All right guys. I worked on this car over the weekend but unfortunately I didn't have time nor the appropriate test equipment to check this out fully. Now first off the system was stock when I started other than an intake setup. All wires plugged in and everything normal. Check engine light on and Matt told me it was something about the throttle body which I'm assuming was the TPS (Throttle Position Sensor). Now I myself installed, with his help, the IC hard piping (GReddy) and the new BOV (This time vented to atmosphere vice vented to intake). We also installed an MBC and a boost guage (I didn't have the time nor resources to install the AFR or the oil pressure guages and Wal Mart didn't have the electrical connectors I needed) (I don't wanna hear it hell where else was I s'posed to shop at 3 A.M. for parts???). (Lemme tell you cut off the mbc almost all the way (Leave open 2 turns minimum as per instructions) and that BOV was LOUD I heard him at my place from AT LEAST 3 or 4 blocks away LOL).

Now it's not the BISS because it's not hunting when at an idle. What it does is when first started it sputters and idles really rough. Then when you get on the gas and then let off, it comes down and sputters before coming back up and idling nicely. I'm thinking it could need a good fuel system cleaning as well as possibly needing the TB cleaned. The vac read god (I had the boost guage hooked up to the intake and it was getting around 25 Hg vac). Also another weird problem we had that did resolve itself was in the boost guage itself. When I installed it it hardly moved. Put it on a vac source and it dropped nicely. Bac on the boost side and nothing... I guess Matt said when he got home it all of a sudden started working... Not sure on that one but that problem seems to be resolved at the moment...

So what do you guys think? He'll be back here so I can finish the rest of the installs but I'd also like to try to figure out what this problem is and fix that as well. BTW it's a '97 Spyder.

 

98 spyder.

 

well i dont totally remember what my car used to run at vac but i think it was around 20 mm hg, not that i think this is a huge difference. Just giving my input

 

VAC should be near 20 mmhg

Sang everything you are describing is what happens on a vented BOV. I speak from experience on that. Idle will bounce for a minute then settle high revs it will dropp reall low like it wants to stal ect.

It is a boost leak\ venting problem for sure.

 

I am going to say tps.

 

I understand that everything described happens on a vented BOV BUT it was doing this BEFORE I installed the BOV. That was the point I was trying to make. He had a BPV (Stock equipment) run to the intake before I started on it. That's why it's throwing me off. And yes when he got on the gas it was getting down to 20 mmHg maybe even a little bit more I don't remember right now. (Mostly cuz I was in troubleshooting mode for the boost guage instead of troubleshoot the other problems).