I think its the CPS again?

[Shorty]

OK i charged my battery and checked the voltage on it 12.81 and I installed it back in the jeep... I attached the guage and nothing Im not getting a reading at all i wouldn't see why my guage could stop working outta the blue so im assuming no pressure pumps no good right? well I told my girl to put the key in the on postion so i could listen for priming of the pump.... and with she did i heard a shhhhhhhh sound coming from the pump for a couple of seconds... is this priming? and does that mean the pump is good?

the sound is the pump attempting to prime the system. It does not tell you that it's getting power when you are cranking (listen again while it's cranking)
and it doesn't tell you that the fuel filters aren't plugged up (remove the inlet for the external filter and see if anything comes out when it primes)

Before you dig too deeply into it, don't forget the obvious-- you DO have gas in the tank, yes?

 

[SINCITY192]

the sound is the pump attempting to prime the system. It does not tell you that it's getting power when you are cranking (listen again while it's cranking)
and it doesn't tell you that the fuel filters aren't plugged up (remove the inlet for the external filter and see if anything comes out when it primes)

Before you dig too deeply into it, don't forget the obvious-- you DO have gas in the tank, yes?

I did check for pressure using my guage and I got nothing while it was cranking even after i charged the battery no pressure.... I cleand the grounds in the engine area and still no pressure i also switch the relays two of them are like new so i made sure the new ones was in the sockets for B+ and also the fuel pump.... I want to figure this out before the parts store closes so i know what i need.....
the inlet for the external filter i assume is where the pump mounts right? its one of the hoses right? I definitely have gas a whole lot of it....

 

[SINCITY192]

19V would be bad.

you're looking for full battery/charging system voltage (roughly 11.5V-12.5V during cranking and 13.0V-14.5V if it starts)

did you check for fuel pressure while it was cranking?

i thought it was that high because i was getting jumped while i checked for that voltage at the connector of the pump.... if its bad what could cause it to be that high or was it just a flacky reading i did have the probes shoved in there!!!

 

[SINCITY192]

ok i disconnected the hose that leads from the pump to the fuel filter... and alot of gas started to come out of the filter and i mean alot as if it was stuck in the filter so i disconnected the filter and blew threw it... fuel flow through the filter so im guessing it isnt clogged also the hose going to the filter DID NOT leak or squirt gas out of it when cranking the engine.... Does this means its the pump? I expected to get a burst of fuel coming outta there......

 

[SINCITY192]

any ideas guys?

 

[Shorty]

ok i disconnected the hose that leads from the pump to the fuel filter... and alot of gas started to come out of the filter and i mean alot as if it was stuck in the filter so i disconnected the filter and blew threw it... fuel flow through the filter so im guessing it isnt clogged also the hose going to the filter DID NOT leak or squirt gas out of it when cranking the engine.... Does this means its the pump? I expected to get a burst of fuel coming outta there......

shoulda had fuel flow when cranking.

you still need to verify the pump is making noise during crank. If it's making noise then, you can reasonably assume the wiring and circuits are operating.

Assuming it's running (the pump, that is), you can look toward reasons for lack of fuel flow. From tank to fuel rail, you may have:

plugged filter in tank
broken pump inlet hose
faulty pump
poorly mounted pump to sending unit
plugged fuel line


If I were gonna buy before the stores close and try to fix it this evening, I'd buy a filter, pump, in tank filter/strainer, a few feet of fuel injection hose, and a handfull of fuel injection clamps. Get it all, and use what you need to get it going. Anything uninstalled/un-used can be returned in the morning.

 

[SINCITY192]

got ya just needed to make sure!! and when the jeep was cranking I can here the pump tryna prime but still no fuel, plus i got volts on the connector when cranking so it must be getting power! the metal lines dont seemed bent or nothing so im assuming if anything is clogged it would be something in the tank this rubber lines arent that old as i change them every time im having a fuel delivery problem!!!

 

[Shorty]

I'd go get the stuff and make a night of it-- good luck.

 

[SINCITY192]

lol i cant man i really got to make it to work tomorrow i got everything u said and part guy agreed that it should be the pump. I Hope it goes well.. thanks ill need the luck.....

 

[CharlesS]

IF after replacing the fuel pump and verifying that you have the proper flow and pressure (approx. 35 psi) at the fuel rail; and the engine still doesn't start.....
I would check the Camshaft Position Sensor (not to be confused with the Crankshaft Position Sensor located on the bellhousing) which is located inside the distributor.
This sensor is used by the ECM to determine which cylinder fuel injector to pulse.

