Hi Guys,
I'd like to tap some of that wealth of knowledge please.
My ZX TD has been unhappy starting for the last couple of months, and I've checked everything. - Glow plugs, heater solenoid, injectors, timing etc to no avail.
Last weekend I just as a last ditch thought checked the cold start waxstat, and compared the cable adjustment to my wifes diesel (both lucas pumps). There was a slight difference in the range that the cable operated over, so I measured her pumps cable range, and adjusted mine to the same.
I presume this is purely to advance the timing and revs on cold start.
Anyway It starts much better now, but still not as good as hers.
So, my question is: Is there a set proceedure for the waxstat cable range adjustment, or is it adjusted by trial and error?
Thanks
Andy
Waxstat adjustment?
Moderator: RichardW
YES Andy -
There is a waxstat adjustment procedure - and it's utterly simple :
the way you allready did it [8D]
In more general terms :
With cold (!) engine - loosen the waxstat inner cable clamp at the rotor pump - then press this arm against the flywheel - & lock the waxstat inner cable clamp. Usually there is a ferrulr on the outer cabling attachment - where any minor slack in cable can be taken up.
With the cable correctly adjusted (tightened) - mark the inner cable protruding out the ferrule with white ink.
When engine is at normal operating temperature - check the white ink marking has moved at least 6mm away from the ferrule - indicating the waxstat is functioning properly.
If you still experience coldstart problems - check the voltage between engine casing & glowplugs - at the tip of the glowplug's connecting (threaded) studs - while the plugs are timed.
Do NOT measure on the wiring (or cable eyes/nuts) to the glowplugs.
The voltage at these points MUST be at least 11V - which your glowplugs also are rated at.
If not - you have cabling or battery problems.
There is a waxstat adjustment procedure - and it's utterly simple :
the way you allready did it [8D]
In more general terms :
With cold (!) engine - loosen the waxstat inner cable clamp at the rotor pump - then press this arm against the flywheel - & lock the waxstat inner cable clamp. Usually there is a ferrulr on the outer cabling attachment - where any minor slack in cable can be taken up.
With the cable correctly adjusted (tightened) - mark the inner cable protruding out the ferrule with white ink.
When engine is at normal operating temperature - check the white ink marking has moved at least 6mm away from the ferrule - indicating the waxstat is functioning properly.
If you still experience coldstart problems - check the voltage between engine casing & glowplugs - at the tip of the glowplug's connecting (threaded) studs - while the plugs are timed.
Do NOT measure on the wiring (or cable eyes/nuts) to the glowplugs.
The voltage at these points MUST be at least 11V - which your glowplugs also are rated at.
If not - you have cabling or battery problems.
Cheers Anders,
The waxstat is functioning correctly, but i've noticed that by adjusting it the engine runs 'more lumpy' if the cable is too tight. Almost like a advance unit on a petrol that has advanced it too far.
I've cleaned all the power and earth cables, both to the starter, alternator, glows and main earth. - Didn't make a difference.
I'm getting over 11v at the glows, however if I leave them on a bit longer the starting gets a bit easier. - They're bosch ones in at the mo., any good?
The car didn't particularly like starting when it was warm, - prior to adjusting the waxstat - Now warm starting is fine.
Cold starting takes about 3-6 turns of the engine, rough runs for 1-2 seconds and then runs fine. My wifes car starts on the first turn all the time. Mine has nearly 190,000 miles on it though, and hers is just broken in at 70000 miles.
Maybe I'm just expecting too much from the car, she always starts first time, but it always gets compared to the other car!
Thanks
Andy
The waxstat is functioning correctly, but i've noticed that by adjusting it the engine runs 'more lumpy' if the cable is too tight. Almost like a advance unit on a petrol that has advanced it too far.
I've cleaned all the power and earth cables, both to the starter, alternator, glows and main earth. - Didn't make a difference.
I'm getting over 11v at the glows, however if I leave them on a bit longer the starting gets a bit easier. - They're bosch ones in at the mo., any good?
The car didn't particularly like starting when it was warm, - prior to adjusting the waxstat - Now warm starting is fine.
Cold starting takes about 3-6 turns of the engine, rough runs for 1-2 seconds and then runs fine. My wifes car starts on the first turn all the time. Mine has nearly 190,000 miles on it though, and hers is just broken in at 70000 miles.
Maybe I'm just expecting too much from the car, she always starts first time, but it always gets compared to the other car!
Thanks
Andy
-
blueboy2001
- Posts: 423
- Joined: 29 Jan 2003, 04:16
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My high mileage TD is a bit rough on cold starting, but will start within a second if I wait until 3 seconds after the glowplug light has gone out. It does start with a puff of white smoke though, I think the glowplugs are getting ready for doing again.
Hot starting has always been more difficult - it will often take 5-6 seconds of solid cranking to get it to go, and it always needs the glowplugs to start.
The engine will run increasingly lumpy if you overadjust the cold start cable - its main function is to advance the timing.
Hot starting has always been more difficult - it will often take 5-6 seconds of solid cranking to get it to go, and it always needs the glowplugs to start.
The engine will run increasingly lumpy if you overadjust the cold start cable - its main function is to advance the timing.
The waxstat cable can not be overadjusted ?
- unless you tighten it such that the cable stretches [:p]
The coldstart adjuster arm on the roto diesel (where waxstat cable attaches) has an adjustable endstop.
This is NOT the cable ferrule I mentioned.
It may well be the coldstart endstop then that needs adjustments - by a diesel specialist with adequate measuring equipment - i.e. the injection timing advance should then be checked with this coldstart arm at endstop.
- unless you tighten it such that the cable stretches [:p]
The coldstart adjuster arm on the roto diesel (where waxstat cable attaches) has an adjustable endstop.
This is NOT the cable ferrule I mentioned.
It may well be the coldstart endstop then that needs adjustments - by a diesel specialist with adequate measuring equipment - i.e. the injection timing advance should then be checked with this coldstart arm at endstop.
Isn't the switch operated by the waxstat device a simple on-off switch?
getting it to come on in the right place isn't very difficult providing the cable pulls tight. Careful adjustment may affect the point at which the device switches off and may be why my TD hunts sometimes at idle a couple of minutes after startup while my wifes ZX has no noticeable transition except for a drop in engine speed.
Must say I've never really thought about that bit before and had dismissed it as the difference between 190,000 and 58,000 miles.
Jeremy
getting it to come on in the right place isn't very difficult providing the cable pulls tight. Careful adjustment may affect the point at which the device switches off and may be why my TD hunts sometimes at idle a couple of minutes after startup while my wifes ZX has no noticeable transition except for a drop in engine speed.
Must say I've never really thought about that bit before and had dismissed it as the difference between 190,000 and 58,000 miles.
Jeremy