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Discussion Starter · #1 ·
I ended up putting this in another post about the MP-8 last night, But its not really the same question. So I thought I would start a new one. I know I'm a "newbie"... just is their any thing that I can do right now?? Here is what happened last night



Hey guys,

New problem with my MP-8.

Everything went good, all the plugs seem to fit tight. Went to try to start the truck and it wouldn't. I've read this post ten times before my MP-8 got here and was assuming that the plug on the cab side of the rail was loose. Just absolutely reefed on it trying to get it tighter and tried to go start the truck again....No starty.....

Then I put the factory plug back in and it acted like it wasn't going to start, then finally started and ran fine, smooth and sounded great.

Then I was like well that connection isn't tight enough. So I put the MP harness back on and tried to get it tight as possible and tried to start the truck again. No starty....

So then I was like F*** it and put the factory plug back in. Just so I could go to the bar and play some pool. Now the truck won’t start with the factory plug in it. I don’t know what to do.

Is there any way that the plug you have to shim could have anything to do with the truck not starting. Could that one plate slide out ( I did re-punch the divots to hold it in place) and cause the truck not to start??? What else could it be??? Is their like some trick to do???

Thanks for the help guys.

John

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Update,

Just took the regulator out and put it in the vise and slowly worked it to just get some movement out of it. Put it back in and the truck started right up. (This is with the factory plug in the end of the rail) Take it for a drive down the street and is say "service immediately" and the truck ran like poop. Took it back to the house and turned it off, then waited about 30 seconds and tried to start it again. And it won’t start....

That’s the update as of now...

Any ideas?

Gonna take the regulator out and remove the shims to see if it runs right totally stock.

Thanks,

John

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So I just took all the shims out and it started and idled....but when I went to put it in reverse it died, and won’t start back up.

Calling it a night and going to get a drink..

John
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Just made a few calls and this one diesel guy in town says that I need to bring it back to Dodge and have them re-flash it to stock... because now the ECU doesn't recognize anything and it wont run.

It never ran with the MP-8 in it, so do you think this guy is right?

John :CRY:
 

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Discussion Starter · #2 ·
Took everything apart again, and it threw this code

P0087-fuel Rail Pressure Too Low

John
 

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is the little pin still in the end of the plug if you lost this then the fuel just goes strait through and will not build enough pressure to run right or yet even run at all
 

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Discussion Starter · #5 ·
is the little pin still in the end of the plug if you lost this then the fuel just goes strait through and will not build enough pressure to run right or yet even run at all
I think you just solved my problem...I don't remember a little pin at all. Can this fall out when you actually take the plug out of the rail, or does it have to fall out when you take the plug apart to put the shims in?

Huge help...

Thanks,

John
 

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It can come out when you take it apart to add the shims. It is about the size of a grain of rice.
 

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Discussion Starter · #7 ·
No pin...So I guess thats my problem. Does cummins have a parts diagram so I can get a part number to order one? Does anyone know where I can get another one anywhere? Being on foot sucks.

Thanks for all the help.

John
 

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Take a good look for it around your vice. I am not sure if it is magnetic, but it might make it easier to find if it is.
 

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4938005 is the Cummins part number for the fuel relief valve. It is about $240. Don't go to your dealer cause it is closer to $500 from them.

The Duramax fuel relief valve is identical and is less expensive but I don't have that part number.
 

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Discussion Starter · #10 ·
might have found it I will post a pic.

you guys are amazing

John
 

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For your wallet's sake lets hope you did:D
 

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Discussion Starter · #12 · (Edited)
Is this it?
 

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That looks like the only one I've seen in person.
 

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Discussion Starter · #14 ·
Thanks Guys,

If your ever around Montana, PM me and I will buy you a beer.

John
 

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that is it glad you found it, put that back in and you should be good, I am glad we could help you out
 

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I am glad to hear that you found it! Is it magnetic? How does your truck run now?
 

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Hey K2 if someone did lose parts from their original couldn't a guy use the plug you sell? I don't remember seeing that part when I did mine and of course even after I read the directions it exploded all over my garage floor. Thanks by the way, I bought my MP-8 from you. I think mine is alright I put about 100 miles on it and everything seems good.
 

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Hey K2 if someone did lose parts from their original couldn't a guy use the plug you sell? I don't remember seeing that part when I did mine and of course even after I read the directions it exploded all over my garage floor. Thanks by the way, I bought my MP-8 from you. I think mine is alright I put about 100 miles on it and everything seems good.
Thank you Eric:thumbsup

Yes you can use the optional plug should something happen to the fuel relief valve. However you only want yo use the optional plug if you are using the MP-8 by itself. If you are stacking you should use the supplied shim kit.
 

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Discussion Starter · #19 ·
Well the truck runs better now. Fuel mileage has been going up on the overhead, only went for a 20 mile drive or so. But anyways happy that my truck runs better than before. Thanks again guys for all the help.

John
 

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Glad to hear you're up and running. You got me thinking though I really don't remember mine having this when I reassembled it. Did you check to see if it's magnetic? I took it for a long ride after I put it together and it ran great so hopefully my memory is bad. But I will probably still rip my garage apart to see if I can find any parts.
 
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