Hard cold start

[TaylorMadeGolfClub]

I noticed the symptoms below after the engine was overspeed (by my father) for a couple seconds. The outside temperature also dropped around the same time. Maybe one or both of these events caused the hard starting?

Symptoms:

• Cranks and sputters for 5-10 seconds before reluctantly starting.
• Large puff of white smoke (much larger than I've seen on this car before the issues).
• Unsteady idle until I give it a little throttle (bounces between 850 rpm and 1000 rpm).
• Low power when driving for about a city block then seems normal after that.
• The car always starts.

Observations:

• The area directly underneath my injection pump was covered in what felt like caked on sand and dirt held together by a thick gummy black goo. I can't tell if it was baked on power steering fluid or baked on diesel fuel. In my experience diesel is usually sticky and wet, not gummy and dry like this stuff was. This goo was present when I bought the car before the overspeeding and temperature drop when I had no issues with starting.
• A little while ago I replaced my glow plugs and ran a can of diesel purge through my fuel system. I used diesel purge because my glow plugs showed evidence of a bad injector. This is the post.
• No bubbles in the fuel supply line to the injection pump.
• The injectors are clean on the outside.
• the entire injection pump is clean.
• Car no longer exhibits these symptoms after the first start of the day.
• The TDI timing under basic settings is dead on according to vcds.

What I have done:

• I have tried priming my injection pump before cold starting and noticed a slight reduction in cranking duration, but no change in the sputtering and unsteady idle.
• Inspected the seals on the thermo t, they didn't look damaged. When I pulled the thermo t out I heard fuel getting sucked back into the tank.
• Checked voltage at the fuel cutoff solenoid it was getting about 13.46V.
• I cleaned up the goo under my injection pump and haven't seen any new leakage.

It seems like the problem is air intrusion, but from what I've checked so far I can't figure out exactly where the air would be getting in. Any ideas for possible causes of these symptoms are greatly appreciated.

 

[KrashDH]

What's your injector contribution with VCDS?

 

[TaylorMadeGolfClub]

Just after a cold start, these are the balance numbers
Injector balance:
Cylinder 1: .33
Cylinder 2: -1.06
Cylinder 3: -.38
Cylinder 4: 1.13

As the car idles these numbers improve.
Injector balance after idling for a bit:
Cylinder 1: .19
Cylinder 2: .14
Cylinder 3: -.02
Cylinder 4: -.33

As I recall you want the difference between any two cylinders to be less than 2 mg/str yeah?

 

[The Cream Dolphin]

Very basic step but I have to ask - Is your static timing set correctly? Mine was retarded, and had long crank, a bit extra white smoke, and an unsteady idle immediately. I did NOT have the low power, and mine did not always start, below -8 it would not. It now will fire sometimes on the first crank, sometimes on the fifth, but incredibly reliable now.

 

[Genesis]

What TCD said -- check the basic injection timing. On the line to slightly advanced (about halfway up the graph) is where you want it. If its retarded it will impact cold starts, especially when its cold outside. I'm assuming the glow plugs are working (no light or code or them, yes?)

 

[TaylorMadeGolfClub]

Very basic step but I have to ask - Is your static timing set correctly? Mine was retarded, and had long crank, a bit extra white smoke, and an unsteady idle immediately. I did NOT have the low power, and mine did not always start, below -8 it would not. It now will fire sometimes on the first crank, sometimes on the fifth, but incredibly reliable now.

timing is dead on according to the TDI timing graph under basic settings.

 

[The Cream Dolphin]

timing is dead on according to the TDI timing graph under basic settings.

Okay, good to know. And what exactly do you mean by overspeed.

 

[TaylorMadeGolfClub]

Okay, good to know. And what exactly do you mean by overspeed.

the engine reached the redline on the tachometer probably about 4700 rpm.

