slidermac

So I was just given a 1995 charokee with a 4.o auto. milage of about 260k. im the second owner my aunt gave it to me because it started to just shut off while driving. and will not start sometimes for a few minutes sometimes a couple of days. sounds like a ground issue to me but was wondering if anybody has experienced anything similar. runs great when it runs. she changed the crank sensor, distributor, do these things ever experience coil, or ignition problems, im just trying to figure out where to start. if I get it running I plan on doing alot of upgrades. i'm an experienced wrench turner looking for some direction. thanks in advance

5-90

I'd say to check the positive battery cable to distribution, where the cable is moulded to the clamp. You can get corrosion starting fairly often there, and it will travel under the jacket and screw with you (but you won't be able to see it, because the jacket is in the way.)

This is why I build cables the way I do...

I had the exact same problem on my 87 - and it drove me batty until I happened upon the cause of the problem by accident (I was doing something else there, I don't recall what.)

slidermac

ill give that a look. just got it today, so just getting started on it, looks and acts like the cps so I found, so wish me luck. got it from my aunt, she already replaced the cps once and did not fix the problem, wondering if its a wire issue. we'll tear into it tomorrow. thanks for the reply

Roler

refreshing all the grounds in there is a good baseline/maintenance thing for future reference too. Gets that off the list.
if it doenst start, follow the no start scenario's for spark and fuel. systemic approach will lead you find the cause. The intermittent character appears as electrical.

slidermac

ok so the cps has been changed, is there a brand that is better, or worse, I saw someone say oem is the way to go. also anybody here of the pcm screws being to long and grounding out? going out to start finding grounds and cleaning connections today, any and all ideas welcome thanks guys.

slidermac

I was told it lost all elec power but really it just dies and wont re start. it has 287k on the odometer, is very clean for the milage, really would make a great rig for one of my kids (or me). wish me luck, seems the cps or maybe a cam censor could be a culprit. so does it have a cam censor and if it does where is it located. and can you test them?

RTorrez1

OEM is the only way to go for a new CPS. All after market are hit and miss with a lot of miss.

5-90

A defective battery cable to distro can still do that - losing electrical power means you lose the ECU, ignition, sensor feeds, ...

DFlintstone

I assume it cranks, but doesn't start? If it doesn't crank: If you hold the key over, and jiggle the shifter in park or neutral and it starts, it's your NSS. http://bc4x4.com/tech/2010/jeep-neut...ty-switch-nss/

Basics, do you have spark when it won't start? If so will it fire with a shot of starting fluid?

On the fuel rail there is a schrader valve, like on a tire. It has a cap over it. If you crank it a bit, turn it off, then go depress the deal in the valve, does it squirt fuel out into the rag you are holding there?

Do you hear the pump run a couple secs when you turn the key on? I'm not sure about 95, but if there is a ceramic resistor on the drivers inner fender by the air cleaner, you can clean it's terminals, or just bypass it for trouble shooting. It's mainly just there to quiet the pump a bit. Might be 94 was the last year for that, not sure.

Battery gasses have a nasty habit of helping a thin, hard crust form on the bat post's and clamps. They can look pretty good, but that micro-thin layer is a surprisingly good insulator. SHINNY! Lead is what you want. I use a pocket knife, (gently), for the insides of the clamps. For the posts I might use one of those post cleaner wire brushes, but still scrape it with a blade. If you have a condition where you have power, (dash lights ect.), then when you hit it power goes out altogether, that's a common result of a layer of oxidization there. Btw, a half *** connection could be expected to get hot during cranking, or while it's trying. Cleaning those is something to do now and then anyway, so it you are having starting problems, you might want to make sure you have bare lead on lead. Might save you some grief!

slidermac

thanks guys, ok so good battery, good connection, it will start run fine thirty seconds, or five minutes, then just die. I found a video on youtube, testing the cps wiring at the plug, says port three(orange wire) should be 5 volts. I get 7.4 ? says the middle wire should be infinity under ohms, I have resistance instead. this tells me what ?? and what should my next step. this hting has new coil, cap,plugs, fuel filter, distributor and cps all in the last three months. it runs great and has good power when running then just shuts off i'm thinking there is a issue with the 7 volts and ground in the cps harness. any thoughts?