Hey guys, I've had an issue with the idle on my TII for a little while now. Thought I'd search for some insight here. I already did a search and really didn't find anything that really describes the problems I'm having. The car is BONE STOCK with 68,000kms on it. It starts fine when cold, revs up to like 2k like it should. As it's warming up though and the idle tries to drop it starts to surge around like 1,500 rpm. Once the car starts to warm up though (temp gauge starts to move), it runs fine again. It will idle away at 800rpm fine. After I push it hard though, it drops to a very rough, low idle and sometimes stalls. If you take it easy for a bit, it seems to be fine again. I'm thinking I have an issue with the coolant temp sensor. Any ideas? Anyone run into a similar issue?

 

No one has seen this before???

 

Do you drive your car hard before it is fully warmed?

 

The surging is pretty normal, It's caused by the thermowax in the throttle body.
The rough running is probably dude to old gaskets and vacuum hoses. AFter you hit it hard you probably open up a vac leak.

The car is over 20 years old at this point. Going through and replacing vac hoses, manifold gaskets, associated o-rings, injector insulators, replacing coolant lines, and flushing the cooling system will probably be a huge help.

 

I always let the car warm up before pushing it hard. It ran flawlessly when I bought it last fall and ran good most of this year as well. I've got a whole list of upgrades to do on the car ,but I'd like to at least put my finger on this issue before I start to modify it. I may plug my Rtek 2.1 in and see what my sensor data is saying when all this takes place. If it was a vacuum leak it should be there all the time, unless it's in the accelerated warm up system or another coolant temp related system. I really haven't spent any time yet trying to figure it out, just thought I'd ask here first to see if it was maybe a common issue.

 

coolant temp sensor? any more info on this

 

is the car goin from higher to lower rpms repeatedly? (up and down up and down up and down)

 

I'd harldy say that the surging is "normal."

Take a look at your TPS! Search for threads on adjusting it, and as others said, it wouldn't hurt to start replacing vacuum lines.

 

Have you adjusted the BAC? to 1 ohm?

 

I haven't really done anything with the car since it's in storage now. Come spring I'll smoke test the engine to ensure there are no vacuum leaks and go through all of the idle adjustment procedures. I also have a spare coolant temp sensor I may swap in. I'd like to get some data off of the original first though to see if it has any glitches in it. I doubt that it's a TPS adjustment issue because it's too predictable. It acts the same way all the time just when the engine is at a certain temperature range, hence why I'm leaning towards coolant temp sensor.

 

Those vac lines are old and might as well be replaced to eliminate any issue. Buy 20ft and replace as you go. Some lines have small plastic peices in them(forget the name)

Yeah I ment TPS in last post.

 

The vacuum lines are actually still in really nice shape even though they are old. They are still really pliable and soft. Unless something has rubbed through somewhere I can't see that being the issue. Never the less, I will check them out. Always good to be sure.

 

Pin 2I is for the Water Thermosensor and it should read 2-3 volts w/key to on w/ the engine cold and .4 volts fully warmed.

 

Buggy,I got a neat little pressure testing thing that I got from Fighters Garage.
I can send you a pic of it,you can make one up for about 10 bucks.,I actually made another one up while waiting for the one from Fighters.
it will find leaks in your system very easily!.send me your email address if you are curious.

 

Thanks Dave, but I can just use our smoke machine at work. Just plumb it in to the intake manifold and watch for smoke coming out. Works slick. Being a mechanic has its perks sometimes.