 

[Shorty]

IF after replacing the fuel pump and verifying that you have the proper flow and pressure (approx. 35 psi) (31psi with vacuum line attached- 39psi with no vacuum) at the fuel rail; and the engine still doesn't start.....
I would check the Camshaft Position Sensor (not to be confused with the Crankshaft Position Sensor located on the bellhousing) which is located inside the distributor.
This sensor is used by the ECM to determine which cylinder fuel injector to pulse.

don't you think there would be pressure to the fuel rail if the cam sensor was bad? It starts with ether (got spark), it's got power to the pump in crank and for prime (circuit seems to function), it has no pressure to the rail (based on pressure tester readings), and without a cam sensor signal the Renix ECU will fire the injectors off the crank sensor signal (all-be-it, possibly one revolution off time).

edit-- missed the "if" in your post

 

[91Red4.0]

The renix will run with no cam sensor. He's getting noise from the tank+voltage during crank. No pressure readings. I'd say it's the fuel pump.. If you wind up getting the airtex brand, the o-ring they give you for the fuel pump assembly to tank SUCKS. I've used airtex on more than one car and both instances I opted to use the OEM oring just because it fit perfectly.. The OD on the airtex was a bit too big for the lock-ring to seat. If your original is too mangled they can be had at the dealer cheaply.

Edit: Good luck! First time I replaced the pump in my XJ it was pretty reasonable.. 2 hours. 30 minutes to take it out and the rest me tooling around trying to get it back into the tank properly.

 

[SINCITY192]

don't you think there would be pressure to the fuel rail if the cam sensor was bad? It starts with ether (got spark), it's got power to the pump in crank and for prime (circuit seems to function), it has no pressure to the rail (based on pressure tester readings), and without a cam sensor signal the Renix ECU will fire the injectors off the crank sensor signal (all-be-it, possibly one revolution off time).

edit-- missed the "if" in your post

yeah i think i'll have to replace this pump in the morning i checked my schedule. I dont work till 1 if i get up early i should have more then enough time to change it out.... I failed to mention too that this will be my 3rd fuel pump since i owned this jeep for last 2 yrs.. so im guessing this should be one time i make sure to drop the tank and make sure things are good inside any advice? Never drop the tank before... and i got a tank of gas....

 

[CharlesS]

don't you think there would be pressure to the fuel rail if the cam sensor was bad? It starts with ether (got spark), it's got power to the pump in crank and for prime (circuit seems to function), it has no pressure to the rail (based on pressure tester readings), and without a cam sensor signal the Renix ECU will fire the injectors off the crank sensor signal (all-be-it, possibly one revolution off time).

edit-- missed the "if" in your post

The IF meant once he has replaced the fuel pump and the engine still didn't start....
Thanks for the reminder about the vacuum controlled fuel pressure regulator on the Renix engines; the '98 HO I drive doesn't have that....
Would figure the engine would start running badly if the pressure regulator weren't working properly....
Guess we will know once the fuel pump is replaced.

 

[SINCITY192]

I put the new pump after hours of tryna drop the tank... but the worse of it was the metal plate above the tank. 1 of its 4 bolts decided to come loose but it wouldn't come out for nothing... It caused alot of damage to the hole of that bolt so no more metal plate under the tank... I think i'll cell fuel tank skid plate cause i shouldn't need it since i dont go into the mountains. anyway with a little priming it started right up.
thanks for all the help... also the inside of the tank wasnt bad at all the fuel seemed real clean.....

 

[SINCITY192]

i forgot to mention now i know i lost fuel from lowering the tank.....
but when i got the jeep on..... the fuel meter (always worked so far) read the last amount of fuel i had in there... which was 3/4 of a tank full and after a drive less then 10 miles I looked at the meter and it read a lil more than 1/4 tank full.. I have check for leaks with engine running and the gas pedal being pressed and i dont see any leaks anywhere!
but if i lost the fuel from dropping the tank why did the fuel meter read 3/4 full when i first started the jeep and started driving...

 

[JJacobs]

You probably got the arm of the sending unit bound up so now it's not reading right.

No need to drop the tank to do that job on an 88, by the way.

 

[SINCITY192]

Yeah u know but since i went through 2 pumps this being the 3rd i figured better drop the tank and check for rust!!!! And whats the arm of the sending unit? I kno what the sending units is but what arm are u talking about.... i only ask cuz i just put 3 1/2 gallons of fuel for work this week and no difference on guage as a matter of fact the guage isnt moving.... when dropping the tank besides the metal skid plate not being able to go back on the ground for the sending unit was broke the mechanic that help out a lil wrap the ground wire after stripping it a lil onto the sending unit ground (the other end it) and bent the metal as to hold the wire there i was a fishy about it but since it started up i thought all was well so how should i approach it some soldier?

 

[kastein]

I can't even figure out what you are asking about but I think it sounds like a bad electrical connection somewhere.

I don't put tanks that are questionable back in... either the tank is good enough to be reused without work, and goes back in, or I am putting a new one in it. It is not worth the risks, if there is rust inside the tank it almost certainly means it came from the outside and the tank is now paper thin and needs replacing.

 

[JJacobs]

The arm with the float on it is what I'm talking about. You know, the part that floats on the fuel?