2002 bad idle, backfire through the throttle body

[Cribbs74]

2002 Jeep liberty. 3.7

Drove fine, shut off to go into store. Went to restart and it wouldn’t fire. Finally started, but only by feathering the throttle.

I can keep it running, but it will not idle, also it backfires through the intake until revved up to a certain point, then it smooths out.

Neighbor plugged in his OBD and it read cylinder #2 misfire, but I am not buying it as it should still idle with one misfiring cylinder.

Anyone come across something like this before?

Thanks,

Ron

 

[ltd02]

I'd check fuel pressure first.

 

[J33Pfan]

How many miles?

sounds like a valve problem

compression test needed

 

[Cribbs74]

130K miles.

No metallic noises coming from the engine. Could be a valve I suppose.

There is some raw fuel coming out of the tailpipe.

I can do a compression test

 

[Cribbs74]

Ok, compression is as follows.


1-200
2-180
3-210
4-0
5-195
6- 205

So, isn’t that great. This thing has been nothing but problems.

Guess I am pulling the head. Of course it’s on the A/C side.

Also, cylinder 2 spark plug is clean as a whistle the rest are black as night. So that’s an issue as well.

 

[ltd02]

Did this thing ever overheat?

 

[Cribbs74]

Not on my watch it didn’t, but who knows about the vehicle history before it came into my possesion. This is my daughters vehicle for school, besides massive wiring problems, this thing had seemed to be mechanically sound. Every time I have driven it has been cool as a cucumber.

 

[Damotee]

What should those compression numbers be?

 

[Cribbs74]

What should those compression numbers be?

Not entirely sure, but I am guessing more than 0 on cylinder 4

 

[Cribbs74]

Broken intake valve spring.

Hopefully I can replace it with the head on.

The real question is when are the others going to go?

 

[Cribbs74]

Fixed, had to order the correct valve spring compressor tool as the generic tool didn’t work. Repair cost was right around $100 all in to include the tool.

At least I have the tool for when the others go. I was lucky in that the spring broke in two but the valve spring keepers didn’t come off. Had they, I would have dropped the valve into the cylinder.

I will say pulling the valve cover was a royal PITA. So much crap had to be removed before I could even begin to think about pulling it. I hate newer vehicles. My daily drivers are 1966 and 1972 model vehicles. I will live with hand crank windows and no A/C just to keep the ease of maintenance.

If you have lots of money I would recommend you take your Jeep to a shop and have the valve done.

Thanks for the help everyone. Especially J33Pfan who took me down the right road.

Ron.