Help with Diagnosis for Newbie

[waveydavey00]

Hi All,

I would be grateful for any assistance anyone can offer.
I have a 3.0 1993 kzn130 which overheated. I have replaced the rad and it's holding coolant, but takes a lot of turning over to start. Once warm it starts a whole lot easier. There appears to be no mixing of oil and water yet, but I have not run it for long. The power, tickover and general running all seem OK.

I have been advised it may be loss of compression. How do I go about testing. I do have a compression tester, but have never used it on a diesel. Will it work? Or do I need a special one?

Will slackening the injectors one at a time and listening for a change in running tell me the answer?

Alternatively, any other advice would be appreciated.

I am hoping it will not need to be stripped down just to diagnose the problem.

Thanks in advance for any assistance

[mickey]

last year i had to call out the AA..my truck was becoming increasingly troublesome to cold start, then the day came, when she threw in the towel..the 5th emergency man suggested it was low on compression, everything else checked out fine..with help from the lads on this forum, we nailed the problem as a battery going down, a loose connection and a dry cell were the culprits, much to my embarresment..i'm not suggesting for a minute that you are as hard of thinking as i, but i really hope your problem turns out to be something as simple...a quick search on "compression" will give you heaps of info..from memory, i believe you need a tester specific for diesels..i'm sure the experts will be along soon though, good luck.

[DaveD]

Wavey Hope you get this sorted soon........My rad blew and after it was changed had **** starting. Many many garages scratched their heads because everything looked good. Eventually after throwing loads of beer tokens at it.....it was Head Gasket. Get the compression tested.
From Tony the surf Maestro...

pressure in a 3.0 should be 441psi, minimum pressure is 284psi, but no more that 71psi difference between all four.

I'm assuming you have tested the Glow plugs/Relay/80 amp fuse.

[waveydavey00]

I'm assuming you have tested the Glow plugs/Relay/80 amp fuse.[/QUOTE]

No- I started by logging on here as I knew there was a good exchange of info. I have a runabout to keep me going at the minute so I don't want to rush it.

How do I test the glow plugs/relay/80 amp fuse?

[TonyN]

I'm assuming you have tested the Glow plugs/Relay/80 amp fuse.

No- I started by logging on here as I knew there was a good exchange of info. I have a runabout to keep me going at the minute so I don't want to rush it.

How do I test the glow plugs/relay/80 amp fuse?[/QUOTE]

Open the fuse box in the engine bay and look at the fuse, then you can put a meter on the bus bar for the glowplugs and check they get 12v when the igintion is first turned on.

If it overheated to could have damaged the head gasket, or jammed an injector.

[waveydavey00]

Open the fuse box in the engine bay and look at the fuse, then you can put a meter on the bus bar for the glowplugs and check they get 12v when the igintion is first turned on.

If it overheated to could have damaged the head gasket, or jammed an injector.[/QUOTE]

Thanks for your help. I will check in the light tomorrow as did not get home from work until late tonight.

[waveydavey00]

Open the fuse box in the engine bay and look at the fuse, then you can put a meter on the bus bar for the glowplugs and check they get 12v when the igintion is first turned on.

If it overheated to could have damaged the head gasket, or jammed an injector.

OK - I have checked the glow plug fuse and it is OK. I have put my test meter across from the the top connection on the second plug (which is accessible) to earth and get 11 volts. There is no second click from the relay for 12 seconds or so. Does this seem right? Do I need to take the connections off the glow plugs to test the voltage and what resistance should I get? CanI test the relay any other way or does it appear faulty?

If I am not heating the glow plugs this would explain a lot would it not?

[Vagrant No2]

OK - I have checked the glow plug fuse and it is OK. I have put my test meter across from the the top connection on the second plug (which is accessible) to earth and get 11 volts. There is no second click from the relay for 12 seconds or so. Does this seem right? Do I need to take the connections off the glow plugs to test the voltage and what resistance should I get? CanI test the relay any other way or does it appear faulty?

If I am not heating the glow plugs this would explain a lot would it not?

Sounds like the relay and timer for glowplugs are working OK . You may still have worn/burnt out glowplugs though . A special ammmeter which clips to the glowplug feed will show this but only by a specialist who has the tool . Only other way is to buy and replace the glowplugs as a matter of course .

[waveydavey00]

[QUOTE=Vagrant No2]Sounds like the relay and timer for glowplugs are working OK . You may still have worn/burnt out glowplugs though . A special ammmeter which clips to the glowplug feed will show this but only by a specialist who has the tool . Only other way is to buy and replace the glowplugs as a matter of course

Is it OK that I am getting only 10.8/11 volts at the buzz bar?
Is it not possible to test the glow plug once they are removed?

[Vagrant No2]

[QUOTE=waveydavey00]

Sounds like the relay and timer for glowplugs are working OK . You may still have worn/burnt out glowplugs though . A special ammmeter which clips to the glowplug feed will show this but only by a specialist who has the tool . Only other way is to buy and replace the glowplugs as a matter of course

Is it OK that I am getting only 10.8/11 volts at the buzz bar?
Is it not possible to test the glow plug once they are removed?

Yeah , you will get some volt drop due to the glow plug draw , so in that case the plugs or least 1 or 2 are possibley OK . Have you tried turning the ign off once the timer drops out and turning on again which will 'double' heat the plugs . If it starts easier doing this it sometimes can indicate lazy glowplugs .

[waveydavey00]

[QUOTE=Vagrant No2]

Yeah , you will get some volt drop due to the glow plug draw , so in that case the plugs or least 1 or 2 are possibley OK . Have you tried turning the ign off once the timer drops out and turning on again which will 'double' heat the plugs . If it starts easier doing this it sometimes can indicate lazy glowplugs .

Yep tried that. Now disconnected all glow plugs from buzz bar and 1.1-1.2 ohms each. I took out plugs 1 and 2 and they seem fine. (The other two are harder to get to) They heat up immediately without any obvious problem.

Someone suggested blocked/burnt out injectors. Do I need to test for these before starting the head removal as I am fast coming to the conclusion the gasket at least has gone. If it was an injestor woul I not get a lot of smoke all the time/ or general running problems? I get a bit of a sooty blast if I floor it and let go, but is that not relatively normal?