glow plugs wont stay on long enough

[RoundHouse]

so this morning in Atlanta the temp was in the low 30s

01 Beetle wouldnt fire.


I checked with a test light and the GPs stay on for about 7 seconds,
go off and dont come back on.




I checked with a test light connected to the battery positive and GP harness removed and the tip of all 4 plugs are grounded,
so I assume they are working


after cycling the ign switch a few dozen times and running the starter long enough it finally cranked,




any ideas?
check engine light is not on.


Im guessing the temp sensor is telling the engine the GPs are not needed ?


how do I check the temp sensor?


the hillbilly in me just says install a manual spring loaded button,
thats how I fixed my old F-350
and how I did my 1KZT toyota transplant into my 4 runner

instead of spending thousands on new relays, sensors, wiring harness etc

hold the button in for 5 seconds and hit the starter.


but I assume the defective temp sensor is also causing other problems that I cant see?

 

[Vince Waldon]

I've never seen an official chart, but 7ish seconds of glow plugs with temps in the low thirtys seems about right, and your TDI should start OK without any glowplugs at that temperature.

Meaning: very likely the cause of your hard starting is elsewhere. Particularly if there's no CEL related to the glowplugs.

The first suspect would be electrical: strong battery, strong starter, proper cranking speed.

Close second would be static injecting timing... need diagnostic software like VCDS to check this out properly.

Distant third in my books might be an air or fuel restriction... dirty filters, perhaps, but distant third... especially if the car has been starting OK when it's slightly warmer.

 

[ItAintRodKnock]

Pull your glowplugs one at a time and test the Ohms of each. With a multimeter, set to the resistance reading; place one lead on the tip of the nozzle, and the other lead on the opposing tip.

Good plugs read under 1.5ohms(mine were near 0.5-0.7ohms)
Bads plugs are over 1.5ohms(two of mine read 6.xx and 7.xx) replaced those with cheapies from Oreillys and now the car starts better. No CEL, who knows how long they have been bad.

Sent from my VS987 using Tapatalk

 

[RoundHouse]

Battery is newish
I Replaced it about 2 months ago

Cranked fine one morning
That afternoon when she went to leave work the battery was dead
And wouldn’t do anything even with two other vehicles hooked up with jumper cables

I got a battery from a nearby auto parts store and replaced it and it cranked fine

Battery showed 12.2 volts this morning
Checked that first thing

Might be the starter
It’s been several years since I replaced the starter
We’ve had beetle for years , has 230k on the clock

 

[ItAintRodKnock]

My car has 292K miles with the original starter. I personally would not focus there just yet.

Being that its a cold issue, i would continue focus on the Glow Plugs themselves or the Battery being the wrong size/rating.

Its well documented that the best Battery option is the OEM VW Dealer batteries. The Group 48(G48) Battery is what our cars are more satisfied with.

Sent from my VS987 using Tapatalk

 

[RoundHouse]

I will check the battery size attemp to remove the GP s and report back

 

[RoundHouse]

Battery is a 48

GP are under 2 on threads

Above 5 at the tip

 

[RoundHouse]

also gotta do the blend door repair soon
https://www.youtube.com/watch?v=lpoSG5i1paY


and add bluetooth and all new speakers

 

[Tdijarhead]

12.2 on your battery, just sitting in your driveway, car not running means your car will start hard if at all.


Likely your alternator is not keeping your new battery charged. Start the car and put your multimeter on the terminals, it should read 14V with the car running, if it doesn't replace the alternator.

 

[ItAintRodKnock]

12.2 on your battery, just sitting in your driveway, car not running means your car will start hard if at all.


Likely your alternator is not keeping your new battery charged. Start the car and put your multimeter on the terminals, it should read 14V with the car running, if it doesn't replace the alternator.

I had a plug in USB charger than also read voltage constantly. Usually, when I am about to start(before i turn the key) I see somewhere around 12.7+ and 13.7-14 while running.

Sent from my VS987 using Tapatalk

 

[[486]]

go to the isle with the crimp connectors and get the female bullet connectors in blue, they fit the glow plugs good
then go over to the snowplow isle and get a solenoid switch
now, get a wire from all four of them to the solenoid, and from the solenoid to one of the unused fuses on the battery block, 50 amps should be plenty

wire it up to a button in the cab and hey presto you've got glowplugs that aren't so damn smart they shut off too early
don't worry about running them too long and burning them out, mine are bosch brand ones and I've run my battery totally flat a few times when the undersized relay I had cobbled together stuck.

 

[Tdijarhead]

12.7 sitting in the driveway not running is a fully charged battery, 13.7- 14.3 is perfect for the alternator when the car is running.

That’s what I would expect to see. However the OP said he was seeing 12.2 that is a borderline dead battery. On a good warm day with that voltage your car should start, on a cold day maybe, or maybe not.

So if the OP has a new battery that’s showing 12.2 sitting in the driveway his alternator is not keeping the battery charged. You can easily check that with a multimeter. Put the leads on the battery terminals it should be around 14v with the car running. If it’s less than 13.7 put the red multimeter lead on the stud at the back of the alternator if it still reads 13.7 or less it’s your alternator, if it reads 14 or so but not the same at the battery it’s your wire.

If you have no glow plug codes it’s likely not a problem with the glow plugs. Seven seconds is more than enough time. 30* is not that cold I can get mine started on the first glow without plugging in my frost heater on the first try at 0*F

Another likely possibility is air getting in the fuel system. Check for fuel leaks under and around the IP. Have you recently done any work like change out the fuel filter?

