Redtop runs like a 3 legged dog

[daryl337]

K. I am officially stumped. I'll fill you guys in on the important parts of the build so you know what I'm working with.

I have a redtop with lower compression pistons (8:1 CP's), fresh build.
Cams are Tomei 270 solids, all are lashed properly.
Running a haltech E8, 810cc injectors.


Compression readings are ~140ish across the board last I checked, which is sort of expected with the lower compression and higher duration. But im getting absolute crap vacuum (8-12 in). I've double, and triple checked the cam timing and I appear to be OK there. IGN timing is a couple degrees advanced over the baseline 15 since I dicked with that to try to get a little more response out of it. I'll back it back down to proper later.

I've started it up and it absolutely did not like to idle. The weight of my foot however would keep it alive, at a reading of .9% throttle input on the Haltech E8. But if I brought it all the way off the car would die. I have mechanically changed the idle by adjusting the throttle body and that has worked, with an idle around 12-1300.

I ran through the rpm ranges up to around 5K with 0 load (in neutral) and began adjusting afr's to smooth the engine out. It runs a little smoother, but it does not respond well to throttle input at all. As a matter of fact, hitting WOT starting at 2K it takes around 3 times longer to climb through the rpm ranges than I would expect. It almost acts like it is running ridiculously retarded.

I decided it was time to drive under partial throttle and get my AFR's straightened out under loads.

Spent the better part of an hour putting around with a driver and adjusting afr's to near stoichiometric while staying out of boost, and then had the driver start to increase loads and run things under WOT to correct those values as well.

In 1st gear, WOT... it still runs like shit. AFR's were adjusted to be ok, but it lacked a lot of power, and was sluggish to respond to throttle inputs. It just felt like it was limping it's way home the whole time.


I could not get this engine to want to build power no matter what afr I was giving it.



Any suggestions on where to start looking?

Also, if there are any tests you would like to know results from, I'll be glad to give them up.

[jr_ss]

Are you map or MAF? Do you have the correct IAT sensor calibration tables? Is you IACV intact? Was it cleaned and functioning properly?

[daryl337]

Running map. Turbo is a garrett gt3582r

Not sure with the IAT table as this is essentially first start up. would this table completely cripple a car like this? Ive been adjusting afrs so id think that manually changing the injector timing would over come any issues of air density with air temp.


IACV was functioning prior to the build.

Ive also noticed my boost curve seems to begin about 1500-2000 rpms later than it should (Gets out of vacuum and starts producing boost at 6500). I disconnected the wastegate signal to let it run on spring pressure to see if i had issues there, but it still came into boost much too late.

But even under boost, at 15 lbs the car does not accellerate at nearly the rate it should.

It has just stumped me.

[jr_ss]

The wrong IAT setup will absolutely make your car run like garbage. I had a similar issue until I figured out I had the wrong IAT sensor calibration. Get that sorted and I'll bet you'll see better behavior from the motor.

[daryl337]

I've resolved the issue.

In order to update this so anyone else experiencing the same issue can see it:

The SR harness I had received for the Haltech E8 had the coil trigger wire pins reversed for cylinder 2 and 3, causing the issue.

I had run a power balance test and saw two holes with a NG. Spent time negotiating with the fuel injectors and coil packs on those two cylinders. Each time I tested them individually, they would pass the test. Even went as far as to get a new igniter, thinking maybe it was shorting and the diodes were doing wonky stuff. After each of these did nothing, I had pulled the exhaust manifold off. Noticed when I cranked the center two were pushing the fuel straight out the exhaust un-ignited... but at times it would give me a flame.



Moral of the story: Don't be afraid to double check wiring pin outs.. and don't assume that a second hand harness was wired properly. A simple pin swap and it started to rev like a pissed off chainsaw.