samsterman99
Active Member
- Joined
- Jan 22, 2013
1993 with a ATK reman motor. 4.0. Installed because old motor was at 200k, low compression and tired and wouldn't hold OD on highway or tow my camper at all.
After install, new motor idled rough, worse when hot. Sounds like it's missing at idle, and picks up again at rpm's. Power has always seemed low in the jeep, and this new motor still struggles on the highway just like the old one did.
Jeep has 33's, AW4, 3.55's. It barely holds OD on the flats. Even just a overpass on the highways requires a downshift. I've driven xj's on 35s and 3.55's that will hold 80 easy with a stock motor. I don't think it should struggle this much, and I'm getting close to throwing in the towel.
I have checked compression, it's 140,145,135,140,140,145. Fuel pressure is good, new distributor, plugs, wires, coil, and 4 pin injectors. Catalytic converter is new, intake was cleaned when motor was changed. I am really really stumped with this one. The only thing I have to run on now is that the exhaust pulses really hard at idle and will almost "suck back" at idle. Bad exhaust valve is my newest idea. When I took the valve cover off, I think I may have smelled coolant. But that could be my mind playing tricks on me at this point. A new motor under Warrenty is easy to come by since this one is a week old, but I want to make sure that is my issue before swapping it out again.
Any help is appreciated. And if you are in Raleigh and want free beer, you are welcome to come and take a look.
After install, new motor idled rough, worse when hot. Sounds like it's missing at idle, and picks up again at rpm's. Power has always seemed low in the jeep, and this new motor still struggles on the highway just like the old one did.
Jeep has 33's, AW4, 3.55's. It barely holds OD on the flats. Even just a overpass on the highways requires a downshift. I've driven xj's on 35s and 3.55's that will hold 80 easy with a stock motor. I don't think it should struggle this much, and I'm getting close to throwing in the towel.
I have checked compression, it's 140,145,135,140,140,145. Fuel pressure is good, new distributor, plugs, wires, coil, and 4 pin injectors. Catalytic converter is new, intake was cleaned when motor was changed. I am really really stumped with this one. The only thing I have to run on now is that the exhaust pulses really hard at idle and will almost "suck back" at idle. Bad exhaust valve is my newest idea. When I took the valve cover off, I think I may have smelled coolant. But that could be my mind playing tricks on me at this point. A new motor under Warrenty is easy to come by since this one is a week old, but I want to make sure that is my issue before swapping it out again.
Any help is appreciated. And if you are in Raleigh and want free beer, you are welcome to come and take a look.
