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17 minutes ago, Marcus2000monster said:

What would cause my truck to start loping when it’s idling? 

 

Either air in the fuel or bad injector pop pressure (too low). If the injector pop pressure is too low the spray droplets get too big and the fuel doesn't ignite easily which creates a lopey idle typically. I would say it time to look at injector pop pressure and verify you have no air in the fuel. 

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Just now, Mopar1973Man said:

 

Either air in the fuel or bad injector pop pressure (too low). If the injector pop pressure is too low the spray droplets get too big and the fuel doesn't ignite easily which creates a lopey idle typically. I would say it time to look at injector pop pressure and verify you have no air in the fuel. 

Gee I don’t want to pull them Iv only got 10k on them now. Air in fuel was my thoughts. Might put in alll new fuel lines and really look over that fuel tank outlet again. That’s where my last AIF issue came from.

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Just now, Marcus2000monster said:

Gee I don’t want to pull them Iv only got 10k on them now

 

@pepsi71ocean only had 28k and he was below 280 bar. 

 

My first set of SAC 7 x 0.0085 injectors where under 280 bar within 7k miles. They do settle sometimes creating these issues. Like my current 7 x 0.008 VCO are somewhere around 80k miles and getting too low in the pop pressure. 

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32 minutes ago, Mopar1973Man said:

 

@pepsi71ocean only had 28k and he was below 280 bar. 

 

My first set of SAC 7 x 0.0085 injectors where under 280 bar within 7k miles. They do settle sometimes creating these issues. Like my current 7 x 0.008 VCO are somewhere around 80k miles and getting too low in the pop pressure. 

Wow that’s surprising. Well looks like I’ll be pulling them. May just send my oem sticks in for a rebuild. Should I do that or buy brand new Bosch injectors?

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2 hours ago, Marcus2000monster said:

Gee I don’t want to pull them Iv only got 10k on them now. Air in fuel was my thoughts. Might put in alll new fuel lines and really look over that fuel tank outlet again. That’s where my last AIF issue came from.

 

When you put the injectors back in did you loosen the blue lock bars before you tightened down on the high pressure nuts? They are to go on snug, and then after you tighten the nuts down then tighten the injector hold down brackets?

Have you tried parking the truck downhill to rule out a fuel leak?

 

As for me, I went from 300 bar to 280 in 33,000 miles. I wouldn't doubt that the injectors could be popping off low.

Edited by pepsi71ocean

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3 hours ago, Marcus2000monster said:

Wow that’s surprising. Well looks like I’ll be pulling them. May just send my oem sticks in for a rebuild. Should I do that or buy brand new Bosch injectors?

 

Just what @pepsi71ocean did was send in his +100 HP injectors and had them re-popped above stock and now cleaned up all his extra smoke and still starting good. I think there is a variable for altitude here that might change some of this.

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4 hours ago, pepsi71ocean said:

 

When you put the injectors back in did you loosen the blue lock bars before you tightened down on the high pressure nuts? They are to go on snug, and then after you tighten the nuts down then tighten the injector hold down brackets?

Have you tried parking the truck downhill to rule out a fuel leak?

 

As for me, I went from 300 bar to 280 in 33,000 miles. I wouldn't doubt that the injectors could be popping off low.

Not sure if I did that or not it’s been a while since I installed them 

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I dont know whether I have done it that way. But I would think it would be the last thing to do in the process just to keep the lines loose enough to  re connect. @pepsi71ocean just wondering what the reasoning is behind this? 

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10 hours ago, Mopar1973Man said:

 

Just what @pepsi71ocean did was send in his +100 HP injectors and had them re-popped above stock and now cleaned up all his extra smoke and still starting good. I think there is a variable for altitude here that might change some of this.

 

I believe that altitude, and injector size affect pop pressure and the amount of overage you can go whithout stalling and operational issues.

 

5 hours ago, dripley said:

I dont know whether I have done it that way. But I would think it would be the last thing to do in the process just to keep the lines loose enough to  re connect. @pepsi71ocean just wondering what the reasoning is behind this? 

 

It was a trick I learned from a diesel mechanic I knew who was in his 70's. he said that you can't have a high pressure leak if you loosen the lock bars and the lines. He told me that sometimes if you have the blue lock bars tightened you can't get a good sealing on those high pressure lines, and while you may think your snug plus a 1/8 turn that your really not. He stated that you need to let the parts seat naturally, and not be forced to be in alignment. He said that in 40 years of diesel work he's never had to deal with a high pressure leak from a diesel when doing it that way.

 

He said torquing goes as follows.

 

Injection Pump->high pressure nut->injector side of high pressure nut->Injector hold down bar-> blue lock bars.

 

i will say that since I've started doing this I haven't had any issues with high pressure leaks since. Although i can say that at least our trucks are easier to align, try injectors for a common rail haha.

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2 minutes ago, pepsi71ocean said:

Injection Pump->high pressure nut->injector side of high pressure nut->Injector hold down bar-> blue lock bars.

Thats pretty much how I guess I do mine. Just never give the blue lock downs any thought. I know I loosen them to get the lines loose and doing them last just seems natural.

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8 minutes ago, Marcus2000monster said:

Good to know Pepsi. When I get the spare money I’m going to buy oem injectors and I’m thinking about having them set them above standard pop so when they settle in hey will run better. 

