaper) and got home to research the difference and found out about the cam differences. The used distributor mount TFI I bought to fit the 88 harness has a cast gear, (pitted, looks casty) the remote TFI dizzy that came with the 92 long block has a steel gear (smooth). So I got lucky because if it started up and I proceeded to put miles on it I would have wrecked the motor after rebuilding the trans!
 
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Old 12-31-2014, 03:11 PM
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Put new distributor on, fired up, idled a lot better. I shut it off then it refused to start, came back in 10 minutes or so and it fired right up. It doesn't rev like it should and I couldn't get it past 3000rpm, would a bad pcm cause this?
 
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Old 12-31-2014, 03:18 PM
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Originally Posted by PlumCrazy7
Put new distributor on, fired up, idled a lot better. I shut it off then it refused to start, came back in 10 minutes or so and it fired right up. It doesn't rev like it should and I couldn't get it past 3000rpm, would a bad pcm cause this?
New distributor as in a "new" distributor or rebuilt? Many "rebuilt" distributors have bad PIP sensors in them...the rebuilder never checks them.
 
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Old 12-31-2014, 03:47 PM
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All new, Richporter tech., even comes with new TFI module
 
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Old 12-31-2014, 03:57 PM
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Back to basics.....spark, fuel, air. Sorry to be the messenger. Even with a warranty the new parts could be bad. Step back then verify the PIP signal is getting to the ICM, then the ICM is triggering, then verify the coil is getting the command to fire, then verify spark is getting to the distributor.
 


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