Checking glow plugs BX2350

[PA-Woodchuck]

I have about 80 hours and it takes a bit longer cranking to fire up. Temps here have been around 20*F.What's the best way to check each glow plug? BTW the light does come on.


I work on VW's and in the old days I always checked the glow plugs by measuring the amp draw of each plug after 10 seconds. Which was about 9amps each.

thanks

 

[Volfandt]

Longer starting times in cold weather is common, the colder it is the longer it takes to get a diesel going, especially indirect injection diesels such as whats found in most tractors (but not all).

3 basic tests you could try but it involves a volt/ohm meter.
1) Disconnect the power lead to each injector one at a time and with your meter set to read DC volts, engage the glow plugs and make sure theres battery voltage at each connector. This'll tell you if power is getting to them.

2) Set the V/O meter to read ohm's and with the lead still disconnected read the resistance from the connector tip of the glowplug to engine ground. I don't have my manual handy but you should read anywhere from 100homs on down to 4 or 5. If it reads "open" or higher than 100 ohms the glowplug is bad -or- if it reads a dead short at the meters lowest ohm scale it "may" also be bad as it needs "some" resistance inorder for it to heat up when current flows through it. A dead short won't drop any voltage and more than likely will blow the circuits fuse anyhow.

3) If your 3 glowplugs pass the above and you still question their operation, pull each injector one at a time, reconnect the power lead and making sure it's making a good connection to engine ground (like in testing a sparkplug), engage the glowplugs, the tip should glow red.... Actually, if the glowplugs pass tests 1 & 2 the probability is around 99% that they are good but some folks need to see the tip glow red before they'll accept them as good

Good luck

 

[PA-Woodchuck]

Thanks for the input, but I think I may have a weak battery. Today on startup with 10second glow ans about 10 or second crank I noticed the cranking slowing down just before it started. I'm going to hav battery tested Saturday but sure it will fail since it's at least 2.5 years old. The manual calls for a 526RA 535 CCA. I'm open for suggestion for replacment.

 

[PA-Woodchuck]

After 2 weeks of snow removal, today was a good time to do a check over the bota, since I was concerned if the glow plugs were faulty I did a check the same way I use to check the old VW plugs. I removed the buss-bar and checked eachone with my cheapy sears multimeter set to the 10amp setting. Each glow plug would when cold would draw just over 10amps and decrease to just over 8amps 10 seconds later. All 3 draw the same amps.

 

[manganos]

To check glowplugs I hookup my multimeter and check the resistance of each plug. If one of them is way off the others it is bad.

 

[EE_Bota]

Alternative ideas...one I have tried, one I have not.

Tried: I have a clamp on DC meter now so I can check all the plugs at once. If I get full amps, they are all good, otherwise...I have to find which one is bad.

Not tried, but may have merit:
Infra-red thermocouples are getting really cheap. I have one now. If I had to do a VW again, I would probably cycle them, and see if I can pick up signs of them heating up directly. They glow red hot, so I would think, after waiting a minute or so, the electrical contacts ought to show a heat increase due to heat conduction from the hot area.

 

[PA-Woodchuck]

To check glowplugs I hookup my multimeter and check the resistance of each plug. If one of them is way off the others it is bad.

True, but with resistance being so low it can be a bit of a guess. Naturally of one reads open it's easy to say it's bad. Mine were all in the 0.3 to 0.5ohms range.

 

[PA-Woodchuck]

Alternative ideas...one I have tried, one I have not.

Tried: I have a clamp on DC meter now so I can check all the plugs at once. If I get full amps, they are all good, otherwise...I have to find which one is bad.

Not tried, but may have merit:
Infra-red thermocouples are getting really cheap. I have one now. If I had to do a VW again, I would probably cycle them, and see if I can pick up signs of them heating up directly. They glow red hot, so I would think, after waiting a minute or so, the electrical contacts ought to show a heat increase due to heat conduction from the hot area.

"Tried, thats a good easy check". So from my testing if all 3 were good then the total amp draw would be 30-33amps.


"Not tried", will have to give that a try some day.


Our newer VW diesels starting in the late 90's do a self check on startup and if they are faulty the check engine lamp comes on. The fault is then stored in the ECU. Makes it easy except on some years the cylinders are 1-2-3-4 and the glow plugs are 4-3-2-1. Example... if cylinder 1 glow plugs goes bad the ECU reports it as glow plug 4!!! Even in Germany the engine development department does talk the the engine management department.

 

[MMH]

Longer starting times in cold weather is common, the colder it is the longer it takes to get a diesel going, especially indirect injection diesels such as whats found in most tractors (but not all).

3 basic tests you could try but it involves a volt/ohm meter.
1) Disconnect the power lead to each injector one at a time and with your meter set to read DC volts, engage the glow plugs and make sure theres battery voltage at each connector. This'll tell you if power is getting to them.

2) Set the V/O meter to read ohm's and with the lead still disconnected read the resistance from the connector tip of the glowplug to engine ground. I don't have my manual handy but you should read anywhere from 100homs on down to 4 or 5. If it reads "open" or higher than 100 ohms the glowplug is bad -or- if it reads a dead short at the meters lowest ohm scale it "may" also be bad as it needs "some" resistance inorder for it to heat up when current flows through it. A dead short won't drop any voltage and more than likely will blow the circuits fuse anyhow.

3) If your 3 glowplugs pass the above and you still question their operation, pull each injector one at a time, reconnect the power lead and making sure it's making a good connection to engine ground (like in testing a sparkplug), engage the glowplugs, the tip should glow red.... Actually, if the glowplugs pass tests 1 & 2 the probability is around 99% that they are good but some folks need to see the tip glow red before they'll accept them as good

Good luck

Good advice - thank you.