Power Problem - AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand

razzle308 · #1 15-01-2022

Hi all.
I seem to have lost a lot top end power and it's definitely not the CAT.

Back story;
I was country driving with a trailer and to help the cruise control, each hill I would drop it back to 3rd. then back to drive at the crest.
I must have forgot to put it back to drive and accidentally dropped it back to second at 100kph. Since that moment I have lost a lot of top end power.
To the point I struggled to overtake even on the flat.

The transmission seems to be fine. Changes ok, Doesn't seem to show any sign of slipping. Fluid is ok, not brown. Still has good torque off the mark. Did the rest of the trip ok with no issue - except loss of power.

Any ideas where I might start looking for problems?

Thanks, Darren.

awg · #2 15-01-2022

Quote:

Originally Posted by razzle308

Hi all.

I must have forgot to put it back to drive and accidentally dropped it back to second at 100kph. Since that moment I have lost a lot of top end power.
To the point I struggled to overtake even on the flat.

Thanks, Darren.

What did the engine do when you dropped it back to 2nd ?..did it redline ?

Its possible you damaged a piston

I would expect this would be detectable by listening closely

If not, do a compression test on each cylinder is the first easy thing I would try

You could also try disconecting each spark plug, one at a time, if the engine note/RPM does not alter, that may indicate a damaged valve spring

LuluBelle · #3 16-01-2022

"I was country driving with a trailer and to help the cruise control, each hill I would drop it back to 3rd. then back to drive at the crest."
Why would you do that? just accelerate up the hills manually once it is in drive it's in drive I only use the other gears in the bush if I need to

razzle308 · #4 16-01-2022

Ok so i have just done a compression test and the cylinders measered 120-125 accross all 6.
Plugs have a good, even, light brown burn.
The engine runs fine. No noises or anything.
As i said we completed the rest of trip fine except the top end power loss

Classic Boy · #5 16-01-2022

That’s a pretty ordinary compression pressure. On a warm engine, with a good battery with wide open throttle one would expect closer to 150psi at least. At 125psi it looks a tired.

alexbrown64 · #6 16-01-2022

If you did the compression test and they are all equal, then i would say no engine damage. Doubt your going to break the Jeep 6 anyway.

You have plenty of torque and she is running well, so im curious as to the power you are loosing at the top end. Has it lost power even when it kicks down, or you drop it back to 3rd to overtake on the flat?

I honestly thought my XJ was gutless at one stage. I did the TV cable mod. Takes one minute and was like a miracle on my Jeep. All the kickdown points changed and the Jeep just gained a ton of power as it was dropping into the right gear at the right time.

If you think it could be related, then give it a go before trying much else.. It worked for me.

Cheers,

razzle308 · #7 17-01-2022

I have done the TV cable adjust before. But this is really just for kickdown yeah!?.

With the compression i didnt open the throttle. Didnt know about that. Admittedly the engine has 370k on it and i know I'm getting close to a rebuild. But even results accross the six indicates that there is nothing wrong.