400 SE what to do
Discussion
Does anyone know how to reset the base idle on a 1991 400 se hotwire. At the moment tickover is high and erratic when warm and sometimes the car blips the throttle on its own accord when stationery. I have tried the usual things ie clean stepper motor, disconnect ecu leave and then drive slowly for a few miles and reconnect etc. etc.
Also is it ok to set ignition advance retard by turning distibutor till car pinks and then back of a few degrees or should it me adjusted with a timing light,I have been given conflicting advice
>>> Edited by beduch on Wednesday 27th November 10:25
>>> Edited by beduch on Wednesday 27th November 10:27
>>> Edited by beduch on Wednesday 27th November 10:28
Also is it ok to set ignition advance retard by turning distibutor till car pinks and then back of a few degrees or should it me adjusted with a timing light,I have been given conflicting advice
>>> Edited by beduch on Wednesday 27th November 10:25
>>> Edited by beduch on Wednesday 27th November 10:27
>>> Edited by beduch on Wednesday 27th November 10:28
To set base idle. check that the throttle is not shutting completely i use a 2 thou feeler gauge top measure top & bottom of butterfly, clamp/ block pipe from throttle body to stepper motor, run engine, 575 rpm is what it should run at, well as near as poss !to adjust idle speed use the by-pass screw (allen key) in the throttle body, check that the throttle pot is giving a reading of 0.33 volts in the closed position (especially if you have adjusted the stop screw)you will need a digital multimeter for this, measure between blue & green wires ignition on throttle closed. ok so if engine is now idling at around 575 rpm switch off, remove clamp/ plug from stepper pipe, disconnect ECU for 30 seconds, always leave the ignition OFF for doing this, reconnect and start engine. the end...
Your idea of setting the timing by driving is fine but its always a good idea to measure what it is actually doing, should be around 28 degrees at 4000 rpm.
Tim
Your idea of setting the timing by driving is fine but its always a good idea to measure what it is actually doing, should be around 28 degrees at 4000 rpm.
Tim
(2 sheds) 400SE tickover
Thanks for advice and quick reply to setting base idle I have checked top and bottom of butterfly with 2 thou feeler gauge its ok, checked throttle pot reading is 0.33 volts its ok, blocked the pipe from throttle body to stepper motor.
Now here is the problem the tickover is still at 1200 rpm as before with everything connected.
Even with the pipe blocked and the by-pass screw turned fully down the tickover is no different, all setting done when engine was warm
What to do now, would appreciate help
Thanks for advice and quick reply to setting base idle I have checked top and bottom of butterfly with 2 thou feeler gauge its ok, checked throttle pot reading is 0.33 volts its ok, blocked the pipe from throttle body to stepper motor.
Now here is the problem the tickover is still at 1200 rpm as before with everything connected.
Even with the pipe blocked and the by-pass screw turned fully down the tickover is no different, all setting done when engine was warm
What to do now, would appreciate help
Hi chaps
Yes the same proceedure applies for all hotwire systems (from 1990 to date)
If your tickover is 1200 with the by-pass tube blocked you have to reduce because the ECU likes to have control without it will "go apeshit" , firstly are you sure that the by-pass tube is completely blocked ? if so and the idle screw is down tight, there could be an air leak, also try re-adjusting/ close throttle slightly, you'll need to re-set potentiometer, has somebody adjusted this recently ??
Heres a thing !Is the vacuum tube from the fuel regulator to the stepper housing in place ?? (about 4mm bore fits under stepper motor and is hard to see)this coming off would also give these symptoms.
Let us know how you get on
Tim
Yes the same proceedure applies for all hotwire systems (from 1990 to date)
If your tickover is 1200 with the by-pass tube blocked you have to reduce because the ECU likes to have control without it will "go apeshit" , firstly are you sure that the by-pass tube is completely blocked ? if so and the idle screw is down tight, there could be an air leak, also try re-adjusting/ close throttle slightly, you'll need to re-set potentiometer, has somebody adjusted this recently ??
Heres a thing !Is the vacuum tube from the fuel regulator to the stepper housing in place ?? (about 4mm bore fits under stepper motor and is hard to see)this coming off would also give these symptoms.
Let us know how you get on
Tim
soddy said: Tim has covered almost everything I think .... you may want to check the stepper motor function however ... sounds like it may be stuck open! Does the idle alter after the engines has fired? Or does it start at 1200 and stay there?
>> Edited by soddy on Sunday 1st December 15:49
Except that if the stepper tube has been blocked , and the high idle persists so the stepper motor can be ruled out. however it is always a good idea to check these as they can get "gunked up".
2 sheds said:
soddy said: Tim has covered almost everything I think .... you may want to check the stepper motor function however ... sounds like it may be stuck open! Does the idle alter after the engines has fired? Or does it start at 1200 and stay there?
>> Edited by soddy on Sunday 1st December 15:49
Except that if the stepper tube has been blocked , and the high idle persists so the stepper motor can be ruled out. however it is always a good idea to check these as they can get "gunked up".
Good point Tim ...
... I will read the post from Beduch more carefully next time ... 
Yes I am sure by pass tube is blocked and I have checked for leaks also tube under stepper motor is ok
No one has reset throttle stop lately
I have just reduced tickover by adjusting throttle stop screw idle now 1000rpm not sure what it should be
If I take off pipe to stepper motor with engine running it has no effect on tickover
No one has reset throttle stop lately
I have just reduced tickover by adjusting throttle stop screw idle now 1000rpm not sure what it should be
If I take off pipe to stepper motor with engine running it has no effect on tickover
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