No Fuel - 88 MPI W/New Pump

Ok, back to my non-starting 88....


At work, over a month ago, I "forced fed" 12v to the plug by jumping between the battery and ballast resistor. I followed teh 12v back teh plug plug and it was there. With no fule pumping, I assumed bad pump. Got to autozone, ordered a new one and let the piles of stuff sit.

Fast forward to yesterday. Pulled new pump and replaced it. Reinstalled it, and turned the key; crap no fuel. Hmmm. Ok, jump 12v so the plug again has power, but no pumping action going on.

Is the ground switched?

Where do I go from here?

Thanks!

V/R
Phil

The ground is not switched, but that doesn't mean you have a good ground. Have you checked for 12 volts at the pump, or are you assuming that the wire between the ballast resistor and the pump is good? Try jumping directly to the pump from the battery. If that doesn't work, jump the ground.

do you have the 4.0 or the 4 cylinder? i have a c.d. i bought from jeep directly that has a search for anything that can go wrong with jeep's just got it today. its for dealer certified mechanics only, although i am not. i have a friend who is. they made it that way because it has all the lil tricks jeep pulled to get the vehicles back in the shop. such as cps's that are blown anywere between 150,00 and 160,000 miles. o2 sensors are set do go out at 66,000 - 75,000 and at 120,000 through 122,000. and so on. but anyways let me know the engine displacement, auto or stick, and last 5 of the vin. i will check it out for you and i can e-mail you what comes up. i ran the search with an auto. 4cyl. and some of the probable causes were. faulty ballist. faulty fuel pump relay. faulty starter relay, o2 sensor wire disconected or grounded. also, did you have the key turned on when you ran the 12v to the pump? if not try that. it has a list of diagnostics here . once you get me the specifics i can send them to you. and we can solve this problem for you

Eagle said:

The ground is not switched, but that doesn't mean you have a good ground. Have you checked for 12 volts at the pump, or are you assuming that the wire between the ballast resistor and the pump is good? Try jumping directly to the pump from the battery. If that doesn't work, jump the ground.

Click to expand...

There are a number of connectors (and the wire color changes at least once and back again), between the front and the back.

90xjpos said:

do you have the 4.0 or the 4 cylinder? i have a c.d. i bought from jeep directly that has a search for anything that can go wrong with jeep's just got it today. its for dealer certified mechanics only, although i am not. i have a friend who is. they made it that way because it has all the lil tricks jeep pulled to get the vehicles back in the shop. such as cps's that are blown anywere between 150,00 and 160,000 miles. o2 sensors are set do go out at 66,000 - 75,000 and at 120,000 through 122,000. and so on. but anyways let me know the engine displacement, auto or stick, and last 5 of the vin. i will check it out for you and i can e-mail you what comes up. i ran the search with an auto. 4cyl. and some of the probable causes were. faulty ballist. faulty fuel pump relay. faulty starter relay, o2 sensor wire disconected or grounded. also, did you have the key turned on when you ran the 12v to the pump? if not try that. it has a list of diagnostics here . once you get me the specifics i can send them to you. and we can solve this problem for you

Click to expand...

Posting for Desert Jeepin, no current access

It is a 4.0 liter auto
Vin last 5 = 18543
New pump installed last night.
12 volts measured @ pump
No fuel @ fuel rail
Tried bypassing ballast resistor, no joy
Tried different relays, no joy
New CPS
Vehicle turns over, just won't start
If I remember correctly, it has spark

You can either post here, email Desert Jeepin or me...
Thanks

ttt again

If you have power to the pump and the pump is not working its still the POS autozone pump. only buy dealer unit the rest are junk!

So is the pump pumping?

Did youreplace the fuel filter?

try burping the fuel lines, remove the return line from the fuel rail and turn on the key till fuel comes out.

Do you have any crushed fuel lines under the XJ? trace em and find out

i just recently replaced my fuel pump, and once i got it in it would run but would not pump. pulled it out, and i had the wires reversed. you might want to check that out, if you haven't.

I'm fairly certain it's not wired backwards.

I have a running Jeep, then intermittently I didn't (usually when it was warm, it wouldn't restart) then it wouldn't start at all. Played with everything, decided to make sure it had fuel at the rail, it didn't. Traced wires, made sure there was 12v at the FP Plug, there is. New filter, new pump, same results.

I took the vacuum hoses apart and had no change.

I noticed, that when I removed the return line from the pump housing as I began the repair, it sucked a LOT of air. But there was no pressure on the feed line to the engine, just a little stagnant fuel that ran down my arm as I pointed the hose toward the pan below.

One more time... ttt

It´s possible to get a volt reading at the pump plug, but not enough amps to turn the pump over, like Eagle suggested, I´d hot wire the pump straight to a power source and make a test. An indicator of poor connectors in the harness, is a voltage drop or line loss. Test the voltage at the end of the resistor (the low voltage end) then again at the pump connector. The difference is the line loss, some is lost due to the length of the wire (normal), some is cruddy connectors or frayed wire (inside the insulation from vibration).
My dome light was getting dimmer and dimmer, cleaned a connector and it´s bright again. Window motor wasn´t working, was getting voltage, but the wire was frayed under the insulation, only a few threads of wire were making contact, not enough amps to make it work.
Some possibilities.
Might be the bumb question of the week, but are you sure you have enough fuel in the tank to cover the pump pickup? I wouldn´t beleive the fuel gauge. Remember going nuts one day on my YJ, trying to figure out why my pump wasn´t working and finally figured out it was fuel gauge wiring (a connector) was dirty (full of mud and water) and the fuel gauge was lying to me, the tank was near empty.

Problem Solved.

Bad Ground Connector on Pump Bracket in tank.

~10ohms across terminals.

~120kOhms. Across Plug. Something must be wrong.

Checked each wire. 0.4ohms on one, and the other was 120k.

Solved that 5 week mystery.