I trust I am in the right place to be posting this

I have 1982 Daimler Double Six (with a 1985 motor in it) that recently started with problems (I bought her as a non-runner, she has been to two garages and i have been chased away on both occasions the second garage at least got her running on all 12) a day after driving her back (with extremely limited power i might add) she was running and I pulled the vacuum lines off the fuel regulators (checking vacuum) and that was the last time she ran well, I also happened to remove the ECU and take the covers off it, after re-installing it she ran normally (this was before I removed the vacuum from the fuel regulators).

She is currently doing the following; she will only start if the throttles are wide open and runs like this for about 7 seconds, incidentally if i try restart her right away she refuses, she likes to be left for a while (I wish I knew the reason).

Other pointers are as follows; the fuel pump was hot wired so that it runs with the ignition (I didn't do this, there was no power to the pump while cranking), she also has very low vacuum to the vacuum advance capsule (I'm in the process of sorting this too) however she has good vacuum to the ECU. I also checked the fuel regulators for leaks and found none, the inlet regulator breaks at about 30 psi and the outlet regulator breaks at about 23 psi.

Any help in getting her to run again would be greatly appreciated, it's nearing 7 months now and I'm getting desperate

Cheers
Nathan

 

my first thought is to try to start it with starting fluid. If it starts good then it's a fuel issue. you can go through and eliminate on thing at a time that way. if it's the same as before, then it's spark issues. easy test.

 

As I recall, holding the throttle wide open while cranking actually cuts off the fuel injectors. If I'm correct then I wonder if your flooding with fuel.... and holding the throttle open lets enough air in to clear the flooding?

Do you sense an excessive fuel condition? Wet spark plugs? Smell of raw fuel? Black smoke from exhaust? Fuel odor in exhaust? If so, there are a number of likely culprits.

Cheers
DD

 

Thanks Amaezing and Doug

As for the cutting of fuel at full throttle I'm afraid I'm not sure, she has the Digital P system, of which I'm still learning...

There was also a problem with the fuel relay... Is it possible for a fuel relay to play up in this manner? For the few seconds that she does run she runs fine, but then slowly dies without popping or backfiring (incidentally she did backfire once while cranking) if I let off the throttle she dies quickly, if I hold the throttle full she slowly dies, if I pump the throttle the revs drop every time I let off, and holds a few rpm when I open up.

The vacuum lines are suspect, as are the many valves in the vacuum plumbing... however she was running fine a few days ago...

I am also aware of the sensor on the throttle itself, might this be at fault? I have a multi-meter that i can check various items with. i am also told that the temperature sensors can play havoc with a non run condition...

Lastly is there any way that I can check basic items or readings at the ECU? or does this not sound like the problem?

Many thanks
Nathan

 

Apologies Doug, i should add that she does not seem to be running rich, there is a feint smell of fuel in the pipes, when she does run for a few seconds (slowly dying every time) she runs well. Oh and i did take the rail off to check the injectors, she's running on 11 due to one blocked one, which i intend to sort later.

Nathan

 

fuel filter??? has that been changed or checked?

mine did something similar when I first got it, ended up being the flapper in the AFM was stuck and I just put a bit of lube on it and it worked better for a little while. It was similar scenario but different, worth looking at.

 

Since the pump has been wired to run whenever the key is 'on' it doesn't sound like it would be the problem



Ok, that does sound like it is running out of fuel.

Check the fuel filter, as mentioned






Maybe.

Hook your voltmeter between the red and yellow wires at the throttle position sensor....you have to backprobe the connector or pierce the insulation of the wires. With the key 'on' you're looking for .32-.35 volts with the throttle at the idle position and 4.8-5.0 volts at fully open position. When slowly opening the throttle you want smooth voltage increases with no voltage drops



A faulty CTS (coolant temp sensor) can cause running problems but engine-starts-then-dies isn't the typical symptom. Still worth looking at, though.

The one you care about at this point is aft of the left side thermostat. If disconnected the engine probably won't run. If the connection is weak you'll likely get rich running. As for the sensor itself the usual fail mode is "skewed cold'....meaning it always send a 'cold' signal to the ECU....resulting in rich mixture because the ECU thinks the engine is cold.




Sort of.

The ECU exists to operate the fuel injectors, so.....

Get a noid light (here's an example...but you can find them at most auto parts stores)....

http://www.summitracing.com/parts/oe...FU2Tfgod1q8ONg

.......to see if the injector circuit is going dead after 7 seconds. Remove one of the fuel injector connectors and slip the little noid light into the connector. It flashes when the ECU 'fires' the injectors. If it stops flashing, you might be on to something


Cheers
DD

 

Good thought but Nathan's V12 doesn't have an AFM


Cheers
DD

 

Many thanks Doug and Amaezing

I'll attempt what I can tomorrow. Unfortunately in this part of the world many an "experienced" mechanic has never heard of a noid light, but I know what you're talking about. I'll scratch around and see what I can find.

Indeed it sounds like a fuel related problem... I am thinking of running her from an external source with external power to the pump to see if this helps (bypassing the filter too).

I will post the results, thanks again for the help and advice.

 

I keep forgetting that. I was even looking at one this weekend and I still forgot.

 

Hi again

So the problem turned out to be a blocked fuel filter, caused by dirt in the tanks (she did stand for about a year if not more).

I am now in the process of sorting the vacuum issue (she has very low vacuum to the vacuum-advance capsule).

Many thanks Doug and Amaezing, you chaps were a great help.

Cheers