Engine starts fine when cold, but with a "stumble/misifre" for first 5 seconds?

5SP TDI

Veteran Member
Joined
Aug 1, 2010
Location
Fort Wayne, IN
TDI
2014 JSW TDI, DSG.
Engine starts fine when cold, but with a "stumble/misifre" for first 5 seconds?

I have owned my 2003 TDI now for 2 years and it has always had some sort of "stumble" or "misfire" for the first 5 seconds after a cold start. When I say cold start the outside ambient temperature and engine temp can be 70 degrees to 10 degrees. Symptoms are more noticeable the colder it is. Car runs and idles perfect after the first 5 seconds, 10 seconds on the really cold days.

I recently replaced the timing belt and associated parts from IDparts and used the Metalnerd ALH timing belt tools. Pump timing and VCDS timing are perfect, actually "slightly advanced". The glow plug harness has been replaced and I just replaced the glow plugs this weekend and still have this stumble.

Is this normal for the TDI or should these cars start and idle perfect from any temp with no stumbling or misfiring type symptoms for a few seconds? If not normal should I check into air leak for fuel system, IQ quantity, compression?

Thanks!
Jeff
 

Devon Miles

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Joined
Oct 23, 2012
Location
south africa, Gauteng
TDI
2003 jetta 4 1.9 TDI
if you did the timing belt its possible that the cam is slightly retarded. As you tension the belt it tends to turn the cam anti-clockwise a small amount. Take the timing belt top cover off, turn crank to tdc using mark on flywheel. when u are at tdc (make you take direct line of sight to the mark, not from to much of an angle otherwise you will be out a few deg) and the pump and cam are at the right point try lock the pump, if the pump is perfectly lined up and the crank has not moved after inserting the pin check if the locking tool for the cam fits in, if not, im guessing the cam will be slightly retarded and you need to advance it. With diesel engines, your marks all need to be perfect. I normally advance the cam slightly so that when i tension the belt it rotates the cam into the perfect position, if u cant get it perfect try get it near to perfect in a slightly advanced position rather than retarded.. be careful with the cam if you are out roughly more than 8deg you will probably bend valves so always manually rotate the crank a few times just to be sure and follow correct procedure when setting the tensioner itself. Even if vcds shows pump timing being fine you're cam can still be out. Make sure of the correct valve timing before suspecting any potential mechanical failures. hope this is helpful.
 
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Devon Miles

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Joined
Oct 23, 2012
Location
south africa, Gauteng
TDI
2003 jetta 4 1.9 TDI
it maybe a "mark and pray" method (never been a problem for me), I was simply offering a quick way to CHECK if the cam is slightly retarded. I wasnt with the guy so can't assume the tensioner was set properly or that the cam locking tool wasn't removed before setting the tensioner. regardless, If he does find that the cam is out as I have seen before even when people have used the correct tools that COULD be a reason for the vehicle problem. The timing belt was recently changed, if done incorrectly that can cause problems so as I said, rather make sure that the timing is correct before taking unnecessary components off. "measure twice cut once"
 

Devon Miles

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Joined
Oct 23, 2012
Location
south africa, Gauteng
TDI
2003 jetta 4 1.9 TDI
If the guy wants put all the locking tools in place then he will, if the crank is locked and pump is locked but the cam lock wont go in then the cam is possibly retarded so an adjustment needs to be made otherwise the poor guy might replace a whole bunch of fuel system components when all that was needed was a cam adjustment.
 

justintime_3

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Apr 15, 2011
Location
Bloomington,IL
TDI
2000 tdi Jetta, 2006 tdi jetta PKG 2
Anyways, to the OP. I cannot tell you if all TDI's do this as mine does the same exact thing and was wondering the same thing. Would like to hear some pertinent responses to your question though.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Not helpful as you are describing a "mark and pray" timing belt job. OP clearly stated he used the correct tools which means he tensioned the timing belt with the cam pulley free to rotate.
I don't understand where this "Mark and pray" comes from. At no point was anything like that mentioned. At least that I can see.

That being said, I think that a small bit of air intrusion is more likely.
 

mr.pulkkinen

Member
Joined
Dec 19, 2009
Location
Europe
TDI
2.5 TDI V6 AFB and 1.9 TDI ARL
Check your cylinder head oil pressure. Could be low oil pressure causing valves not to open fully especially when cold. If pressure are low inspect your oil pressure at the oil filter console. If pressure are ok at filter console. Inspect Cam Shaft and Cam Bearing Carefully and replace. Check oil pressure again afterwards.
 
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wmgeorge

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Jun 22, 2012
Location
Central Iowa
TDI
2000 New Beetle GLS 1.9L TDI
Anyways, to the OP. I cannot tell you if all TDI's do this as mine does the same exact thing and was wondering the same thing. Would like to hear some pertinent responses to your question though.
Mine does the same thing. OP stated its been going on for 2 years and he just recently changed the timing belt. Don't see how the two are related?

I'd guess your oil pressure is higher with the colder oil and lower when it gets hot. That's the way its been on every car/truck/ tractor I've owned. If the cam was bad wouldn't it be apparent on something other than a cold start?

Could the lifers be losing oil overnight and it takes 5 seconds to refill?

