First set of new injectors from dap, had to send back for warranty, put 2nd set in then had to do the same thing again. With this being the 3rd set am I just having really bad luck with injectors or is something else causing it? 

I keep getting a knock/ping and sounds like a bad miss if u (more prominently)coast and very lightly tap or ride the throttle and just runs rough/ just not how it should. Runs rough and knocks when normal driving the same just more so as stated above.

Why do I keep getting this knock etc? Is the vp44 causing this to go down stream? Fuel psi is consistently 16psi, no codes or check engine light (doesn't mean awhole lot but..) 

This has all been in a very very short period of time. The last thing added was the quadzilla adrenaline but I don't see it being any issue? 

 

Only things I can think of is 1- injection pump (runs great) 2- injector lines or tube (mating surfaces looked good) 3- just getting bad injectors. 

 

What the heck?

Edited November 10, 20213 yr by Stanley

I think at this point we're all scratching our heads. Next logical thing is to change vp I suppose. I don't see how running bigger tubes and lines will hurt anything with regular pump. I can see when you go to a bigger pump that you would need them so you get full potential of the flow it can produce, going backwards shouldn't matter in my opinion but I honestly don't know just thinking out loud.

I don't think it would work to well, essentially the injectors would just suck the lines dry cause it can push/handle large amounts out but the pump can't fill lines/tubes back fast enough for next round. At least that's the way I see it. I mean if someone's done it with large lines and knows what to expect I'm all ears. I'm gonna have to inspect my stock lines and I'll post pictures. 

Did some digging, bigger lines and tubes can cause an aggressive lope and stalling with a normal vp44. You can use just the larger connector tubes with no issue, to the point that one person saw a 5hp increase with them vs stock.. but i dont think its worth 5 hp, 10 is the general number to feel a difference on the butt dyno.. but even then they are inaccurate and impossible to calibrate..

24 minutes ago, Silverwolf2691 said:

Did some digging, bigger lines and tubes can cause an aggressive lope and stalling with a normal vp44. You can use just the larger connector tubes with no issue, to the point that one person saw a 5hp increase with them vs stock.. but i dont think its worth 5 hp, 10 is the general number to feel a difference on the butt dyno.. but even then they are inaccurate and impossible to calibrate..

Yea I read kinda the same stuff, tubes are ok with stock. Idk which way I'll go on that...

 

So what do I make of the tank pressure? The vapor "smoke"? Contribute that to the pump as well? 

Here's those injector lines. 

 

 

No need for bigger tubes or lines like said above when your over 600 to 700 HP. Keep in mind bigger lines and tubes are going to offset timing more retarded being it will take more pump time to Reach pop pressure.

35 minutes ago, Mopar1973Man said:

No need for bigger tubes or lines like said above when your over 600 to 700 HP. Keep in mind bigger lines and tubes are going to offset timing more retarded being it will take more pump time to Reach pop pressure.

This is what's throwing me off, I didn't think liquid is compressible unless diesel is. 

I was just saying if you didn't have good stock lines and tubes he could maybe use the oversized ones. 

The lines expand and pump components deflect under the high pressure which creates delays, then there's line propagation for the pulse to reach the injector. Delivery valves help keep some residual pressure in the system. The pump cam is curved not squared off so fuel delivery is non linear. The first few degrees of injection is only a small amount then increases with every degree as the cam profile becomes more aggressive. Bigger injectors get more fuel in quicker and earlier. Big shots of late fuel tend to cause high EGT and smoke.

If yall think those lines above (pics) are usable after a good clean and polish Ill use those and my new tubes so Ill be back stock on that part. 

Lines yay or nay

 

Stock lines might give me the ability to use my AC finally with out the huge lope/lug...

 

Now on to that fuel tank deal. Ive read a bit on it but idk if my situation would contribute to that or is there another issue? Top of the fuel tank is wet, probably would be obvious in conjunction with... 

8 hours ago, Stanley said:

 

Stock lines might give me the ability to use my AC finally with out the huge lope/lug...

Absolutely... 

I guess I'm looking for reassurance in the lines above and the pump making my tank pressurize... 

I tend to over think things alot so this is why I ask.

Anymore thoughts on the tank issue?

Pressure in the fuel tank is not a good thing. Typically that is cause by compression gases being forced into the return rail back to the fuel tank. 

• Injector copper not sealing
• Cracked head
• Blown head gasket

Just the few reason I've seen for pressure in the fuel tank. I would look at the injectors again and making sure the crossover tubes are tighten first then the injector hold down. Then been sure to tighten the injector hold down to 89 inch/pounds.

Hopefully not either of the last two... 

Everything that has happened has been directly after injectors and I guess I can add the quad in there too. 

 

I'm thinking everything has just all been fuel related craziness. So there will be a new  sovp44, re try those 6x13's, new oem injector tubes, clean up those stock lines above hopefully and use those. Back to a known standard operation. 

Guess what I found? 

Was about to get started on pulling stuff out to replace lines, tubes, 6x13 back in and new vp44... Didn't really do much after finding the  code so I'm just now seeing this...

 

Broken injector hold down, just laying there, glad it didn't get into anything... This is prolly my tank pressure...

 

 

Edit: it is #3 injector.

Yup that would do it. The injector will lift up a bit losing some compression making it lopey and also routing that pressure into the fuel tank from there.