i have just bought a series 8 pretty much in stock condition .the car idles at around 1500 rpm when at operating temp.also when driving the revs stay at around 4000rpm when changing gears.if clutch left in it will slowly drop back down to 1500 rpm .can anyone help me

 

Could be a bad (very bad) vacuum leak, spray with brake cleaner to try and track it down.

Also check all your throttle body adjustment screws.

 

check the throttle cable also to make sure it isn't sticking.

 

have just given it a run revved it up using linkage on throttle body if u rev it over 3500rpm it will stay free revving then drop back in revs slowly .i adjusted the screw on the front of the throttle body and now idles at1250 rpm sprayed aerostart everywhere while idling and saw no difference so i can assume not a vacuum leak maybe

 

also on a seperate note are HKS GD clutch max clutches any good and having a diff locker diff a good idea because i have found out they are both fitted to my car

 

Check the air bleed screw located under the elbow that bolts to the throttle body inlet. Use a short flatblade screwdriver, turn clockwise to close it all the way.

 

Check and verify the components in the area like TPS, ISC, Dashpot. Also, make sure to spray around the LIM to engine connection. Typically when there is a hard to find vacuum leak, that's where it is....

 

ok i have just bought a replacement series 8 when i first got it it idled at 1500 rpm got it down to1250 after tweaking best i could with limited knowledge on adj idle speed and when revved over 3500 rpm would stay revving then slowly return to 1250.just installed power fc now revs at 1650 rpm but solved the other rev problem .can anyone tell me why it revs so high at idle and how to adjust or fix the problem TIA jason from australia

 

Hey Jason,
Have a quick look at the stopper screw for the butterflies, It may be wound out a bit which could be preventing the butterflies from returning to closed. Also pop the intake elbow off and try actuating the butterflies with your hand, You may find that they are sticking, A frayed throttle cable could be causing this.

If you have the time it is probably worth pulling the throttle body off and double checking everything with the workshop manual, and give it a good clean while it's off.

Cheers
Aaron

 

Did you cut the 4 wires necessary for the Apexi PFC to not idle high? If not, search and you will find it.

 

Austraiian cars do not have EGR or AWS, there are not 4 wires to cut

I would start looking for a vacuum leak, possibly in the S8 solenoid box.

 

update spraying aerostart on the black hose at the outlet of the throttle body (which contains water which i found out the hard way its hot when engine is hot) this causes the idle to drop .what is this hose for the aerostart may be cooling it down

 

update fitted power fc fixed the sticky rev issue now revs perfect but still revs at 1650 rpm at idle .i dont need 2 cut any wires on my car its japenese. i sprayed aerostart on the outlet on the back of the throttle body that has a black hose attached that contains water and the revs dropped. i assume a cooling effect of the aerostart maybe but why is this so and what could be wrong

 

I think you are talking about the thermo-wax coolant lines. Spraying starter fluid on it will not do anything. Sounds like your TW actuator my be slightly out of adjustment or that the coolant finally got hot enough to push the piston out far enough to drop your idle.

It is winter there currently, right? What are your water temps on the commander?

Here is the TW assembly by the TPS. See the screw with the tension spring? It rests against a piston that moves out when your coolant gets up to temp. The screw goes through a little lever, push it down and see if your idle drops to normal.

 

i recently bought my 2nd fd (first one ended up in a fence for a second or 2 but insurance coughed up) and had endless problems with it. i took it apart found missing gaskets and bolts everywhere. i put it back together properly and a few needed mods thanks to everyone now and past for ur advice have it runnin like a purring kitten and goin like a cheetah. its a 2000 model RB limited edition cheers jason from townsville australia

 

If the original OEM fiberboard gasket between the Lower Intake Manifold and the rotor housing is leaking air into the engine due to deterioration, it will be very hard to find by spraying... it's almost impossible to access that area without dismantling the right-side peripheral components of the engine. The cure is the upgraded stainless-steel gasket, if that is the problem. Mazda's gasket P/N is N3A1-13-111A for a U.S. version 1994 FD. (It cured my high idle.)