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2001 24 valve Cummins

3K views 35 replies 14 participants last post by  firehawk 
#1 ·
Just got my Cummins back together after forever.... Needed a head gasket. Had head cleaned up, all new gaskets, new head bolts, etc.....
Starts fine, and runs fine(above idle), but seems like it's idling rough, and is blowing smoke(at idle). Check engine light was on this morning on my way to work....it's off now.
Where should I begin my investigation?
 
#8 ·
Yea I hear you can rent a old gas in diesel fuel meter from auto zone... LAY LOTS OF PIPE The code will stay stored until cleared even if the lights off. I would start with finding out what the code was. Any idea why the idle is high? Check for boost leaks. Doesn't really sound like a lack of fuel problem.
 
#11 ·
Ok....now for today's findings.

Started truck today after work...running pretty rough...left without letting it warm up...pulled out into traffic, bogged bad, big cloud of black smoke and it took off like a bat outta hell! Immediately got stopped at a light, and it idled like a purring kitten....with no smoke...

Hmmmmmm....

Noticed as it got closer to operating temperature, it started to "miss" again...warmer it got, worse it ran, and the smokier it got(at idle).
Stopped at autozone for a scan...came up with a bad IAT, and a bad MAP.
 
#16 ·
With a bad map sensor it will still run 100% fine....it will just have no power at all till 12-1400rpm then it will take off and run fine....this is because the sensor does register boost so it doesn't fuel....once it gets up so far it just defaults and takes off. At least that's what mine did when the map sensor died. I am betting yours is an injector issue caused by sitting. Why was it apart so long? That head gasket is super easy.
 
#17 ·
Lol. Lack of time and money(mostly time).
The more I read...the more I think I may have multiple problems. Did a few full throttle blasts this evening, and it almost seems like it's missing under heavy throttle, ONLY when the tuner is on and turned up though. Tuner off....no surging or missing under heavy foot. Idles the same tuner on or off(horrible and smokey).
I hope I you guys can help me figure this out! I don't have a lot of money to just throw at it until something fixes it....
 
#19 ·
Ok.....left work today(again without warming up first), stepped on it, bogged, giant cloud of smoke...went like a bat outta hell.

Again....

Got up to operating temperature, but was still running fine. So.....that leads me to believe it's not the operating temp of the motor itself, but something around the motor that is getting hot from the heat coming off the motor. I say this because not too far down the road, it started the missing and smoking again.


Also noticed that in o/d at lower speeds, it's bucking.

This thing is starting to sound worse and worse!
Does anyone know a diesel mechanic in my neighborhood that's not gonna try and rape me? Maybe someone who can tell me what's wrong so I can fix it. I just can't afford that kind of labor, on top of possible parts.
 
#22 ·
Update: pulled valve cover to check valve train noise...started motor and proceeded to fill it with coolant from the open heater core feed. DOH! Was planning on changing the oil soon....just not THIS soon. Lol.
Soooooooo......on my way home from Walmart with my three gallons of oil, I was surfing the net to see if the computer on the vp44 could be replaced, and ran across a diagnostic write up. There was a section that described my problems almost exactly, which were attributed to the vp44 computer going bad. So that's hopefully the problem.
After I changed the oil...decided I should check valve lash clearances...they seem to be pretty tight. Will be adjusting those Saturday.
Will let you guys know if and when I get it fixed.
Orrrrrrrrrr.....if anyone knows anyone who could fix the computer for me, that would be great :)
 
#26 · (Edited)
With all the different posts I've made....i should probably clear everything up...

Idles rough when first started. Once I "clear it out", it idles and runs great, until....it gets warm(operating temp'ish), then the rough idle and smoking start.
Like I posted earlier...all signs of rough idle and smoke point to that computer. I just don't know how it could have possibly gone bad just from sitting!
 
#27 ·
Just beware.....everyone likes to blame any and every problem with these motors on the vp 44 pump.....i had a reputable diesel shop swear up and down two different occasions that my pump was bad and causing my issue...i ignored them both times and good thing i did as they were wrong both times.

How much fuel pressure do you have?
 
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