Turbodiesel erreicht V-max nicht trotz voller Leistung!? | Posts 16+

Haha, that was a complete disaster.
The LMM swap didn't achieve anything at all.
I just drove about 120 km, including four trips of 15 km each (twice up and down the A555 highway), all at full throttle.

After Bonn, speeds of 158-160 km/h, occasionally reaching 162 km/h with a slight headwind.

Heading towards Cologne, at speeds of 160-162 km/h, just before the road starts to gently slope downwards, I lightly brushed against something at speed 170 km/h with a slight tailwind.
Alle Werte lt. Hey.

It's definitely lacking at least 10-15 km/h compared to the claimed top speed of 170 km/h.
Damn, now what?

Are different wheels/tires installed than those originally specified?

These are brand new Goodyear UG6 winter tires in the smallest permissible size, 175/65R14.
The tire pressure has been set to 0.3 bar above the normal level since yesterday in an attempt to further reduce rolling resistance, but it hasn't made any difference.

Standard summer tires are even in size 185/55R15, almost the same circumference but 1 cm wider, and I don't even want to think about how slow it will be with those.
I spoke with the workshop again today. They are going to inquire at headquarters about other possible causes and will get back to me later today to schedule a new appointment. Additionally, I will receive a replacement vehicle free of charge for the duration.
Adjusting the injection timing would likely cause a complete failure with this DTI engine, as it could lead to metal shavings ending up in the cylinders, he said. It's also possible that the turbocharger is faulty and not building enough pressure at higher RPMs, although it seems to be working relatively well within the 2000-3000 RPM range (although it feels more like 60 horsepower than the advertised 75).

Hi,

Here are a few more ideas from me.

-> Are the brakes dragging? You would usually be able to smell and see this (smelling burning rubber) after longer "maximum speed" sections. However, it's always a good idea to carefully check for unusually hot rims. If only the rear wheels are affected, that could explain the good performance on the trainer (the rear wheels are not rotating freely).

-> Are the intake passages restricted by carbon deposits from the EGR system? This can be checked by reading the mass airflow sensor (MAF) values during a full-throttle run (of course, the boost pressure must be okay!!).

-> Are the cooling air passages blocked by the intercooler? Check as described above + check the charge air temperature (if possible to read).

Hello,

"Something definitely doesn't seem right here. Has the speedometer been tampered with? I don't know if it even has an EGR valve or a coolant level sensor. However, Opel should be able to determine what's wrong during a test drive. The fact that the mass airflow sensor was replaced based on suspicion doesn't exactly inspire confidence in their competence."

Best regards,
Christian.

@ulf
The rims aren't getting hot; I had already considered that possibility.
According to the workshop, no errors were stored in the control units.
@chris
The speedometer was not calibrated; instead, it was measured on a dynamometer, which showed an error of approximately 7-8 km/h at speeds of 120-140 km/h. Therefore, the actual top speed is likely around 155 km/h.
My DTI has a low-pressure cooling system (LPC) and an EGR valve, while the less powerful DI (65 hp) version has a turbocharger without an LPC.
Today I drove my 60 horsepower Ford KA (gasoline engine) again, and it seems to have roughly the same or even slightly better acceleration than the 75 horsepower DTI.

The master mechanic from the workshop (a large Opel dealership with multiple branches throughout North Rhine-Westphalia) wants to connect with other Opel workshops and the Opel headquarters to discuss possible causes and solutions, as they want to avoid replacing parts unnecessarily. They will then contact me to schedule an appointment.

Okay, here's the translation:

'I have some news. I managed to track down the previous owner, and he told me that from day one, he felt like the car wasn't pulling properly, and that it could only reach its top speed when going downhill with a tailwind. It was his first diesel car, and he thought diesels were naturally slow, so he didn't take it to a workshop. After a year, he bought a 100 horsepower diesel, which he said performed extremely well compared to the 75 horsepower diesel.'
The car has been driven 50 km twice a day, mostly on the highway, and usually at speeds of 120-130 km/h. You can't really go much faster during rush hour. If that's correct, then the car definitely hasn't been run into the ground or overused.

