im no good at diagnostics. please assist me.
01-13-2010, 07:41 AM
#1
Junior Member
Thread Starter
im no good at diagnostics. please assist me.
well, ive got more work right now than i can shake a stick at, between rebuilding my 3.4, rewiring an rx7 track car, having two rooms of the house under rennovation, etc.
the truck has to stay running with the current 2.8 tbi setup in it until everything is finished and i can devote time to my 3.4 MPFI swap.
it is a 87 s10 with a 5 speed and an 8062 PCM
the last couple of days, it has been acting up a lot.
under light throttle, especially in higher gears, it is bogging, popping through the intake, and unresponsive to gentle throttle application. it really gets bad when im trying to g easy on it.
under heavy throttle, it seems to clear up higher up in the RPM range and run strong.
plugs look good, noo odd noises, still getting halfway decent fuel milage.
no check engine lights.
im stumped. it feels like its just not getting any fuel under part throttle.
im currently trying to get my winaldl setup up and running, but that is proving troublesome and aggrevating. so until that point, what diagnostics should i do?
it really doesnt feel like ignition timing being off, but ill check after work anyway. also doesnt feel like a vacuum leak, but again ill check.
shouldnt be the EGR valve, as there is no vacuum running to it.
any ideas?
and how to test the sensors for those ideas?
Michael
the truck has to stay running with the current 2.8 tbi setup in it until everything is finished and i can devote time to my 3.4 MPFI swap.
it is a 87 s10 with a 5 speed and an 8062 PCM
the last couple of days, it has been acting up a lot.
under light throttle, especially in higher gears, it is bogging, popping through the intake, and unresponsive to gentle throttle application. it really gets bad when im trying to g easy on it.
under heavy throttle, it seems to clear up higher up in the RPM range and run strong.
plugs look good, noo odd noises, still getting halfway decent fuel milage.
no check engine lights.
im stumped. it feels like its just not getting any fuel under part throttle.
im currently trying to get my winaldl setup up and running, but that is proving troublesome and aggrevating. so until that point, what diagnostics should i do?
it really doesnt feel like ignition timing being off, but ill check after work anyway. also doesnt feel like a vacuum leak, but again ill check.
shouldnt be the EGR valve, as there is no vacuum running to it.
any ideas?
and how to test the sensors for those ideas?
Michael
01-13-2010, 01:11 PM
#2
Re: im no good at diagnostics. please assist me.
Good contacts inside the distributor? Bad sp.plug wires?
Fuel filter? Good fuel pressure?
You can do the old school plug wire check-- check them in the dark & watch for halos, jumping spark, etc. at idle & about 2000 RPM.
(Outside or a WELL ventilated garage)
Fuel filter? Good fuel pressure?
You can do the old school plug wire check-- check them in the dark & watch for halos, jumping spark, etc. at idle & about 2000 RPM.
(Outside or a WELL ventilated garage)
01-13-2010, 07:58 PM
#3
Junior Member
Thread Starter
Re: im no good at diagnostics. please assist me.
found one bad spark plug. porcelin had cracked, and it was arcing to the head on number 1.
plug wires are not having the halo
timing is spot on. no vaccum leaks.
got winaldl up and running. unfortunatly the battery in my laptop is junk, so until i get an inverter, i cannot run it down the road for a datalog. but i can say that all sensors are operational and responding, and we are going into closed loop. so the more i think about it, im leaning towards either a fuel pump going bad, or a intermittent fault in the fuel pump circuit.
possibly even a FPR going bad. but that seems very, very unlikely.
os there any way that i can check fuel pressure ithout some fancy adapters or anything? what ive got is one for a fuel rail with a schrader valve, and a couple of ones for low PSI systems.
any other thoughts?
michael
plug wires are not having the halo
timing is spot on. no vaccum leaks.
got winaldl up and running. unfortunatly the battery in my laptop is junk, so until i get an inverter, i cannot run it down the road for a datalog. but i can say that all sensors are operational and responding, and we are going into closed loop. so the more i think about it, im leaning towards either a fuel pump going bad, or a intermittent fault in the fuel pump circuit.
possibly even a FPR going bad. but that seems very, very unlikely.
os there any way that i can check fuel pressure ithout some fancy adapters or anything? what ive got is one for a fuel rail with a schrader valve, and a couple of ones for low PSI systems.
any other thoughts?
michael
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