cccbycox

I am new to this site and not mechanically inclined. I apologize in advance if I use the wrong terms from time to time. I have a 1992 Jeep Cherokee Laredo with 170k miles, 4.0 I6. Last Friday 01/27/17 it suddenly lost engine power and I barely got it home. Long story short, hopefully. I started reading this site to figure out what was happening. Seemed to have good fuel flow and learned from this site how to test all the sensors. Everything test fine. I am a computer repair tech so I had an oscilloscope and other things on hand. Eventually I decided to just start replacing things. Here is a list:

IAC, TPS (MAF), spark plugs and wires, coil, entire distributor including cap and rotor, fuel line I found had a pinhole leak, fuel filter, any vacuum lines that were cracked or brittle, coolant temperature sensor.

I am replacing the MAP sensor today as it won't start at all with it connected.
Eventually got a fuel pressure gauge and found only 7 psi at fuel rail. So I replaced the fuel pump yesterday.

Jeep is hard to start but it runs fantastic after a few seconds. But when I shut it off for more than a few seconds it is really hard to start again. I can hear the gas rushing back out of the fuel line when I turn it off. I can also hear the pump prime when I put the key forward. Don't know what is causing it.

But here is the strangest symptom. When I was working on it last night I noticed a red glow that seems to be reflecting onto the engine on the drivers side, just under the exhaust manifold. It isn't there with the key forward and engine not running. And only appears after the engine has been running for a couple of minutes. It gets brighter the longer the engine runs. I can't tell where exactly the glow it coming from. Please, any help would be greatly appreciated.

I have learned about all of the parts I have replaced through the fantastic posts on this forum. If it weren't for all of you I wouldn't know what any of those parts were, what they do or how to test them. I am now a lifer to this site. Which, at my age, may not be saying as much as it sounds. LOL

Basslicks

The fuel draining back is symptomatic of a bad fuel pressure regulator.

https://www.rockauto.com/en/partsear...tnum=53030001+ 77 bucks plus shipping for the OEM Mopar part on Rockauto.com

The red glow (combined with the loss of power and hard start) sounds like perhaps the catalytic converter is clogged and it's heating up the pipe upstream to a red glow.

Try posting here for more input, but that's where I'd start to look....

https://www.cherokeeforum.com/f2/ask...6/#post3356010

cccbycox

I am going to get back to it first thing in the morning and will update on progress. Thanks for the advice. As of a few hours ago the new pump failed and when I opened the gas cap, I got sprayed with gasoline. It was like I had shaken a can of pepsi and opened the tab. Getting weirder all the time. New pump will be in this Tuesday. I am getting really good at dropping the tank.

Basslicks

Do yourself a favor and use only a Bosch fuel pump. Some have also had pretty good luck with Carter and Walbro, but I've never heard of anyone having a problem with a Bosch. Just whatever you do, don't buy Airtex.

cccbycox

I have returned the fuel pump and gotten another one, Bosch of same model. I figured since the one in it was a Bosch, that was the way to go. Tank pressure problem went away and this pump is quieter. I have a fuel regulator coming in today. The Jeep is currently really hard to start. But eventually it does and runs really smooth after a few seconds but bogs down really bad. Hard to get up past 25mph. I am really hoping this fuel regulator does it. I placed a clear piece of line on the return from the fuel pressure regulator. With the vacuum on or off the return flow seems not to change. Even when I try and rev the engine it seems to stay the same. My friend hasn't been back over to test my fuel pressure with his meter. But it seems the regulator is going to be the last problem. The only things I have not replaced now, literally, crankshaft sensor, fuel pressure regulator, the engines computer and none of the fuel injectors. Fingers crossed.

Basslicks

Glow still there?

cccbycox

Haven't really been looking for it lately. As soon as I can get it running right I will give it a good look over. I can only see it at night though. Thanks for asking. Almost forgot about it.

Basslicks

If it's still there (and your cat is still there), I'd strongly suggest inspecting that cat thoroughly.

cccbycox

I just got the catalytic off and still the same problems. Very hard to start and no getup and go. Now I have replaced the Fuel Pressure Regulator, IAC, MAP, Entire distributor, plugs and wires, TPS, Fuel Pump, Fuel Filter, Coil, Engine Temperature Sensor, Replaced part of the fuel line, Replaced old vacuum lines.

At a complete loss!!!

Basslicks

Try this... I know the 92's came equipped with the renix-style distributors. Try finding top dead center http://cruiser54.com/?p=65 and then index your distributor using Cruiser's tip #13 http://cruiser54.com/?p=68

At this point, I'm thinking it's either that, or the timing chain is worn enough that it has jumped time.... or (God forbid), you have an extreme compression loss.

cccbycox

From what I can tell mine is not a Renix. Renix was stopped being stock in 1990 and optional in 91. No Renix From 92 on. Mine is a 92. Could find #13 in the article even though is mentions it at the bottom as it suggests doing #12 before #13. But no #13. I am going to check the timing chain and a friend is going to come over with equipment to test the compression. Thanks so much. The battle continues!

Basslicks

I think you misunderstood me. I know when Renix ended. But there were a lot of "carryover" parts from the Renix era. The distributor that came on the '92 is one such carryover... unless the previous owner changed it out to the newer style - which is possible.

If you pull the cap off and your dizzie looks like this:



It's the Renix-style distributor.

If you pull it off and it looks like this:



Then it's been changed to the newer 4.0 HO style.


I left the link to both tips in that post. "Distributor indexing" http://cruiser54.com/?p=68 is tip 13. "Setting your 4.0 to #1 TDC" http://cruiser54.com/?p=68 is tip 12.

cccbycox

It is the second one. And just to be sure of things, I just pulled the fuel rail off and tested the injectors. Good spray on all of them. 15 to 16 ohms each. But will have to replace the O-rings. One of them was warped and the others look pretty bad. The grime inside the engine ports is really bad. Cleaning them before installing the new O-rings onto the injectors. As far as the timing chain. How can I tell if it has slipped when I get a good look at it? Its next.

Basslicks

There will be timing marks on the cam sprocket and crank sprocket



They should line up exactly vertical of each other

cccbycox

I replaced the crankcase positioning sensor last weekend with no change. I just replaced the ECM about an hour ago and charged up the battery. Still no change. I am going after the timing chain next as you have suggested. Thank you so much for the diagram and photo. I just have to learn how to get to it. Back to YOUTUBE for more video lessons. LOL