 

[JETaah]

I'm with Vince on checking the injection timing.
30*F should not be that challenging.

Do you happen to know where the timing is set?

 

[RoundHouse]

No clue what the timing is set to

It’s been serviced by both of the Tdi gurus in Georgia
It would have been set at the last timing belt change

I will check the batt voltage tomorrow morning before and after startup

 

[Gun-driver]

go to the isle with the crimp connectors and get the female bullet connectors in blue, they fit the glow plugs good
then go over to the snowplow isle and get a solenoid switch
now, get a wire from all four of them to the solenoid, and from the solenoid to one of the unused fuses on the battery block, 50 amps should be plenty

wire it up to a button in the cab and hey presto you've got glowplugs that aren't so damn smart they shut off too early
don't worry about running them too long and burning them out, mine are bosch brand ones and I've run my battery totally flat a few times when the undersized relay I had cobbled together stuck.

Great idea!! Can you give an example of the solenoid switch please.
Guessing one like this:https://shop.advanceautoparts.com/p...KeSSOFCzWeTFw6wPhnxoCmLUQAvD_BwE&gclsrc=aw.ds

 

[[486]]

yeah that'll work

 

[RoundHouse]

I got some new GPs ordered


Will install them and see if it helps

I think any Ford starter relay would work

 

[[486]]

I think any Ford starter relay would work

yeah that'll work

also, a VW "relay 100" will work but it's less weatherproofed

 

[wonneber]

yeah that'll work
also, a VW "relay 100" will work but it's less weatherproofed

I do NOT think the 100 relay will have contacts or internal wiring to handle the power of 4 glow plugs.

 

[RoundHouse]

Not many auto parts stores with snowplow aisles in Georgia though

Be nice to have a light on the dash that shows when the glow plugs are actually on

I’m replacing the coolant glow plugs as well
Maybe that will help the heat
Also gotta do the blend door fix

At least the heated seats still work ....

The old 6.2 Chevy diesel I had would cycle the glow plugs for some time after the engine was running
Didn’t have a light but you could hear the relay clunking

 

[Tdijarhead]

Did you ever measure your battery? Rereading your thread it doesn’t sound like you have a glow plug problem. It sounds more like battery/starter/or air getting in the fuel lines. 7 seconds in warmish 30 degreees is more than enough time for a proper glow.

If you don’t have any glow plug codes in your cars computer then your glow plug system is operating fine. It’s that 12.2 v that you mentioned that suggest that your battery is weak/dead which if it’s new probably means your alternator has crapped out.

If you’re having problems with heat and you know the blend door is bad that will cause it. That or an old thermostat.

 

[oilhammer]

You do not have a glow system problem. You have something else wrong.

Loss of fuel prime would be my first guess.

Battery should be 12.6v nominal. Should be able to hold around 10.5v during cranking.

 

[[486]]

I do NOT think the 100 relay will have contacts or internal wiring to handle the power of 4 glow plugs.

Mine's been working for a couple months now, just using the larger coolant GP one. May well burn up, but everything's temporary.

All 4 together seems to draw 30a when warmed up, more when cold of course, haven't measured initial current.

 

[wonneber]

Can you measure the battery voltage before starting the car and while cranking it?
Does your tach display the cranking RPM?

 

[RoundHouse]

Can you measure the battery voltage before starting the car and while cranking it?
Does your tach display the cranking RPM?

Voltage is 12.3
Drops to 10 during cranking
Slowly goes up to 14.2 at idle

I replaced the GPs

71 yesterday. Supposedly be in the 30s tomorrow night

Never looked at the tach during cranking
Will have to check that

 

[Tdijarhead]

Your battery is close to dead, your'e going to need a new one. At 14.2 idling, your alternator is ok. Your starter might be a little weak but a new battery should solve that issue also.

 

[RoundHouse]

Your battery is close to dead, your'e going to need a new one. At 14.2 idling, your alternator is ok. Your starter might be a little weak but a new battery should solve that issue also.

Battery is only a few weeks old
Although most are made in Mexico now so quality is not as good

I also tested the expedition and it was exactly the same
12.3 drops to 10 during cranking and back to just above 14 at idle

 

[Tdijarhead]

If its only a few weeks old, your battery should be at 12.6 maybe even 12.7. At 12.3 your in dead to dying range. On a cold morning at 12.3 you will probably start it will just take a little longer, at 12.2 you might start and you might not on a cold morning.


If your battery is that low you might try fully charging it and keep a close eye on it with your multimeter. If it's not maintaining a full charge either your alternator is not keeping up or you have an old battery. See if you can find a manufacturing date on the stickers.


You said your alternator is at 14 so that's unlikely to be the issue unless under load it drops off.

 

[Nero Morg]

I agree with tdijarhead. New batteries can unexpectedly go bad on you. Unlikely but happens. I have an interstate battery out of my 00 I need to have warrantied, will hold a charge but as soon as you put a load on it, it goes flat.

Don't let auto parts stores test them with a digital battery reader. They never are accurate. Have them test it with a good old fashioned carbon pile tester.

 

[Vince Waldon]

Given the accuracy of the average off-the-shelf multimeter and the fact that temperature plays a role as well I personally think your voltage readings are fine... at least fine enough to not be a cause of hard starting at fairly mild temperatures. A couple tenths of a volt here or there are well within the range.

Did the new glow plugs resolve the issue?