Morning Backfire

DMAC

Well-known member
Joined
Nov 19, 2009
Location
Philadelphia, PA
TDI
2009 Jetta TDI
Every once in a while (around every 2 weeks), I turn on my 09 Jetta TDI and it starts without any problems. About half a second after the engine starts, I hear what sounds like a backfire in the engine. It only does it when the engine is cold. This is my first diesel so I don't know if this is common. Is it bad? Should I take it to VW?
 

Lefty

Veteran Member
Joined
Oct 21, 2005
Location
Lazear,Colorado Population 60
TDI
Jetta, 2000,Green GLS
DMAC said:
Every once in a while (around every 2 weeks), I turn on my 09 Jetta TDI and it starts without any problems. About half a second after the engine starts, I hear what sounds like a backfire in the engine. It only does it when the engine is cold. This is my first diesel so I don't know if this is common. Is it bad? Should I take it to VW?
Are you letting the glow plugs to warm before starting? Not sure if this falls under the Warm up Hic-up or not.
 

tnteggroll

Well-known member
Joined
May 21, 2006
That reminds me, my glow plug light goes off within probably a second of turning the key on. Is that normal, or is it malfunctioning?
 

kcfoxie

Veteran Member
Joined
Feb 6, 2007
Location
Raleigh, NC
TDI
'12 6-spd JSW
The GP is only needed if the temp is below 40F. If it's above that a sub-2 second illumination is normal.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Yeah, them spark plugs are igniting the left-over "gasoline" just after a cold start! Well, some do talk about their "gas" milage! Heck, it could be a gasoline diesel!
 

Lefty

Veteran Member
Joined
Oct 21, 2005
Location
Lazear,Colorado Population 60
TDI
Jetta, 2000,Green GLS
DMAC said:
My glow plug lights go out after maybe 1 second. The problem happens even when it's 80 deg. outside.
Well that is not normal. Before starting the car when it is cold out turn the key on for about 8 seconds and then start the car. Should fire up . Have a Scan done on your car so you might get an idea why the glow plug light is only coming on for 1 second.
 

NMRJock

Veteran Member
Joined
Aug 26, 2003
Location
Grand Rapids, MI
TDI
'09 Jetta DSG
Lefty said:
Well that is not normal. Before starting the car when it is cold out turn the key on for about 8 seconds and then start the car. Should fire up . Have a Scan done on your car so you might get an idea why the glow plug light is only coming on for 1 second.
It sounds normal to me. Our glowplug light in the '09 is only on for a flash when it is in the 40's or 50's. The glowplugs stay on considerably longer in the '00.

We don't get any sort of 'backfire' when we start it though. I'm not sure what that's about.
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2017 Alltrack SE; Totaled 2015 Passat SEL, BB 2010 Sedan Man; 2012 Passat SE w/ Nav,
do a search for a warm up hicup or warm up shudder, it was noted that a few 09s had an issue when the car was warming up the loss of power for a rev then everything normal, people think that this is an exhaust valve shutting.
What might be happening is your valve might be acting up and slamming shut then poping open causeing what would sounds like a backfire.
I haven't looked into all the parts of the emissions system and this is just a wild guess.
But what you have doesn't sound GP related, as my GP light flashes for a second at 80 too, and the longest i've seen it on was about 4 seconds when it was 29 degrees last week.
 

Lefty

Veteran Member
Joined
Oct 21, 2005
Location
Lazear,Colorado Population 60
TDI
Jetta, 2000,Green GLS
DMAC said:
My glow plug lights go out after maybe 1 second. The problem happens even when it's 80 deg. outside.
So even when it is Warm out the hicup happens?

Is the 1 second glow time even when the car is cold or when over 40 Degrees?
 

DMAC

Well-known member
Joined
Nov 19, 2009
Location
Philadelphia, PA
TDI
2009 Jetta TDI
Lefty said:
So even when it is Warm out the hicup happens?

Is the 1 second glow time even when the car is cold or when over 40 Degrees?
1. yes
2. The coldest it has been here since I got the car is 40 and it's in a garage so it's warmer than 40. It happens no matter what the temp.
 

Lefty

Veteran Member
Joined
Oct 21, 2005
Location
Lazear,Colorado Population 60
TDI
Jetta, 2000,Green GLS
DMAC said:
1. yes
2. The coldest it has been here since I got the car is 40 and it's in a garage so it's warmer than 40. It happens no matter what the temp.
I don't know the answer you need. Someone will though.

On a side note: 40 Degrees is the lowest temp there so far? Wow I was in single digits this morning.
 
Top