 

I wouldn't set them above 300 bar if they are stock injectors. IMO then you run a risk of starting issues. Popping them higher is only useful on larger injectors and its a theory with only 4 members reporting back about using them.

 

The larger the injector the more slippage you can get, I have heard that some guys can set them 10% higher without issue on stock injectors, but then your missing timing.

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I'll be the next to head down this trail. I going to do the 320-325 bar range but most likely jump to 7 x 0.010 injectors. I'm going to use my OEM stock injector bodies and have them nozzled up and jump in the game. 

Edited by Mopar1973Man

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All this talk about injector failure makes me hesitant to pull the trigger on a set. I certainly don't want to replace injectors every 20k miles.What brand injectors are we talking? I trust and like DAP but I realize it's a budget injector. Is it worth spending more money for a better injector like Infinite? Or is this a performance injector problem in general?

Edited by dave110

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36 minutes ago, dave110 said:

All this talk about injector failure makes me hesitant to pull the trigger on a set. I certainly don't want to replace injectors every 20k miles.What brand injectors are we talking? I trust and like DAP but I realize it's a budget injector. Is it worth spending more money for a better injector like Infinite? Or is this a performance injector problem in general?

 

I don't think its any one company per say. I think that anytime you have larger injectors this is a possibility. granted that my truck running stock seems to be fine with smoke and performance. But my start the smoke started right after it dropped pop pressure off. But I didn't know it.

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2 hours ago, dave110 said:

All this talk about injector failure makes me hesitant to pull the trigger on a set. I certainly don't want to replace injectors every 20k miles.What brand injectors are we talking? I trust and like DAP but I realize it's a budget injector. Is it worth spending more money for a better injector like Infinite? Or is this a performance injector problem in general?

 

If you’re staying on the smaller size, I think you’d be surprised at how little a price difference it is between Infinite and others.

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It is definitely worth spending more money for a quality injector; pays off in the long run, which is what Cummins are all about.

 

I will give Mark @ DieselTuff.com a shout out.

 

He has Genuine RV275s in stock (there's plenty out there who sell aftermarket RV275s) as well as higher HP units in whatever flavor you want.

 

Hand built & POP'd to your specific application, unlike the middlemen resellers who I don't care to name for the sake of civility; turnaround with Mark is barely a couple days before he builds & ships.

 

And yep, Weston is great at what he does as well :thumb1:

Edited by ofelas
sp mistakes

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So.... I'm kinda thinking here... why are we having problems with injectors loosing pop with 20-30k on them? And originals go for 100k +. Could it be similar to front coil spacers, you put a spacer in for a heavier bumper or a plow, or just for looks, but it doesn't really support much more weight. Or you buy plow springs or springs that are longer to eliminate the spacer. Same with injector, I doubt springs get changed, more than likely just reshimmed. 

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1 minute ago, Dieselfuture said:

So.... I'm kinda thinking here... why are we having problems with injectors loosing pop with 20-30k on them? And originals go for 100k +. Could it be similar to front coil spacers, you put a spacer in for a heavier bumper or a plow, or just for looks, but it doesn't really support much more weight. Or you buy plow springs or springs that are longer to eliminate the spacer. Same with injector, I doubt springs get changed, more than likely just reshimmed. 

‘‘Tis very interesting. I plan to go stock with my next set which is hopefully soon. Genuine Bosch injectors. Nothing against DAP but I don’t like the way my 75s run. It could be another issue such as air in fuel but we will see. I still am going stock either way becuase the OE injectors obviously last longer and won’t have lag and smoke for those that don’t have tuning. 

13 hours ago, ofelas said:

It is definitely worth spending more money for a quality injector; pays off in the long run, which is what Cummins are all about.

 

I will give Mark @ DieselTuff.com a shout out.

 

He has Genuine RV275s in stock (there's plenty out there who sell aftermarket RV275s) as well as higher HP units in whatever flavor you want.

 

Hand built & POP'd to your specific application, unlike the middlemen resellers who I don't care to name for the sake of civility; turnaround with Mark is barely a couple days before he builds & ships.

 

And yep, Weston is great at what he does as well :thumb1:

Does he sell oe stock hp injectors? 

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His site is performance oriented, but give him a holler (sales@dieseltuff.com) & ask him, he seems to always have stuff that's not on the web site.

 

Ask him about spray angles/piston bowls & POP pressures for your application/intended use.

 

Having said that, the RV275s are a Bosch injector off the slightly higher HP motorhomes, I feel they're the best stock type injectors available for the 98.5-2002 24v.

 

 

Edited by ofelas
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If you looking for flow amount most like the lower pop pressures. Now if you are looking for economy you need higher pop pressures.

 

Low pop pressure will flow more fuel over time but the droplets are larger and tend to create more black smoke. Now high pop pressures create better atomization but does reduce the flow amount over time. Not to mention high pop pressure means slightly retarded timing as well.

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1 hour ago, Marcus2000monster said:

I may go with a set of RV275S that is a possibility. 

That's as close to stock as you can get.   Make sure they are the Bosch RV275 and not some cheap knock off junk.  I bought mine from DAP last spring.

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10 hours ago, Dieselfuture said:

And originals go for 100k +.

240k+ on my oe ones. Never lost any milage or performance that I noticed.

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