Thread was originally posted in the Evo General but decided to move it here because of my previous success with this section of the forum. Thanks for understanding.

Having a multitude of issues with a 03 EvoVIII, that all seem to be interlaced.

Car recently received a new low mileage bottom end, and had the head gone through. There was an immediate oil pressure issue, that wound up being the brand new oil filter housing was missing the valve for the oil pressure relief valve, which took a while to find, so the car had sat for almost a year after the "rebuild."

Now the car is having wierd issues. It will idle fine, then will randomly dip to 6-700rpm, 4-6 in/hg of vacuum, and sit at ~10.5:1 AFR. Sometimes blipping the throttle will bring it back to 950rpm and 12in/hg and 14-15:1. (272 cams)

When sitting in neutral, if you give it light throttle, it will build revs all the way to redline perfectly fine.

BUT, and it's a big one, once you are past 25% throttle or so, the car will build boost FAST, and will keep building til you cut throttle. It will build 5-10 psi by 2500 rpm, 15-20PSI by 3500rpm. If you go WOT at anytime, it will stop building revs completely, and stack boost FAST. This is all while sitting at a dead stop. Clutch in or neutral.

It is acting as if the car has a VERY good staging limiter/antilag, but the car does not.

This also happens when trying to drive, and the car refuses to accelerate faster then as if it were a Yugo. You have to go half throttle just to keep up with traffic, and it will build boost like crazy (read 15-20 lbs and barely accelerating.) Car is not being driven obviously because of this.

There is also a random rev-hang, right at ~2000rpm. Happened a few times, and slowly drops back.

Also, when trying to set Idle with SAS mode via Evoscan, the car dies, no matter the position of the BISS screw. Have completely disassembled the throttle body and cleaned, with no luck.

I found that when the engine was put together, they put the cam sensor reluctor wheel on backwards. Fixed, and no change.

Unplugging the Cam sensor also makes NO change as to how the car acts. Have replaced the sensor, with no change.

Map sensor wiring was hacked. Fixed, no change.

AIS replaced with a newer metal one. Idle is def more stable, but still acts up.

Throttle body gasket was smeared with silicone, and passages plugged. Fixed, no change.

Intake manifold gasket was leaking on #1. Fixed, no change.

Cam timing is dead on.

Flipped DV so it couldn't leak, no change.

Plugs were fouled from all the rich idling, so switched to hotter champion RN9YC's from the NGK Br8's gapped to .22 to keep them from fouling while diagnosing. The car idled smoother and revved up cleaner, but still had the same issues.

Removed downpipe to check for plugged cat, no change.

TPS has thrown a code once this whole time for P0121 Throttle Position Sensor/Switch A Circuit Range/Performance Problem. Cleared and it never came back.

Also threw codes for O2 no activity, from running PIG rich at idle when the idle dipped, and letting it idle like that for 5 mins or so.



Car is running a Fp Red, HKS 272, reputable local dyno tuned, all supporting fuel modifications, forge DV running recirculated, ect.


Have Evoscan and a FTDI cable and can log if needed.




SOLUTION


As I had guessed the crank sensor had been installed backwards. If you see the knotch in the bottom left of the trigger plate it is supposed to be in the 11 o'Clock position rather than the 7 o'clock like it is. Thanks for all the help and suggestions. 250 Miles so far and everything seems to be going good!

 

flat out the car needs a better tune on it. and yes i read everything you just posted here.

if timing is dead on, there are no boost leaks, its the tune.

 

only time iv ever had anti-lag type boost build in neutral was in my old dsm when the timing had jumped tensioner failed id triple check all timing marks. Maby even throw stock injectors and stock tune back on see if that helps

 

Only way I can think of building boost in neutral is with timing. Sounds like you need to check that out as well as a good tune.

 

my evo does this too. i had a very reputable tuner tune it too. not sure wtf to make of it!

 

Seems like something is mechanically wrong, or something electrically messed up in ignition harness .

Turn ignition to "on"

While watching crank pulley, rotate shaft slowly and monitor when the MFI makes an audible click/whine. It will happen 4 times, but one of them should be right at "†".

Yes/No?

Make sure coils are hooked up correctly. Have you individually checked if each cyl is sparking?

Have you tried the compression check?

 

The coils are correct as well as each cylinder sparking. Compression check was also good. Will check the crank pulley after work. I might have figured out what the problem. The crankshaft trigger plate may have been installed backwards with the notch in the 7 o clock position rather than the 11 o clock. I am fairly confident this is the issue as it would cause most if not all of these issues. I will update thread tonight after I am certain.

Thank you for the replies and advice. It is greatly appreciated.