Hesco stroker question?

[s7tech]

Well me and couple of buddies, and a little bit from Bennie at Hesco and Ive gotten no where. My orginal 4.0 was throwing codes for random cylinder missfires. Found oil in my coolant, so long story short I got a smoking deal on a Hesco built 4.5 with an alumium head. Swapped motors and still getting the missfires codes. What I have Is a 2001 with the 2 pre-cats after the manifold, with 2 O2 sensors before the pre cats and 2 after. I am currently running with stock injectors. I called Bennie at Hesco and he said that he was supprised it runs with the stock injectors and sent me 24 pounders. I put them in tonight and it runs like crap, it is runnning really rich with the new injectors. So I swapped them back to stock ones so I can still drive it. I have pulled the valve cover and adjusted the push rods, with no changes. My next step is to find someone with a 2001 so I can borrow their computer and see if it helps. I was wondering if anyone has had simular problems. I have also had the dealer put the most up to date flash in it which makes it less prone to the misfire issue.
Thanks for any help.

 

[gradon]

Did you install the cam position sensor correctly? How's the coil pack? Any chance your buddy would let you try his to rule that out? Double check that all grounds are clean, shiny and tight.

 

[s7tech]

The Cam sensor was set with the factory scan tool. I tried a new coil pack and no change. What ground are you talking about?

 

[gradon]

There's a couple at the dipstick tube, one at the inner fender by battery, one from firewall to head, one below the pcm, and the big main ground that goes to the block(goes to coil block on pre 2K models). You have an s7?

 

[s7tech]

No I used to be the production lead on the entire build of the car.

 

[gradon]

Very cool--I just noticed an s7 in the garage of an old skating buddy, Jason Heffner, so methinks it has/will soon have his twin turbo setup: http://www.youtube.com/watch?v=9VGrgSCX1co So what's your new project?

 

[s7tech]

Yea all the 07 and 08 S7s had twin turbos. We even build 2 with 1000 horse power. Scary fast. I used to drive every car 250 miles for brake in.

 

[Talyn]

You will be better off with the 24lbs injectors. Did you reset the PCM after you did the swap?

When does your misfire happen? Any back firing to go along with it? Whats your fuel pressure? What about your spark plugs?

 

[s7tech]

You will be better off with the 24lbs injectors. Did you reset the PCM after you did the swap?

When does your misfire happen? Any back firing to go along with it? Whats your fuel pressure? What about your spark plugs?

Misfire happens at various times. Never the same. Sometimes hot start sometimes cold start. Sometimes just while driving down the freeway. Never backfired once. Haven't checked fuel pressure but I will. I'm running rc9yc that is what Bennie at hesco said to run.

 

[gradon]

I'm running rc9yc as well--will ping 2k-3k if using rc12s.

 

[FiveNdime]

I had a similar symptom with another rig of mine, turned out to be a couple bad spark plug wires. Kinda like yours, it would do it at totally random times. I would check that just to make sure, ya never know.

 

[Talyn]

turned out to be a couple bad spark plug wires

He doesn't have those