88 Intermittent Low Fuel Pressure
MyGalRosie
02-17-2011, 09:56 PM
My 88 is giving me crap. It's been doing this for 4 months now. But it's definitely getting worse.
It will be running fine, then no power at all. It jerks, on and off, dramatically, fast and random. Sometimes it stays on for weeks, and then will loses power leaving me struggling to do 15 mph. i pull off and restart, it doesn't roar to life, but I can usually coax it back on the road in a few minutes. Weirdest thing.
Been diagnosing it for a long time, too. Been getting a P171 code which is a lean bank 1. Ok. Also a misfire code, from time to time, but the lean code is steady throughout the ordeal.
Based on the lean code, I checked the fuel pressure. It's at 18 Psi, I far cry from the healthy 48-55 psi. Again, it's only at 18 psi "sometimes" and back at normal when it runs ok.
One by one I replaced the fuel filter, the fuel pressure regulator and finally the fuel pump. No luck.
I've noticed that when I take the battery cable off, it sometimes gets better for a few days then gradually gets worse starting with a single stroke misfire then gradually getting worse to what I described earlier.
Is it possible that a misfire could cause low fuel pressure? I'd be happy to go change the sparkplugs wires and all if it could be the problem, but I don't see how that could be related to the fuel pressure issue, see what I mean?
Any help would be appreciated. It's driving me nuts. :banghead:
It will be running fine, then no power at all. It jerks, on and off, dramatically, fast and random. Sometimes it stays on for weeks, and then will loses power leaving me struggling to do 15 mph. i pull off and restart, it doesn't roar to life, but I can usually coax it back on the road in a few minutes. Weirdest thing.
Been diagnosing it for a long time, too. Been getting a P171 code which is a lean bank 1. Ok. Also a misfire code, from time to time, but the lean code is steady throughout the ordeal.
Based on the lean code, I checked the fuel pressure. It's at 18 Psi, I far cry from the healthy 48-55 psi. Again, it's only at 18 psi "sometimes" and back at normal when it runs ok.
One by one I replaced the fuel filter, the fuel pressure regulator and finally the fuel pump. No luck.
I've noticed that when I take the battery cable off, it sometimes gets better for a few days then gradually gets worse starting with a single stroke misfire then gradually getting worse to what I described earlier.
Is it possible that a misfire could cause low fuel pressure? I'd be happy to go change the sparkplugs wires and all if it could be the problem, but I don't see how that could be related to the fuel pressure issue, see what I mean?
Any help would be appreciated. It's driving me nuts. :banghead:
maxwedge
02-18-2011, 04:10 PM
Try another gage to verify your readings.
inafogg
02-18-2011, 05:12 PM
what year is the 88??3800 engine??
Jrs3800
02-19-2011, 11:09 AM
If this is a 92-99...There could be one of a few things happening here...
#1 thing to check is for ground... On the right front of the car under the carpet you'll see the wiring harness wrapped in electrical tape, in this harness will be the Ground Bus( grounding strip more or less ) we have time and time again seen these corroded,, You will want to check it just to be sure...
#2 your Fuel Pump Relay may be having issues, can't say that for certain, but its worth a check...
#3 if you haven't done this clean the positive cable...
When you replaced the pump did the wires going to the pump inside the tank look good?
#1 thing to check is for ground... On the right front of the car under the carpet you'll see the wiring harness wrapped in electrical tape, in this harness will be the Ground Bus( grounding strip more or less ) we have time and time again seen these corroded,, You will want to check it just to be sure...
#2 your Fuel Pump Relay may be having issues, can't say that for certain, but its worth a check...
#3 if you haven't done this clean the positive cable...
When you replaced the pump did the wires going to the pump inside the tank look good?
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