The new appointment is for next Tuesday and will last at least two days. The Opel dealer now wants to thoroughly inspect the engine, starting by checking the fuel injection pattern of the injectors to see if any injector might have been faulty from the beginning. They are confident that they will be able to fix it.
So, I want to be optimistic too.

AndreV wrote:

I have some news. I managed to get in touch with the previous owner, and he said that from day one, he felt like the car wasn't pulling properly, and that it could only reach its top speed going downhill with a tailwind. It was his first diesel car, and he thought diesels were naturally slow, so he didn't visit any workshops. After 1 year, he bought a 100 horsepower diesel, which was extremely good compared to the 75 horsepower diesel. The car has been driven 50 km twice a day, mostly on the highway, and usually at speeds of 120-130 km/h. You can't really go much faster during rush hour. If that's correct, then the car definitely hasn't been run into the ground or overused. The new appointment is for next Tuesday and will last at least two days. The Opel dealer now wants to thoroughly inspect the engine, starting by checking the fuel injector spray pattern to see if any of the injectors were faulty from the beginning. They are confident that they will be able to fix it. So, I also want to be confident sometimes.

Oh dear... it sounds like something went wrong at the factory already.
I don't want to depress you, but I don't think you can find out much without completely disassembling the entire machine.
Here's another tip: Check the fuel temperature sensor and its wiring. If your engine control unit (MSTG) detects that the injected fuel is very cold (high density), it will adjust the injection volume, even if the fuel itself is extremely hot.

Injectors: A poor spray pattern with a loss of power should be noticeable through excessive black smoke. You haven't mentioned anything about that, so I would actually rule it out.
Good luck anyway!

Best regards, Rainer.
Best regards, Rainer.

Okay, let's say a nozzle is no longer 100% clear due to a very thin piece of debris. This debris could be stuck somewhere in the line or elsewhere.
Well, I'm giving the guys a chance to get the car, especially since it has exactly the features I was looking for. And if it ever becomes too much of a hassle, after two attempts at fixing any issues, I have the right to return or exchange it.

Hello,

This would likely result in an uneven spray pattern. However, testing the injectors externally isn't a big deal. I suspect that the ESP (Exhaust Gas Recirculation) system, in conjunction with the engine control unit, might be doing something strange. It could also be due to an EGR valve that wasn't completely sealing from the beginning, insufficient boost pressure, or something similar. Based on your description, you're missing about 15 horsepower, which is significantly more than what's typically allowed within engine tolerances, and a professional diagnosis should reveal the cause.

Best regards,
Christian.

Opel has a problem: they are having issues with their Tech2 diagnostic tester. It's designed for older technology and is unsuitable for the new technology. They have implemented many restrictions in the diagnostic interface, making it difficult to get any meaningful data displayed. I think this will lead to a high rate of errors!

Okay, so the car was back at the workshop for a second round of repairs, and this time it took a whole 5 days!
They had a comparison vehicle available and measured and tested everything on both cars, but couldn't find any faults. All the readings (boost pressure, diesel pressure, exhaust emissions, temperatures, etc.) were identical.
'Only mine performs noticeably worse and jerks when you suddenly accelerate between 2000 and 3000 RPM. Also, the fuel injectors have been checked and found to be working properly.'

Then, they systematically replaced and tested one part at a time using the comparison vehicle. Additionally, the mechanic took the car home in the evening and drove it on the highway to see if it could now reach its top speed. In total, the workshop drove approximately 200 km for testing. (During that time, I drove 500 km with a complimentary loaner car.)
In the end, they eventually replaced all the fuel injectors.

And ultimately, it was the fuel injectors!

The car is now traveling at 180 km/h according to the speedometer and it's no longer shaking.

Okay then, have fun with your car.

Best regards, WarLord.