Stupid Problem

[NickMOSU]

So last night I was sitting in a parking lot and my friend wanted to hear the bov and i rev'd to around 5k and let off the gas. When I let off it kept revving like the throttle cable or pedal was stuck. I quickly killed the car and checked the pedal and cable. Both seem to be perfectly fine. I then started the car and it rev'd on its own up to around 7 grand quickly so I killed it again. I figured the throttle body might be stuck or just the cable but neither were the culprit. All the IC pipes and vac hoses seemed to be in place. It being new years eve, 11pm, and us on our way to the store I left the car and I'm heading back to try to fool with it. Any ideas? The car couldn't rev that high with the throttle body being closed or another source of a lot of air, right? Thanks. Nick

 

[NickMOSU]

Ok, well having had the time to look at things and play around with it I figured out what was wrong. For some reason the throttle plate is staying open just a little bit after I let off the gas. It's about a millimeter and it won't close itself completely I have to do it by hand. I tried to adjust it and i moved the plate as far away from the throttle body as I could to try set it correctly. However, even with a little play left in the cable it does not close completely by itself. It sticks open just a little bit. So I drove it home with it idling around 2500 because it was sticking home, it did jump up to about 3000 after I got all of the way home. Any Ideas? Wd-40 the heck out of it see if it helps? Thanks, Nick.

 

[Robby Camero]

I dont think wd-40 is a good idea. I heard it will eat seals and thats bad.

If you have the time, I would dissassemble it, clean everything (make sure you dont get anything in the FIAV) and while your at it, replace the shaft seals. If you want to lube it, try using die electric grease because it is not petrolium based and wont eat any seals.

Your throttle plate might have moved or shifted a little as well. If the shaft seals were replaced before, the two screws holding the plate to the shaft might have loosened a little but highly unlikely.

Hope this helps a little

 

[Woody91GSX]

I agree with Robbie. Dismantle it, clean it well with a solvent, put ALL new seals in it (don't use the old ones!), and put it back together. If oil gets in the induction system then it will cause problems. The oil coagulates and forms a hard oily substance. Kind of resembling oil that has coked. Clean it out, and reassemble. I believe it will be running better.

 

[GTM]

Originally posted by NickMOSU
....
For some reason the throttle plate is staying open just a little bit after I let off the gas. It's about a millimeter and it won't close itself completely I have to do it by hand.
...
it did jump up to about 3000 after I got all of the way home. Any Ideas? Wd-40 the heck out of it see if it helps? Thanks, Nick.

You should take a look at all the gound wire from the battery to the engine and the body to the engine. What happens is the main ground will become loose and or corroded, this leave a couple of #10 ground wires to carry the starter and charging loads. Since this is inadequate it will find other paths which include the throttle cable which in turn gets very hot and tries to weld it's self to the outer sheath. The grease and lube burn up and thus give you a sticking throttle. So use the WD-40 and if you can get some grease or a few drops of oil in there so much the better. Worst case will require replacing the cable from a wrecking yard or buy new. Most of the "rubber" parts under the hood are not rubber any more, they have been designed to accept exposure to fuel and oil for decades.

This isn't an absolute 100% certainty but a known problem for some cable operated throttles including DSMs. It is possible the throttle plate has worn but usually they give a gradual notice as service degrades with increasing higher idle RPMs. That is not what you reported so I tend to think that should be one of the last items to check.

Let us know what you find.

Cheers,
GTM

 

[Defiant]

Originally posted by Robby Camero
I dont think wd-40 is a good idea. I heard it will eat seals and thats bad.

I've _never- heard anything of the like. If you have more, please do tell.

 

[Robby Camero]

Wd-40 is petrolium based, is it not? Petrolium based oil products are not good to use to lube areas where a seal is present like tb shaft seals where boost is being held. I got this from the v-faq.

"Grab some silicone dielectric grease or something similar, to lubricate the seals and ends of the shaft with. I recommend that you use silicone dielectric grease, because it is not petroleum based, and will therefore not tend to harden the new seals prematurely."

http://www.ca.dsm.org/faq/tb-shaftseals.html

I assumed by sparaying wd-40 all over where the cable attaches to the throttle, it would work its way into the shaft seals.

If I am incorrect, I appologize.

 

[NickMOSU]

Yeah, I'm going to just take it all apart clean everything up real well tomorrow and see if it fixes my problem. Thanks for all of the information. Nick

 

[GTM]

Originally posted by Robby Camero
Wd-40 is petrolium based, is it not? Petrolium based oil products are not good to use to lube areas where a seal is present like tb shaft seals where boost is being held. I got this from the v-faq.

