Glow plug light does not come on. Therefore, sluggish in starting, especially during cold weather. Anyone with suggestions? Also, how difficult is it to change the plugs? Are these the nutty things sticking out of the cylinder block about an inch below the fuel injectors? Thanks.

Sandy

I have no trouble pulling all five plugs in under 10 minutes. Although, I have done this quite a few times. If you would like, PM me with your email address, and I can give you the 'Glow Plug Diagnostics' sheet that I have on my computer. This sheet will walk you through what to do about your light not coming on. Also, You are identifying the glow plugs location correctly.

I am curious to see if you were able to get your glow plug light to come on. I also have a 1983 300d and the glow plug light never goes on. I am thinking it is probably a bad relay. I checked the fuse and it was ok. From what I have read on this website, bad glow plugs show up as a blinking light, while a bad relay shows up as no light at all.

Were you able to fix your's?

Deeph8, no light ususally means one (or more) glow plugs are bad.

A blinking light after start may mean one or more bad, on some models.

Don't assume it's a bad relay. Check the glow plugs, it's really easy to do.

Best Regards,
Jim

Definitely the glow plugs... I wonder if they are still the original ones, up to you if you want to replace just the bad ones or all of them.

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Audi TT

Before you pull them, check the strip fuse in the relay (pull the cover on top off). Also, once you have turned the key to the "glow" position, give the relay a thump with your fist. If that makes the relay kick into gear, then its just a bit sticky inside - unbolt the relay, and open it up (4 screws) and you will see the actual relay and two contact points...betcha they have crud on them and could use a little cleaning.
The reason I mention those things first is ...well,... is because they don't cost you anything but a little time. After that, you can check the plugs.

Hope this helps...

-Larry

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Testing Glow Plugs

scroll down to the test proceedure by JimH

Dave

__________________
1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

I checked the glow plugs using the procedure described above and also took apart the relay and cleaned the contacts. The plugs all showed continuity and the relay was pretty clean inside. The strip fuse in the relay was good. I am going to try installing another relay to see if that is the problem and will let you know what happens. So far I have been lucky in getting the car to start, although it runs rough for the first minute or so. Thanks.

Plugs are 10 dollars a piece so they are probably cheaper than the glow plug relay.

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Audi TT

deeph8

Sounds like you're doing a fine job of troubleshooting. I'd be curious if the relay is 'seeing' 12V when you turn the key. You could check the input to the relay.

Pull the control plug and use a VOM. Turn the key to Pos II and check for voltage from the input to the ground pin. If the relay is getting voltage and the glow plugs have checked OK, it then could be a bad relay.

You could feel the relay to check for a click when a helper turns the key. No click, it's not pulling in. If it clicks but doesn't power the plugs, bad contact(s) or something else internal.

If you have access to a known good relay, by all means try the substitution. If you have to buy a new relay, some additional testing might save you $$, or might just confirm that you need a relay.

Keep up the good work, and let us know how this turns out.

Best Regards,
Jim

If you do end up needing a relay, I got mine from MTUpower, and was very pleased. He is a good reliable source for used parts from my experience.

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John