kirk158

Hey so I got this 89 2.8 and been fixin and I was told previous owners had fuel pump problems . The local auto shop some years back put a hot lead to the aldl ground to get the fuel pump to run, this they did not know.SO can some one tell me why ? NO schematics for this area

I took the hot wire off and replaced a blue wire to what I thought was a ground in the right hand side of the engine compartment back up and I had fuel pump again as normal. Then I lost it?

Fuel pressure guage results turnning over motor no pressure for 15 sec. then get pressure(40psi.) motor starts. pressure drops instantly after stopping. no fuel out the regulator and pump does work via (G terminal). I have replaced oil switch ,pump relay, have done wire open test and that was good also.

Code 54 , rough idle, runs good, fuel pressure loss after turnning off

PneumaticTire

check to make sure you have power coming back out of the fule pump relay. It was a Tan/White wire on my 305tpi dont know about yours. Could be the same, could not be. Get a book and see. If you dont have power coming out of the relay when you back probe this wire, then your problem is still the relay. I just had this problem. I bought a new relay, and it still didnt fix my problem. Out of a last ditch effort, I got another relay, and the pump works fine now, and it's 3 days later. It is possible to get faulty new parts. GOOD LUCK!

kirk158

back tested the tan/ white wire, fuel pump signal ...it jumps to about thirteen volts after ignition on seems to be fine. or can I test the fuel pump signal after the relay.

I have no initial fuel pump on at ignition start... still relay?

Ok then what about fuel pressure loss from idle of 40 PSI to after turning ignition off 20psi and then nothing after 5 mins. seems its either fuel pump check valve (is their one ) FPR or leaking injectors . I tried to test injectors with the fuel rail out of the heads could not get pressure to injectors yet G- terminal to 12volts had the fuel pump running .

some one help with testing options thanks

thunderstick

so you're saying, too, that you don't get that initial 2-second prime when you turn the key on? that signal supposedly comes from the ecm. oil press switch only runs the pump in the event of an ecm failure, i believe. there's a switch inside the ecm...

kirk158

Thats right , I did not know that the signal came from the ECM.
I thought it came from ign. switch through relay guess I better look closer at the schematics

Maybe that is why the jumper wire from 12volt fuse box over to the aldl ground is in place to compensate for the ECM

anyways I would like to get it all back to nornal and find out the real problem.

any suggestions as to checking fp loss .Wish I had a clear line I could put in lineon the fuel line and see if the fuel runs back to the tank

Maverick H1L

iTrader: (8)

Okay, now that you have done the ALDL trick (bypassing the signals from the oil pressure switch and the ECM) and the pump runs, and also you know the oil pressure switch works (crank for a while and then when the oil pressure comes up, closing the switch and running the pump), there's only one thing you have left to examine: the ECM. If the fuel pump wiring passed the 12V to ALDL "G" terminal and ground test by running, then the ECM, or the wiring to the ECM, is faulty. Try swapping in another ECM (can be found at junkyards for cheap) and see if the pump works.

I originally had this problem with my 2.8 and the reman ECM that came on the car.

As for the engine losing fuel pressure, check to see if any of the injectors are leaking. Since you don't have a cold start injector (or do you? It's connected to the fuel rail by a white fuel line screwed into the rail on the driver's side) we can rule that out. When was the last time the fuel filter was replaced? Your fuel pressure is a little on the low side. It should be close to 44-45 PSI, IIRC.

Red Devil

You mean there is a switched 12V hot going to the 'G' terminal in the ALDL right? Probably had a bad f/p relay and this is someone's mickey mouse job of fixing it. Once fixed they were more than likely thinking of minnie too much to go back and fix it properly.

kirk158

yea there is a hot wire from fuse box battery spot to the ground on the aldl not just to G terminal .But to the aldl ground at the diagnotic link. Terminal A

And yes, this 2.8 has a cold start valve on the fuel rail and I did try to pressurize system using G-terminal with injectors out of the cylinders but no pressure build up. I could hear the pump running
The fpr reg. is not servicable acording to haynes manual no fluid leaking out but can taste it when I draw on the vaccum connection located at the throttle body.

things that have been done :
tps: that cleared code 22
fuel pump relay
maf relay: that cleared code 34
fuel filter
injector O- rings
gas cap
air filters
oil & filter
And a multitude of non engine work on body an other mechanical parts Thanks everyone
topped all fluids
rear cylinders and brake pads
plugs, wires,cap, rotor
battery
oil sending unit
ecm ordered.....fuel return line clamped off ,standing with 42 psi just checked and the pressure is down again, its not leaking back to the f/p

whats left: injectors,f/p reg. cold start valve ? I do not smell gas in the manifold area

Maverick H1L

iTrader: (8)

The cold start valve can be a problem. Mine sticks open, which is why I don't use it anymore, but I have to keep it in the back of the manifold since it plugs up a pretty big hole thats back there.

What you can do to check for leaking injectors is remove the rail and cold start injectors from the manifold and hold them over a drain pan or something along those lines, and pressurize the system. If any of the injectors lets out more than a couple of drips over a five min period (not sure on this, but they should still hold pressure for five min) then they are leaking, or sticking open.

IIRC, the only thing the FPR does is regulate the amount of fuel that goes back to the fuel tank through the return line. Someone on here, most likely in the TPI forum, will know how to test for either a bad FPR or fuel pump by clamping off the lines.

kirk158

TIME TO EAT CROW... cuz the 12 v. line was to G terminal aldl up side down you know unscrewed from car thought I was looking at it right . my big butt did it again ,I can be my worst enemy!!
tracked every wire checked everything . the only thing not checking out was ecm so to the junk yard I went came back with two of them and since I didn't get to pull either one and found them laying in the seat got both ( you know my luck ) Any ways one was a reman just like the one I pulled out originally same sticker and all from same rebuild I guess , same stuff no f/p 2sec. start up 54 code. The other was great 2 sec. start up and was fine for about 1 minute then it died.. shootin 34 code ....maf seems and checks fine ....the car will run with gas applied at about 10-12,000rpm .

Time to look at ignition so thinking module , took cap off and noticed rust around rotor area location and the wire insulation around the distributor coil winding was loose and comming off .

IS it time for a distributor, help! My car will be all new parts soon and this is gettin exspensive
added new.. fuel pump ,screen , no pulsater avaliable today

kirk158

Installed new icm but no change using either ecm
no.1 starts after oil switch engages, rough idle, code 54
no.2 f/p 2sec. start will not run unless use throttle at 10-12,000 code 34 map

kirk158

maf not map

Maverick H1L

iTrader: (8)

Check the relay located near the MAF to see if it is any good before you shell out the $250 for a new MAF. There is also a fuse somewhere near that area, mounted on the frame rail. The fuse has black and red wires running to it. If you pull the one with the orange and red wires, you will reset your ECM...