OK my car is kind of highly modded; here is the main problem and a short synopsis of the situation:
I blew my motor in Cali march 2009, the car sat in Ohio from may 2009-july2010 when I put a new short block in it(good compression on both rotors ~98). It is an s4 short block which is the same as the previous motor. The ports on both motors are stock so the tune should be fine for it as far as i know.

I got everything put back together and I got the car to idle perfectly, BUT it runs awful under load, it cannot hold an rpm at all under throttle; I have recently replaced the TPS, it had a crack in it and moisture had gotten into it. But the problem is still bad. SO any ideas of what the problem could be are helpful.


It has a 3rd gen apexi power FC with the banzai adapter
I haven't worked on the car since October(I live in Maryland and the car is in Ohio) but I am going to Ohio for 5 days this weekend to work on my cars and would really like to get it running well.

 

The car has been sitting for nearly 2 years? Bad gas? Clogged secondary injectors? Faulty fuel pump? What is your fuel pressure set at? Why did the first engine blow up?

This is just the starting places to look. Then on to the ignition system...plugs, wires, coils, amp etc.

Do you have the FRT wire on the PFC adapter connected to the 3F wire?

You really need to list your mods, stating that it is "highly modded" does not mean much.

You might also just need to tune your car, each engine is different, so is moving the car to a different elevation (Ohio)

 

The gas is new, the secondaries have been cleaned, the fuel pump is good; the plugs wires and coils have all been checked/replaced
the first engine didn't have the best compression by the time it got to cali and running 15lbs it was only a matter of time until it blew

nothing wiring wise has been changed from what is was in the original setup;

The car was initially built and tuned in Ohio; i'll list the engine mods to keep in simple
It has a T043B turbo
1680cc primaries 720cc secondaries
FD UIM, S5 LIM
greddy intake elbow
FMIC
Blocked off manual OMP(run premix)
external 38mm wg
Full emission delete,
3 inch straight pipe exhaust
greddy type s bov
tuned on 93

I was keeping the thread short, last time i made a thread i got no responses, probably due to being long winded

 

Without info nobody can help you.

Assuming you are running the FD TPS and TB.... what are the VTA1 & VTA2 readings?

Got a wide band installed? What are the AFR's when the issue occurs?

 

My VGA readings were very off with the old tsp. At WOT I was only getting 3.7 v previously.
But I haven't tested the new one yet as I installed it before leaving and didn't have the time to work on it.
I do not have a wideband in the car

Like I said in the IP I'm not near the car currently but will be working on it this weekend, I'm looking for ballpark causes. I'll be ready to get into exact science on saturday

 

I had a similar problem.

Pull the fuel pump and replace the sock. When I got my car, it had sat for 3 years and it had nasty fuel in it. It gummed my sock up and you couldn't even blow air through it.

 

need to get a wideband on the car to get a real idea of what is going on, i have a feeling you are having a secondary injector issue which may have been what caused the first engine to fail. lower compression is still not really grounds to say it was the engine at fault, 95% or more of the time it is something external and not the engine at all.

did you replace the injector clips on the engine harness? if not i would start by inspecting those. one of the largest drawbacks to installing a PFC onto a car is you are still utilizing the 25 year old wiring.

what RPM, what sort of load and/or PSI is it occurring at?

 

9 out of 10 times those 25 yo harnesses work far better then the hack job Microtech and Haltech installations I see with "new" harnesses utilizing speaker wire and duct tape to run the car.

Check your TPS settings when you get the work on the car. After that you probably just need to get the car tuned. I checked out your previous post and you were questioning the timing. Did you restab the CAS?

 

lol so true, i use as many new connectors as possible since its simplified it's just dumb using the old connectors from the original harness or using anything less than solder and heat shrink. i also weatherproof the harnesses so they're better than new.

but i wouldn't use that as a comparison, the FC TII harnesses have a tendency to have broken pin locks which easily push the wire back into the connector after a few removals/reinstalls. mainly susceptible to that particular failure is the injector clips and thermosensor all which will cause the car to run like *** at varying levels.

 

yeah i had to use new injector clips with all the injectors on the first swap; I did restab the cas yes, it helped to steady out the idle once it was timed, but it still runs terrible under load; I'll look into getting a wideband when I get home, I am definitely going to take a look at the fuel sock, I hadn't thought to check that and i imagine it is fairly dirty.
I'm sure i will put up a very long post Saturday or Sunday afternoon of the things i've worked through and what i'm not sure about. Keep ideas coming though!

 

Just out of speculation, did the new short block have the same compression ratio?

 

They were close. Not the same no

 

Just saw this:

1680cc primaries 720cc secondaries

This is a mistake, right? I hope you do have them the other way around.

Are you running resistors or the FJO?

 

yeah the secondaries are 1680s, sorry about that, i'm running resistors

 

ok, i've gone over a few things so far on the car today, i replaced the fuel sock on the pump, which is good, it was in pretty bad shape. Also i took the TPS readings
2nd wire from top closed .089 open 4.89 which is acceptable
but the bottom wire is 4.8-4.9 whether its openned or closed, it will not change, do i have a short or a ground problem? it's cold outside so i'm taking a few minutes inside to warm up

 

Your reading on that wire (Brown based with a stripe) is just fine as that is the Vref wire which powers up a number of the sensors on the car's engine. Normally registers 4.5 to 5 volts.

 

Don't bother with voltages at the wires on the TPS, look at the commander sensor screen.

VTA1 and VTA2, what do they read?