once again, more problems

I finally got my jeep to a shop where I could work on it and got the wheel bearings fixed and replaced the tps sensor. It drove fine for about an hour. When I left the shop it was idleing at around 3000 rpms, so my buddy loosend the bolts on the tps sensor and it went back to normal and I drove it about twenty miles. I went to a buddies house and while I was waiting in his driveway it just cut off. It did the same thing it was doing before I replaced the tps sensor. It would run fine and then slowly lose rpm and then shut off and it just does it over and over. I had some wiring that was right next to the headers so we cut it and rewired it to a place where it wasn't right next to something hot because it was melted down to bare wire. Any ideas as to what it could be? My buddy thinks that when its getting hot its causing something to short out. I'm bout to go and get another tps sensor and see if the heat is causing something to short out. This is starting to get really aggravating because when the jeep runs, it runs good and fine but its all these little things that keep giving me hell. We know it has fuel pressure and spark. I drove it for nearly an hour and went about 20 miles.

Clean the idle air controller, it controls airflow into the throttle body when your foot is off the gas

i already did that, even replaced it

k.allen90 said:

We know it has fuel pressure and spark. I drove it for nearly an hour and went about 20 miles.

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do we know "for sure" that you have both when it stalls? I've seen coils and fuel pumps suffer from thermal failure-- work until they get hot and quit 'til they cool a bit.

I'd try replacing the fuel filter (if it's not new) as well-- it can plug up as you run the engine and have just enough crud settle when you stall to allow it to restart until it plugs up and so-on.

What vehicle are we working on?

Its an 89 xj, it supposedly has a newer motor and trans but i have no clue to as how new or if this is even true.

The fuel filter was the first thing I replaced. My buddy checked the fuel pressure for me, but it was doing this before and we would take the tps sensor off and it would start and run but like crap and as soon as we put it back on it would shut down. So I bought a new one and it ran fine to the hobby shop and all the way around town to my apartment. Then it shut off while I was waiting for my friend to come out. When it does run it doesn't have any misses and we checked all the spark plugs and they're good. The motor does seem to run hot but the dash says its running at 210 but i'm goin to pick up one of those laser thermometers from work and see if i can get it running to see if the dash is true.

Does it have the C101 bulkhead connector above the brake booster? Those tend to develop bad connections over time. A good cleaning inside, tighten up the terminals inside, fresh dielectric grease may help. They eliminated the connector and went with a solid harness at some point.

JJacobs said:

Does it have the C101 bulkhead connector above the brake booster? Those tend to develop bad connections over time. A good cleaning inside, tighten up the terminals inside, fresh dielectric grease may help. They eliminated the connector and went with a solid harness at some point.

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'88 was the end of that harness mess. '89^ had the solid harness through the firewall.

1. I doubt you would get a thermal failure on the TPS.

2. The CPS/CKP crank sensor is subject to thermal failure, it is bolted at the top left of the bellhousing--were the burned through wires you fixed leading to it? The crank sensor is ABSOLUTELY essential to the engine's running. You can measure its resistance with an OHM meter--200 ohms + - 75 ohms.

3. Have you bypassed the fuel pump ballast resistor on the driver's side fenderwell?

Originally Posted by k.allen90
We know it has fuel pressure and spark.

double check when it doesn't start

Shorty said:

'88 was the end of that harness mess. '89^ had the solid harness through the firewall.

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Correct. However, check the brake and clutch MCs, if they leak inside the cabin the fluid will corrode the fuse block and wiring quite rapidly.

i don't know what the wires went to exactly we look but didn't know what it all was, we know some went to the o2 sensor but there is one cable that is just hanging there but its filled with silicon like its not being used. I have no clue what it is supposed to go to though. When it doesn't start we checked fuel pressure and it still has it. I checked to make sure the fuel pump is still working to and it is. I've never heard of a crank position sensor, so i looked online for the location and I still didn't find it but i'll double check again with the info I was just given. I know the brake mc is good I just looked at it today when I was doing brakes. Sorry if this is a dumb question but its an auto so does it still have a clutch? One other is that who ever wired this motor didn't label anything and with the chiltons book I can't figure out where the fuel pump resistor is. I'm not good with cars when it comes to the really technical stuff. I know enough that I can read the book and do it how the book says. My buddy who is a lot better is helping me out but he is just as lost as I am, because we don't know what wires go to what or what fuse is what. Nothing is labled and its all in different places then what the book and pictures say. Does this make sense for yall?

Fuel pump ballast resistor is a white ceramic part bolted to the fenderwell, with two wires attached, just remove them from the resistor and jumper them together.

No, with an auto you don't have a clutch MC--this is one reason it is very important to give the BASICS of your XJ each time you post, Year/Engine/Transmission/Transfer Case, etc.

I don't know anything bout my engine or trans but where can i look to find out more about them? I know its the inline 6 and it supposedly has the 4.0 h/o but I can't find the ecu to check and see if its true. I've parked next to a jeep the same year as mine and they don't sound anything alike and when mine did run, it was a lot faster and had more power then his. I've looked for s/n and data tag but i can't find them. Maybe i'm not looking in the right place.

The only inline six cylinder in the XJ is a 4.0, your engine management system is a dual venture of Renault and Bendix, and is commonly referred to as a Renix era XJ. The 4.0 was introduced to the XJ in 1987 and used throughout production of the XJ until 2001. The HO is the same 4.0 engine with some changes starting in 1991, all 4.0 engines 1991-2001 are HO engines.

Here is a link to everything you need to know about the sensors of your Renix, be sure to bookmark it: http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

If you have an automatic transmission it will be the AW4--Aisin Warner 4, Dex III, damn hard to kill it is a good transmission. If you have a manual transmission, and the production date is 3-9-89 or earlier you may have the BA 10/5, a Peugeot transmission that has a reputation for failure. Post 3-9-89 it will be an AX15, an excellent transmission.