weaselman

need help diagnosing a problem.

drove abt 20 min to see my girly. everything was going fine. parked the truck.
then i decided to check to see if i had any codes. so i checked and i did. 4 blinks and 7 blinks. so i removed efi fuse to see if they came back or not. then i let the truck sit for abt 15min.

then i came back to start it. and it just cranks and cranks and sputters. so i start looking for vacuum leaks and what not. checking spark. etc...

i cracked the fuel line at the intake. nothing, until i turn key to start position (truck wont actually crank tho becuz i didnt push the clutch in or push the saftey cancel button.) then fuel everywhere! lol.

so then i tighten the line and try to run it. not it runs and idles like total crap for abt 5-7 seconds the dies out.

fuel pump? not holding pressure?
clogged filter??

when does the fuel pump come on in my truck?
i thought it should be constantly on while the key is in the on position..

where is the fuel pump jumper connector?
what side of truck...

Western Canuk

My '88 EFI doesn't pump gas until you crank the engine. Then it pumps it out at 40 psi so I discovered. There's a jumper in your computer diagnostic behind the fuse block, behind the battery. I don't know what it is off hand though, sorry.

When my fuel line started to leak badly it was hard to start a couple times then it wouldn't start period (and everything reeked like gasoline).

weaselman

so this is the fuel pump tester jumper correct?? green circle correct?

what is the pink red and blue for??

the yellow is my check engine light diagnostic port.. what do the rest doo?

what should happen when i touch these two together? becuz nothing happens when i touch them together.

i know that when i turn the key to the start position the engine is getting fuel. (verified this by cracking the line at intake and turning the key.).



after letting it sit overnight i can get it to idle fine for abt 4-7 seconds. and if i try again and step on the gas. it runs for abt 2-3 seconds and sputters. so i know the injectors are working correctly at idle. could it be a clogged filter? or bad pump?

what tells the fuel pump to stay on and give engine more fuel??

weaselman

anybody?

if i hold the flapper door open on the afm i can get the truck to idle (for as long as i want) and rev up to around 3 grand if i barely step on the throttle. if i hold the throttle down on the truck, it dies.

milehigheric

The jumper terminals are in a little box under the hood. You need to jump B+ with Fp...when you do the fuel pump should run. If It doesnt you either have a bad COR, bad fuel pump or bad wiring. If it does, your VAFM is your next check.

pntbol11

iTrader: (1)

no guys, yall have a different code system. He does not have a diagnostic port. He has a bunch of plugs for different tests on the drivers side behind the air box. The green circle is your fuel pump test connector. Here's a link for you...

http://www.4crawler.com/4x4/CheapTri.../FuelPump2.jpg

myyota

If you havn`t replaced the fuel filter in a long time, then i would start there first. How many miles on the fuel pump ?, its possible that it might be going bad, but also test the AFM and the TPS, they can also be related to fuel problems.

weaselman

it was a bad circuit opening relay. it was full with water and rusted into position. open (key off) position.

put in a new one.. 111 effing dollars and it now works

abecedarian

hmm... doesn't explain why you had fuel pressure just from turning the key, 'cause STA to the COR needs the clutch or clutch start cancel to work too... unless I'm totally mistaken
even then, doesn't make sense. all the COR does is turn the fuel pump on in response to cranking the engine and movement of the VAFM flap, and the fuel pump was obviously on, per your descriptions.

weaselman

it doesnt make sense to me either. but i took it apart and found this...





i manually operated the relay and the truck ran great. replaced the relay and now it works great.