Engine not starting - ideas / suggestions?

[BeckyJC]

Cracked elements?

Not sure yet - couldn't take them out, as it was getting too dark so boyfriend's going back tomorrow to take one out and go and find replacements. Would we be able to see a cracked element by looking at them once they are out?

 

Cheers,

B

[OptedOut]

Not sure yet - couldn't take them out, as it was getting too dark so boyfriend's going back tomorrow to take one out and go and find replacements. Would we be able to see a cracked element by looking at them once they are out?

 

Cheers,

B

 

Yep, but not always easy to spot, put a battery and lamp accross the terminals and give the element a bit of a wiggle.

[Big Steve]

Right, don't think it is the timing now afterall. Just had friendly mechanical engineer over to take a look at my engine - he turned it over by hand and checked the timing marks / chain alignment. Also said it sounded OK turning over... was getting fuel at the injectors...BUT it seems that 2 of the glow plugs are dead (0 voltage on 2 of them and 11.x volts on the other one, tested repeatedly to be sure).

 

My brother had already tested the glow plugs when he had them out (and thought they were OK), but maybe something happened when he was putting them back in. So my darling boyfriend is off to try and get some replacement glow plugs tomorrow. I will be SO SO SO pleased if this actually fixes it now.

 

Fingers crossed,

B

That's confusing. If a glo plug is dead you'll get 12v across it, not 0v. If it's got 0v on it it must be the supply to it. But they are normally all in parallel, so should all read the same. Perhaps I misunderstand your test.

 

The knocking noise may be a valve hitting a piston 'cos the timing is one link out on the chain. It happened to me with a old Citroen car, it did start but sounded like a bag of nails,the timing belt had jumped one notch due to a dodgy belt tensioner. You have to be very careful timing diesels, use the proper method as shown in the book, probably involves studs in the flywheel to lock the engine at TDC and studs in the OHC chain pulley too.

 

Fingers crossed for you.

[Malarky]

How hot did it get when the hose leaked? Could it have been harder to turn due to a slightly warped crank, that has now squished its journals to spin more freely, but is now knocking?

[chris w]

That's confusing. If a glo plug is dead you'll get 12v across it, not 0v. If it's got 0v on it it must be the supply to it. But they are normally all in parallel, so should all read the same. Perhaps I misunderstand your test.

I agree with Steve's analysis. Only a short-circuited glow-plug would read 0v and then, because they are all in parallel, they would all read 0v. As Steve suggested, it sounds like the 12v supply to those two glowplugs is not getting to them. Even if they had gone open-circuit, you would still read 12v (albeit with no current flow).

 

Chris

[Sir Nibble]

Sometimes glow plugs are fused in pairs. Also, if you test plugs by putting a meter to B+ and each plug in turn, you will read 12V on one with electrical continuity, 0V on those without. Bizarre way to test but there we go.

[chris w]

Sometimes glow plugs are fused in pairs. Also, if you test plugs by putting a meter to B+ and each plug in turn, you will read 12V on one with electrical continuity, 0V on those without. Bizarre way to test but there we go.

That's because with the ignition switch OFF (ie: open), you will have 12v on one of the voltmeter probes and an effective earth on the other end, actually a 1 ohm resistor (the glow plug) to earth. If the plug is open circuit (ie: blown), then there is no path to earth and there will be no voltage difference measured on the voltmeter. This won't, of course, test the connection to the glow plug unless you move the "earth" probe further back up the chain. Further if the plug failed short-circuit this test will still show 12v and could be misinterpreted as good.

 

Chris

[Sir Nibble]

That's because with the ignition switch OFF (ie: open), you will have 12v on one of the voltmeter probes and an effective earth on the other end, actually a 1 ohm resistor (the glow plug) to earth. If the plug is open circuit (ie: blown), then there is no path to earth and there will be no voltage difference measured on the voltmeter. This won't, of course, test the connection to the glow plug unless you move the "earth" probe further back up the chain. Further if the plug failed short-circuit this test will still show 12v and could be misinterpreted as good.

