Engine won't start when using Frostheater

jorioux

jorioux

Veteran Member
Joined
Jun 1, 2014
Location
Montreal, Canada
TDI
2013 Touareg TDI
When I use my Frostheater in the morning (I usually let it heat for 0.5 to 1 hour), the glow plugs won't stay on long enough when I start the car. I'd say they stay on the same time as if it were the summer, like if it thinks the engine is already all warmed up.

The result is a no-start. The engine keeps cranking, because the glow plugs didn't stay on long enough to warm the cylinders (i guess). I have to keep cycling the key on and off to get the glow plugs to warm a little bit, and by cranking long enough, it kinda warms the cylinders and it ends up starting, but it takes a couple of full length cranking tries.

Although when I DON'T use my Forstheater, the glow plugs stays on for ~8sec (depending on the temp), and the engine starts right up! What is wrong?
 
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Tdijarhead

Tdijarhead

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Nov 10, 2013
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Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
I had this problem two years ago, last year I didn't even bother using the frost heater. I changed my cam this past summer and now I have almost instantaneous starts even the several times I've used the frost heater on those below zero mornings.
 
G

germerican

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Sep 25, 2011
Location
St. Louis, MO
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2000 Jetta TDI
That's probably not enough time for the Frostheater to really shine based on how north you are. When the coolant is being heated it flows from convection. One of the first points that heated coolant hits is right where your coolant temp sensor is. Your ecu thinks it's nice and warm therefore the short glow time.

Try extending the time you have the heater on, see if it improves starting. Then go from there.
 
BobnOH

BobnOH

not-a-mechanic
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May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
The plugs do stay on a bit longer than the dash light, so when you cycle leave the key on for 10 seconds or so.
 
Nogas4me

Nogas4me

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Jan 19, 2009
Location
DC Metro
TDI
99 Golf GLS TDI, '04 New Beetle TDI, '05 Passat TDI
My 1999 Golf TDI with 238K miles starts with and without the Frostheater. I started it at 15F today without the heater - the glow plug light stayed on for about 7 seconds. I had to let the engine run for a few minutes to let the oil circulate and the engine to quiet down.

I ran the Frostheater during the arctic cold spell we had, which dropped the temp here in Maryland to 0F. The Frostheater was run for 3 hours and the coolant temp needle was 2/3 to the 190 mark on the temp gauge. The glow plugs went on and off as though it was summer, the engine spun a lot faster and started right up without smoking. I didn't really have to wait for the engine to quiet down as the oil was much thinner.
 
M

maxmoo

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Jan 19, 2011
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Lakefield, Ontario, Canada
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2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
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Vince Waldon

Vince Waldon

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Apr 25, 2009
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Edmonton AB Canada
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2001 ALH Jetta, 2003 ALH Wagon, 2005 BEW Wagon
It's possible to make the engine wish you hadn't bothered with the Frostheater at all... by running the Frostheater long enough to warm up the coolant and fool the glow plugs, timing, and fuel maps into thinking it's warm out... but not long enough for the Frostheater to actually warm up the block itself.

When this happens the car actually starts worse than no Frostheater at all... since all its cold-starting smarts are being tricked and defeated.

I've done this a couple times in my quest to find the optimum time for my overnight timer, and of course it is heavily dependent on the ambient temperature at the time.

Barring an actual problem with your car, I'd suggest adding a couple hours to how long you're running the Frostheater before trying to start the car... to see if that makes a difference.

Here in the great-white north I won't plug in the Frostheater if I can't be sure it will get to heat a good 4-5 hours before I need to drive the car again.
 
h4vok

h4vok

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Denver (ex MN)
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2003 Jetta TDi 5sp 171k
You need to plug it in for 2 hours+ or don't plug it in at all. The temp sensor is reading warm coolant when the rest of the engine has cold coolant so it glows for a short time and it is not enough like you said. My 03 started instantly with this morning at -5f because the frost heater was left on for hours before hand. Then leaving work when it was 1f I gave it 2 glow cycles and it started fine with no heater(not as smooth but running without a problem).
 
jettawreck

jettawreck

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Joined
Aug 2, 2004
Location
Northern Minnesota-55744
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2001 Jetta and 2003 Jetta
Another thing to check is after you let the Frostheater run for two hour starts or longer and then if you still get unsatisfactory starts, make sure the hose out of the heater unit is gradually inclined all the way to the head connection. Otherwise you may be only getting the coolant in the outlet hose and the coolant sensor heated, not getting thermo circulation all thru the system. Glow plugs will time out quickly and still have cold head and cylinders.
 
jorioux

jorioux

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Joined
Jun 1, 2014
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Montreal, Canada
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2013 Touareg TDI
maxmoo, I think you're right!! I haven't paid attention to this until now: when I start the engine warm (ie: start the engine after I drop/pickup my daughter at the daycare), it takes longer (sometimes 2-3secs) to start, as opposed to when I start it cold, it starts instantly.

