NEXTIME

Hey guys,

When i bought the car it had a high idle and the rpm gauge doesnt work at all.

I have researched about the high idle and heard it could be a vacuum leak or something but what steps do i take to fix this rpm gauge?

All the other gauges work except the rpm gauge and oil pressure. The car doesnt over heat.. and it looks like some hoses have been cut and blocked off..

NEXTIME

anybody?

LunchboxCritter

iTrader: (9)

Your tach is electronic. Have you removed the instrument cluster to make sure it has a good connection?

What year is your car?
Is your car Turbo or NA?
Can you take a picture of the engine, and show us what you are talking about is blocked off?

High idle could be several different things (including but not limited to the following):

Vac leak
TPS out of adjustment or faulty
Timing Off
Idle screw adjustment
Throttle cable too tight
Bad Ground
Pressure Sensor

satch

iTrader: (1)

There are two plugs connected to the trailing coil. One of these plugs has four wires with one being a Yellow/Blue wire. This wire connects to the tach. One thing you could do to see if the tach will work is as follows. There is a Black wire that is connected to nothing that hangs from each of the leading coil and trailing coil. Run a jumper wire from one of these Black wires to the other and start the car and see if the tach works.

K-Tune

iTrader: (26)

confirm that the trailing coil is firing for the tach issue.

all idle issues have been covered, search.

NEXTIME

Thank you!! Ok i found the two wires you were talking about. One was black with a little black tube like connection on it and the other one was yellow with a blue strip with a white tube like connection. I put a jumper wire into both and the rpm gauge worked right away

The only thing now is that my RPM gauge is reading 1600 RPM and my idle is obviously too high.

My car is a 1987 Non turbo. The only thing i know and can see that is done to it is the 3.5 inch exhaust.. i know.. ridiculous.. lol

Is this a permanent fix for the rpm gauge? Can i just cut off those tube connecters run a "jumper wire" from one connection to the other? and what should i do first about the high idle?

satch

iTrader: (1)

Both tubed wires should have been Black so that is a bit strange. Do as K-Tune suggests and verify if the trailing coil is working or not. Remove one of the plug wires to the trailing coil and place it back close to the bore leaving an 1/8 th of an inch space between the plug wire and bore. Then start the car and observe for spark. Do this for both trailing plugs. If there is spark then go to the Yellow/Blue wire "in" the four wire plug and clean up the connection if need be and then check if the tach works w/o the use of the installed jumper wire. If the tach doesn't work then ***** the wire in the 4 wire plug with a pin and measure for voltage from this wire with engine running.

NEXTIME

Ok perfect ill go try that right now, If it doesnt work can i not just install a permanent jumper wire from one coil to the other so i have a working RPM gauge? or would that cause futher issues?

satch

iTrader: (1)

The jumper wire was suggested to see if the tach actually worked or not. Now that it works it should be imperative to finding the cause for it not to work. If all else fails then a permanent jumper wire could be used I guess.

NEXTIME

I got my dad to hold the plug wire close to the coil and there was no spark.. So i put it back on and the car wouldnt start.. Then there was a hissing noise coming from the engine bay when the car was on the on position.. which im guessing is the fuel pump or something? So i let it sit for a while and the car started back up :S

NEXTIME

And the high idle is weird.. If i start the car and im in neutral the RMP's will be high 1600. But if i put it in gear and start driving the RPM's will act normal and drive like a normal car.

satch

iTrader: (1)

The coil, in this case the trailing coil, needs to be firmly mounted to the fender for the coil/igniter to be grounded properly. Without the ground the coil won't fire. Perhaps cleaning the contact point via sanding might be a good idea. The Black/Yellow wires at the trailing coil, two of them, need to have battery voltage w/key to on as this powers the coil. Pull the two wire plug to check this.

NEXTIME

I dont know if this matters at all but.. When i got my dad to hold the plug wire i told him to hold it 1/8 inch away from the little silver *** that it came off ( bore? ) but the plug obviously has rubber around it right? I think he was holding the end of the plug wire away from it and not actually sliding the rubbing part over the bore a little to get it close enough to spark? Correct me if im wrong? or if that even makes sense.. i tried to explain it lol

EDIT - Stupid question but will probably save alot of time if im doing this wrong.. by plug wire you are referring to the 2 thicker rubber wires that are going from the trailing coil to the side of the engine? I dont know much about rotarys but those plug wires are going from coil to spark plugs? hence why you call them plug wires :P..

InsomniacFC

iTrader: (4)

Does the car idle at 1600 rpms when it's cold, and then go back down to say 7-800 rpm's when it's warmed up? Or does it just stay at 1600?

NEXTIME

To be totally honest i have only owned the car for a few days and havnt really driven it.. and when i was driving it, it was only for 2 minutes down the street and back and the rpm gauge was not working.. therefor wouldnt have been able to see an actually reading. BUT now that i have been told how to get it working.. I can take it out for a drive tomorrow and let it get warm and report back to you! What are you thinking the problem is?

EDIT - I also live in Canada, its already getting pretty cold here so with common sense.. everytime i start the car its as cold as could possibly be :p

InsomniacFC

iTrader: (4)

There's an accelerated warm-up process when you start the car. If it's really cold it will go from 3k to 1.5k before settling down to around 750 rpms when it's warmed up. If it's not extremely cold it will start at 1.5k. That could be why your idle is so high. I'd let it warm up for a while and see if it goes down when you get the tach running.

NEXTIME

Thank you for clarifying that! I was actually just reading about that in the FAQ section That would make a lot of sense and i really hope thats what it is. I will report back tomorrow morning!

Ps - sleeping pills help LOL

satch

iTrader: (1)

Correct.

You can peel back the rubber boot some but if you cover the bore too much with the boot then chances are you won't see spark. Check to see if the coil is properly grounded and for voltage on the B/Y wires as suggested.

And I also agree with the high idle at startup which takes a while to drop based on how quickly the engine warms up.

NEXTIME

OK new update! I have not yet checked the black and yellow wires for voltage yet, but i am going to. BUT i hooked up the tach with the jumper wire like you suggested to try and i started the car. The car idle was sitting at about 1900 RPM and then gradually decreased down to about 900 after 5-7 minutes. I took a bunch of pictures and a video to show you guys. I also have a few more questions. Let me know what you think and thank for very much for your time and advice! I appreciate it tons!


Here is the video:


If i cant get the gauge to work without the jumper wire, or just need a temp fix so i can see the rpms can i cut off this tube on both ends of the wire ( at the coils ) and wire a jumper wire across? ** As you can kind of see the one wire isnt black comming off the trailing coil :S Its yellowish blue.. But works? )


Why is this hose blocked off? Some sort of emission delete? Is that ok? ( the one above the air intake )


And this one aswell? Right by the rad? :S

satch

iTrader: (1)

The reason why the tach isn't working is likely because the trailing coil isn't working as the tach relies on the trailing coil for the signal. No signal means no working tach.

NEXTIME

Would anything else not be working due to the trailing coil not working satch?

NEXTIME

Any input on those pictures guys?

satch

iTrader: (1)

In the first pic if the hose you are referring to is the one with what appears to be silver clamps and this hose is connected to the air pump then it is for emission purposes.

NEXTIME

Ok perfect, thank you

AGreen

iTrader: (11)

The 2nd pic seems to be for the overflow bottle. You have an S4 AFM (so I'm assuming your car is an S4) and an S5 radiator. This could possibly be why it's plugged off. Do you even have a coolant reservoir? S4's (because I don't own or haven't worked on many S5's) have theirs located in front of the radiator. If it's there, is there a hose attached to it?

BTW, neither hose has anything to do with an idle problem.