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Miss at all RPMs

TFaoro
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TFaoro

TFaoro

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Ordered? Ok so what did you pay for it? From who did you order it?

The "slug" or whatever it's called that goes in the injector hole I ordered from Star Products. They say it will work on the CR too, so at least I can use it on my brother's truck if need be. I went to Cummins today and the guy I talked to had the wrong part number. He looked up some sort of injection psi tool??? Come to find out Cummins doesn't even make it. I couldn't see spending 120 bucks on a snap-on one when this one was 49.70. I looked it up and people on other forums seem to have had good luck with it. As for the gauge I went with the one Mulcher suggested. It should be accurate enough to tell me if there is internal damage on any of the cylinders. 

 

This is what's bad... People start doing the swapping of parts and never exactly know what had failed or failing and continue to install parts till its fixed. This is a very expensive method of repair. I'd rather invest money in a few tools and bench test properly and know without a doubt what has failed and deal with it properly than guessin'.

Admittedly that probably wasn't my smartest move, but I did want to get a bigger set before the warranty was up. It only cost me 100 bucks to go from DAP 90s to DAT sac 125s. And I would have to say these injectors now are WAY better than the 90s.  

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TFaoro

TFaoro

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It says it's in there... But I can't tell which one. I've got the gauge with me and the slug is supposed to come in Monday. Tuesday night I will know the condition of the internals! On a side note I put the original crossover tubes back in tonight and it has lessened how harsh the motor sounded. Before when the grids would kick in it would make the motor lope a and now it's smooth. 

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TFaoro

TFaoro

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Ok guys I got #1 and #4 compression tested. #1 had right around 440 psi and #4 had somewhere around 430 psi and I plan to test all of them tomorrow. But from the looks of it number 1 is ok. I am also going to leak down test each cylinder but I'm not sure how to hold the engine still without a baring tool? Any ideas??

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MnTom

MnTom

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Heading out this morning to compression test all 6 and do a leak down test on all 6!

I was going to tell you to test all six. Testing one or two doesn't mean much. The main thing with the comression readings is to have them within 10% of each other.

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TFaoro

TFaoro

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Results: I cranked the engine over for 4 seconds with a timer for each cylinder

1- 410 

2-415

3-400

4-410

5-400

6-410

 

Compression looks good for all of them. 

As for the leak down I have one cylinder that has a very small leak coming out of the intake when at 100psi. It also sounds like it is gurgling a bit so I think there is oil leaking down on it. 

 

None of this points to a problem that would cause a miss like it has though. I may look at some new valve seals but I'll have to see. Any ideas guys?

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Mopar1973Man

Mopar1973Man

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Well you confirmed the cylinder health is good now you'll have to move on to the injectors. Have them pop tested.

 

TFaoro was that compression test supplied by Harbor Freight have all the right fittings for testing? If so I'm going to look into buying a compression gauge myself. I work on enough diesel locally I really could use it.

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rancherman

rancherman

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The  cylinder that  is  sizzling/gurgling is the one  I'd  expect  that is  not firing  quite right.   It's probably  'wet',  and  that 's what you're hearing.    Wet from  fuel, and not  oil.

 

Now,   to zero in on why it's  coming  back through  the  valve,  might  be  just  a blob of  wet  crud  that  should  hammer out  when  it  (cylinder)  is firing  hot again...       It  doesn't take much of a  crumb to hold a valve  off  it's seat.

 

Your  compression numbers  are  nice and even...   I've sure seen    higher spreads  and   we  put  a  lot more hours  on it before  a rebuild!

Safe to say  you've eliminated several  possibilities today!

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Dieselfuture

Dieselfuture

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I guess I'll send the injectors out during Christmas. I may do the VP at the same time... No the kit did not come with the slug. Here is where I got my slug https://www.tooldiscounter.com/ItemDisplay.cfm?lookup=STATU-15-27

I don't know if this will help at all, but I had a miss that went on for few years, finally listened to all smart people on this site and changed injectors and immediately miss was gone. But my truck only did it when pulling trailer and putting load on it. But a year or so went by and I just experienced same miss last time pulling. Really pissing me off. So yeah it's hard to believe new injectors can be bad but I don't see another reasonable explanation. I've done almost all tests to eliminate sensor and vp problems and it lead to replacing injectors. And now I just haven't had time to call dap and see if they can test their rebuilt 60hp injectors correct problems if any and see if it does it this time. I hope they do as they have good reputation. Good luck with your problem, I feel your pain.
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Dieselfuture

Dieselfuture

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I don't know if this will help at all, but I had a miss that went on for few years, finally listened to all smart people on this site and changed injectors and immediately miss was gone. But my truck only did it when pulling trailer and putting load on it. But a year or so went by and I just experienced same miss last time pulling. Really pissing me off. So yeah it's hard to believe new injectors can be bad but I don't see another reasonable explanation. I've done almost all tests to eliminate sensor and vp problems and it lead to replacing injectors. And now I just haven't had time to call dap and see if they can test their rebuilt 60hp injectors correct problems if any and see if it does it this time. I hope they do as they have good reputation. Good luck with your problem, I feel your pain.

P.s. I would wait on vp, no reason to change it if it's still kicking. I almost changed mine tracing my problem and glad that I didn't, never know new one can have a bad computer in a year or sooner.
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Mopar1973Man

Mopar1973Man

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I would opt for the injectors to be tested. If cylinder health is good then its a fuel issue... There is only 2 things needed for diesel to fire. Compression and fuel. So if the compression is correct then its going to be a fuel issue. I still think injector pop testing is in order. It might be just a poor tuned injector maybe or something sticking? Won't know till you do some more testing.

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TFaoro

TFaoro

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Thanks for the tips guys! Sorry I have been away for the holiday. If I do anything with the VP it will be sent to Industrial Injection to be tested. I will not just replace it for the heck of it. I will likely hold out on the VP and send the injectors in to be tested over Christmas. I'm not sure why changing from one hole to the other didn't make a difference though?? I took it to a guy who owned a diesel shop for years and he said it sounds like an injection knock. On a positive note I drove back to school today and netted 23.6 mpg (Distance was calculated using a GPS)  It was about 30 miles at 65mph 50 miles at 77mph and the rest at 70. That is my best mileage to date.. Even better than the 90hp injectors! Oh and forgot to mention the first 50 miles I had a HARD head wind to fight.

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