Can I fix this without having to add a tune chip?
 
M

maxmoo

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Jan 19, 2011
Location
Lakefield, Ontario, Canada
TDI
2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
jorioux said:
maxmoo, I think you're right!! I haven't paid attention to this until now: when I start the engine warm (ie: start the engine after I drop/pickup my daughter at the daycare), it takes longer (sometimes 2-3secs) to start, as opposed to when I start it cold, it starts instantly.

Can I fix this without having to add a tune chip?
Click to expand...
2) https://www.youtube.com/watch?v=rhfkjJMtVSU
- fool the ecm into thinking its a cold start by temporarily disconecting cts.
- https://www.ebay.com/itm/13196603507...84.m1555.l2649
 
B

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
I have the same problem. Changed the glow plugs, still no start. Leave it plugged in for a few hours with a in line coolant heater and it uasually starts. Recently it has difficulty starting even if plugged in or even after driving. I have to crank the engine for a long time along with cycling the ignition key on and off. I live in north eastern Canada with temps below 0 degrees constantly in the winter. The nearest dealer is a 8 hour drive so I can’t realy bring the car to them but I did manage to read the code, it threw after a long engine crank and with a BLueDriver, P0726 “engine*speed*input*circuit*range/performance“ came up. Is this the wiring or the sensor. RPM reads fine when started and driving, doesn’t really move when cranking, just jumps from 0 to about 500 then back to zero. I contacted the dealer and says the TSB for glow plugs was never addressed in this vehicle, still has the 7v glow plugs. Can any one help.
 
jorioux

jorioux

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Jun 1, 2014
Location
Montreal, Canada
TDI
2013 Touareg TDI
The glow plugs are definitly not the culprit if it's long to start when the engine is warm. Because when the engine is warm the glow plugs are of no purpose. Moreover if your glow plugs were bad, you would have a CEL.

As I understand, when you crank you don't read a constant ~300rpm? ...500rpm seems high for a cranking speed.
 
B

Bluecharm

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Sep 28, 2017
Location
NEWFOUNDLAND
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2004 BEW Jetta
Like I said, the rpm jumps from 0 past 500 then goes back to 0 and lays there while cranking, when the engine starts the rpm read fine.
 
jettawreck

jettawreck

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Northern Minnesota-55744
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Bluecharm said:
I have the same problem. Changed the glow plugs, still no start. Leave it plugged in for a few hours with a in line coolant heater and it uasually starts. Recently it has difficulty starting even if plugged in or even after driving. I have to crank the engine for a long time along with cycling the ignition key on and off. I live in north eastern Canada with temps below 0 degrees constantly in the winter. The nearest dealer is a 8 hour drive so I can’t realy bring the car to them but I did manage to read the code, it threw after a long engine crank and with a BLueDriver, P0726 “engine*speed*input*circuit*range/performance“ came up. Is this the wiring or the sensor. RPM reads fine when started and driving, doesn’t really move when cranking, just jumps from 0 to about 500 then back to zero. I contacted the dealer and says the TSB for glow plugs was never addressed in this vehicle, still has the 7v glow plugs. Can any one help.
Click to expand...
Your 2004 starting issue(s) has little to do with the OPs warm start issue.
Best to start a new thread, it just confuses the current and past replies.
But, you should get the GP service done/checked as long as it's a warranty TSB. Have the codes (if any remaining) properly scanned and checked, timing/torsion values checked and the cam lobes for wear. Battery load tested and cables inspected as well as all major grounds.
 
Windex

Windex

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Apr 1, 2006
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Cambridge
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05 B5V 01E FRF
Was this a genuine frostheater kit?

If so, then the hoses and bracketry will be setup for correct convection, and you just need to let the heater run longer.

1/2hour is enough to warm the coolant around the coolant temperature sensor, but not yet enough to have warmed the block.

If you want to confirm, get an IR temp gun and take the temperature of the block after 1/2hour of the frost heater on. You are essentially fooling the ECU into thinking the engine is fully warmed.
 
BobnOH

BobnOH

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Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Bluecharm, for better results try a different thread, yours sounds like glow plugs or maybe fueling.
jorioux- Do you have better starting if you run the Frostheater like 3 hours instead of 1? The 99.5 definitely has a hot start issue if not tuned out, but I can't believe it's that. Interweb guessing you're just hitting a "sweet" spot where part of the motor is warm.
 
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