Well, I'm 99% sure Inow know what my issue is. I will update with details soon, but long story short, is that 99-00 Intake Manifolds have a stupid Air Injection system that links with the fuel injectors. Its basically a pocket of air moving around by my injectors and throwing everything out of wack

Going home in an hour to JB Weld those ***** shut, we'll see how it works out..

 

Well I just finished flushing the cooling system, replaced thermostat upper and lower hoses, and thermostat seal, new coolant and I also bled the coolant from the air valve on the upper hose. And ...its still the same. I took off the IAC again and examined it some more. I noticed that the screw on the right port that controls how much air comes in, was all the way open.When I noticed this it was right after I turned the car off and the car was still hot,and I remember that when Icleaned the IAC the first time the engine was coldand thescrew on the right port of the IAC was exactly the sameas it waswhen it was hot.

I dont know if this reasoning is correctbut Iam assuming that my IAC is bad, Im justgonna buyit.

 

Well, probably not what you want to hear, but I'm back up and running as of 8:00 last night. freaking WOOOOOT!

Note to anyone planning on using a 99-00 y8 intake manifold on ANY other motor besides the 99-00 y8, you have to seal the holes circled in the picture below. They sit just above the gasket line, and leak like a ****. I took my intake maniold in to a welding shop last night, they sealed up the holes for me, and BAM good as new! Here are the holes I'm referring to.. I had him fill the ones circled, and the big on in the middle straight down from the nipple





ACE_92 -If theresone thing I've learned throughout the last couple months, its that buying new stuff and throwing it at the motor in an attempt to fix a problem is not the answer.

Lets take her one step at a time. Walk me through your coolant bleeding process. Do you hear any leaks of any kind while the motor is surging? Have you gone through with a fine tooth comb to make sure that you've got everything hooked up, properly, and all electrical connections are made?

Also, I don't remember you ever saying anything about your FITV. Have you given that a thorough look through yet? Your issue may be as easy as simply adjusting the FITV.

 

what the heck are those holes for?!

 

It's an Air Injection system that works in cooperation with the fuel injection.

It's so useless, that 90% of aftermarket intake manifolds dont even use it. [:@]

 

ive found that anything most companies do to improve on the theory of a basic combustion engine are useless...glad to hear that youve ironed that out..i wish that my car had those...so i would know whats wrong.

 

No there are no leaks of any kind, vaccuum or coolant, all connectors are in place and perfectlyintact. Also there are no abnormal noises. I've listened very carefully to the motor while it surges and it sounds exactly the same as itused toexcept obviously the surging rpms.

When Idid takeoff the old thermostat it was stuck open.And like I mentionedearlier the IAC valve stays in the same open position all the timedurring hot or cold operation.

I had one of my friends who runsa dyno and tune shop andhetried to diagnosis it fora couple hours, hecant be certain what it is either.

But there is something under my TB with atleast one coolant line, and I think an electrical connector. I don't know if thats a FITV or not but there is something under the TB.

 

Yes, that is your FITV. Check this link for details on a fix, CLICK ME

 

Yea, I pulled apart the entire TB and cleaned everything. The FITV youguys mentioned had a spring/valve type thing inside a tube where coolant flowed. It seems like it works like a thermostat only when it opens / closes at a certain temperature more / less air is taken in.

I read the article and mine had also come undone and was flush with the housing. I screwed it back in and it idled perfect for about 10 minutes and then it went back to the surging.

So I just dropped it off where my buddy works Stage 6 Performance and there gonna fix and or replace the FITV & install a SPOON p28 chip and then dyno tune it.


Question; What model does the y8 motor go in the DX & LX ?

 

Neither, EX