Hi Kevin, I will post what was wrong when I sort it (ever the optimist)
Nick
"kevin_sar <k@xxxx>" <k@xxxx> wrote:
I think you need to speak to Mark Bourne or David Howarth on this,
when yo find the answer make sure you post the answer.
Kevin
--- In doc-uk@xxxxxxxxxxxxxxx, "nickandkathryntomlinson
<nickandkathryntomlinson@xxxx>" <nickandkathryntomlinson@xxxx> wrote:
> To All Delorean Tech-heads.
> Please excuse me if you have heard of this problem before but I am
> fairly new to the world of Delorean ownership.
>
> I have a problem with the idle speed on my car (Automatic) when the
> engine is cold. It also appears to run rich although this maybe
> associated with this problem.
> I have just tuned the engine and have performed the following
> changes/ tests.
>
> Changed spark plugs (plug gaps set to 0.68-0.70mm)
> Checked throttle is fully closed (including checking the throttle
rod)
> Checked microswitch engages correctly and is electrically OK.
> Checked Distributor timing and vacuum advance shut off solenoid.
> Checked Fuel Canister purge valve/ isolated carbon canister
(removed
> and plugged hoses)
> Changed Lambda/O2 sensor
> Checked Frequency valve `buzzez'
> Checked Supply voltage and earth return at Fuel Control Pressure
> Regulator.
> Checked for 35 ohm resistance for Fuel Control Pressure Regulator
> heater.
> Adjusted Fuel Distributor flap so frequency valve duty cycle
> oscillates between 32 and 45 on a dwell meter. (Note I have re-
> plugged the adjustment hole when taken a reading).
> Check Idle Speed control valve for operation.
> Pins 1 and 2 approx 100 ohms
> Pins 2 and 3 approx 100 ohms
> Pins 1 and 3 approx 200 ohms
> With +12v on Pin 2, momentarily earthing Pins 1 and 3 in succession
> successfully opens and closes the control valve.
> Checked continuity of cabling from the control valve back to the
> plugs on the idle speed ecu.
> Checked thermistor resistance at idle speed ecu. Reads approx 1.8-2
> Kohms with engine cold, approx 220-290 ohms engine warm.
>
> When the engine is warm the engine idles pretty smooth, varies +/-
50
> RPM at approx.780 RPM.
> The engine speed does drop when the air conditioning/ heated rear
> window and lights are put on.
> As a further test I have at the ecu end put a manual variable
> potentiometer (resistor) that can vary the resistance between 0 and
> 5k on the ecu to simulate the idle speed thermistor. I used short
> cables to connect the other connectors to the ecu using standard
> spade/ blade male female connectors.
> I presumed that changing this resistance would make the engine idle
> speed raise and lower as it would change the duty cycle
oscillations
> on the idle speed valve but this has no effect.
> Am I right in thinking that my idle speed ecu is at fault?
> I've check the other connectors i.e. supply voltage, earth, idle
> switch operation, connection back to coil, continuity to idle speed
> valve, protection diodes etc.
>
> My other test tonight when the engine is cold would be to use a
> standard auxiliary air valve used on standard volvos to simulate
the
> extra air required for a cold engine. OK, I don't have the correct
> valve so I've improvised (don't laugh) by using a 22mm plumbing
> isolator valve in place of the idle speed valve (in effect a gate
> valve). I tried this out on a warm engine and it raises/ lowers the
> idle speed ok. (Can't imagine screwing this slowly down while in
> traffic !!)
>
> Can anyone advice anything else I can try before I buy a
replacement
> idle speed ecu?
> Can anyone let me know what the idle speed of their Delorean is at
> cold and how long roughly it is high for? My car is an automatic.
>
> When warm the engine drives really smooth and is a joy to drive,
when
> cold I have to use my left foot on the brake.
>
> Thanks all in advance for any further help
> Nick Tomlinson ? DOC Member 241.
>
> p.s. If anyone has a "spare" ECU I could try then i'd be v.
grateful.
> If this is a common problem I could try and source and test a few
> from a breakers yard. Apparrently the same ECU could come from a
> Volvo 200 and 700 series with the PRV engine.
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