1989 Cherokee Backfires

I have a 1989 Jeep Cherokee Limited. I bought the thing back in September and the only problem that I have with it, is that it took about 8 seconds to start. I figured that it took so long because of the miles on my Jeep. The Jeep ran great, tons of power and very reliable. I have about 234,000 miles on it. Slowly I started to notice when I would go up hills I would hear a loud bang and loose some power. All of a sudden I would gain it all back. Eventually it got worse and louder and I would hear it more often. Then all hell had broke loose.

As of now the problem that I have is once i get out of first gear i loose power and it backfires on me. I have to floor it just to go and every gear does it after first. When Im cruising down the road, i have to really hold the pedal so i dont loose my speed. It drops really fast. The new problem now is I have to start my car about three times in the morning before I go to work. For the past 2 weeks I have been reading and trying to figure out whats wrong with it and I have no idea. If you have any idea please help me.

So far what I have done is a dyno test. The results were a 1 knock in the engine and my O2 sensor volts would bounce up and down. I replaced the crank case sensor, egr valve, ran a compresion test, and vacum test. My compression test came back fine. On my vacum test, it would hold and sometimes bounce down a little. But come right back up. When I bought the Jeep. I replaced the Spark Plugs, Fuel Filter, Wires, Rotor, and Distriputer cap and I have looked at all those things. Honestly I have no clue what this could be. When I floor the engine, it runs like it has great power. If someone can help me, God Bless You..! I look forward to a response if someone has one and I hope you all have a great day.

matt <><

Have you check the timing?. It might be set to high

[QUOTE=LAXmaniak02]I have a 1989 Jeep Cherokee Limited. I bought the thing back in September and the only problem that I have with it, is that it took about 8 seconds to start. I figured that it took so long because of the miles on my Jeep. The Jeep ran great, tons of power and very reliable. I have about 234,000 miles on it. Slowly I started to notice when I would go up hills I would hear a loud bang and loose some power. All of a sudden I would gain it all back. Eventually it got worse and louder and I would hear it more often. Then all hell had broke loose.

As of now the problem that I have is once i get out of first gear i loose power and it backfires on me. I have to floor it just to go and every gear does it after first. When Im cruising down the road, i have to really hold the pedal so i dont loose my speed. It drops really fast. The new problem now is I have to start my car about three times in the morning before I go to work. For the past 2 weeks I have been reading and trying to figure out whats wrong with it and I have no idea. If you have any idea please help me.

So far what I have done is a dyno test. The results were a 1 knock in the engine and my O2 sensor volts would bounce up and down. I replaced the crank case sensor, egr valve, ran a compresion test, and vacum test. My compression test came back fine. On my vacum test, it would hold and sometimes bounce down a little. But come right back up. When I bought the Jeep. I replaced the Spark Plugs, Fuel Filter, Wires, Rotor, and Distriputer cap and I have looked at all those things. Honestly I have no clue what this could be. When I floor the engine, it runs like it has great power. If someone can help me, God Bless You..! I look forward to a response if someone has one and I hope you all have a great day.

matt <><

P.S. - someone asked If i looked at my timing. I went and looked at my timing chain the other day. It was tuff to get too. When I checked the chain it self it felt tight, I dont think that it jumped or got loose at all. As far as I could tell the everything else looked good. The strange thing about the car is like the first 5 minutes in the morning when Im driving the car it doesnt do anything, it drives fine. Also, when I go down hills it doesnt give me any problems. I really dont understand what it means.

I wanted to know if you have fixed the problem and if so would you tell me how you did so my jeep is having the same problems thank you very much

I wanted to know if you have fixed the problem and if so would you tell me how you did so my jeep is having the same problems thank you very much
Welcome to AF.
It's a good idea to start a new thread on your specific problem.

Misfiring problems can be caused by many different things; some are easy to fix, (like new spark plugs and wires) or are difficult to fix...... (repair leaking valves).

Other people's car problems may sound like yours but be somewhat different. We can help you more if you can describe to us exactly what problems you are having with your Jeep.

did you fix the problem and how. i have a 87 and it dose it all the time i did a tune up it ran a lot batter but it backfires and skip

Have you check the timing?. It might be set to high


The timing on these engines is set at the factory and monitored by the CPU and cannot be changed or reset.

But back to you problem...you may want to check your MAP sensor. It is located on the firewall in the engine bay on the driver's side. This can sometimes cause backfiring and poor driving from a stand still (stop light).

also look at the timing chain, timing gear, crank sensor, cam sensor, or vacuum leak.

Mike

This thread has been brought back from the dead one too many times...first 3 years without a post, then 1 year.

Please start a new thread and provide details about your problems there.

Closed.