Throttle body
 

My advice to anyone with an SVX is to "Clean the throttle body!" what a difference, no surging, great idle,it actually seems to shift cleaner. I did not have the high Idle problem either. It actually appears to have dropped the idle a couple of hundred RPMs. The biggest difference is the low RPM range under load. much smoother. Took all of an hour and a half. There was an actual ridge of gunk behind the butterfly, all gone now. All I need is a fanbelt for the TR-8... it'll be 80 degrees here Tuesday

Collins 92 pearlie
80 TR-8

Re: Throttle body
 

That's because you did not open up and clean your IAC or TPS. when you remove them, it will take you a long time to re-adjust the RPM issues. In my case, IAC was clogged so I had to take it apart to deal with that. Anyone can just remove and clean the throttle body but the pain comes when you remove the IAC and TPS both. a milimeter of movement on the IAC or TPS can change between 500-1500 on the RPM scale. My advice, do not do it unless you have time and you know there is something wrong with it.

L

My advice, for whatever thirty-three years of experience as a pro-wrench are worth, are to not only clean the throttle body but to also replace the PCV valve - it suffers from clogging also. First word of caution: do not undo anything that looks like an adjustment. The throttle blades have what some may consider to be an idle stop. The idle is controlled by the computer and IAC (idle air controller), not by the throttle stop. The stop is precisely adjusted at the factory to allow full closure without allowing the blades to contact the throttle bores.

The TPS (throttle position sensor) can be cleaned - kinda. It is not made to be disassembled and nobody should try to do so. However a squirt or two of carb cleaner followed by some air blowing or ample drying time can help remove some of the worn carbon inside and make its operation less electrically 'noisy'. To re-adjust it will require a volt-ohmmeter. Do a search here and you'll find several ways to accomplish the task.

The crud that builds up inside the t-body occurs over a period of time. While the crud is building the throttle blades and IAC are being forced into different positions. The computer 'learns' how to make allowances for these new positions. As a result of cleaning the computer will need to relearn the new positions. Sometimes this can take a few days until everything falls back into place.

Cleaning the t-body and MAF and replacing the PCV valve are common maladies to all modern port-injected engines. Some days it seems to be all I that I do. Customers come in with their MIL lamps glowing, I pull the codes - usually P03xx (misfires) and/or P040x (EGR malfunction of some sort) or P017x (O2 sensor malfunctions). A great deal of the time the misfires and O2 problems are caused or are related to crudded t-bodies and MAFs.

BTW - pouring stuff in the gas tank absolutely won't help reduce these deposits. Don't waste your money if this is what you're trying to accomplish.

Cleaned the throttle body today with some synthetic valvoline stuff in a gray can. Used about half the can in there and tried to get it in as deep as I could to clean the intake runners too. Started the car and it was coughing and gargling like a big block cigarette boat with above water exhaust. It sounded so cool I took video of it. I think it was just burning off all the crud and spray in there and sounded like it was misfiring a little. Maybe I used too much. Ran it for a little while to clear up all the gunk and then it idled smooth. Time to go for a drive and see how she does. I love weekends with sunny skies and nothing to do. :D

You should change your oil right away. That corrosive stuff shouldn't stay in your engine for too long. Change your oil ASAP man.

- Rob