Lil Red 7

Well this started a few days ago and i can seem to figure it out.
it doesnt do it all the time but it is pretty regular. the 7 is surging really badly around anywhere between 700 to 800.

I cant seem to figure it out. the only thing i have done since this started is i put a breather filter for the airpump to have its own filter. i figured this would make it so the airpump isnt pulling air out of the intake. but i dont think this would cause the surging problem.


any help would be much appreciated.



Thomas

Lil Red 7

Hey guys give me some info please

Lil Red 7

well it is still doing it after a long hunt for loose hoses. any input please

zinx

iTrader: (3)

What kind of vacuum are you pulling at idle? If you are sure you've checked all your hoses, do a compression test.

PhatManBUD

doesnt sound too unusual about these cars, when i had stock twins, i just disconnected the airpump electrical connector all together. It made it run better i thought and it didnt make that weird WOOOO-ing sound that makes the car sound like a space ship

Vader

Misspost. Sorry.

Lil Red 7

i am pulling like 15.5 to 16 at idle. that is when it isnt surging like crazy

onequikson

Chaeck the electrical connector on the air pump. Sometimes if that is dis connected it will change the amount of air going in to the engine, essentially changing the AFR.(so I hear)

spurvo

Does the surging seem connected to whether you are in gear or not while idling? Like, put the clutch in, shift into 1st gear, and the surging starts?

If so, replace your clutch switch, the one on the top side of your clutch pedal, where the body of the switch sets the height of the pedal when it's up. When the switch goes bad, the ECU can't figure out if you have the clutch in when you are in gear at low idle. I think the logic is to assume the clutch is out (i.e circuit open which either happens when the switch is not broken and the clutch is up, or the switch is broken and the circuit is open), you are in gear (as found by the condition of the neutral switch on the tranny), and the revs are low. These conditions are likely to involve the idle speed control varying the idle speed, and maybe air pump fluctuations to boot, but this is specualtion...

Lil Red 7

well spurvo it usually happens when i just pull into my house and leave it in nuetral and pull the pbrake and then is starts surging. or at a red light in nuetral it does it as well. any other ideas. i will check out your theory though with the clutch thing.
thomas

adam c

iTrader: (2)

I have an extra brand new OEM clutch switch. PM me if you want it.

DaleClark

iTrader: (55)

Check the TPS - it's a bit weird to check and adjust, but it can easily cause a surging idle.

Dale

Lil Red 7

got any links on the tps thing. I just figured it would be something simple. I am gonna try to take the filter off of the air pump and put it back the way it was(where the air pump pulls air from the intake and see if that fixes it.

TwinTurbo93

http://www.scuderiaciriani.com/rx7/TPS_adjustment.html

Lil Red 7

thanks twinturbo93, do you have any ideas as to my problem

TwinTurbo93

No problem,
How long ago have you had the tune-up done?
The air pump connection (under the crossover tube) as someone already mentioned can give you this kinda problem.

I can't think of anything else right now.

Good luck.

Lil Red 7

well john, i was looking at the connection today and the plastic connector that comes off the airpump is fine but the plastic piece that comes from the harness is broke and it is just stuck into the other connector. so i am gonna splice the 2 wires together and see if that fixes it. I am thinking that maybe with the two metal wires just stuck in the connector, maybe it isnt getting a good connection and causing it to surge.


do you think that me putting that breather filter on the airpump has anything to do with it.

I havent had a tuneup done since i bought it. i am gonna order new wires and plugs and a new fuel filter. do you reccommend all 9's for my plugs or what. I will update my sig with my current mods in a second, so you can see

thanks for your help
thomas

TwinTurbo93

There is only 1 wire that powers the air pump, easy fix, just splice it, but before you do that, with the car on, idling, try to play with the connector sort of in and out to see if you any change in idle accurs, I had that problem and play'd with it and realized that was the case so I replaced the little harness.

I strongly doubt that the brather filter on the air pump makes any difference,

I saw your sig. (pretty nice btw), I'd suggest you stay with 7's and 9's still, once you move up to higher boost levels and all other bolt-ons than go with all 9's, you'll not be able to tell a difference anyway.

Tune-up would be a good thing to do asap anyway, even if that might not be the problem.

Start w/the Air pump connector, than move on to tune-up, check the TPS, (here is another good thread that explains in details how-to fix the idle by adjusting tps).

Good luck.

Dan Schechter

Check the secondary throttle plates adjusment screw (small screw on the front of the throttle body with an 8mm nut and a hex). Sometimes if this is open too far the car gets "confused" because it doesn't take that air into account, and starts surging to find and correct the correct idle speed. Also, if the problem is random, it could be from a turbo oil seal leaking and coating the plugs and combustion chamber. You can tell by seeing if there is an excessive amount of oil in the ic piping (a little oil is normal). or you can pull the plugs to see if they are coated in oil, and the exhaust will smell real rich. If you had a bad air pump connection, the air pump would be switching on and off at idle. It is supposed to stay on 100% of the time at idle. I don't think thats your problem. Surging of 100 rpm fluctuations is usually fine, and is considered normal.

Lil Red 7

well the air pump has two wires i am assuming one is positive and one is negative, i hard wired that and it made no difference. so i am gonna check the secondary throttle plate.

well there is not really any oil at all in the intake pipes or the intercooler pipes so i dont think it is that.

I am running 11 pounds on high boost so do you think i should still go with 2 7's and 2 9's or should i go with all 4 9's. twin turbo you said to go with the 7's and 9's for now until i run higher boost. what amount is higher boost.

thanks dan and john for your help.
dan i will check the secondary throttle thing, now how tight should it be or what exactly should i do to see if it is too loose. a link or description would help alot, thanks

Thomas

Lil Red 7

also what is a normal idle rpm for a rx7?

DaveW

The FSM states 700-750 RPM.

Lil Red 7

please someone a link or description of how the secondary throttle adjustment should be. should i close it all the way or where should i set it too

TwinTurbo93

Doh, yea man, sorry about that, I totaly mixed it up with the colant level sensor wire connector, my bad, I had that single wire pictured in my head for some reason.

By high boost levels I mean 13-14 psi or higher (of course with corresponding mods), I don't see a need to run all 9's for now.


You can disable double trottle (safe, I even removed mine completely long time ago) by simply pulling out and plugging the vacuum tube that feeds into the double throttle actuator from the extension manifold's (firewall side) and see if that will change anything, see pic below...

Lil Red 7

well john i checked the 8mm hex nut and i put back on the hose that went from the intake to the air pump and no more surging but i am pretty sure it was because of the hose.

anyways i am picking up my spark plugs from the local auto shop on tuesday. i will do 2 7's and 2 9's since you think that would be best for now. cause hey you know more about this crap than i do.

I am gonna order new wires and a fuel filter this week. so i will replace those too when i get them

thomas