High idle speed.
Discussion
I am slowly getting all the niggling things sorted.
You fix one and another rears it's head.
I am running no lambdas and the green tune resister
Timing spot on
Stepper cleaned and viewed moving in and out
stepper well sealed to housing
Stepper connector on
Vacumn pipe connected to regulator + no splits
Rubber pipe to plenum fitted + no leaks
Car starts ok, idles cleanly at 900 rpm when stone cold and revs then gradually rise to 1600 rpm.
The air screw on the plenum is screwed down all the way, if not the more you unscrew it, the higher the revs!
Funny thing is that when the idle was normal and it started from cold, it always ran very rich till it warmed.
Now it runs cleanly from cold and when warm, idling at 1500 rpm shows 12.3 or thereabouts on the fuel ratio gauge.
Suggests huge air leak/AFM/Gerbills???
I've run out of ideas and look to you guys for an answer............
You fix one and another rears it's head.
I am running no lambdas and the green tune resister
Timing spot on
Stepper cleaned and viewed moving in and out
stepper well sealed to housing
Stepper connector on
Vacumn pipe connected to regulator + no splits
Rubber pipe to plenum fitted + no leaks
Car starts ok, idles cleanly at 900 rpm when stone cold and revs then gradually rise to 1600 rpm.
The air screw on the plenum is screwed down all the way, if not the more you unscrew it, the higher the revs!
Funny thing is that when the idle was normal and it started from cold, it always ran very rich till it warmed.
Now it runs cleanly from cold and when warm, idling at 1500 rpm shows 12.3 or thereabouts on the fuel ratio gauge.
Suggests huge air leak/AFM/Gerbills???
I've run out of ideas and look to you guys for an answer............
Speed sensor signal present when it should not be. You need an ECUmate- you know you want to, go on 
You still must have an air leak if the engine still idles with the stepper clamped off, it should stall with the base idle screwed right down, end of story. The ECU will also throw up a fault code if it cant maintain the idle as it should, and if the idle is increasing it would be safe to assume the ECU is moving the stepper due to speed signal input or possibly some other fault condition. Ive been told (but never seen) the ECU will raise the idle under certain fault conditions. The ECU could be running the get you home map, that throws another spanner into the works. You will never guess you way around this fault, as I suspect there is more than one, and you really dont have enough data to go on, only multiple symptoms. Hence the ECUmate (no Im not on commission!)
You still must have an air leak if the engine still idles with the stepper clamped off, it should stall with the base idle screwed right down, end of story. The ECU will also throw up a fault code if it cant maintain the idle as it should, and if the idle is increasing it would be safe to assume the ECU is moving the stepper due to speed signal input or possibly some other fault condition. Ive been told (but never seen) the ECU will raise the idle under certain fault conditions. The ECU could be running the get you home map, that throws another spanner into the works. You will never guess you way around this fault, as I suspect there is more than one, and you really dont have enough data to go on, only multiple symptoms. Hence the ECUmate (no Im not on commission!)
Edited by blitzracing on Wednesday 18th April 13:05
I have a similiar problem except I cannot get Idle control, Just to ask a question if I clamp the pipe going to the stepper should the car idle at all or just stall ??? all mine does is drop the idle from 1400 rpm to 1000rpm ish
My stepper isnt moving, thats another thing I am trying to sort. at the moment its fully retracted
Base Idle screw on the top under part of the throttle linkage ?? is there any other adjustments ??
My stepper isnt moving, thats another thing I am trying to sort. at the moment its fully retracted
Base Idle screw on the top under part of the throttle linkage ?? is there any other adjustments ??
Edited by hiltonig on Wednesday 18th April 13:51
Edited by hiltonig on Wednesday 18th April 13:53
Edited by hiltonig on Wednesday 18th April 13:54
From the man who designed it
It reports and clears all 40+ fault codes not just the 14 or so basic ones.
It displays information on the lambda sensors so you can see how they are responding.
It displays the actual voltages so you can set up the throttle pot and see how this affects idle mode.
It does a ECU power up check to check that the fuel pump is priming and for stepper motor reset.
It allows you to turn the fuel pump on and off.
It allows you to move the stepper motor at will.
It displays when the ECU goes into idle mode and the conditions that cause it to do so.
It can detect noisy throttle pot movement.
It also describes the map type: region, cats or no cats
Manual download here if you want the nuts and bolts:
http://www.shengltd.com/tvrextras/docs/Ecumate%20i...
It reports and clears all 40+ fault codes not just the 14 or so basic ones.
It displays information on the lambda sensors so you can see how they are responding.
It displays the actual voltages so you can set up the throttle pot and see how this affects idle mode.
It does a ECU power up check to check that the fuel pump is priming and for stepper motor reset.
It allows you to turn the fuel pump on and off.
It allows you to move the stepper motor at will.
It displays when the ECU goes into idle mode and the conditions that cause it to do so.
It can detect noisy throttle pot movement.
It also describes the map type: region, cats or no cats
Manual download here if you want the nuts and bolts:
http://www.shengltd.com/tvrextras/docs/Ecumate%20i...
Getting somewhere I believe.
Throttle position sensor was out, corrected.
AFM, correct reading.
Blocked stepper hose and adjusted air screw, idles now at 900 RPM.