 

Chris

Yes, I know.

[chris w]

Yes, I know.

I know that you know - it was for the others who may not.

[Sir Nibble]

I know that you know - it was for the others who may not.

I knew you knew that I knew, 'cos I know you know that I know.

[johnjo]

I knew you knew that I knew, 'cos I know you know that I know.

 

 

[alan_fincher]

I knew you knew that I knew, 'cos I know you know that I know.

 

The Kursaal Flyers, number 14, in November 1976 ??

 

 

Oh, sorry! - This isn't the intros quiz thread, is it ?

[Sir Nibble]

The Kursaal Flyers, number 14, in November 1976 ??

I don't know.

[RLWP]

I don't know.

 

I know, but I don't know - Blondie, Parallel lines

 

Richard

[Sir Nibble]

I know, but I don't know - Blondie, Parallel lines

 

Richard

C*nt.

D.H. Lawrence.

[RLWP]

C*nt.

D.H. Lawrence.

 

F*ck.

Father Jack.

 

 

Richard

[BeckyJC]

I agree with Steve's analysis. Only a short-circuited glow-plug would read 0v and then, because they are all in parallel, they would all read 0v. As Steve suggested, it sounds like the 12v supply to those two glowplugs is not getting to them. Even if they had gone open-circuit, you would still read 12v (albeit with no current flow).

 

Chris

 

Hi all,

 

Just to clarify - ....got a glow plug here in my hand now so hopefully I can explain clearly enough.... friendly engineer was testing each plug individually by putting negative end of multimeter on the engine block (earth) and the positive end on the nut at the top of each glow plug with the ignition key in the "heat" position. On each glow plug, between the bar that connects them all together / supplies power and the part where he was testing is an insulating plate / washer. The theory was that in order for the power to get to the nut where he was testing each plug separately, the power would have had to go through the glowplug element (i.e. heating). This happened on 1 plug, but not the other 2, indicating that they were dead. The connecting bar that supplies power to them all WAS reading 12-ish volts right the way along, so there was current getting TO the glow plugs, just not through them. Does that make sense?

 

As for the knocking, he didn't think it was anything to worry about for the moment and likely caused by the easy start.

 

Been trying to source glow plugs today, but no luck yet - anyone know where I might get hold of some for an Isuzu 3kc1? Seems parts for this engine are pretty hard to come by now!

 

Cheers,

Becky

[johnjo]

Hi all,

 

Just to clarify - ....got a glow plug here in my hand now so hopefully I can explain clearly enough.... friendly engineer was testing each plug individually by putting negative end of multimeter on the engine block (earth) and the positive end on the nut at the top of each glow plug with the ignition key in the "heat" position. On each glow plug, between the bar that connects them all together / supplies power and the part where he was testing is an insulating plate / washer. The theory was that in order for the power to get to the nut where he was testing each plug separately, the power would have had to go through the glowplug element (i.e. heating). This happened on 1 plug, but not the other 2, indicating that they were dead. The connecting bar that supplies power to them all WAS reading 12-ish volts right the way along, so there was current getting TO the glow plugs, just not through them. Does that make sense?

 

As for the knocking, he didn't think it was anything to worry about for the moment and likely caused by the easy start.

 

Been trying to source glow plugs today, but no luck yet - anyone know where I might get hold of some for an Isuzu 3kc1? Seems parts for this engine are pretty hard to come by now!

 

Cheers,

Becky

 

Does your plug have any ID, No:s or letters, on it. I've Googled it [as I'm sure you have] but can only find road based catalogues with Model & year.

 

Meant to add, I've a friend in the trade who might be able to help if so.

