doc_

Looked for hours on this site and others so if this question has been asked before with this symptoms sorry. 1988 Jeep Inline 6 cranks no start. Has brand new fuel pump on it, it will run on starting fluid so I know it has spark also have fuel at fuel rail. So I thank I have it down to an injector issue. Read on this site somewhere that the cps does injectors and spark but I have spark so could the cps still be bad?

RTorrez1

If it start with starting fluid the first thing you need to do is verify your fuel pressure on the fuel rail with a mechanical pressure gauge. If I'm not mistaken for your year the pressure should be between 32 and 39psi. Also what brand of fuel pump did you install. I hope not an Airtek. They are garbage. The one you want to get would be is a Bosch or a Carter. But the Bosch is the better of the two.

DFlintstone

You might check your sensor ground circuit. (Check out the info in my Signature). On your inner fender there is a ceramic resistor. You can bypass that so 12V is going straight to the pump. (out the rear). Filter? Like RT says, checking the fuel pressure would be nice. You should hear the pump run a couple of seconds when you turn the key on. It just takes a second to check the CPS, and yes, both spark and the injectors use it. Really the ECU. Anyway since if runs on fluid your problem is likely elsewhere. The injector wires go through the C-101 connector near your brake booster.....See crusers stuff in my sig....Welcome!

RTorrez1

I always forget about that resistor most of my cars never had one. The couple that did I always removed it.

DFlintstone

Ha...glad you posted RT "inner fender right by the air cleaner!"

cruiser54

Check the fuel pump ballast resistor:

doc_

Will check fuel psi when I get home in a few days. But yes I can hear pump run when key is turned. The pump is a ADP inline pump with 100 micron filter before it and stock filter after. I did take bleder out of fuel rail and jump pump relay to make sure nothing was it the line. How many volts should be at the injectors?

DFlintstone

What? Inline pump? Maybe we found the problem. The injectors get a pulse from the ECU...the voltage of that is not normally measured as it only lasts a fraction if a second.

Me thinks if you have a fuel problem, and an "in line" pump, the (lack of a), pump is the issue.

Google "noid light" to see how to check for a pulse at your injectors.

I did it on my first (and only?) Youtube vid>

doc_

The inline pump says it is rated for 70-90 psi. Had a inline Bosch pump when I got the jeep 2 years ago. Replaced it because it locked up.

DFlintstone

I heard a funny line..maybe waz CCken. "went over my head like an f-14" Got me. I guess if you are seeing around 39lbs with the vac line off the regulator, and around 31 with it on, fuel pressure might not be the problem. I gather from Cruiser it's never a bad idea to clean that C-101 connector. It's just on 87-88, my 90 ain't got one. Still that sounds funky. So it DID work OK with an inline pump? (that, "locked up"). Is this something someone told you, or did you actually see it?

DFlintstone

Just to be clear, it has been running with the inline pump for two years?

doc_

Yes it ran just fine with the inline pump and yes I took the original inline pump off. And yes the old one locked up " quit pumping"

freegdr

Having fuel and having fuel pressure are two different things.