1984 idling at 1200rpm and up to 50mph without touching accelerator

[slashnick]

Today I got the oil changed at a Kwick Car. While the car was in the garage getting the work done, it started to rain. When I got in to leave, I pulled out of the parking lot and stopped at a stop light. The engine was idling at 1200rpm and would not slow down. I had to press the brake very hard to keep from rolling away (auto transmission). When the light turns green I let off the brake and the car accelerates to 50mph without even touching the gas pedal. When in neutral the rpms are up to ~2400rpm.

I returned to the Kwick Car and told them this just started when they did the work. They could find no reason for this to happen.

The gas pedal feels as if it may be sticking, possibility from the humidity. But I know there could be dozens of other explinations.

Also the car has an aftermarket X-ram intake manifold. Because of this there are loose hoses and tubes that go nowhere. I am getting the name of the guy who installed it so he can take a look.

Until then, has anyone else had this happen to them, or any other suggestions?

 

[jim coulter]

I haven't had that problem, but if it feels like the gas pedal is sticking, then it could be (dont know why, unless they had the breather top and base off looking for pcv filters or something) Could they have taken it off and not put it back on straight so that something underneath is binding. I dont recall there being many hoses not hooked up with the x-ram, except for the EGR, but you can find the x-ram info at www.x-ram.com. Sorry I couldn't be more help. I haven't worked on the 84 much except to trace out a short.

 

[vigman]

You might check the following

I had one of my spark plug wires get goofed up in the linkage for the accelerator.. holding it open an extra 7mm ( the size of the wire ) which gave the same effect.

Something you might want to try.



Vig!

 

[geekinavette]

What Vig said!

I had the exact same thing happen! Wouldn't allow the throttle linkage to return all the way.

Bill

 

[slashnick]

thanks for the feedback.

 

[evolution]

I had something similar happen to my Chevy van a few years back. Problem was, the throttle linkage was fried by the exhaust manifold and caused spongy acceleration and even worse yet, stuck throttle.

Put a new one an and lo and behold, true WOT! YEEHAAW! :eek :J ,in that order :gap

 

[Mad-Mic]

you also might want to check the main connection the linkage goes into on top of the manifold that controls the actual throttle bodies. sometime this spring wears out with age and will not close the throttle bodies all the way. i had this happen in my 82 Z/28 CF car once

cheap fix: get a sturdy spring and connect it to the metal linkage part and back to the distributer metal housing under the plastic cap. under the cap is a metal lip that the HEI distributor has and with a sturdy spring that is tight but yet gives you the flexibility of the flaps opening will do the trick. one nice thing about this it really gives you a firm pedal most cars don't have. me personally i like a nice firm gas pedal.

you also might want to check the vacuum lines going into the throttle bodies. if these are rochester throttle bodies (which i'm sure they are) there is 1 vacuum line with a soft rubber body wrapped around the hard vacuum 5 mm line. what happens if once the soft rubber gets old and wears out they will easily slip off the nipple that holds it to the throttle body. most likely what happened if they did a full service oil change and checked your airfilter's it's possible that the decking lid pulled away from the manifold slightly and pulled one of these vacuum lines off. this will replicate your problem. if this is the case zip tie them with black zip ties for a quick fix. usually when one of these line come off it will shoot a code. sometimes it won't. my experience here is with my 82 Z/28 CF car not a CF vette but what i was told everything mostly the same except for comsetics.

hope this helps!

 

[sumoboy]

This is one of the mods for the x-ram,maybe you want to check to see if anything is loose or broken.
There are only 2 slight modifications that need to be made.
A small hole will be required to be drilled in the throttle linkage
and the kick down linkage (for automatics) brackets, to connect
the bracket plates to the top of the manifold. And the rerouting
of the heater and vacuum hoses.

 

[DkBG]

On mine it turned out to be the gas pedal itself rubbing on the plastic underdash piece . If someone was in there that didn't have experience getting in and out of a c-4 they may have knocked something around . Doesn't cost anything to check this , right ? Cliff

 

[vigman]

This was an all of a sudden thing, right?

Did they replace the PVC valve? Those get VERY brittle after time and SNAP... That COULD have been a likely suspect.. I do not think they removed the air cleaner base.. but I'll bet they were close to the PVC valve, and on an 84.. it's a "T" style valve ( 2 port )..I would check that out as well!


Vig!

 

[slashnick]

fixed it

thanks for the help, i figured out what was happening.

the x-ram has no EGR valve, so the tube running out of the valve cover just runs under the air cleaner to appear as if it connected. when i took off bottom of the air cleaner to expose the manifold, i saw the EGR valve tube had become wedged under the throttle linkage. when they changed the oil in the car, they had to fill it thru the EGR valve, there is no oil filler cap on my valve covers. i didnt put them on, but im switching back to the stock ones soon. when he replaced the EGR valve he must have jammed it under the air box and throttle.

 

[jim coulter]

You might check the valve covers and make sure the old ones will fit. One of the things recommended on the x-ram site is to change you rockers out to roller rockers that are 1.6 instead of 1.5 ratio, so depending on whether he did that or not and what type he used if he did, I would check to make sure the old covers fit. I've heard they will fit with 1.6, but haven't tried it myself to know for sure.

 

[oldace84]

I have an '84 vette with 87K miles.....never seen this type of problem....sorry I can't help you.....but must be something very simple....have you found out why yet....????I'd sure like to know...
thanks
tony

 

[slashnick]

oldace84,

yeh i figured it out, look 2 replies up from yours.


-matt