gz91rx7

My 89T2 has a really low idle and has only like 10 vaccum. The engine has maybe 8k on the rebuild and it runs fine once I take off. It is just this damned idle that is pissing me off.
My vaccum lines all seem to be ok.
I did find that I was missing a bolt on my downpipe, maybe that might have something to do with it?

Any advice would be greatly appreciated.


Josh

GLHS

How can you be missing a bolt on the DP????

Aren't those studs on the turbo?

Are you saying your missing a nut?

Your crappy idle may just be timing or A/F ratio @ idle.

Doesn't sound like a vaccum leak.

ALTurbo2

That does sound like a vaccum leak to me. Is your engine street ported? 10 inches of vaccum seems pretty low for a stock port. Spray starting fluid everywhere to make sure you don't have a leak.

-Rocky

rico05

TPS bro, check the TPS. ANY idle problem should be checked in this order:
1. TPS
2. Vac. leak
3. Intake leak (cracked elbow)
4. Timing
Good luck!


BTW..It is very possible that the TID is cracked. Hot turbo + plastic TID = crack.

DaleClark

iTrader: (55)

Actually, the stock TID is rubber. Heat and time turn rubber to plastic, though .

I've seen a new TID before - you can squeeze and flex the part that attaches to the turbo like a radiator hose!

Anyhow, I would start with vacuum leaks before TPS - vacuum leaks are a common culprit, and cause all kinds of problems.

Dale

gz91rx7

WOW guys thanks for the replies.

I have a street port on the intake and exhaust.

Yes I am missing a nut, not a bolt. sorry!

I dont have the stock TID. It is one that was made from Home Depot. I have a feeling it is that. I just got home and it is waayyyy to late to go out and check.

Rico- If I am not mistaken the S5's have a auto adjust TPS. How would I go about checking that?

Thanks again.

Josh

The Ace

Crappy idle => first thing to check is vacuum leaks. Start with the TID. Then work your way around the engine with some CC or starter fluid.

Crappy idle + low idle => could be the TPS. I had a similar problem (well, just lumpy idle), and it turned out that it was a combination of both: TID was cracked, a vacuum hose was slightly torn, and the TPS was also slightly off.

Search the forum for TPS, adjustment, S5, and you will probably get the same threads that I got. In 3-4 of them, you will see the instructions (not too hard though, if you take off the IC and look around, you will finally figure it out, and you'll just need the correct values)

gz91rx7

Thanks ACE!

Good info!

gz91rx7

Well here are a few more symptoms. If I have any electrical things on the idle goes down. I checked my batt and that is fine.
I just wanted to shed some light on what is going on just incase anyone else had the same problems.

I looked at the TID and it seems to be ok! I didnt find anything at all.

Is it possible that you could get bad plugs new from NGK?

Josh

gz91rx7

bump

Fox4Life

iTrader: (4)

if you turn any electrical things on an your idle goes down, That sounds like your BAC isnt working.

gz91rx7

That could very well be. Because when I took the acv off I was taking the plug into the bac off and a wire pulled out of it. I made a new plug for it and it idled fine since I fixed it but this whole idle thing just popped up after I changed my plugs and oil.

Before I changed my oil and plugs, if I was out on the highway and hit it the boost would go up but I would not accelerate! So i just figured that it was the plugs and that they were fouled out.

Hou would i check to see if the bac is working or not?

Thanks

Josh

Fox4Life

iTrader: (4)

The BAC valve may be stuck. Using jumper wires, connect 12V across the solenoid leads, being extremely careful not to create a short. If you didn't get an open-circuit reading when you measured the resistance of the BAC valve, the valve should click. If it is stuck, doing this a couple of times should free up the valve. I would also recommend removing the BAC valve from the intake manifold (this can be accomplished without removing the water hoses connected to the valve) and spraying WD-40 into it. Work it a few more times with 12V. If you can't get the thing to click this way, replace the BAC valve.

-Jerry

gz91rx7

so I should run 12v to both terminals on the bac?

gz91rx7

Ok today I did some work under the hood and found a few interesting things.

1. One of the lines that went into the acv I had caped off and the cap had melted and cracked. So there I found a leak!

2. I did find that one of my wires into the bac didnt seem to be connected very well.

3. I tested the bac and it clicked every time I connected it.


When I put it all back together I had to adjust the bac to damn near all the way open. It idles good now but I have noticed a few things.

1. My vaccum at idle is only at 14" normally at 15 or 16
2. Boost is maxing out at 11 normally 13 or 14 psi


I checked all my vaccum lines with starting fluid and I found nothing! I think that there might be a vaccum line under my intake manifold that has a leak because I had a lack of boost in the summer when I had alot of heat under the hood.


Well if anyone has had any of these symptoms and had any advice please post any info.

Thanks,
Josh

gz91rx7

Well some more news to my problem.
When my car is at idle it makes a poping noise out of the exhaust. I dont know really what the could be.

Any ideas?

Josh

gz91rx7

Well I found out that when you remove the acv it makes the popping noise that I am hearing and I found my intake leak. It is at the BAC the gasket had cracked and when I was spraying starting fluid around I found the leak at the top of the bac. I went to tighten it and the stud broke off!!!

So if anyone knows where to get another that would be cool. I am going to the local parts stores to look for another.


Josh