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Odd injector misfire


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  • Owner

Another project I've been working on. Last week running the Cummins it would come to a idle and lightly misfire for a very randomly. Out of respect for Eric at Vulcan Performance I didn't want to post this till I found a solution or it was resolved. But I pull them all the injectors out, inspected them and didn't see any thing wrong with them so I assembled them back into the head. Still had the misfire with a warm engine. So I pull them back out and contacted Eric and sent them in to be inspected by him. As far as what I was told by Eric there was nothing wrong with the injectors and popped tested fine. So I got them back today and made sure to clean all the tips of the cross over tubes, injector lines, etc. Added my dab of grease for copper shims and lubed the cross-over tube o-rings. Paid attention to torquing and assembly order. Went back together and... No miss now. Plain weird. But I figure I would post up my adventure in Cummins... :truck:

 

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  • Owner

How would the cross over tubes cause a misfire???

 

Well I might of damaged on cross over tube with a injector that came loose some and might of distorted the tip of the cross over tube enough not to seal any more. It's a gambling guess because there is no way to see if the tube is leaking or not. But the difference between TFaoro and myself is my does NOT miss on a cold engine only after hard running. Then after it idles for a extended period it goes away and fire normally.

 

The reason I had Eric pop test again was that was exactly how my RV275 injectors failed. They got down to about 240-260 bar and pissy. Which created the misfire issue. Well Eric verified the injectors and they are all still within 100 PSI of what was originally set. So the injectors are not the cause. But he suggested looking at the cross over tubes next. But ultimately it "might" be VP44 time. :sofa:  I'm not going to go there yet because there is no error codes, no issues other than the mild misfire at idle.

 

For me to to just place my foot on the brake pedal heavy or just turn on the A/C and the miss goes away. :shrug:

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Well I might of damaged on cross over tube with a injector that came loose some and might of distorted the tip of the cross over tube enough not to seal any more. It's a gambling guess because there is no way to see if the tube is leaking or not. But the difference between TFaoro and myself is my does NOT miss on a cold engine only after hard running. Then after it idles for a extended period it goes away and fire normally.

 

The reason I had Eric pop test again was that was exactly how my RV275 injectors failed. They got down to about 240-260 bar and pissy. Which created the misfire issue. Well Eric verified the injectors and they are all still within 100 PSI of what was originally set. So the injectors are not the cause. But he suggested looking at the cross over tubes next. But ultimately it "might" be VP44 time. :sofa:  I'm not going to go there yet because there is no error codes, no issues other than the mild misfire at idle.

 

For me to to just place my foot on the brake pedal heavy or just turn on the A/C and the miss goes away. :shrug:

 

 

I was gonna suggest that it may be the VP, but I didn't want to make you cry!!! :cry:  :doh:

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  • Owner

190k miles as it stands right now. I was hoping to clear 200k miles before it was replaced. I might just do it anyways. Cram the last 10k on her and then... But first try the cross over tubes first. I'm not going to complain much being that pump is 11 years old and 190k miles. Served me well. The OEM VP44 was replaced at 50k miles in 2004 under dealer warranty with a P0216 error code and heavy white smoke issues in the mornings.

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190k miles as it stands right now. I was hoping to clear 200k miles before it was replaced. I might just do it anyways. Cram the last 10k on her and then... But first try the cross over tubes first. I'm not going to complain much being that pump is 11 years old and 190k miles. Served me well. The OEM VP44 was replaced at 50k miles in 2004 under dealer warranty with a P0216 error code and heavy white smoke issues in the mornings.

 

 

So you're around 240,000 miles on your truck now???  I hope for your sake it is the cross over tubes.

 

I'll be turning 220,000 on Mighty Whitey this weekend on my annual SEMO snow goose hunt.

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I  thought the sure fire way to  'see' if  cross over tubes  leaked....  was  to park the truck  uphill overnight.   and see if it   starts easily  the next morning?

 

Then   I'm wondering if  your 'lope'  is   a stuck  timing advance piston..   which  hasn't  come  back to 'home'  after your  hard pull?

 

You've   proven the  injectors are   ok..   other than    a  crossover tube,  or  too much  timing at idle.. air in the line  (how dare  air  being in Mikes'  line!)      That's about all  there is  with a  lope..

 

 

edit,,   this is about  lope isn't it?    I was  directed to this thread  from another post  dealing with lope..   But  Mikes  talking about  a slight miss  here..     which is it??

Edited by rancherman
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My 02 had a really good lope with the HRVP44 from II and was the worst at full operating temps on hot days, cooler was less pronounced than hot conditions, It was like a top fuel dragster lope with smarty on top of the HRVP44 with the 155 injectors and was totally undrivable no matter the Edge comp smarty stack combinations and was when The smarty went down the road for it.

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My 02 had a really good lope with the HRVP44 from II and was the worst at full operating temps on hot days, cooler was less pronounced than hot conditions, It was like a top fuel dragster lope with smarty on top of the HRVP44 with the 155 injectors and was totally undrivable no matter the Edge comp smarty stack combinations and was when The smarty went down the road for it.

I remember  reading  in a  bluechip  article about  their  'box'  would do this,  and   it's  expected...  at a  certain setting.    IIRC   either  chip or  doug   added to  the article about  some other  sort of   'early warning' of  the  44     when  the lope   suddenly   started (without a tuner that is)

Edited by rancherman
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My lope started when I installed the HRVP44 fresh from II with everything already in place, with an SO pump no lope added HRVP and it loped and put 90K+- on it that way up until I sold the 02. Just a few months before selling it I swapped from 155 bd injectors to 100 hp Scheid injectors and it made the lope a wee bit less but still definitely there.

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