"Grab some silicone dielectric grease or something similar, to lubricate the seals and ends of the shaft with. I recommend that you use silicone dielectric grease, because it is not petroleum based, and will therefore not tend to harden the new seals prematurely."

http://www.ca.dsm.org/faq/tb-shaftseals.html

I assumed by sparaying wd-40 all over where the cable attaches to the throttle, it would work its way into the shaft seals.

If I am incorrect, I appologize.

Yes WD-40 is petroleum based... actually mostly Kerosene.

Your statement grossly misrepresents factual automotive and to some degree, aerospace engineering design. The author of the article gives no distinction on the use of "rubber" when describing seals or "O" rings. He gave no supporting scientific data other than what he experienced and you have taken that and further distorted the information. Consider that the complete drivetrain from the crankshafts, camshafts, transmission, differential, wheel bearings, steering, and suspension, are all petrochemical based lube. About the only place I can think of where silicon based lube is useful is on certain silent blocks where squeaks can occur such as sway bar bushings, window glass slides, and weather strip gaskets etc.

It just so happens that silicon based lubes are mildly reactive under normal conditions to brass based metal and in a vacuum actually become an abrasive which has caused NASA to ban them from all electric motors, actuators, shafting, etc. when used in a vacuum environment. So while you have _possibly_ protected the seal from reacting to the silicon grease you have introduced an _abrasive_ to the bushings and shafts. What we do know is mechanics will use highly corrosive solvents such as found in carb choke cleaners to degrease throttle bodies and the first contact will be with the seals which _may_ over a period of time have some of the polymers washed away by some of these exotics. My point is that the common greases available to most mechanics will not damage seals including these; however; solvents can and will do harm plus using a silicon based grease will damage brass motive parts. Further it is best to know the intended use of the "rubber" made part, certainly brake hydraulic master cylrs have had high percentage of rubber as well as wheel cylrs for drum brakes. With the wide spread use of disk brakes which run at incredible temps rubber has been excluded for it can't handle those temps. Buying a selection of "O" rings for a variety of applications is risky for you can only guess at their design application, are they reactive with glycols, (brake fluids, antifreeze etc.) or petroleum based fluids and greases including the exotics.

I'm not meaning to antagonize or detract from the overall intent of the article which covers the subject, he expressed a lube opinion which could prove to be more expensive for future repairs than a simple maintenance seal replacement. Many of these articles are written by lay persons without degrees covering all aspects of their chosen vocation and therefor extracting some singular point as credentialing your position is only spreading urban myths or a lack of knowledge. I hope you do not mistake my intent or tenor in pointing out the un-qualified and blanket generalizations which others would use with reckless abandon.

Cheers,
GTM

 

[Defiant]

Originally posted by Robby Camero
Wd-40 is petrolium based, is it not? Petrolium based oil products are not good to use to lube areas where a seal is present like tb shaft seals where boost is being held. I got this from the v-faq.

WD-40 is also a fair bit silicone, but it's mostly aromatics which evaporate (and Displace Water in the process) and leave the lubrication agents.

You're right about using petroulum-based lubes on rubber and latex (no Vaseline on condoms, for instance), but there's so little left behind from WD-40 that I don't think -nor have I experienced- it'll damage automotive seals.

 

[Robby Camero]

Thanx for all the facts guys. Learn something new everytime I log on here.

 

[GTM]

Originally posted by Defiant
WD-40 is also a fair bit silicone, but it's mostly aromatics which evaporate (and Displace Water in the process) and leave the lubrication agents.
...

Yegads, I knew it didn't contain silicon but straight off thier website:

http://www.wd40.com/Brands/wd40_faqs.html
.......................
What does WD-40 contain?
While the ingredients in WD-40 are secret, we can tell you what WD-40 does NOT contain. WD-40 does not contain silicone, kerosene, water, wax, graphite, chlorofluorocarbons (CFCs), or any known cancer-causing agents.
....................

Something tells me there is more to the no kerosene disclaimer... it may be lamp oil, it may be white spirits for the boiling temp is very close. Really bugs me for I had been informed within the first 5 years of the company's birth it was kerosene. Grrrrr
....................
Edit:

A bit more discovery on WD-40 ingredients reveals it is about 70% stoddard solvent which is used in most shops as a parts degreaser with the washer pump and brush.
I guess that how they can claim it's not cancer causing.
Cheers,
GTM