In any event my miss lasts the same as his and the car runs perfect after those 5 seconds.
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Just considering the basic symptoms, I'd suspect one of the temperature sensors.
Check them when cold and when hot and look for oddities.
Here is a thread showing where they're at
 

Grussing

Well-known member
Joined
Aug 31, 2012
Location
Mn
TDI
99.5 06 Jetta 14Cummins
Mine dose that some times only on cold start up, are you getting any smoke? What condition are your nozzles in? I just took mine out and a pop test revield two of them were leaking, I am hoping the Sprint 520s will fix it,
 

5SP TDI

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Fort Wayne, IN
TDI
2014 JSW TDI, DSG.
I used the crank lock tool, cam lock tool, and injection pump pin when performing the timing belt change. I also used the cam gear puller so the cam pulley could rotate freely when tensioning the new timing belt. Timing on the mechanical side is perfect (cam, crank, and injection pump). I replaced the engine coolant temp sensor last winter as I had a fault code for it, I assume it is still good. I did buy the sensor from NAPA if that make any difference.

I have no smoke on startup, unless it is 10-20 degrees. I think it is a whitish smoke if I remember correctly. If there is any air intrusion in the fuel system where should I start looking? Nozzles are original, so I suspect they can be an issue. Is there any type of "cleaner" I can run through the fuel system to help clean them? Thanks so far the responses guys!

Jeff
 

bigtom111

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Joined
Sep 8, 2004
Location
Kentucky, USA
TDI
99 Beetle, 97 Passat, 03 Jetta
How many miles is on it? The injector nozzles might be getting worn out and if the spray pattern is poor they can misfire until the cylinder heats up.
 

mohawk69

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Apr 27, 2005
Location
Richmond Hill, GA (Savannah)
TDI
1996 B4, 1996 B4V, 2000 Beetle TDI
"That being said, I think that a small bit of air intrusion is more likely."

X2. My 96 B4 acted this way and actually leaked a little from the IP if it sat for a few days between uses. I found and started using some B100 as an additive and it was cured. I haven't been able to get any B100 lately (250 miles away) but the problem has not returned. We'll see...
 

vwdsmguy

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Jul 5, 2004
Location
Syracuse, NY
TDI
2002 Golf black 5-spd
rough on start up

I posted with the same problem a few days ago, also under MK4 sub title. Lets get to the bottom of this.
 

Devon Miles

Member
Joined
Oct 23, 2012
Location
south africa, Gauteng
TDI
2003 jetta 4 1.9 TDI
How many miles is on it? The injector nozzles might be getting worn out and if the spray pattern is poor they can misfire until the cylinder heats up.
I agree, maybe even leaky injectors making it difficult to heat the diesel mixture enough with compression to get it to ignite efficiently.
 

5SP TDI

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Aug 1, 2010
Location
Fort Wayne, IN
TDI
2014 JSW TDI, DSG.
I unplugged that MAF today and started the car with a cold engine. No sputter/misfire or stumble on startup! This weekend will be a true test as to whether the MAF is the cause to my issue since it is getting down into the 30's/40's in Indiana. Will report back with an update in a day or two.

Jeff
 

wmgeorge

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Jun 22, 2012
Location
Central Iowa
TDI
2000 New Beetle GLS 1.9L TDI
I unplugged that MAF today and started the car with a cold engine. No sputter/misfire or stumble on startup! This weekend will be a true test as to whether the MAF is the cause to my issue since it is getting down into the 30's/40's in Indiana. Will report back with an update in a day or two.

Jeff
Wonder it that's what is wrong with mine? When I had it hooked up a month or so to check the timing that was right on, and temperature sensors all read the same, cold anyway.

Won't a bad MAF show up in a scan?

Like most everyone else since never owning a diesel before at least a TDI VW anyway I just assumed they all did it.
 

5SP TDI

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Joined
Aug 1, 2010
Location
Fort Wayne, IN
TDI
2014 JSW TDI, DSG.
Looks like I will be ordering a new MAF from IDparts this week. I did 5 completely cold starts over the weekend with the MAF unplugged and it started without any hiccups or misfires (coldest ambient temp was 33 degrees). I went ahead and plugged the MAF back in and waited a while for another cold start and the engine stumbled/misfired for about 8 seconds before it smoothed out. I also had some CRC brand MAF cleaner and cleaned the MAF. Did another cold start - same stumbling/misfire issues. Will update in another week or two when my new MAF comes in!

Jeff
 

5SP TDI

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Joined
Aug 1, 2010
Location
Fort Wayne, IN
TDI
2014 JSW TDI, DSG.
I had already extended my glow plug time with VCDS and it did not help with my car. But, it is a very good idea to do for anyone else who has not done it yet.
 

lirunaway

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Joined
Feb 17, 2010
Location
Mooresville, NC
TDI
2006 VW Golf TDI, Model Year:2006 Code:6 MFG:07/05 Vin:9BWGR61J364004114 Sales Model:9B1 538 Description:1.9 TDI High 100 Engine:BEW Type:TD CCM:1896 KW:74 Description:Pumpe-D... Transmission:GPC Type:A Number:09AH GVWR:4097 Front:2269 Rear:1850
I'm not sure if I'm having the same issue or not. My wife's starts fine cold and if you try to go right away it stumbles or stalls and upon stepping on the peddle it does nothing even floored. It's like making a request and the car says nah maybe later. Give it a minute and everything is normal, actually nice good torque. My wife said yea it's to the point she starts it and goes back in the house. I always thought warming these cars up was pointless because it doesn't generate enough heat at idle and your supposed to start and go.
 

Diveguy

Well-known member
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May 25, 2008
Location
Portland, OR
TDI
04 Golf GLS TDI PD
somewhere is a thread about the initial startup inject amount. As I recall it said to increase the idle injection quantity
 

simbolo

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Joined
Jul 24, 2006
Location
USA
TDI
2002 VW Jetta
Did any one resolve this issue by getting a new maf?

I cleaned mine and it seemed to help, it was pretty dirty as far as
Mafs go
 
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