Ever since i bought my car ive had high idle problems.
Ive checked every where for vac leaks and could not find one. I have adjusted my TPS countless of times and still it maintains a high idle. Today i went through the emission section in my hanes to check all the valves like the EGR, BAC, dashpot and all of them are performing to spec.
Then it occured to me while reading through the emissions section that i have removed the 2 largest and most important parts of the emissions control system and those are the airpump and the ACV valve. So how in the hell can i expect to fix my idle problem if the idle system is designed around having these 2 components installed or at the very least to have the car in stock form.
I think the reason so many of us have idle problems is because we modify our cars so much that were taking it so far from its stock level that its causing all kinds of malfunctions like idle problems.
All those who have idle problems ask yourselves if your car is stock, then if it is you can follow every diagram in a FSM or a Hanes to a T to fix your problem because those are all based on the stock system.
My point is that how am i supposed to know how to fix my idle if all the service manuals are based for cars that have all stock components attached.
My only resort now is to attempt to make my emissions system stock once again and try to make it idle with those systems intact the way its supposed to work.
I think anyone who removes there emissions system from there cars is gaurenteed to have idle problems, and very unlikely to have any way to solve them unless they redesign there engine to idle without any emissions and that would take what? At the very least a standalone ECU.
Id be interested to know if those who go with standalone ECU's have any idle issues...

 

Sorry to bust your bubble Ryl, but i've removed every peice of emissions equipment thus far (down to bare block) and the car still runs and idles perfectly. I've not noticed any ill side effects other than she runs rough whilst warming up.


Maybe it's vehicular dependant, i dunno

-Markus

 

There are so many components that will affect the idle, that it can be hard to adjust them all. Coupled with old wiring and hoses, you can have a lot to go wrong. The TPS seems to be a common failure point, even fairly new ones. They never seem to stay at the correct voltage after you adjust them.

I've removed all of the idle controls on my car, and I don't have any idle problems. I adjusted my TPS and idle screw on the TB, and haven't had any problems.

 

my car idles real smooth. no acv or air pump here. i even discoed the bac wire once and she idled just as smooth....

 

OK!
Well then i guess im completly wrong and now really have no clue were to start or how to fix this.
If this is the case then what is controlling the idle on your cars??
Anyone else have all there emissions stuff removed and have a perfect idle?

 

I don't have too much idle problems and I run a standalone. All emissions removed too and blocked off. I still have my BAC though because I feel there is no point to removing it really. It not like its big anyways or in the way of anything like the other emissions stuff.

 

No need for a theory, there is an answer: Stock efi....

 

I have worked on 3 motors with high idles that where all easy to fix by simply adjusting the throttle cable. If you have looked at everything else and the car runs fine otherwise just loosen it up a little.

 

The airpump and the acv have nothing to do with the idle at all unless the acv is leaking internally past the antiafterburn valve into the intake. Another exception is if the EGR's diaphram is busted. Put a vac hose on the EGR nipple and suck. It should hold a vacuum, if not it's busted and will leak and effect the idle.

There is a starting point though. Set the timing making sure the idle is below 900rpm when doing so.

Then set the tps.

Then adjust the idle speed using the bac screw and making sure the initial set coupler is installed. The idle should be approx 750 with the initial set coupler installed.

If you still can't get down to a 750 idle speed, remove the throttle body and adjust the throttle plates to the fsm spec. Make sure the thermowax is functioning and the water passages to it in the throttle body are free of crud. Then adjust it to the fsm.

Perhaps prior to doing the above you should buy two cans of starter fluid and spray the hoses on the engine. The intake duct b/t the afm and turbo has a tendency to crack where it clamps to the turbo. Remove and examine with your eyes. Spray the short hose on the bac at its clamps. Spray at the back of the throttle body. And last and not least, make sure the grommets at the base of the fuel injectors are not leaking. They should be pliable, not hard as a rock. They will leak air if cracked or hard as a stone.

When the throttle body is off make sure the throttle stop screw has not been screwed in so much that it keeps the throttle plates open past the fsm requirement, I think it's .017 approx.

Some bacs have been known to stick open too much. They need cleaning. IF you suspect the bac.....make a plate that will fit inbetween the bac and the manifold so that air will not pass and then attach the bac and see what the results are.

Remember what Chairman Mao said......a journey of sixty miles begins with one small step....or words to that effect. humor.

 

Hey thanks Hailers, i guess nothing is ever as simple as it seems. Ill try that stuff out.

 

I know why we have idle problems. We all have rotary engines!

 

There are several reasons why idle problems are commong:

1. 10+ year old sensors. TPS sensors, AFMs, temp sensors all wear out.

2. Vacuum leaks. The rotary runs hot, which is hard on hoses and such. Combine this with the need for the AFM (ie. not a speed density syste) and you have a problem.

3. Hack job by previous/current owner. Mechanics that randomly turn screws, owners that take stuff off the car without understanding it's effect, etc.

FWIW, all my RX-7s have idled perfectly after I fixed the problems caused by the above (mostly #3).

 

Bare block and it idles fine/starts just fine and idles just fine when it's -5 (coldest it's been yet). However my GTUs has an issue with deciding which is better, 1k rpm or 1.5k rpm

 

should a car idle fine with open exhaust manifolds, with no exhaust or backpreasure whatsoever?