truck falling on its face under load

[dieselmandustin]

Truck is a early 99. Fully built motor w/ (s468, P.I.S 300/400, HB Jr. Hpop). This is a new build with only about 3k on it. Under any sort of load at all, in all tunes it starts to miss and fall on its face. If I let out of it and get back in it most of the time it will smooth out and take off. Just like it's running out of fuel when it's missing but it's holding 60 psi of fuel pressure. I know the Hpop is not enough but another upgrade is in the works. It's dropping down to about 1600 psi at wot but when it starts to miss its still at like 3600 psi. I can't figure out of its an oil problem or tuning or injectors or what. Dynoproven built the motor and I'm running his tunes although it has not been live tuned yet. Have any of you guys with 400% nozzles had an issue like this? I have not gotten to talk to Jonathan about it yet. just thought I would ask here first since I won't get to talk to him til probably after Xmas.

 

[dieselmandustin]

Also it's smoking white when at idle really bad. So much that people are like what is wrong with your truck! Lol

 

[Swsignal5]

I know it's stupid but have you checked your air filter? Mine did the same

 

[dieselmandustin]

Yeah the air filter was new when I had the motor built. It don't have many miles on it at all.

 

[Swsignal5]

I have 200 nozzles in mine and I had pinched one of the o rings on the sticks on install and one dirty filter. That's what caused mine to do that.

 

[dieselmandustin]

I haven't pulled the injectors to check o-rings yet. Jonathan put them in I wouldn't think he would have cut one but who knows anything can happen.

 

[Swsignal5]

Yeah I would check easier things first but I can't think of any. I also had a picky idm once that would randomly start acting up

 

[dieselmandustin]

Now that could be a possibility. When Jonathan first put some tunes in my truck it ran fine for a bit then all my tunes started doing Crazy stuff. Then my air dog died and I decided to get one of his fuel systems, so while it was down waiting for that I sent him my chip and he reburned it with some tunes he had just put on a truck with the same sticks. I just got the fuel system on and got it running again. The chip seems to be working correctly as far as switching to high idle setting and all but it still has this miss. The air dog started dropping pressure one day and The truck ran for a few hours with about 40 psi of fuel while I was messing with the regulator on the air dog then it died. No longer than it ran with low fuel pressure I wouldn't think it would have messed up the injectors that fast. But I guess it's possible idk.

 

[dieselmandustin]

Also for the first approx 1500 miles I was having issues with my Hpop. It was a billet stealth. That's why ended up with the HB Jr just to get me going again til Jon either gets his Sr. Done or I get the money for a gen 3. The air dog and stealth were upgrades I had done when I was running 250/100's. I don't think the stealth would have caused injector issues either. It was just the usual no hot start, not holding pressure deal. I'm just trying to list everything that has happened in case any of that could have resulted in this miss.

 

[Swsignal5]

Also for the first approx 1500 miles I was having issues with my Hpop. It was a billet stealth. That's why ended up with the HB Jr just to get me going again til Jon either gets his Sr. Done or I get the money for a gen 3. The air dog and stealth were upgrades I had done when I was running 250/100's. I don't think the stealth would have caused injector issues either. It was just the usual no hot start, not holding pressure deal. I'm just trying to list everything that has happened in case any of that could have resulted in this miss.

Also what about valve cover harness? Those things suck and cause your symptoms.

 

[Magnum PD]

Buzz test?

 

[dieselmandustin]

You mean the main harness or the harness that runs thru the valve cover? The valve cover gaskets are leaking pretty bad. I was holding off on replacing them cause Jonathan wants to do a hot retorque on my heads next time I go to his shop. Probably in Jan. But I can do them anytime if that's my issue.

 

[dieselmandustin]

Buzz test?

Haven't done a buzz test. I don't have anything to do it with.

 

[Swsignal5]

Yeah those gaskets might be your problem

 

[dieselmandustin]

They need to be replaced anyway so I'll give it a shot.

 

[co04cobra]

You can ohm them out first. That way you're not just spending money you might not have to.

 

[dieselmandustin]

You can ohm them out first. That way you're not just spending money you might not have to.

I'll do that next day I'm off work. Also I just noticed something I didn't pickup on yesterday. When I can get the truck to get past the miss and open on up, my oil pressure falls to 15-1600psi as to be expected being pump is not big enough for the demand. I knew it was doing this but the thing I found odd is dc never goes over 39%. Shouldn't that be higher since I'm working the pump so hard?

 

[Magnum PD]

Isn't that tuning?

 

[co04cobra]

Yea I'd say Jon is doing that with the tuning.

 

[dieselmandustin]

I don't know. He put the same tunes on my chip that he had just put on another truck with the same sticks. I know every truck is different but I would think it would be closer than this.