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Cold Start Sensor ???

Posted: Wed May 24, 2006 1:27 am
by n_dorphin
Hey All,

Having Trouble starting my 2.5 TD when cold.
I have had Injectors replaced, Glow Plugs Checked/serviced, Service with timing etc done.
The Glow Plugs only stay on for a few seconds (same time if hot or cold). Is there a cold start sensor or a Timer for the Glow Plug solinoid?
Any other ideas what problem might be? Runs great otherwise.

Cheers
Jason

Posted: Wed May 24, 2006 9:59 am
by -Scott-
I've heard similar problems where new glow plugs were the fix. Glow plugs are very low resistance, and I think a fraction of an ohm can make a significant difference to their effectiveness. I've also read of the wrong glow plugs being used, which also reduces their effectiveness.

Have you tried turning the key off/on again, to put the plugs through multiple cycles, and count the total "on time" required before it starts normally? That should tell you if it's just a matter of more glow time, and also how long you really need. Hopefully, somebody here will be able to give you a comparison figure.

Don't work off the dash light, either. Modern diesels do stupid things, so the light on the dash doesn't necessarily indicate when the plugs are on. Stick a test light on the plug rail under the bonnet.

Scott

Posted: Thu May 25, 2006 12:03 am
by n_dorphin
The glow plugs were checked and are the correct type for engine. Its in a 89 SWB Pajero which doesnt have a dash light for the plugs. I've tested the curcuit which seems to run fine. I've also tried multiple glow plug times by using ignition key which does not seem to help much.

I have now run out of ideas.

Thanks
Jason

Posted: Thu May 25, 2006 8:24 pm
by 6G74
Buy a petrol, coolant temp sensor and ya laughin - not to mention no more smokey, noisy gutless, rattley pos under your bonnet :D

Moving on from been a jerk - I saw a 2.8 with cold starting problems, actually turned out to be the pump. When it started it only run on 2 or 3 cylenders after a fair bit of cranking, bit of a rev or idle and it was all good. Theory was hardened gaskets and seals causing low inital pressure.

If your confident your glow plugs are operating as they should, your only left with injectors (shouldnt cause starting issues) and your pump.

Posted: Fri May 26, 2006 9:48 pm
by Rossco
Have you considered a glow plug timer, similar to a turbo timer but switches the glow plugs on and off a set amount of times, fairly cheap and could solve your problem. Also use genuine glow plugs as non genuine (bosch) plugs will burn out quickly :D :D

Posted: Sat May 27, 2006 1:06 am
by 6G74
Rosscoe - Although that will prolly will work. The original design worked fine, so your really only maskin the underlying problem...

Someone else actually said something interesting (perhaps yourself or lambie) but after the glow plug light extinguished there was stlil power to the rail even once the engine was running for a few mins when cold...

You said yours doesnt have a glow lamp... but how long after ignition on does the rail get power for?

On the 2.8's im assuming the coolant temp sensor is for this feature, to govern how long the plugs get power for when cold (or hot for that matter)

If yours has a 2 sensors sittin in coolant, you could prolly take an educated guess that this is wat one is for.....

Posted: Thu Jun 01, 2006 4:17 pm
by n_dorphin
Hey Guys,
Still having trouble with cold starting.

Have now done/tested the following.
Found that there is a glow plug light on dash, Glode replaced (twice) and still not working.
Located second temp sensor, How do I test these?
Glow plugs still did not run longer when plug was removed from sensor.
The Glow plugs on run for about 4 seconds before start up and then dont run when motor is started.

Ani Ideas?

Jason

Posted: Thu Jun 01, 2006 5:48 pm
by 6G74
They are resistance based, so as temp increases resistence changes etc. This is only guesswork on my behalf, im not familiar enough with them, but it is possible that the sensor is completely dead, and when d/c and open circuit, its designed to only stay on for a preset limit. Check the resistance of the sensor cold, and then again hot and compare.

Hopefully someone may be a little more familiar with the 2.5s.....

Another thing, hook power to the rail for a few more seconds (10?) and start.... see if it solves your problem, also try starting after a only the usal 4secs but keep power to it for a few more secs.... Just to ensure your chasing the right area, maybe..... :roll: