[Diy_efi] Re: Diy_efi Digest, Vol 9, Issue 14

[Bill Washington]

Ian,
	Temperature sensors are generally variable resistance with temperature and have 
two main failure modes short circuit, or open circuit - disconnecing a short 
circuited Temp sensor would certainly show an effect, but disconnecting an open 
circuit Temp sensor would have no effect. This could be your problem - worth 
checking...
	If you have the manufacturer and model number of your IP you could try a google 
search on that info, also don't discount your local library, Technical book 
shop, or tertiary institute/ trade college libraries for specific information on 
your pump/engine combination. From those sources you may find some specific 
troubleshooting guides.

Regards
Bill
>>Ian,
>>    The cold start mechanism on my diesels is mechanical, ie a cable to 
>>a lever on the side of the pump - that lever controls a mechanical 
>>advance in the IP - I have now seen this on Bosch, Roto-diesel and Lucas 
>>Diesel injection pumps.
> 
> 
> Well, my IP has only one protruding 'control' of any kind - a spring 
> loaded lever, attached to the throttle cable.
> 
> theres just two vaccum actuators that also affect the lever. One is the 
> cold start rev boost, which is vacuum actuated, but controlled by a 
> solenoid valve from a button on the dash. The other is a 'dashpot' and 
> controlled by vacuum from the airbox.
> 
> neither of these moves *at all* when the idle increases. nor does the lever.
> 
> Theres also a vacuum actuator on the top of the pump which is the boost 
> compensator.
> 
> It appears that the engine *always* starts with the right idle speed. if 
> its warm, then a few seconds (10-20) later, the idle will increase.
> 
>  > the same function could be done electronically,
> 
>>and probably was on some the generation after mine ... and then.... in 
>>the new common rail diesels its all done in a computer and the injectors 
>>have changed to electronic and the IP is simply a 'very' high pressure 
>>delivery system.
> 
> 
> Theres nothing electronic on my IP other than the fuel cut relay and rev 
> counter pickup.
> 
> 
>>    I would check the resistance of your temp sensor(s) hot and cold  
>>and compare them the the manufacturer's spec.
> 
> 
> surely disconnecting them would have an effect on the problem?
> 
> either way, they all appear to be good.
> 
> this is one weird problem.
> 
>