RedX7

Dude, thanks for the tips. I checked the idle settings on my commander. The top A was set to 900, the E was 1000, and the bottom A was 1100. And no I haven't played with the idle screws yet.

So I should set all three idle settings to zero, and then adjust the TAS and AAS?

Dudemaaanownsanrx7

iTrader: (23)

yes and you may also need to adjust your idle fuel and ignition maps to get it set just right. which after you adjust them you will have to go back and adjust the TAS adn AAS. You may need to repeat the process a few times to get it all set correctly. Also take note of the TPS voltages and make sure they are set correctly. once you adjust the butterflies the voltages will change and may need adjusted to be in the correct ranges.

RedX7

Wow, so much just to set idle. Thanks for the help man, really.

Dudemaaanownsanrx7

iTrader: (23)

No problem, you may not have to adjust too much to get it right, but you should at least have an idea of what all will effect it. Checking the voltages on the TPS is easy with the PFC commander. Under sensor check its right there one for narrow band and the other for wideband. let me know if you need to know the correct voltage ranges for each.

RedX7

What mode should the car be in to read these? ACC, On, cold idle, warm idle?

Dudemaaanownsanrx7

iTrader: (23)

just key in the on position. i think they recomend getting the car to operating temperature, but i doubt it matters. Just key on car off.

wstrohm

This is all very interesting, but does anyone have any input on the problem if it occurs on a stock 1994 RX-7? (Assuming that the idle has been adjusted per the FWM, the TPS is in spec, the IAC valve and AWS valve are working properly, and the MAP sensor has been checked with a MityVac and a multimeter and is in spec.)

Dudemaaanownsanrx7

iTrader: (23)

What are your symptoms? does it jump around all the time? Just when the clutch is pushed in? Car in gear? After you rev the engine? Does it bounce or is it just low?

EDIT: i just noticed you posted above

I dont think it's from the EGR valve, though you could try unplugging it and see what happens. Fluctuating idle is usually the computer trying to adjust it. Check your dashpot is could be sticking a little. The clutch switch can also play a roll in boucing idle if there is a problem with it. Try spraying carb cleaner on vacuum hoses and around the manifolds to see if the idle drops.

Dudemaaanownsanrx7

iTrader: (23)

You can also unplug the ISC and see if the idle stays solid, though i know you said you sprayed the rods and wd40 and they appeared to work properly.

RedX7

Dude, I went into the sensor selection and looked at the voltages. Which one is for the TPS? As I didn't see anything that said TPS.

wstrohm

Symptoms are a proper idle, steady at 720 rpm or so when set with "TEN" jumpered to "GND" in the Diagnostic Connector, just like it should be. But if the car is then taken out and driven, at the 1st or 2nd stoplight the idle will be up at 1100 - 1200 rpm. Then at the 3rd & 4th stoplight, still high. But at the 5th, it will be back at 720, where I set it to begin with. Also, if the idle is high, there is a miss similar to what is caused by a vacuum leak...putt......putt... but at 720 rpm, no miss. The idle does not "bounce;" it is steady in either one of the two states.

Dudemaaanownsanrx7

iTrader: (23)

The correct sensors are VTA1 and VTA2 for the TPS adjustment.

VTA1 is full range and the voltage range is 0.1-0.7 when closed and 4.2-4.6 when full throttle. It it referenced off the black wire on the TPS harness

VTA2 is Narrow range and the correct voltages are 0.75-1.25 when closed and 4.8- 5.0 when full throttle. It is referenced off the green/red wire on the TPS harness.

Two screws on the TPS need loosened and the tps rotates slightly for adjustment. Hope this helps.

Dudemaaanownsanrx7

iTrader: (23)

Well my best suggestions are to check for vacuum leaks with carb cleaner, try adjusting the dash pot out a little more and check that it opperates smoothly. Does it make a difference if the car is in gear or not?

wstrohm

Dude,

Thanks for your suggestions. I know the dashpot is OK, because I have already checked that out; it works smoothly and is adjusted correctly. But since wife usually drives the car with me as passenger, and it's been a while since I drove it, I'll have to check on whether the problem is the clutch switch or not, and post back here. I tend to resist spraying carb cleaner on my new Viton hoses, but if it comes down to that, I will. (Unfortunately, 95% of those hoses are below the UIM, and with the UIM off, the engine will not run.)

