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Miss at all RPMs

TFaoro
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MnTom

MnTom

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If you want to know for sure go ahead and swap it with another cylinder then check temps. If it follows the swap you know for certain. If not it could be anything from a cracked piston ring to your VP.

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TFaoro

TFaoro

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Like Mike said, I would probably be having them injectors pop and flow tested if possible. At the very least its pretty cheap and it will rule out the injectors for sure.

True, but like stated when I first dropped these injectors in the miss was the EXACT same as it was with the old injectors. A new crossover tube helped lessen the miss, then I put these drilled out ones in and the miss did not change. This leads me to believe it is a fuel delivery issue, but I could be way off. 

 

If you want to know for sure go ahead and swap it with another cylinder then check temps. If it follows the swap you know for certain. If not it could be anything from a cracked piston ring to your VP.

I think I might give that a go tomorrow just to see if it helps. I didn't think the VP could stop pushing fuel to only one cylinder, at least that's what Mike said. As for cracked rings I guess it's possible but I don't have any blowby out of the valve cover

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Mopar1973Man

Mopar1973Man

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Thatt's why I still suggest pop testing. Then you can rule out the injectors completely. Right now you randomly tossing money at parts without any proof of a fuel issues and where?

 

Hmmm, a couple days ago, you had a 'cold' #6, today, it's #1..

 

But still if it was me I would pull all the injectors out and pop test. While the injectors are being pop tested I would do a compression test just to verify and the injectors are out so it makes getting two birds with one stone.

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TFaoro

TFaoro

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This is my DD though... I can't have it down at any time. I think I am going to swap #1 and #3 injectors and see if the problem moves to the #3 cylinder. That would rule out the injectors. 

 

Hmmm, a couple days ago, you had a 'cold' #6, today, it's #1..

Could have been changing the crossover tubes.. If 6 wasn't seated and now it is, and 1 could not be seated I guess

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Mopar1973Man

Mopar1973Man

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Hmmm... Me I would call around and fine a shop that does free injector pop testing. Then see about renting a diesel compression test. Have a friend run the injectors out and have then tested. Then you can do the compression test. By time you finish you buddy should be finish and coming back. Shouldn't take much more than 1-2 hours tops if everything is planned out.

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TFaoro

TFaoro

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I called around ad couldn't find anyone to test the injectors for free, and everyone wants to take them apart. So I went ahead and switched #1 injector with #4 injector and it made no difference. #1 is still 177F while all others were 212-215F

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TFaoro

TFaoro

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Latest news on this: I just got back up to college. I went as planned and used an infrared temp gun. I found number 1 was 40-50 deg cooler than the rest. Number 6  was 10-20 degrees cooler than the rest as well. I decided to replace both of those crossover tubes to see if that would fix my issue. It definitely helped some, as the miss only sounds half as harsh as it did before and the exhaust has a less harsh miss feel to it. I didn't not have time to pull the valve cover and loosen the injectors before installing the new tubes.... So I'm hoping that is my issue. I forgot my temp gun at home so I won't be able to use that when diagnosing for the next couple days. Any thoughts guys?

If you look back in the posts I said that #6 was 10-20 deg cooler than the rest.... which it may have been just because the engine was cold and 6 is on the back side of the engine. #1 has always been significantly cooler than the rest and continues to be. 

I think I will go ahead with the compression test to tell me if the internals are okay. If they are I am going to have to look at the VP, ECM or PCM. Any ideas Mopar Man?

 

Does anyone on here have a compression tester they would let me borrow? I would pay shipping and some on top for letting me use it. I just don't want to go buy one of these to use once. 

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TFaoro

TFaoro

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I don't have any 8mm wrenches... So there was no way for me to loosen the right side injector hold down... And to re-torque them properly I had to have it off. And yes I used the valve cover bolt but thank you for the tip!  :thumb1:

There is nothing clogging any of the lines. I had them all off and cleaned the tips and blew them out. 

 

Talked to my performance guy... He is leaning toward a cracked exhaust valve, as is a friend of my dad's who owned his own trucking company for 20 years. 

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Ilikeoldfords

Ilikeoldfords

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Oh. I totally forgot those earlier posts!! You may be able to rent a compression test kit from a parts store for fairly cheap. That would definitely be the next place to look for problems. It would appear that you have covered the fuel system diagnostics pretty well. Injectors, lines, tubes, etc. I dont believe the VP could be at fault with only one hole not firing like that.

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TFaoro

TFaoro

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I guess I'll give him another call tomorrow... I need this thing in by thanksgiving though whichever route I go. I plan to test compression and do a leak down test next Tuesday. If all comes back well internally what else could it be?? Is it possible the VP is screwed up? Just looking for thoughts to try if the pistons, rings, valves, and gasket are good. And how likely is a head gasket? I've hit 52-53 psi a couple times but I don't see any leaks around the sealing surface

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