Extremely hard starting 03 ALH w/ VAG-Com 17656 Code

I have an 03 Golf at ~228k miles that threw a P0252 OBD-II code a week ago and once scanned with VAG-Com I get: 17656 Start of Injection Timing Regulation, P1248-35-00 – Control Deviation. At the time of the light there was no noticeable change in the Golf (I was on the highway and suffered no loss of power or other ill-effects).

The car has been running rougher as time has progressed but there have been no tidal changes. My power has dropped some at the low end and my fuel economy is not as high as it has been but I am running on the rich side with an 11mm IP and 520 injectors (VAG-Com shows ~3.8 on IQ). The car has been smoking more recently but I had been attributing it to the more than adequate fueling. I have also had a cold start (engine not ambient) issue for quite some time 40k+ that I have experimented with changing glow plug timing with minimal effect. The engine has always started fine when warm or when on the block heater (FrostHeater) regardless of ambient temp.

After the light came on and I scanned with VAG-Com I did a timing check and found that I was “too advanced to plot” so I retarded the IP and got it within range. I cleared the code and drove it around a bit to confirm everything seemed OK which it did. The next morning the car took a lot of cranking (several 3-4sec cranks spaced out over a minute or two) before finally starting with a huge cloud of smoke. This was repeated after work that day for the return trip home, acting almost as if the IP had lost its prime and had air in the line. I tried to check timing when I got home but it was saying that the coolant temp was too low (despite a 15min drive in 75+F air temps). I parked the car for a couple of days, changed to a new fuel filter and refired the car (same as before with a lot of cranking and a lot of smoke), drove it around until the coolant was above 80C and checked timing again only to be told that it was once again too advanced and this time it also told me my fuel temp was too high.

Service history (aside from 10k oil/filter/cabin/fuel changes using Mann filters and AMSOIL 5W-40 European oil):
- 100215mi – Full Timing Belt Service w/ Water Pump by Dealer
- 126500mi – MAF Sensor Replace
- 152630mi – New Battery Installed and new Injection Pump installed by dealer
- 177500mi – New Intake Manifold Installed and EGR valve was cleaned (I also adapted the EGR down using VAG-Com)
- 194200mi – New Glow Plugs
- 194215mi – MAF Sensor Replaced
- 200208mi – Full Timing Belt Service w/ Water Pump & Serp Belt done by me with engine out of car using Metalnerd Tools; Oil Pan Gasket and Rear Main Seal Replaced; used (151k) 02J 5spd swapped in place of original 01M Auto along with associated PS lines and other components
- 203513mi – Liqui Moly Diesel Purge to clean the fuel system
- 204545mi – Installed Bosio 520 DLC Injectors
- 205449mi – Installed new soft lines between fuel filter & pump (both black, should have gotten one clear I know)
- 205900mi – New Coolant Temp Sensor
- 219800mi - New Battery

Known issues:
- My anti-shudder valve is disabled and has been for 70k+
- There is a fair amount of oil leaking from the PCV? Valve in the valve cover. I’m not entirely sure what to do about that short of replacing the whole valve assembly.
- I do have a valve cover oil leak stemming from my timing belt service that I intend to rectify when I get to the 230k oil change
- I have an oil leak at my oil cooler which I recently replaced the seals on to no avail at the 220k service and will attempt to fix again at 230k
- My flex-pipe has failed due to using an aftermarket down-pipe that didn’t quite fit right which makes things a little on the loud side especially the turbo spool whistle). It is on the list of things to correct along with some suspension bushings and such assuming I can get the car back to running properly.

Any thoughts or direction would be greatly appreciated. I have had less than stellar luck dealing with the local VW service departments and I would prefer not to waste my time or money.

With the car idling check the injection timing in measuring blocks, it should be about .5 degrees BTDC.

ADVNTURR said:

I have an 03 Golf at ~228k miles that threw a P0252 OBD-II code a week ago and once scanned with VAG-Com I get: 17656 Start of Injection Timing Regulation, P1248-35-00 – Control Deviation. At the time of the light there was no noticeable change in the Golf (I was on the highway and suffered no loss of power or other ill-effects).

Click to expand...

Sounds like something is wrong with the SOI valve in the Injection Pump. Maybe the valve is stuck in the full retard position (it is spring return). This is why it would work ok at idle and on the highway...the specified and actual timing were likely pretty close. However, under acceleration, you likely aren't getting any SOI timing advance.

So...if the SOI valve isn't working...it can be a mechanical problem with the valve/bore/plugged screen in the IP, or low side fuel pressure is too low, or there is an electrical problem between the ECU and the IP.

You can cycle the SOI valve in the test section when in VCDS.

