I have a 1990 YJ 2.5. Here is what happened. My exhaust pipe worked it's way loose from the manifold. I drove it like this for a couple of days (out of necessity) before I parked it. About 3-4 days later, I went out and tightened up the bolts where the pipe goes into the manifold and now it won't start. It will start up for about 2 seconds and then die. After that, it will crank but won't start. If it sits for about 20 minutes, it will start for 2 seconds then die and won't start back up. There is also a PSSSSSSS noise after I turn the key off and the engine is stopping. I checked and there is spark at the distributor cap and at the spark plugs. I had a friend check the injector while I turned it over, and there is gas. Since it has been sitting I have: put in new plugs and wires, changed the fuel filter and put injector cleaner in. all to no avail. I am hoping that someone on here will be able to give me a place to check. Thanks in advance for your help.
01-10-2011 08:11 PM
Ide start with checking the firing order unless you changed them one at a time.Try the easy stuff first
01-10-2011 08:23 PM
Thanks my1stnicejeep. I did change them one at a time. It wasn't starting before I changed them and I hope that it would help. It didn't.
01-10-2011 08:31 PM
It sounds like a timing issue.I know running with just an open exhaust manifold is not ideal.Hopefully nothing happened to the intake/exhaust valves.How many miles do you think you put on it with the bolts loose?Highway stop and go driving?
01-10-2011 08:33 PM
I'd say about 50 miles... combination of highway and surface streets.
01-10-2011 08:42 PM
Was it completely disconnected?Was it running really rough or just loud like would be expected considering the open/loose exhaust.With only 50 miles I doubt any damage was done.
Try spraying some starting fluid in it.If it doesnt start then you know its electrical.
01-10-2011 11:28 PM
Sounds like a exhaust restriction to me. You can loosen exhaust pipe or remove O2 sensor and give a try.
01-11-2011 07:14 PM
90YJinPC. You nailed it. loosened the exhaust pipe and it started. It is running, but running terrible. I have the gas pedal to the floor and it is barely at 1000 rpm. Any suggestions...
01-12-2011 02:58 AM
Probably still not breathing well enough would be my guess. I would suggest a new cat. and make sure no pieces of it broke loose, causing blockage further down the line.
01-12-2011 07:48 AM
01-26-2011 10:06 AM
Well you guys were 100% right. Got a new Cat and new muffler and it is running great. Thanks for all your help. You guys definitely know what you're talking about,.