Edited February 16, 2009 by johnjo

[Iain_S]

Just to clarify - ....got a glow plug here in my hand now so hopefully I can explain clearly enough.... friendly engineer was testing each plug individually by putting negative end of multimeter on the engine block (earth) and the positive end on the nut at the top of each glow plug with the ignition key in the "heat" position. On each glow plug, between the bar that connects them all together / supplies power and the part where he was testing is an insulating plate / washer. The theory was that in order for the power to get to the nut where he was testing each plug separately, the power would have had to go through the glowplug element (i.e. heating). This happened on 1 plug, but not the other 2, indicating that they were dead. The connecting bar that supplies power to them all WAS reading 12-ish volts right the way along, so there was current getting TO the glow plugs, just not through them. Does that make sense?

 

IMO. no The test shows no connection between the bar and the plugs reading zero; it tells nothing about the condition of the plugs themselves. except that I would not expect 12V, more like 8 or so if there was current passing through the plugs.

 

Disconnect the bar, measure RESISTANCE between plug top and engine block. Should be around 1 ohm.

Iain

[BeckyJC]

Does your plug have any ID, No:s or letters, on it. I've Googled it [as I'm sure you have] but can only find road based catalogues with Model & year.

 

Meant to add, I've a friend in the trade who might be able to help if so.

There is nothing printed on the glow plugs themselves, but we have managed to find some info:

 

The Isuzu part reference number is apparently 9-82511978-0 and Zenith make (or did make) some glow plugs to fit : ZI-42

 

Other part numbers that I believe to be the same are:

 

HKT PI-42

NGK Y104

 

However from ringing round some motor factors those models aren't made anymore.

 

Cheers,

Becky

[johnjo]

Zenith still list it :-

http://www.zenithglowplugs.com/isuzu.html

 

I'll give him a ring in the morning and see what he can come up with.

[BeckyJC]

Just to add to my earlier post - I've found a DIY-guide to testing glow plugs that describes a similar test to the one we used:

 

http://autorepair.about.com/od/enginerelat...l/aa081404c.htm

 

Extract:

"Testing glow plugs is easy and can be done with them still installed in the engine. Just disconnect the wire going to each glow plug. Connect a test light to the POSITIVE (+) battery terminal and touch the point of the test light to each glow plug terminal. If the light lights, it's good. "

 

Hope this help explain,

Becky

[Iain_S]

Just to add to my earlier post - I've found a DIY-guide to testing glow plugs that describes a similar test to the one we used:

 

http://autorepair.about.com/od/enginerelat...l/aa081404c.htm

 

Extract:

"Testing glow plugs is easy and can be done with them still installed in the engine. Just disconnect the wire going to each glow plug. Connect a test light to the POSITIVE (+) battery terminal and touch the point of the test light to each glow plug terminal. If the light lights, it's good. "

 

Hope this help explain,

Becky

 

Was your bus bar disconnected? And readings taken between top of plug and bus bar?

Iain

[cornet]

Hello !!

 

Becky's significant other here

 

Decided to register and jump in on this thread to clarify some things.

 

Was your bus bar disconnected? And readings taken between top of plug and bus bar?

Iain

 

No the bus bar was not disconnected during the test, we just measured the voltage from the glow plug casing to a suitable earth point. 2 of the plugs read 0V indicating that they are blown

 

I'm going to contact a few places tomorrow to see if I can track some glow plugs down but any help with sourcing them would be greatly appreciated.

 

 

Cheers,

Nathan

 

btw: Thanks to everyone who has helped so far, especially to Eeyore and steelaway (sorry Alex I managed to misplace your phone number )

[chris w]

No the bus bar was not disconnected during the test, we just measured the voltage from the glow plug casing to a suitable earth point. 2 of the plugs read 0V indicating that they are blown

 

I'm going to contact a few places tomorrow to see if I can track some glow plugs down but any help with sourcing them would be greatly appreciated.

 

 

Cheers,

Nathan

If the bus bar was NOT disconnected, this is a meaningless test.

 

Also, the test suggested above about connecting a test light is also meaningless because the glow plug may have gone short circuit or doubled in resistance for example and then the bulb will still light.

 

The only meaningful and easy test is to measure the individual resistance of the glow plug between its casing and the top terminal. As someone else suggested above it should be about 1 ohm.

 

Chris

Edited February 16, 2009 by chris w