Another P7100 Injection Pump Quest. (Post Search)
11-12-2006, 10:09 AM
#1
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Another P7100 Injection Pump Quest. (Post Search)
On my 97, it lost power..still runs and drives fine..but no power. We've chnaged fuel filter, Overflow Vlave, and Lift Pump. The shop (who is a buddy of mine, but doesn't know much about Cummins) said it was really hard to bleed the lines.
1. Before I buy a new 7100, or rebuild mine, how do I know its bad? If I can't check it, how do I know how a good shop can check it?
2. I was quoted $900 to $1,000 to take mine off, send it off for rebuild, and reinstall it; does this seem reasonable?
3. How hard is it to switch out the 7100, can I do it, or is it pretty involved?
The truck has 265k miles on it. I bought it used at 260 and don't have any history. Unfortunately, I don't have any guages on it yet.
Thank you.
1. Before I buy a new 7100, or rebuild mine, how do I know its bad? If I can't check it, how do I know how a good shop can check it?
2. I was quoted $900 to $1,000 to take mine off, send it off for rebuild, and reinstall it; does this seem reasonable?
3. How hard is it to switch out the 7100, can I do it, or is it pretty involved?
The truck has 265k miles on it. I bought it used at 260 and don't have any history. Unfortunately, I don't have any guages on it yet.
Thank you.
Last edited by AltavistaLawn; 11-12-2006 at 10:11 AM. Reason: typo
11-12-2006, 11:22 AM
#2
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I would be more inclined to look at possible fuel delivery problems to the pump, timing slipping or clogged (dirty ) injectors than a bad P7100. Hows the air filter and turbo? Not saying the pump doesn't have a problem but it would be one of the last suspects on my list.
11-12-2006, 11:53 AM
#3
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The price you were quoted is very good.
It could very well be your timing has slipped though.
What makes the decision difficult though is that it normally costs around $200 to have your timing changed. I'm sure in your quoted price the timing could be set to whatever you want. 16° is great.
It could very well be your timing has slipped though.
What makes the decision difficult though is that it normally costs around $200 to have your timing changed. I'm sure in your quoted price the timing could be set to whatever you want. 16° is great.
11-12-2006, 01:52 PM
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Are you having rough idle? White smoke? I am leaning towards timing as well. I just went through a crash course so to speak about the cummins motor in the last month.....
Start with the inexpensive and easy to check items first.
Check timing then put some gauges on it.....
Start with the inexpensive and easy to check items first. Check timing then put some gauges on it.....
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11-12-2006, 06:53 PM
#8
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if it runs fine but feels gutless, I'm looking for a torn AFC diaphragm...
no AFC means the fuel lever arm doesn't go very far forward at all, espeically on a stock truck with lots of AFC tension! if that's the case, it's like only being able to press the pedal down about 1/4 way
no AFC means the fuel lever arm doesn't go very far forward at all, espeically on a stock truck with lots of AFC tension! if that's the case, it's like only being able to press the pedal down about 1/4 way
11-13-2006, 07:39 AM
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just pull the afc and the plate, put a piece of tape over the open hole and take it for a short test drive. if it smoke like crazy and runs like he11 it is in the afc.
11-13-2006, 08:56 PM
#11
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One of my guys is going to tackle this tomorrow. Is this the plate he removes, the cover with the 4 screws and cover this opening with tape? , and go by this article?
http://www.cumminsdatabase.com/read.php?id=58
Thanks, Billy.
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picklesweet (06-12-2023)
11-14-2006, 06:13 PM
#13
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Gun, and you other guys, you're the bomb! Or I should say Bomb-ers. 
We did the tape trick. Heres what happened:
At first the truck barely would run, then about a mile down the road, it broke loose, it make a loud psssst noise, then the black smoke rolled, and it ran like a demon. My buddy was driving it, he said, "I never would have believed a diesel would pin you to the seat like that!"
Now the peculiar part, he reassembled it, and it still runs fine. Other than the fuel shut off solenoid was either broke, or we broke it dissambling it .
Either something was seized in the pump (hooking to the AFC) or the fuel cutoff was partially closed, and it opened up after the drive??
Anyway, looks like the 7100 is fine, I drove it about 50 miles this evening and it done fine.
Now to find a good source for the fuel shut off solenoid.
Thanks everyone.
We did the tape trick. Heres what happened:
At first the truck barely would run, then about a mile down the road, it broke loose, it make a loud psssst noise, then the black smoke rolled, and it ran like a demon. My buddy was driving it, he said, "I never would have believed a diesel would pin you to the seat like that!"
Now the peculiar part, he reassembled it, and it still runs fine. Other than the fuel shut off solenoid was either broke, or we broke it dissambling it .
Either something was seized in the pump (hooking to the AFC) or the fuel cutoff was partially closed, and it opened up after the drive??
Anyway, looks like the 7100 is fine, I drove it about 50 miles this evening and it done fine.
Now to find a good source for the fuel shut off solenoid.
Thanks everyone.
11-14-2006, 06:36 PM
#14
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OK, now to hi-jack my own thread.
New topic, Fuel Shut-Off Valve. I found this link in a search , posted by "Infidel":
http://www.fostertruck.com/dodge/default.htm
Mine doesn't have that lower section, so half of mine is gone. My FCS ends where the rubber boot used to be.
So I don't gues I can rebuild mine?
New topic, Fuel Shut-Off Valve. I found this link in a search , posted by "Infidel":
http://www.fostertruck.com/dodge/default.htm
Mine doesn't have that lower section, so half of mine is gone. My FCS ends where the rubber boot used to be.
So I don't gues I can rebuild mine?
11-14-2006, 06:53 PM
#15
Registered User
Personally if I ever had a shutdown solenoid fall I'd just replace it with a choke cable type manual shutdown. Easy to do, about $150 cheaper and infinitely more reliable.
No more blue wires, relay or starter contacts to worry about.
No more blue wires, relay or starter contacts to worry about.