Should it still be running like crap?

bhicks

NAXJA Forum User

Location

Forest Falls, CA

• Apr 16, 2009

• #1

I recently replaced my 4.0 motor out of my 2000 with a reman motor from nihonmotors. It ran terrible when I first put it in because I didn't have the cps lined up with top dead center. I got that straightenend out but the engine still seems to be running a little rough. It also seems like I have less horse power than my old motor. Should a new motor run rough at first? Will it improve over time or have I done something wrong?

 

E

Erik Litchy

NAXJA Forum User

Location

Pekin IL

• Apr 16, 2009

• #2

no a fresh motor is smooth from the get go. sounds like maybe some inector wires are crossed or bad plug, or a coil pack lead problem

 

bhicks

NAXJA Forum User

Location

Forest Falls, CA

• Apr 16, 2009

• #3

Erik Litchy said:

no a fresh motor is smooth from the get go. sounds like maybe some inector wires are crossed or bad plug, or a coil pack lead problem

Click to expand...

Thats kind of what I thought. I am going to spend Saturday doing some more trouble shooting. I am going to yank all the plugs and inspect, check the connections for the injectors, test the fuel pump, etc. I am hopeful this thread will give me some insight from people who have swaped in a reman motor and have had similar problems.

 

W

winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• Apr 16, 2009

• #4

Verify the mechanical side of the rebuild with a compression check of all cylinders.

 

E

Erik Litchy

NAXJA Forum User

Location

Pekin IL

• Apr 16, 2009

• #5

winterbeater said:

Verify the mechanical side of the rebuild with a compression check of all cylinders.

Click to expand...

the only thing i can think of would be a cam that flat spotted, flat tappet cams are very sensitive to the break in oils. most of todays oils do not have the zinc content needed for a safe break in.

 

W

winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• Apr 16, 2009

• #6

Could be rings not seating, valves not sealing, head gasket leaking. With a 2000, it could be a cracked head.

 

99_XJ_

NAXJA Forum User

Location

Howard, Ohio

• Apr 17, 2009

• #7

The 00' and 01 years are known for cracked heads. Happens more often than one would like to think. I would throw in a can of Restore or some Lucas. Something to swell up those internal gaskets. Start small then work your way up.

 

W

winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• Apr 17, 2009

• #8

Check the compression.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Apr 17, 2009

• #9

Might have that distributor a tooth off.

 

W

winterbeater

NAXJA Forum User

Location

Royal Oak, Michigan

• Apr 17, 2009

• #10

What about the toothpick alignment of the CPS (Cam Position Sensor). If you didn't do this let us know and I'll find link. This is the same idea as the tooth off (for a 2000).

 

J

j99xj

NAXJA Forum User

Location

Colorado Springs, CO, USA

• Apr 17, 2009

• #11

Did you disconnect the battery while doing the transplant? If not you might have fried something expensive.