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Old 06-22-2010, 10:18 AM
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soothappens soothappens is offline
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Quote:
Originally Posted by barry123400 View Post
How about feeding the engine from a small container of fuel first? If normal in primary fuel filter and idle is much improved with that then go backwards. You could reverse the pickup and return lines as well I suppose. You need 1/2 tank or so of fuel to enable this I understand.

I am a little leary of doing that as any gunk built up over time in the return line might migrate through the injection pump. Inserting a small primary filter and piece of hose in the return line would protect the injection pump though I suppose.

You do not want to land up doing more under there than required. Unless it is benificial overall like getting the base pressure of the injection pump corrected as you did.

It is becoming strange that so much improvement in the system is available just by correcting the base fuel supply pressure properly with a gauge as you have done.Yet so many still ignore it. After the idle problem is solved you will find that even if it took a fault to get it done it was usually worth having the fault to enable it happening.

Or after you correct the first one for base pressure you will at least check any subsequent or existing cars of this type. My suspicion about the number one rod bearing remains unproven but get the base pressure in the proper area as well on that two forty if it is not. Anyway you look at it the additional power on the two forty is wanted if available usually.

As people have mentioned it could be soft motor mounts but just as easily an imbalance of power pulses in the engine.

I have recently added the ideal of adding the check of the delivery valves test for leakage to the list of probabilities to be examined if what we currently consider normal things do not restore good idle. This at this point is somewhat of a shot in the dark so I will be looking for candidates for this issue as time goes forward. Your car is not there yet.

Unfortunatly for you since we tend to think a little along simular lines as I mentioned awhile ago. Once you clear the fuel supply system as a cause. Time to read the milli volt method to locate the imbalance if not the engine mounts. I guess it would be wise to check the valve clearances first.

On the otherhand if it is just an injecting fuel problem the milli volt thing will locate it quickly enough. I have almost concluded that the occassional bubble up through the primary filter may not be signifigant enough. I just do not know at what point the amount of air becomes a real issue. In theory again there should be none.

The appearance of foaming in the primary filter may allow a lot of very small bubbles up the line that are not visable as basically the fuel may be entraining air . It may become interesting to get to the botttom of your problem. Unfortunatly for us observers there is still an excellent chance that just air in the fuel might be involved.
That's a good idea on the aux fuel source. The simple things sometimes elude me in my quest to reinvent the wheel.

I did the valves two weeks ago all were tight. I could have sworn I did the check valve as well , but it turned out I did it on the engine that came out. That's the valve I'm using now.

I also did the millivolt method and all were dead on. Reconfirmed that with a thermocouple on each glow plug and injector. They were all in the same temp range.

After sleeping on it I wonder if the A/C is just bringing the Idle down to low. These older cars don't have any provisions to raise the idle when the A/C kicks on do they ? Other than the governor ?

I'll try an aux source of fuel tonight. thanks Barry
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