Possible Causes

• Start of Injection Timing Regulation not OK
• Injection Pump Control Range blocked/dirty (e.g. by Metal Particles)
• Engine has stalled / ran out of Fuel recently
• Wiring/Connectors from/to Injection Valve (N108) faulty

Possible Solutions

• Check/Adjust Injection Start. See TDI Timing Checker
• Check Fuel Supply
• Check/Replace Fuse(s)
• Check/Repair Wiring/Connectors from/to Injection Valve (N108)

Excellent job in documenting things!

Other than the IQ looking a bit low (stock should be around 3.8, I think- on the low side will make starting a bit tougher and smokier), the thing that jumped out at me was the timing seemingly having shifted that much.

If the timing codes are not longer popping up then you may have that licked and are now on to something else.

What CTS did you install? (possible premature failure? disconnect and see if it makes any difference)

What about the thermostat? Are you confident that it's working as it should? No idea whether VCDS can be wrong in reporting temps, but it has to get it from the car's sensors, in which case if those sensors are flaky then VCDS numbers aren't going to match reality. May need to do a direct measurement to be sure.

Below is a screen capture I grabbed just before performing the IP Timing check last night:



UhOh - The CTS is the Green 4pin OEM directly from IDParts.

Additionally, I did not mention that when I installed the new injectors that I adapted the IQ value to the max software limit in order to reduce fueling (I have not yet performed the "Hammer Mod").

In your screen shot...group 4, was this before you retarded the timing, or after?

What is your requested vs. actual IQ?

With two DTC's related to stuff inside the Injection Pump, it sounds like there's a problem in the pump or the wiring going to the pump...

I'm no VW expert, but with a fuel metering DTC and a injection timing DTC, the problem(s) are narrowed down to the internal IP, or the control circuit of the IP.

Where is your timing now?

Have you run any logs to check IQ and timing specified vs. actual?

The screenshot is from after I adjusted timing originally as a result of the CEL. When I ran the motor immediately after adjusting it showed in the upper range of timing (slightly advanced). The screenshot is from just before I re-checked the timing after putting in a new fuel filter yesterday which again said it was too advanced to plot (summary: too advanced, adjusted into range, near no-start, new fuel filter, screenshot, too advanced again).

I have not run any logs or checked IQ requested vs actual (I'm just competent enough with VAG-Com to be dangerous). I will try to get the car started and see if I can get another screenshot with IQ measuring blocks.

I just went out and got the car started and ran around the country block to get the engine up to temp. While I was out I grabbed 1 screenshot at partial throttle under load:



Then I grabbed a second screenshot right before I checked timing:



And finally I grabbed a shot of the Timing Graph (once again telling me my coolant temp is too low despite being over 80C):



I also grabbed a quick video with my phone trying to catch a weird sound that it makes from time to time right after start-up (it’s hard to hear but it kind of squeals – possible cavitation?) that I uploaded here:

https://youtu.be/KXUHulpfTbY

See that yellow line? See a corresponding horizontal line meeting up with it? Neither do I. Your timing is off the charts, WAY advanced. You need to get that adjusted down. It's possible that this is occurring because of the temp issue, but I am not sure. No idea why VCDS thinks your temp is too low when you're saying that it isn't.

On that noise, possibly your starter solenoid is staying engaged a little long. That or you've got a boost issue (though you should be able to reproduce it at just about any time).

Update:

I ended up taking the car into a local dealer yesterday to see if they could help point me in any direction along with the information that I had collected and the information everyone here provided.

What they found is that my pump is loosing prime and air is getting into the line whenever the car sits for any period of time. They suspect a check valve in the IP or possibly a leak in a fuel line somewhere. They also noted the my IP output pressure was high.

Unfortunately they couldn't/wouldn't give me much more than that because the car is so modified in their opinion. To their credit, they did waive the diagnostics fee for me since they did not actually tell me the root cause.

I am going to order and replace the thermostatic T fitting on the top of the fuel filter since it is original to the car and it's cheap and a possible source of air getting into the system. I'm also going to look for any sources of leaks on the pump or around the injectors. The lines between the filter an the IP are new as is the filter itself. Any other places I should be looking? Is anyone aware of any check valves in the IP that can be serviced/replaced?

The biggest question I have is, how could messing with IP timing make the car go from rough starting to almost not starting in relation to air in the line. Is it possible that it is a compounding of errors and now I have my IP timing off and I'm getting air in the line?

Someone else could chime in here, but I think that with advanced timing and less fuel/more air it'll struggle to torch off. Need to get that timing set and leave it alone and then get on with taking care of the air intrusion issue. When you get to this point it's possible that you have an IP issue; but, first go for the easy stuff.

Wonder if there's any air intrusion via the fuel return lines. Didn't see that these had been touched.

Though not likely to contribute to this problem, I'd set that EGR adaption back to stock. It's been proven that this does diddly-squat other than knock your fuel mileage down: the ONLY real way to alter it and get beneficial results is via the maps (tune).

Put a couple check valves in the fuel lines.