P1248 Cold Start advance code

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
I was going to add to an existing recent thread but couldn't find it so I started a new one.
Donna's car was throwing this code, with advanced timing off the chart and noisy throughout the rpm range. Also, the duty cycle for the N108 was stuck at 2.8%. Cold start timing actual was above specified.
After cycling the N108 in output tests I could see my timing fluctuating in block 2 of the chart, as the N108 still cycled after I backed out of the output test. When I hit basic settings to get to the timing graph, the N108 quit cycling. The timing was still way advanced, but it showed on the chart until I hit the throttle and it resumed it's off the chart advanced position.
I ran the same tests on my car and noticed the duty cycle of the N108 varied with rpm and load.
I didn't feel like pulling the pump to get at the N108. Always preferring the easy way out, I thought I would try something.
Her car was due a filter, so I filled the new filter with Liquimoli Diesel Purge. I found a drift and hammer that would reach the case where the N108 is housed. I opened output tests and started the car. I then cycled the N108 with VCDS and tapped on the pump case. I did this three times. When I went to measuring blocks and checked specified and advanced timing, they were the same. I took it for a run and the duty cycle for the N108 was happy again!
FYI, only symptoms were the engine code and noisy pump. The code did not always show a lamp.
Hopefully, this can help someone else free one of those up also, I was damn glad to not have to pull that pump.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
We continued to have issues with this. So, since her car was due for a timing belt, I swapped in a known functioning advance solenoid. Still having problems. I suspect some worn internals so I picked up a used pump that had been sitting.
I filled it with fuel and cycled it in a vice. I have some seal kits coming and I will put the new seals in it after cleaning. Going to let it sit with fuel in it for a while first to soften up any fuel that dried in it.
Going to see if I have something in the steel pile to make a flange to bolt to the coupler. Then I can run the pump with an impact without putting it on the shaft nut. Put an in line filter on, a hose in to some liquimoli, and flush it out before installation without concern of sending anything to the injectors.
 

Nero Morg

Top Post Dawg
Joined
Oct 19, 2017
Location
OR
TDI
2014 A6 TDI, 2001 Jetta TDI, 2014 Passat TDI
Injection pumps that are noisy can sometimes be cleaned up with diesel purge, otherwise, it has worn internals and needs overhauled or replaced.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
True enough, I think something in the internal timing mechanism is worn. It always gets stuck at full advance eventually. The car does 30 to 60 miles daily, so I don’t think it’s an issue of sticking catch because it’s fouled, pretty sure it’s worn.

So I’m going to swap it out and tear it down. Been wanting to get inside of one of the pumps to check it out anyway.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Resealed and installed the used pump I found. Purrs like a kitten, specified and actual timing mirror each other and IQ stays pretty steady. But of course the car still had to bite me in the a$$, the fresh coolant looks like it has oil in it, looks like the oil cooler dumped on me. Going to pressure test a spare and put that on if it checks out. See what happens
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Good to hear, I have a feeling that probably would have worked here also, but for whatever reason I didn’t bother trying. Came out ok though, a $75 used pump that I put in a vice, filled with LiquiMoli and let sit for a couple days. I then put two bolts in the coupler and rotated it. It was rather stiff at first but loosened up. It’s been serving us very well since. And during my search I also came across an inexpensive 11mm pump with lines and clamps
 
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