 

[The Cream Dolphin]

That should be no problem, I think the true redline is at 5k. 47 is just a general guideline, I have hit 47 before too, I doubt it would be related to any of your issues. Have you checked your MAF? Try unplugging it and seeing how the engine runs. And just to double check, you are checking timing in basic settings? Check your IQ in Block 0̷0̷1, and the cold start duty cycle in Block 0̷0̷4.

 

[Genesis]

the engine reached the redline on the tachometer probably about 4700 rpm.

That indicates that either (1) the pump is toofed (the quantity adjuster is sticking, which explains the crappy idle until it warms up as well) or (2) much worse, you actually started on OIL and had a hydrolock situation.

#1 is time to have the pump rebuilt before it jams wide open which is obviously bad news; #2 is much worse in terms of possible damage. You likely have no internal damage from #1, but I wouldn't let that go as a sticking QA is unlikely to get better. Also check the wiring carefully to the QA plug (the big one that goes to the pump.)

 

[The Cream Dolphin]

That indicates that either (1) the pump is toofed (the quantity adjuster is sticking, which explains the crappy idle until it warms up as well) or (2) much worse, you actually started on OIL and had a hydrolock situation.

#1 is time to have the pump rebuilt before it jams wide open which is obviously bad news; #2 is much worse in terms of possible damage. You likely have no internal damage from #1, but I wouldn't let that go as a sticking QA is unlikely to get better. Also check the wiring carefully to the QA plug (the big one that goes to the pump.)

I must have misunderstood, this happened while idling/of its own doing? I thought you meant it got driven to redline, my mistake. If so, listen to what Genesis said for SURE do not to mess around with this

 

[Genesis]

It sounded to me like it did that on start without application of the loud pedal.

Running some diesel purge through it might free it up, but if it was stuck badly enough to produce that sort of an RPM excursion I'm uncomfortable for obvious reasons (if it does that when you're in traffic.....)

 

[P2B]

That indicates that either (1) the pump is toofed (the quantity adjuster is sticking, which explains the crappy idle until it warms up as well) or (2) much worse, you actually started on OIL and had a hydrolock situation.

If the incident was spontaneous I would agree, but the OP said his father caused it.

 

[The Cream Dolphin]

If the incident was spontaneous I would agree, but the OP said his father caused it.

My thoughts exactly. Let us know TaylorMGC

 

[Genesis]

Ah ok... my bad -- if you stick your foot on the loud pedal that response is expected.

 

[TaylorMadeGolfClub]

so at this point it sounds like two things may need a rebuild. The injectors or the pump. I would like to be sure the pump is having issues BEFORE sending it out as professional pump rebuilds are expensive. Is there any way to be more certain that the pump is the cause of my symptoms and not the injectors?

 

[TaylorMadeGolfClub]

(2) much worse, you actually started on OIL and had a hydrolock situation

I don't think I'm in situation 2. The smoke smells like diesel, not oil and yes this is not a runaway engine situation. My dad really put his foot in the car.

 

[Genesis]

How many miles on the car and have the injectors ever been serviced?

 

[TaylorMadeGolfClub]

How many miles on the car and have the injectors ever been serviced?

not many miles, 93,500 ish. Injectors have never been serviced other than 2 cans of diesel purge.

 

[Genesis]

I would probably run a can of diesel purge (see the multiple threads on how here) through the pump and injectors before tearing things apart and spending big money. The odds aren't great that it solves it, but its cheap and neither injectors or a pump rebuild are. The only good news is that WA is close to DFIS for the pump -- but at ~100k miles I would not EXPECT it to be toofed (assuming it was NOT run on WVO or other "alternative fuel" at any point in its life) -- but you never know.

 

[TaylorMadeGolfClub]

I would probably run a can of diesel purge (see the multiple threads on how here) through the pump and injectors before tearing things apart and spending big money. The odds aren't great that it solves it, but its cheap and neither injectors or a pump rebuild are. The only good news is that WA is close to DFIS for the pump -- but at ~100k miles I would not EXPECT it to be toofed (assuming it was NOT run on WVO or other "alternative fuel" at any point in its life) -- but you never know.

