AJM Engine Repair: Tips for VW Golf 4

Hello fellow mechanics!

I'm excited about the community, so I'm joining you all here!

I received a Golf 4 in my workshop with an AJM engine that I need to work on. I could simply assemble it now, but there's a problem:
According to VW:
The customer was driving on the highway when the car suddenly lost power at 240 km/h and stalled. He restarted it and drove to the nearest VW workshop, where it then experienced misfires. The VW workshop read the error codes, which included: 1. 17958 P1550 011 - Boost pressure control difference.
2.16685 P0301 035 Cylinder 1 Misfire

After that, the cylinder head was removed, and a diagnosis of engine damage was made.
According to me:
Then the customer brought the car to me because VW was too expensive and their explanations were unbelievable.
Okay, I've taken a look at everything, and I don't see any damage to the engine block, crankshaft, cylinder head, turbocharger, or any other parts. Unfortunately, I couldn't inspect the head gasket; it was already discarded by VW. Since I have limited experience with these engines, I would appreciate your advice and a repair manual.
My opinion is that there probably isn't anything majorly wrong, but as I said, I lack experience with these engines.

???????????????

The customer was on the train when the car experienced a failure at 240 and shut down.

Sure, with 115 horsepower! He probably over-revved it going downhill. Does it spin freely without any issues?

When using boost pressure regulation, the boost pressure is simply reduced. I'm not familiar with the term 'combustion interruption' at this time.

How does VW explain the engine failure?

Regards,

Manuel.

The "crystal ball" problem. What can we say? If there was a fault during combustion in cylinder one, I would start looking there. There is a lot of information available here regarding differences in boost pressure.

I'll just leave the misfires at 240 without any comments .

'I got the 240 value from the customer; he says it's been running like that since he installed the *** chip!'

'It's not a problem that it's spinning out of control; it was supposed to run, but it's running unevenly...'

I didn't receive any information from VW, and the master technician wasn't available.

Hi,

Ah... so, a chip!

Perhaps you should first write down everything you know about the car. For example, the mileage would also be helpful, as would the supposed performance of this chip.

Have you ever calculated how high the engine RPM would be at 240 km/h with this transmission? Maybe there's already something interesting in there.

Best regards,

Jan.

Hey guys.

AJM --> 240 ???
Well, my little Golf reaches about 210 km/h on the speedometer in 6th gear, at around 4000 RPM, but whatever.

[JokeMode=ON]
Perhaps he has one of these new super diesel fuels in the tank; according to the advertisements, they promise approximately 300% more power with 100% less consumption .
[JokeMode=OFF]

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Best,

Well, at 4,500 RPM and with a slight speedometer discrepancy, that could certainly be the case.

Were there only misfire codes in the error memory, or was there also something related to cylinder 1?

Best regards, WarLord.

Hi,

We can ignore the speedometer discrepancy... the 240 will be what the speedometer shows. The relationship between the engine speed and what's displayed on the speedometer depends only on the gear ratio and should therefore be the same for all identical cars, because the speedometers are designed to overstate the speed and this is calculated by software based on the wheel rotations.

4000 RPM at 210 km/h would translate to 4571 RPM with a display reading of 240, which shouldn't be too bad – my car's speedometer already showed higher readings on the highway without any tuning (of course, going downhill).

Best regards,

Jan.

Are you sure the turbo is okay? Does it spin freely, with minimal play, and are there no visible signs of wear on the compressor or housing? Also, is there no oil in the coolant?

And did the car make any unusual noises, either during or after the malfunction?

Best regards!

JA´s Car Service wrote:

VW read out some errors, and the following were found: 1. 17958 P1550 011 Boost pressure control differential. 2. 16685 P0301 035 Cylinder 1 Misfire

The issue with the turbocharger pressure might be due to modifications.

Misfires indicate a faulty distributor.

Unfortunately, all I can tell you is what I've been told by the client, and if this thing only runs at 200, I'm also very frustrated.

I just need a repair manual for the shop and some good advice from you!

He WarLoard, there's also something about spark plugs mentioned on the 1st.
Do you have any insightful ideas?

'Stupid question, what does PDes mean?'

JA´s Car Service wrote:

Stupid question, what does PDes mean?

Pump nozzle Elements

Hey, to be honest, do you think you're the right person for this engine? You should have some knowledge of repairing newer VAG diesel engines. Especially, you should be very familiar with the injection system, as it seems to be causing the problem. If you remove the cylinder head, you'll find not only valves and glow plugs, but also the injectors. When you take off the valve cover, you can see these from above, essentially looking at the pump. Unfortunately, it's very difficult to tell if they are defective just by looking at them. Therefore, it would be a good idea to connect the assembled engine to a workshop-grade diagnostic computer (which you can find in our online shop, at least the necessary adapter with software) to diagnose the problem. Otherwise, you'll be left with randomly replacing parts. However, your customer is probably not willing to spend endless amounts of money, so start with suggestion number one. Because a PD injector element costs a significant amount of money.

Alternatively, I strongly recommend that you read the technical articles to at least get a basic understanding of how such an engine works.
Sorry, I don't mean to be rude, but I find it strange when someone has a workshop and talks about customers, but doesn't know the basics.

Hello,

My advice: Decline the repair and send the customer back to VW. If you're not a skilled mechanic with insider knowledge of the Pumpe-Düse TDI system, you'll only be doing yourself a disservice by attempting the repair. The lack of specialized tools alone will make the repair a nightmare. It will only lead to problems with the customer later, especially regarding warranty issues.

By the way, I love this clientele. They pay a fortune to have their engine tuned at ***, drive like maniacs, and then want to get it repaired for free at a friend's independent garage.

If you choose to get chipped, then you should also be prepared to deal with all the advantages and disadvantages that come with it.

Okay, I heard your opinion! It would have been easier for me if I had received the complete information! And with a better error description! I may not have the knowledge about these engines yet, but everyone starts with something! But I also have other areas where I excel, which others struggle with. Fortunately, the problem is now resolved; the error has been found ...... According to information from a well-known tuner, the first piston is cracked in the combustion chamber, and it's not the first time he's heard of something like this!

Thank you all!

The rest will take care of itself, and maybe I can share some more or less useful information with you soon! }

Okay, then.

Since you mentioned in your first text that you had checked everything (including the "Kopf Block Turbo") and found no errors, it's a bit confusing.

"That wasn't meant as an accusation. Of course, it's impossible to know everything, and I understand that. I just wanted to point out that you could run into problems with the customer if you make a mistake in that area. My suggestion remains: if you have more VAG vehicles in your workshop, it's a good idea to find a suitable diagnostic tool. In the case you described, however, it wouldn't have made much difference because the engine had already been disassembled."

P.S. Exactly where is the piston cracked? Shouldn't there also be other signs of combustion to be found in the combustion chamber?