Took car for a short spin, when you stop engine idles at 2200 RPM and within the next 5-10 seconds, dropps back to 900 RPM in 3 stages, 2200, 1700, 1200, 900.
Switched off engine, waited a mo, started up and it goes through the 2200-900 routine every time you start her up!
Disconnected stepper plug while engine running and problem now solved.
Why?
Throttle position sensor was out, corrected.
AFM, correct reading.
Blocked stepper hose and adjusted air screw, idles now at 900 RPM.
Took car for a short spin, when you stop engine idles at 2200 RPM and within the next 5-10 seconds, dropps back to 900 RPM in 3 stages, 2200, 1700, 1200, 900.
Switched off engine, waited a mo, started up and it goes through the 2200-900 routine every time you start her up!
Disconnected stepper plug while engine running and problem now solved.
Why?
Obviously something to do with stepper then Peter. Mine sometimes from a hot start will tick over at 2k for sometime. Clearly the stepper is letting in more air than is needed when this happens, Why, not sure. Is it the stepper on the way out, maybe getting a bit sticky in operation or an ecu problem as the ecu drives the stepper. OR, is it one of the temp sensors telling the ecu, engine is colder than it actually is.
Mine only does it from a hot start and only occasionally, never when coming to idle whilst driving. My engine drives spot on so i`m guessing a sticky stepper.
Mine only does it from a hot start and only occasionally, never when coming to idle whilst driving. My engine drives spot on so i`m guessing a sticky stepper.
All good points Ian.
The steppers are very robust, I ran my engine the other day with the stepper out and you can see it trying to close off the port as it moves out so I believe it's OK.
I tried a different ECU, sameo.
Haven't road tested this late PM as it's hissing down, probably test tomorrow but I anticipate a poor start with the stepper disconnected.
Hmm, possibly a sensor telling the stepper wrong info.
Another case for the ECUmate?
The steppers are very robust, I ran my engine the other day with the stepper out and you can see it trying to close off the port as it moves out so I believe it's OK.
I tried a different ECU, sameo.
Haven't road tested this late PM as it's hissing down, probably test tomorrow but I anticipate a poor start with the stepper disconnected.
Hmm, possibly a sensor telling the stepper wrong info.
Another case for the ECUmate?
Yes it really is ECUmate time to see what is going on. Some of the screens were designed specifically to identify idle problems.
I have been working on this for some time and basically cracked it over the weekend. I can generate these symptoms at will now on my engine simulator and found that high idle is a combination of bad throttle position, poor base idle, incorrect stepper position and finally the speedo signal that goes into the ECU from the TVR speedo box. The degree of high level is dependent on all of these factors which is why it is extremely difficult to diagnose. To be honest, ECUmate is the only device that lets you see what is actually happening in these circumstances.
To completely solve this, the TVR box needs to be replaced. I have a design almost complete that generates an ECU friendly signal that doesn't confuse it and is programmable. It will also allow the speedo to be calibrated. The hardware is designed, the PCB laid out. This will be a straight plug in replacement.
In the meantime. setting the throttle voltage correctly to 0.35V and setting the base idle correctly will help dramatically but won't remove all the problems. ECUmate will display the the throttle voltages and you can use it to help set it up.
I have been working on this for some time and basically cracked it over the weekend. I can generate these symptoms at will now on my engine simulator and found that high idle is a combination of bad throttle position, poor base idle, incorrect stepper position and finally the speedo signal that goes into the ECU from the TVR speedo box. The degree of high level is dependent on all of these factors which is why it is extremely difficult to diagnose. To be honest, ECUmate is the only device that lets you see what is actually happening in these circumstances.
To completely solve this, the TVR box needs to be replaced. I have a design almost complete that generates an ECU friendly signal that doesn't confuse it and is programmable. It will also allow the speedo to be calibrated. The hardware is designed, the PCB laid out. This will be a straight plug in replacement.
In the meantime. setting the throttle voltage correctly to 0.35V and setting the base idle correctly will help dramatically but won't remove all the problems. ECUmate will display the the throttle voltages and you can use it to help set it up.
carsy said:
Obviously something to do with stepper then Peter. Mine sometimes from a hot start will tick over at 2k for sometime. Clearly the stepper is letting in more air than is needed when this happens, Why, not sure. Is it the stepper on the way out, maybe getting a bit sticky in operation or an ecu problem as the ecu drives the stepper. OR, is it one of the temp sensors telling the ecu, engine is colder than it actually is.
Probably an easy swap, is that the one at the front of the nearside inlet manifold?carsy said:
Mine only does it from a hot start and only occasionally, never when coming to idle whilst driving. My engine drives spot on so i`m guessing a sticky stepper.
Take it out and give it a good clean, easy peasy.Hi guys.
I had similar thing a couple of weeks ago all running really well at the moment.
Only thing different is i was advised that when you block the stepper hose the base idle should be set to between 450 and 550 rpm. Then when you unblock the rpm will raise to between 900-and 1000 rpm.
When i now come to a stop the rpm drops straight to about 1300-1400 before dropping to idle.
I had similar thing a couple of weeks ago all running really well at the moment.
Only thing different is i was advised that when you block the stepper hose the base idle should be set to between 450 and 550 rpm. Then when you unblock the rpm will raise to between 900-and 1000 rpm.
When i now come to a stop the rpm drops straight to about 1300-1400 before dropping to idle.
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