Cylinder 1 misfire

[new2jeep]

Calling all jeep savants and detectives.

I have a 2001 TJ, that I recently had to replace the 2.5l engine. The old engine was tired and had a broken piston skirt but still did ok considering. So i purchased a long block from Powertrain Products ( I suggest you don't do the same). Upon the completion of the install (which I did myself), the new engine has a rough idle to the point of a high lift performance cam.
It ran terrible, so the troubleshooting began.

1. Ohmed the injector signal from the computer to the injectors.
2. Checked timing, spark plugs and wires.
3. Bought new injectors.
4. Sent 2 computers to Wranglerfix.
5. Hand over Hand checked wiring.


At this point I sent it to a mechanic where he checked.
1. Fuel Pressure.
2. Timing.
3. Spark.
4. Compression.
5. Leak down.
6. Injectors (flow test)
7. Injector signal
8. Computer.

The warranty department has had the shop send the head to a machine shop, it checked out ok and had the mechanic change the lifters.
And still the number 1 cylinder doesn't contribute. you can pull the injector wire to number 1 and the engine makes no change in idle or performance. when doing the same to the others there is a very noticeable change.

Any one have any tips or insight because I'm out of guesses. Sorry for the long post, but I tried to put as much detail as i could.

 

[macleanflood]

Well you've effectively eliminated all causes of misfire except maybe changing the spark plugs.

I'd like to know the results of the compression and leakdown test.

I'd throw out all your troubleshooting and start over.

And nobody HAS to replace a 2.4. They choose to do so. The rest of us just drops in an LS or 4.0. =)

Just Dex It...or DeXJ on YouTube chased a bad misfire for a while and found it was a cheap Mexican cam...ground all wrong.

-Mac

 

[new2jeep]

Well you've effectively eliminated all causes of misfire except maybe changing the spark plugs.

I'd like to know the results of the compression and leakdown test.

I'd throw out all your troubleshooting and start over.

And nobody HAS to replace a 2.4. They choose to do so. The rest of us just drops in an LS or 4.0. =)

Just Dex It...or DeXJ on YouTube chased a bad misfire for a while and found it was a cheap Mexican cam...ground all wrong.

-Mac

Thanks for the reply, I've put at least 2 new sets of plugs in it since this started.
Leak down was less than 5% and compression was just slightly different between cylinders cant remember the numbers. Ill look at Dexs channel because that is the part that the warranty department does not want to change for some reason. So I'm paying the mechanic to change it out just to eliminate it. It has the 2.5l and I just wanted a simple easy factory replacement.

 

[macleanflood]

I get the simple and easy.

I don't think there's a single engine rebuilding shop out there right now that's putting out a quality product... maybe S&J out of Spokane.

When my 4.0 goes I'm just going to rebuild it myself. Have a machine shop deck the head and blocks, slap in new bearings, valve seals.l, etc etc etc.

-Mac

 

[new2jeep]

Well, it seems that after 4 months of fighting with Powertrain products (who I purchased the 2.5L long block) the mechanic and I finally found that It was a bad camshaft. Thanks to Macleanflood for suggesting that I watch Dex's Jeep Youtube channel as he had a very similar problem. Once the mechanic put in the new camshaft it is running as it should. Not sure what is wrong with the old cam, but the new one runs just fine.