ST Swap Overboost

[Christopher Andrews]

So I got the ST Engine swapped into the Figaro. I finally managed to get it running after it sitting in the garage for about three weeks. It turned out the spark plugs were fouled despite running for two days before deciding to give up the ghost.

Anyhow, before it died, it had a pretty rough idle. When you snap the throttle, it will bog down and nearly die before recovering. I pull the vacuum line on the MAP sensor to check the vacuum with a gauge and the idle comes up, which is strange.

When I drive it, it's super hesitant and you can barely get it off of idle. When the supercharger does come on, it pulls okay but you have to feather the throttle to keep it going and it never seems to go above 2000 RPM. The PCM isn't showing any trouble codes so that isn't terribly helpful.

Beyond that I'm mostly looking for suggestions on what to start looking at first. Any help would be appreciated. Thanks.

Pic before I got the wiring all done up.

 

[Christopher Andrews]

Hello Again,

I got the Figaro running with the engine swapped over. After a lot of fiddling around with data-loggers, wide-band sensors, the Japanese factory manuals, the solution was pretty simple. I used the Figaro air filter box and MAF housing with the ST sensor installed. I never thought to check the bore on the two MAF housings. Needless to say when the sensor is calibrated for a 45mm bore and it's shooting through a 35mm housing, the car ran super rich and I couldn't drive it. In any case I'm doing a bunch of shakedown drives in the car and it pulls pretty hard but I'm having the following issues.

-Idle is super low, around 400-500 RPM. I have adjusted the right-most screw on the idle adjustment and the idle doesn't come up at all
-The car surges like crazy in 2nd gear. It feels like a bucking bronco
-At highway speed in 5th gear, it sounds a BOV is pulsing on and off. I don't have a boost gauge installed, but my guess is that something is opening and closing to modulate the boost pressure

I'm going to go through the Engine Manual and check each of the solenoid valves for the vacuum, bypass and see if they are operating. I would hate if the UFO valve or something like that was broken. Any thoughts on what might be an obvious item to check.

 

[Christopher Andrews]

Hello Again,
After some noodling around this summer with building my garage, I finally got some time back on the Super Turbo. Since the last post, I mentioned that I was getting some swooshing sounds from the engine when I hammered on the throttle and it sounded like the engine was coming on and off boost. I fitted a boost gauge to the engine and saw that when I throttled the car, the boost would go way over 21 psi then drop back down, cycle up to 21 psi and repeat this. This happens in any gear and on the highway under acceleration it's pretty bad. I popped off the housing on the backside of the turbo to see if the wastegate was stuck and pumped up the actuator with a hand pump. At 13-15 psi, the waste gate opens then it slowly bleeds closed. I'm thinking that the wastegate has a leak, and is probably not opening up properly.

My questions are the following
-What pressure should the wastegate open up at with a hand pump (discounting exhaust back presssure)
-Could a faulty bypass valve/UFO valve drive the upstream pressure on the supercharge beyond 9 psi
-What other factors could be affecting boost pressure.

Let me know your thoughts and hopefully I can get this thing driving like it should.