Rx-7fetish

okay my car has ran decent ( a little miss ) till recently, now its weird not like crappy running but when i start the car and the rpm runs high like its cold, they just stay there, even after i drive it enough to heat it up, like 1200-1500, but if im sitting at a light or whatever with the clutch in, if im in gear and i let out on the clutch a little to put load on it so the engine strains a little and the rpms drop to about 7 or 8 when i push the clutch back in they stay there, i think i need a new throttle body ( or rebuilt one ) but im not sure, the one on it now is off the original engine that had 160000 miles on it, maybe i just need to adjust something, its a new engine its only got like 15000 miles on it if that. Help!!!

Bama420

iTrader: (1)

tamper with the throttle body retention spring. Sounds like it may not be retracting the butterfly valve.

Rx-7fetish

Thats what i was kinda thinking but what direction should i turn it, its my dd so i dont want to make it worse and undrivable till its fixed

Craiger

iTrader: (1)

I know what your talking about, my car was doing this before I did my rebuild and Megasquirt. I not 100% sure since I never attempted to fix this since I was doing other work but I think it is an electrical issue. I would clean up all of the grounds and clean as best you can the connector to the BAC valve.

I doubt it's the throttle body since if it was putting load on the engine without moving the TB wouldn't do anything.

When I had this happening I attributed it to either to the weak engine or the crispy wire harness. If your engine is strong then it is probably wireing... if your engine is weak your not going to get a good idle anyway and it could be a mix of both.

Rx-7fetish

It idles good just at to high of an rpm

cmanns

Check if its assisting the idle, isnt there alittle motor that opens the throttle alittle bit for the cold start assist? maybe thats malfunctioning

Rx-7fetish

Ive never heard of that, anyone else want to back that up, maybe with a pic?

Rx-7fetish

Ooh my cold start assist has been acting dumb and not working in the cold but working when its 60 plus outside maybe this is mucking stuff up? would taking it out help?

Wheres Icemark any second he should just pop in with like a three word reply or a link that will solve everything

Rx-7fetish

Thats not what my problem is, it starts just fine but the idle wont come lower than 1500 unless i put load on it at a stop by letting out on the clutch a little without giving it gas so it starts to strain, thats why i think its the throttle body messing up like the butterflty valves are sticking and not closing, i just dont know how to fix it

Craiger

iTrader: (1)

Check or replace the plug for your BAC valve. It is a bosch style plug. Clean it with some kind of electric contact cleaner, or if the plug is cracked and looks to be at the end of its life replace it.

Rx-7fetish

can i get a pic or a link to a diagram of this plug? i have a shop manual but the pics in it are up close drawings of the parts and not view of where on the engine its located, and that wax thing that adjusts the fast idle cam, whats the life on those, could mine have crapped out after 20 years lol

Rx-7fetish

i adjusted the throttle position sensor, that was off but it still idles high, but my throttle response is better lol

ultrataco

iTrader: (2)

hmm...
I had this problem once. I think it was just a stuck throttle cable. I fixed it once just by tugging on the cable a bit, but the problem came back. But then it just went away. Now my idle is ok (a bit rough, but not too high).

Sorry I can't be of any help.

Rx-7fetish

I checked that already but thanks, keep these suggestions pouring in guys

satch

iTrader: (1)

That particular feature is not supposed to work and is over ridden when the temp in the radiator drops below a certain temperature to prevent the engine from reving up while the engine is operating in an environment where the ambient temp of the atmosphere is cold.

Craiger

iTrader: (1)

I don't have a pic of one on an N/A... my car is a turbo.

On an N/A I believe it is on the drivers side of the UIM just below the TB. it should have one large vaccume line going into it from the intake, and have a coolent in and out line. There is just the one plug on it and it is the same kind of plug that you injectors use. If you look at the TB/UIM area of the motor from the driverside of the car you'll be looking right at it if I remember correctly.

P.S. I assume you have an N/A based on your picture. If you have a turbo it's in a completly different place.

Rx-7fetish

Huh? sorry im not understanding all that, if it does not work when its cold whats the point, i think im not understanding what that thing does at all, anyways lets not change the subject to much i still have a problem lol

micah

Vacuum leak?

Icemark

I'd be looking at the cold idle assist thermowax and cam, or a bad BAC, or a mis-adjusted cruise control cable.

Rx-7fetish

Thanks, i dont have cruise so i can rule that out, ill have to check the other stuff i got the idle down to a grand by adjusting the tps, it needed it bad, but i really dont know what im doing with the other idle adjustments, i just turn and hope for the best little by VERY little

satch

iTrader: (1)

Check out the link below. This is for an S4(86-88 model)

http://www.cochran-racing.com/FSM/s4...SYSTEMS_NA.pdf

Go to section 4A pages 77-78.

Rx-7fetish

Okay guys i think i figured out my problem, my thermostat was stuck open so i dont think my car was heating up enough to release the wax pellet, i just ordered one from mazda, holy crap 30 bucks though