Tips For Solving Diesel Starting Issues.

Frequently asked technical questions and common modifications/improvements

Tips For Solving Diesel Starting Issues.

Post by M »

Diesels need a few things to ensure that they will start up.

The first of these is a decent battery. Sometime before the winter comes, Check the battery charging voltage. If it isn't getting to 14 Volts or more with the engine idling, then either the alternator belt is loose or the olly itself is low output.
Paris Rhone alternators can be removed and the black brushgear and cover may be removed with nothing more than a screwdriver. Check that the Lucar terminal is tight (the thin wire that plugs in) and that the post terminal is clean. Once the brush gear is off, check it all for wear and give it a good scrub.
The connector that makes to the alternator body may be corroded as may the nuts either side marked b+ and b-. Take them off, clean the nuts, posts and washers with a wire brush as well as the alternator mountings. Ensure you have a good half inch of brush left.
Reassemble the lot and consider fitting a cable from the alternator to the battery directly.

Remove the engine earth from the engine at the gearbox before cleaning it up and replacing it tightly.

Now check the battery terminals and if they are not in good condition, replace them. Replace the battery every three years with a good one.

A precautionary clean of the starter motor brushgear every couple of years will save you from trouble there but they rarely fail.

Assuming that the fuel lines are tight and not leaking air which causes fuel to run back to the tank, (And in turn, wasted energy pulling up fuel on the starter,) the next problem to avoid is that of the glowplugs.
You will need a meter for this. Power the car up and listen. Once the light goes out, the glow plug relay holds in for another ten seconds or so. (If your battery is weak, wait until it drops out before attempting to start up. The plugs will be hotter and there will be more power available to spin the engine.) once the relay is in, check that the voltage is getting to the plugs. You should see 11 or more on the wire linking the tops of the plugs if you have a well charged battery.
If you are dropping more than 2 Volts between battery+ and plug, then strip and clean the blue glow plug relay terminals and if necessary the contacts themselves.

Rough running after startup, coughing and smoke etc. is usually down to a duff glow plug. To find out which one, simply remove the feed cable from the tops of all the plugs and measure the resistance of each plug with the meter. They should all be about the same, under an Ohm. Any that are much higher will be faulty.

That really is all you need to know 8)

With Thanks to Tom for the above write up.
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kermit the frog
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starting diesel engined bx's

Post by kermit the frog »

all of the advice in this post is absolutely spot on and is well worth following before you go to your friendly diesel fitter for a sharp intake of breath.

one small thing that i personally do when starting my grand old bx is when the heater plug light goes out watch and listen. :!: (watch the dash lights after the light goes out for approx 10 seconds) they will get brighter
and listen for the click of the relay.
the warning light goes out before the relay turns off if you do this every time the car will start with ease in les than 1 second
works every time

and my bx has now got 280295 miles under her belt and the engine is still original
she still regularly returns 670 miles to every tank full of diesel

ALAN S an oracle of knowledge sadly missed by us all RIP Mate
Green Hornet well I don't really know.GS project gone to pastures new
Blue Streak 1996(P) XANTIA VSX TD (130K.)
Rev. Dick Deluxe
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Post by Rev. Dick Deluxe »

All good advice there. 8)

One thing i would add that is a common problem on older diesels is the stop solenoid in the pump is prone to failing stopping the fuel getting to the injectors.
You can bypass it by unscrewing it and removing the plunger, this will allow the car to start but it wont stop on the key, you'll have to stall it to shut it off.
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Post by Alcyone »

I don't agree, that's bad practice, stalling the engine to stop it. Increased clutch wear, a hit on the crankshaftbearings every time, and in case of an auto, virtually impossible.

As an alternative, one could attach a cable to the stop-lever on the pump, the other end of the cable fitted in the interior with a nice knob. This is what I'm going to do, since I like the idea of an engine that keeps running regardless of available electricity.