JMO413

It idles well but doesn't drive well over 2000 rpm. I'm going to try the old ECM tomorrow I guess and see what happens.

Yes it worked correctly on both. I have done the ground refresh and the sensor ground refresh. The readings on the scanner jump around with it running or just key in running position. The engine stays at idle and idles nicely. It drives fine under 2500 rpm then it's like there's no input.

Just put everything back together my fuel pump wouldn't stop running. Fuel pump shuts off now but I have a new issue. With the engine running or shut off the ECM shows all the settings are jumping around. This is with a snap on scanner hooked up. There scanner shows rpm jumps between 750 and 3000 rpm and the tach stays steady at about 1000. Not sure what happened. All the sensors reading like they are jumping around. It runs okay. Not sure what happened?

I had to replace both front sockets to get mine to work. If you look inside the socket where the bulb goes the ground likes to rust off. Bought mine at the local Napa.

I hope but something tells me it won't be. This truck only has 109000 miles on it but I believe she had a hard life!! Thank you again for the help!

So I found another spot where the fuel pump feed wire was rubbed through to a green wire with black tracer. Cleaned the ECM connectors again. Hooked it all back up and it works as intended. We're on start and shut down 10 and all is good. I believe it was the last short I found. Will update if it changes. Now I just have to put it all back together again. Thank you everyone for your help with this!!!

I pulled the connectors at the ECM they are all in great shape. Checked the ECM pins all are straight. Not sure what you meant by AO

I cleaned the connectors going to the ECM and the ECM is a reman looks brand new. What really gets me is that it worked right the first three times I started it. Now it never stops running like it did those three times. It would prime and stop. Now it just runs. The fuel pump is also very loud when it continues to run. The times it worked right it was quiet when the truck was running. I found seven or eight wires that had bare spots showing repaired them but still not fixed. The fuel pump still continues to run with all the relays taken out of the engine compartment, the ballast resistor unhooked, & unhook the starter relay. It only stops if you disconnect the pump or battery cable. It does not come back on when you hook them back up unless you cycle the key after that. It is getting power somewhere just got to find where.

Well that was short lived. If you turn the key to on it keeps running again even if you shut the key off. If you unhook the fuel pump at C157 and then hook it back up it no longer continues to run. It's also doesn't stop after primed in the first key position like it did the first couple times when it worked right today.

I got tied of tracing wires. So I put in the later 89 ECM I already had purchased. I was looking for the idle stability and better starting and power. Now my fuel pump shuts off. Not sure how or why!

Thank you for moving this. Still tracing wires today and still have not found a short. This is a weird one. I have spent the last two months fixing all the other issues.

1- Join this site and fill out your profile and signature 2- Bookmark Cruisers site, then get busy 3- Find a good wiring diagram and keep it handy 4- Don't give up

Glad I saw this post never thought about it before. Is this good?

How do I do that?

Did you ever figure it why this was happening? I currently have the same problem.

Did you ever get this problem figured out? I'm having the same issue

Thank you. I will post if I figure anything out

The PO had went around C157 with a toggle switch and ran power to the switch also. I had to go out of town for work and am going to try again today or tomorrow. The connection at C157 is nasty I think that's why he by passed it. And yes I have done allot of work to this truck. Got rid of the PO horrible wiring job. He was a fan of scotch locks. I have done almost all of Cruisers updates. Headlight overlay, 4 hole injectors, cleaned and added grounds. I finally had the truck running right and all the lights working. I also installed a 4.5 lift, changed all the fluids, got new tires and an alignment. Washed the truck really well for the first time in who nows how long. And then my fuel pump just kept running.

Okay that's what I was afraid of. Thank you again!

Okay just checking only post I found about this issue. Yes I pulled all four relays,the ballast resistor, the starter relay leg, and disconnected C352 and the fuel pump runs. So if I understand you correctly I am getting voltage from another circuit shorted to the fuel pump wiring?

I will start digging tomorrow thank you for your help. I found one other post about a Cherokee with a fuel pump that wouldn't shut off his final fix was an ECM does that make sense to you?

Hooked up C157 runs again

Single wire barrel connector I want to call it? It's unplugged now.

Did that. No fuel pump now