I do appreciate your responses!

arghx

iTrader: (3)

a good way to test for vacuum leaks is to use a pressure tester. http://www.boostpro.net/prodtester.html sells them or you can make your own. Now I have a single turbo, but I think the 300zx testers they sell basically plug one of your intakes and then you pressurize the other one. Then you can feel air escaping, hear it hissing out of any leaking areas, or spray soapy water and watch it bubble around any leaking spots.

wstrohm

arghx,

Can you be more specific about the location where the "one intake" is plugged? I'm interested in everything downstream of the throttle butterfly, but unless I am wrong, the intake vacuum is common to both rotor housings until you get into the LIM. If the intake to only rotor #1 is plugged, I think it would have to be at the LIM interface. And if there is a vacuum leak, seems like it would be before the LIM... somewhere in the 68 vacuum hoses or in a bad check valve, etc.

Dudemaaanownsanrx7

iTrader: (23)

I think he is refering to the turbo inlets (where the filters would be)saying to plug one and then, clamp that pressure tester in there. Basically all it does is close up the inlet and then you have a tire valve to force comressed air in there. The gauge isn't needed but allow you to see how much pressure is in there.

Installing it at the turbo inlet allows you to test the boost pipes and intercooler for leaks, but I dont know how well it would work for vacuum leaks. it seems like the air would just escape if you were to open the throttle body. But maybe not?

Dudemaaanownsanrx7

iTrader: (23)

one thing I'm finding odd is you said it stays at the idle. whether it be 750 or 1200. So it's not fluctuating up and down as though it's hunting. Its like something opens up and allows more air in at times. Usually vacuum leaks are there or they aren't. interesting problem

your throttle body butterflies aren't gummed up at all are they?

wstrohm

Dud,

Throttle butterflies work smoothly, and blipping the throttle has absolutely no effect on the idle speed if it is in the "high" idle state. Don't know yet about doing that in the low state. It isn't the clutch switch, because the idle rpm in neutral doesn't change if the clutch pedal is depressed and the gearshift is moved into a gear.

RedX7

Checked the PFS again, my VTA1 read .66-.67v and my VTA2 read 1.5v. Is the VTA2 too high?

Also, I may be receiving the dumbass of the week award tomorrow. I checked my throttle linkage play and it was WAY off. 1/4 inch deflection is about standard right? I had well over a full inch!!! I've been so paranoid about all the really technical stuff that I forgot about the basics. The irony in this is that I always tell my students to KISS a problem. (Keep It Simple Stupid)

I'll know for sure tomorrow. I only had like 15 minutes to play with her today. Wish me luck!

Dudemaaanownsanrx7

iTrader: (23)

yes your VTA2 is too high. should be under 1.25.

I'm not sure how much slack you need in the cable i usually keep mine fairly tight but enough to where it isnt pulling the throttle open at all. Too much slack and it wont open fully. too little and it can leave the throttle open.

Dudemaaanownsanrx7

iTrader: (23)

wstrohm :

does turning on any accessories have an effect on the idle? i'm really not sure if i can be any more help, my knowledge on the system has pretty much reached its limits in this thread. Did you ever try unplugging the ISC solenoid to see if the idle would stay constant?

RedX7

I must now remove myself from the "can't fix idle" club. I just wanna start by thanking Dudemaaanownsanrx7!

I had adjusted my throttle play yesterday. Once the car warmed up though, it was idling really low and hunting. I played with the TAS a bit and got her to hang in the 725-775 range. Unfortunately, she started hunting again. So I played with the Rev/Idle settings like Dude said. I dropped them all to 500 (lowest). Still hunting, but felt better. So I played with the top setting A*E. At 690 it smoothed out and leveled out at 750ish. Runs and sounds great!

Again, Dude, I really appreciate the help. If you ever find youself in San Diego, I owe you.

Dudemaaanownsanrx7

iTrader: (23)

Great glad to hear you finally got it sorted out.

gracer7-rx7

iTrader: (16)

I"m a little late to the party but in case you didn't see the links in the FAQ on idle and TPS stuff here they are

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fixed-my-idle-problems-backfiring-bucking-more-170731/
https://www.rx7club.com/showthread.p...&highlight=tps