High Idle problem

[GrahamU]

I'm new to this forum and to ownership but I do have this idle problem on my small turbo EECIV cossie

I have searched and seen many people discuss it but not found anyone write an actual solution to how they fixed it.

When you pulled up, mine would continue to rev at around 2000 with the clutch down until you stopped, it would then drop to around 1100.

I have noticed that it is connected to the VSS and found that if I were on a hill and let the car roll when not in gear the revs would rise again to 2000 and drop again at standstill

With some googling, I found the VSS input was on pin 3 of the ECU, I then found there was a speed input for the stereo fudged into this wire so having seen problems with these inputs on other cars I removed it.

That has had a positive effect on it, the car is now much more drivable and does not fight you as you slow down for junctions but it does still hang the revs at about 1400 until you stop moving, so is this normal for this ECU or is there still an underlying problem with it?

P.S. I have written this in the Problems Registering area as although I seem to be a member, I did not receive an email to confirm and this is the only area of the forum I can see

[jsa]

Welcome to the forum and ownership.

Until the engine warms up it will idle at those sort of RPM.
If it is up to temperature, then you have an issue as they normally idle around 900rpm.

ECT sensor might be faulty.

Other causes are low battery volts as measured by the EEC-IV, fuelling error, ISCV issue or air leak.

What mods does it have?

[GrahamU]

Thanks jsa,

Is there a way to check the ECT? is there a voltage to check at the ECU or something like that

I have tried the ISCV and that didn't make a difference, I've also pressure tested the system up to 0.5bar and that was good, no leaks at all

I'll check the voltage to the ECU


Mods are a bit of an unknown, it has a superchips plug in module, recirc valve deleted, turbosmart boost valve turned down to min, 4bar FPR and it boosts to about 1.2bar shown on the gauge on the dash, I need to get another gauge to confirm how accurate that is.

I have tried to get the chip details but superchips dont hold info from back then

[jsa]

If you let the car sit until the engine is at ambient temperature both the ACT and ECT should measure the same temperature / voltage.

Yes you can measure the voltage at the ECU connector with a multimeter or scope. You could also read live data out of the ECU if you acquire tools to do so.
This table is the ACT/ECT Volts/Temp transfer function converted from the ECU binary file. At operating temperature you should read about 0.7V.

Volts	Temp ºC
4.64	-40.0
4.48	-23.3
4.18	-6.7
3.68	7.8
1.46	56.7
0.74	82.2
0.4	105.6
0.26	123.3

If you have a meter that can measure duty cycle, you should have about 33% duty cycle on the ISCV at warmed up idle.

Sounds like a typical "305" chip, which they have failed to adjust the injector specs within, for the increased fuel pressure. They will be relying on the ECU to adjust for the extra fuel, so until it self learns, it will idle rich and at higher RPM. You could measure HEGO voltage at the ECU. It will be about 0.45V at warmed up idle with transitions each side of that voltage once the adjustment is learned and remembered.

You say the recirc valve is deleted, has it been replaced with a dump valve?
Is it just a turbosmart wastegate actuator or controller setup that removes boost control from the ECU?

Have you checked if the ECU is holding any fault codes?

[garet]

I'm new to this forum and to ownership but I do have this idle problem on my small turbo EECIV cossie

I have searched and seen many people discuss it but not found anyone write an actual solution to how they fixed it.

When you pulled up, mine would continue to rev at around 2000 with the clutch down until you stopped, it would then drop to around 1100.

I have noticed that it is connected to the VSS and found that if I were on a hill and let the car roll when not in gear the revs would rise again to 2000 and drop again at standstill

With some googling, I found the VSS input was on pin 3 of the ECU, I then found there was a speed input for the stereo fudged into this wire so having seen problems with these inputs on other cars I removed it.

That has had a positive effect on it, the car is now much more drivable and does not fight you as you slow down for junctions but it does still hang the revs at about 1400 until you stop moving, so is this normal for this ECU or is there still an underlying problem with it?

P.S. I have written this in the Problems Registering area as although I seem to be a member, I did not receive an email to confirm and this is the only area of the forum I can see

Hi,
have you checked your idle valve or TPS,it defo sounds like one of these two..

[GrahamU]

Sounds like a typical "305" chip, which they have failed to adjust the injector specs within, for the increased fuel pressure. They will be relying on the ECU to adjust for the extra fuel, so until it self learns, it will idle rich and at higher RPM. You could measure HEGO voltage at the ECU. It will be about 0.45V at warmed up idle with transitions each side of that voltage once the adjustment is learned and remembered.

You say the recirc valve is deleted, has it been replaced with a dump valve?
Is it just a turbosmart wastegate actuator or controller setup that removes boost control from the ECU?

Have you checked if the ECU is holding any fault codes?

Thanks John, Those voltages will be a big help for checking it, probably the most help I've had on this car has come from you and I appreciate that

The standard FPR is 3.5bar isnt it?

It looks to have a reasonably new oxygen sensor on it, but it could still be that

No dump valve fitted, it has the tee piece for one and had the vac pipe blocked off but no valve, I have seen on here someone found one from a SAAB fits the original recirc on the turbo so I have bought one of those, just need to work out how it all fits

The turbosmart is a boost tee, between the turbo and the actuator, looks like the boost control has been removed and relies on this turbosmart valve, I have found the plug for the original boost control but thats all

I dont have a code reader for this car, not even sure where the plug is

[GrahamU]

Hi,
have you checked your idle valve or TPS,it defo sounds like one of these two..

I swapped for another idle control valve, that made no difference, I think I need to adjust the TPS as it idles around 1100 when the idle does settle

[jsa]

While looking at the TPS, make sure the throttle blades closes consistently against the throttle stop.

Yes 3.5bar, but leave the 4bar in place while you are using the chip/turbosmart. The 4bar pressure raise injector flow rate to handle the extra fuel requirements. It's a kludge, as they were too slack to program the chip for the extra flow rate.

Without the OEM boost control valve connected, it likely has a fault code stored for that at least. Definitely a line of investigation.

Diagnostic plugs are to the back of the left hand strut top. Fault code reading can be as simple as using a jumper, LED and resistor. A better option is the Czech made ForDiag which will read out live data as well as fault codes. The most powerful is the Moates QH emulator / BE / GHAJ0 definition trio which adds access to more data and ability to adjust ECU parameters so you can fix the fuel pressure injector kludge.

[GrahamU]

Thanks John, I'll look into the diag tools