I thought about the vacuum part of it the other day. I was wondering if maybe somehow it was failing and causing either something to get into the opti or just not venting it like it's designed to do. I've never messed with it before. I will look into it! Does anyone have specs for the vacuum system?

I'll also look into the waterpump thing. I JUST changed it 2 months ago. It's a Delco straight from the dealership as well. There's not a huge evidence of weep hole leakage, but I'm still not ruling it out.


On the over-revving part: In the 2 1/2 years I've owned the car I've never taken it over 5k rpm's personally. I rarely take it over 4k, and the only time it's been over 5 was when it was dynoed 2 years ago (5.5k rpms).


Thanks a lot for the help,
Kyle

 

A buddy of mine was having low resolution opti problems and traced it to the wiring connector that plugged into the opti. One of the contacts got bent and would make interminent contact causing the car to act very wierd. He ended up replacing the cable and it solved the problem. Only after the problem was fixed, did he find the bent contact. You could hardly tell by looking at it, but once the issue was pointed out, it was very evident.

Just something to check into,
TOM B

 

That's the other first thing I'm going to check. I just bought a new connector plug/harness from casper's when I did the last change, so I hope there isn't any problems with it, but who knows.

 

do you run with your cut-out open? or otherwise have a very loud exhaust? or something else that causes vibration in the car?


if so, this could be causing the opti bolts to rattle loose. What happens then? well, the little opti shaft that slides into the camshaft impacts the camshaft and destroys the sensor.

Hence why I don't run a cutout or SLP Loudmouth or other ridiculously loud exhaust... with all that rattling and vibration, it doesn't just rattle your skull.... it rattles bolts/screws loose.... all for an OPTIMISTIC 10hp gain.....

*this is fact* it happened to me and cost me a bunch of money

 

Welp, finally figured it out! Decided to do a pressure test on the cooling system and found out that at around 17-18 psi the radiator hose going into the thermostat was leaking fluid right onto the opti plug!! Took off the opti and it was all corroded inside, only after two months. I spent a few hours cleaning and bead blasting it and put it all back together with new hoses and clamps, and it fired up great!!

This whole time I was thinking that replacing the water pump would fix it and all along it was ONE hose. Who knew after 167k miles the hoses would need to be changed! I better not have to change another opti for a LONG time!!

Thanks for the all the help and suggestions guys. I'm glad I was wrong with my first post after all!

Kyle