I'm pretty confident this car has only seen diesel through the fuel system. I'll try Diesel purge again.

Will I be able to tell if things got better looking at group 001 or group 019 in vcds? Seems like being able to quantify the problem would be helpful.

 

[Genesis]

Well, maybe, but your injector balance numbers look ok from up above. That's one of the reasons I suspect the QA is sticking. I'm assuming (as you haven't mentioned it and the MIL will be on if this happens) the glow plugs are all working; all four are individually monitored on an 03 so even one being dead (e.g. bad wiring harness, etc.) will trip the light and, from my experience, even with one not working at all in near-zero temps the car starts fine -- it just is a bit rough on idle for the first 10-15 seconds or so.

At this mileage an internal engine problem (e.g. bad compression) is quite unlikely as well.

The only "gotcha" is that other thread with those glow plugs -- those look like, as noted, bad spray pattern caused -- but you'd expect that to show up in injector balance and it isn't, and wasn't in your previous thread either. If you have two or more holes with injectors that are not firing properly I would definitely expect trouble starting in colder temperatures but that there's no evidence of trouble in balance is a bit puzzling as usually -- but not always -- a bad pattern WILL show up there.

 

[KrashDH]

If your injectors are the issue, cold or warm temps, the idle will be rough.

 

[TaylorMadeGolfClub]

What's your injector contribution with VCDS?

sorry got confused between injector balance and injected quantity. Injected quantity just after the engine fires up and while the idle is bouncing is between 12-14 mg/str. Once the idle steadies out it is 9 mg/str. This is with the coolant temp at .9 degrees C

 

[The Cream Dolphin]

sorry got confused between injector balance and injected quantity. Injected quantity just after the engine fires up and while the idle is bouncing is between 12-14 mg/str. Once the idle steadies out it is 9 mg/str. This is witch the coolant temp at .9 degrees C

Sounds like an issue right there. Get coolant to 90̷, turn all electrical loads off, and see what it is at then. I suggested this earlier, I still think it will be valuable

 

[TaylorMadeGolfClub]

Sounds like an issue right there. Get coolant to 90̷, turn all electrical loads off, and see what it is at then. I suggested this earlier, I still think it will be valuable

when the coolant is at 90 degrees C the injected quantity bounces between 3.2 and 3.4 mg/str

 

[runningallday]

Whoa everyone is suggesting a lot of expensive repairs. Are you sure your glow plug harness is working properly? I recommend using a homemade harness, mine has been flawless for the last 5 years. It is very easy and cheap to do.

 

[P2B]

Whoa everyone is suggesting a lot of expensive repairs. Are you sure your glow plug harness is working properly?

If it wasn't there would be GP related DTCs stored

I recommend using a homemade harness, mine has been flawless for the last 5 years

So has mine. It's OEM

 

[Genesis]

What @P2B said -- on an '03 all four glow plugs are individually monitored and you'll get a light if any of them are not working. Never mind that even with one completely dead cold starting just gets smokier but other than a bit of roughness in the first few seconds is otherwise not impacted (from personal experience here, even at negative outdoor temperatures.)

One other thing to check is that the coolant temperature sensor is working properly. If you have VCDS you can check that on a cold engine it reads ambient temperature before you start the car. If you don't have VCDS temporarily disconnect it; the ECU will presume it is very cold. That WILL set a code that you'll have to clear. These sensors are sneaky as there actually two of them in there -- one that reads on the dash gauge and the other one that reads at the ECU itself, and you can have a working gauge but the one to the ECU is borked and that will impact cold starting quite a bit.

 

[BobnOH]

This may be a concern

.........................snip.........................engine was overspeed (by my father) for a couple seconds.........................snip.........................

Have you put the car up in the air, removed lower cover and checked for loose pipes?