1989 Cherokee runs like crap!

Hi,

If you FLOOR it it seems to run ok but otherwise it jerks, chokes, sputters and runs crappy. Here is what I have replaced.

1.) Map Sensor
2.) TSP Sensor
3.) Sensor up near the flywheel, (around bell housing -- what a payne to reach around there!).
4.) Plugs, Wires, Cap and Rotor.
5.) Fuel Filter.

Apparantly this year does not have a code to read from the computer.

Had it into the local machinac who said it was the TSP sensor. He wanted $160.00 for the part so I did it myself.

At this point I have replaced so many parts I am beginning to wonder if it an electrical problem or something.

Any ideas on what I should do next? Was thinking of replacing the computer or the Idle Air Control valve.

Thanks in Advance!
Rick

Hi,

If you FLOOR it it seems to run ok but otherwise it jerks, chokes, sputters and runs crappy. Here is what I have replaced.

1.) Map Sensor
2.) TSP Sensor
3.) Sensor up near the flywheel, (around bell housing -- what a payne to reach around there!).
4.) Plugs, Wires, Cap and Rotor.
5.) Fuel Filter.

Apparantly this year does not have a code to read from the computer.

Had it into the local machinac who said it was the TSP sensor. He wanted $160.00 for the part so I did it myself.

At this point I have replaced so many parts I am beginning to wonder if it an electrical problem or something.

Any ideas on what I should do next? Was thinking of replacing the computer or the Idle Air Control valve.

Thanks in Advance!
Rick


HAVE YOU CHANGED AIR FILTER, CLEANED THE THROTTLEBODY AA WELL AS THE IDLE AIR CONTROL VALVE. PUT A FUEL PRESSURE GAUGE ON IT, CHECK PRESSURE A VACUUM GAUGE CAN TELL YOU ALOT ALSO. :2cents: DALE ALSO CLEAN AND CHECK THE CVC SYSTEM & LINES

It sounds like you cat may be plugged. You might want to have a muffler shop check it out.

I have swapped out the following with no luck.
1.) Air Control Valve.
2.) Computer.
3. EGR Valve.

Cleaned the throtle body.

I will try disconnecting the cat to see if it may be the problem, (thanks for the suggestion!).

What is the CVC System?

Tried disconnecting the threaded metal cap at the front end of the fuel injection rail -- it that the cap I would remove to check the fuel pressure?

Thanks,
Rick

yes , that is the cap you would use to hook up your fuel pressure tester. Also you may want to check the egr valve, just below the throttle body, dissconect the vacum to the egr to see if it runs better.

I disconnected the cat which did not resolve the problem. Also disconnected Fuel Injection Pressure Regulator. With this off a stedy flow of fuel was pouring out of the end of the injector rail. Not sure what the pressure should be here if I were to test with the proper guage.

Next step will be to take a look in the fuel tank for any thing that may cause fuel flow problems, but this seems like a long shot.

Any other ideas on what this could be?

B.T.W. It does not sputter a little -- it sputters alot and runs terrriable. It seems to idle good and rev while car is setting ok but as soon as it is under any kind of load what so ever it really really craps out til you FLOOR it then it takes off!

Thanks,
Rick

there is also a pickup coil (sync sensor) in the distributor that I just replaced on my 89. You have to remove the dist to replace it. It did seem to help mine out, starts up a little quicker. Its used for ignition timing and to sycn the fuel injection with valve opening.

Pressure should be approximately 31 psi with vacuum hose connected to pressure regulator and 39 psi with vacuum hose removed from pressure regulator. I think this is an important test to determine if there's sufficient fuel pressure.

Have you tried running injector cleaner in your gas?

I figured it out!

I removed the fuel tank and there is a small hose inside , (about 2 1/2 Inches long), and one of the clamps was a bit loose and the hose was not completely seated good on one end. I re-seated the hose and tightened hose clamp and now she runs perfect!

It was amazing to me that my local mechanic thought it was a TSP or a Idle Air Control Sensor. He said he did not think it was a fuel issue but reading the board here I saw some similar and decided to double check in the fuel tank. It has 250K miles on it and I figured something may be up.

Thanks all for the help!
Rick

Nice catch. Thanks for the followup.