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New DAP 100HP SAC 7x9 injectors


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I just got my replacement injector yesterday since one of them from the original 6 was causing a severe miss at idle, like the pop off pressure wasn't set right.

 

I put the injector in my 01 Dodge Ram 2500 Cummins HO 6 speed 4x4 that I bought 12/5/2020, and it doesn't miss now, but it lopes like it has a cam in it. Unbeknownst to me as this is my 1st HO Cummins (my two previous were '99 Ram 2500 Cummins with a 47RE trans and SO VP44 pumps. I just found out that my Industrial Injection VP pump that is on my pickup when I bought it, is the HO pump. Apparently since the HO pump is a low volume/ high pressure pump, it can't provide enough fuel to feed the 100 HP injectors, hence the idle not being as smooth as normal. I removed them last night and installed my stock Bosch injectors and it runs smooth like it did before I installed the 100 HP injectors.

 

Since I only put 10 miles on the injectors, can I send them back and exchange them for 75 HP SAC injectors?

 

Thanks,

 

Doug

Edited by 99_Cummins_4x4
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I would send those 100 HP injectors back for pop testing under warranty. I know a lot of injector builder have set there pop pressure lower 300 to 305 bar (4,351 to 4,423 PSI) to increase the fuel flow. Myself I went the other direction. I'm running 7 x 0.010 popped at 320 bar (4,641 PSI). It does make a difference in MPG and longevity because the bottom limit 293 bar (4,250 PSI).

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I already sent one new injector back and just installed the replacement in it, and it acts like there's a rv camshaft in the motor. It ran great going down the road for a few miles, just noticed the lopey idle.

 

I took the 100 HP injectors out and put my stock HO injectors back in, and the motor runs smooth like normal again.

Edited by 99_Cummins_4x4
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I talked with Brayden at DAP a little bit ago. He sent me a RMA to send the injectors back to test their pop off pressure. 

 

He said DAP sets their 100 HP SAC injectors at 312 Bar. Their 75 HP SAC injectors are set to 308-310 Bar. He looked it up on their system and said they show stock injectors at 307 Bar. 

 

 

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DAP won't take the injectors back and exchange them for 75 HP injectors for me, but they will test the pop-off pressure on them under warranty.

 

Should I have them set the BAR on them to a certain pop off pressure since I have the HO pump? I'm new to understanding the pop-off pressure aspect of the pump and injectors.

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Remember the pop pressure only controls the starting point of injection at what pressure. Both HO and SO pump can reach upwards above 18,000 PSI.

 

Like my injectors being raised in pop helped for efficiency and longevity but it makes the timing late so ive got to add more timing on the Quadzilla.

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