cold start issues

hi im john, my 90 has a bad cold start problem and we have done everythin appart from changing the lift pump, we hav tried but hav recieved the wrong lift pump twice in a row. my landy is 1987 and is a 2.5td, not 2ootdi! the pump in mine at the moment looks like its from a series 3 and has a shorter arm than these new ones, does anyone have any ideas why im having trouble or hav a solution for me ?, thanks

Hello and welcome!

Have you checked to make sure that the cold start mechanism is initiating on the injection pump? Basically all you need to do is ensure that there is some slack in the throttle cable (ie. absolutely no revs or tension on the throttle cable what so ever). If the throttle is even slightly tapped during startup, it will throw the cold start mechanism out on the pump and the extra fueling will not kick in. In theory, all you should need to do is press the clutch peddle and turn the key (after 20 to 30 seconds of glow plug warming of course). You have tried changing the glow plugs, or checking that they are working properly too?

-Pos

yea all new plugs, we think its the non return valve in the lift pump. cold start wont happen without me pining the throttle down if i downt the batt wil jus die its crankin that long. and im gettin good cranking speed too

It could well be the lift pump, but have you tried without slamming your foot to the floor though? Thats one thing which does knock the cold start off. Any tension in the throttle cable when you're starting her up and the advanced injection timing and richer fuel inlet will not be engaged. It's worth a try. Decking your foot to the floor to feed it more fuel is slightly different because it doesn't advance the timing. You can usually tell if a lift pump is working properly by disconnecting the pipe between the lift pump and the injection pump. Try turning it over, if there's a hell load of fuel, its fine!

-Pos

yea i have an it jud never fiers up, jus keeps cranking

Next to the fuel return line there is a little spring loaded lever, jam a stick or something between the pipe union and the lever before you next try a cold start and tell us what it does. Oh and while trying this keep WELL away from the throttle and as POS says make sure you have a little slack on the throttle cable as any pull on the throttle will stop the low RPM cold start functioning.

It could also be air in the system, when you switch the engine off, the diesel is leaking out somewhere and being replaced with air, this will cause starting issues, but after enough cranking it will start.

Is yer starter motor engagin'? Not too sure on the set up of yer motor but have ye checked to see if ye're gettin' fuel through to the filter okay?

yea the motor in engagin fine, an are ay on about the lever on the fuel lift pump

The TD lift pump is the same as fitted to the 200TDi, if you have the wrong one them it could be struggling to maintain fuel pressure at low RPM, so it may have an effect, possibly fuel starvation when cranking so the injection pump cannot 'overfuel' to start. I have a spare lift pump if you want it, PM me.

What about yer fuel cut off switch/ solenoid thingy?

my what ?

brucher said:

my what ?

Click to expand...

If ye've got an injector pump then it should be round there somewheres. If the fuel cut off switch is goosed then ye might not be able to start it

oh na it does start eventually

Ah'd maybe just check the wire wire goin' to it just incase. That's it, ah'm out of ideas!

hmmm i am watching this one, didn't know about the cold start setting on the pump cheers for that one pos

brucher said:

yea the motor in engagin fine, WHAT ARE YOU on about the lever on the fuel lift pump

Click to expand...

Its not on your lift pump, its on your injection pump.

yea thanks guys, i hav more things to try now.

theres a priming lever on the injector pump ?

iannotts said:

hmmm i am watching this one, didn't know about the cold start setting on the pump cheers for that one pos

Click to expand...

The cold start kicks in when the rpm is below 100ish rpm and it will advance the injection timing and it will throw in HUGE slugs of diesel (hence the black smoke on most diesel start ups).

If you have the throttle cable tight on the throttle lever on the IP and therefore the throttle is being help open slightly, the cold start mechanism won't work, and the same goes for putting your foot on the throttle for starting. On a properly functioning injection pump any throttle will actully hinder the starting process.

This is why idle timing speed should be altered by the little lever which sits against the fuel return pipe union.

right ok kool, do u know if there is a non return in the injector pump ?