Wastegate solenoid pressure/vacuum pump readings
Hi All,
I think I have a problem, but am not sure. Excuse the amateur antics from the onset.
I have a G300TD and a E300TD. The engine in the e-class, even after trying to compensate for the fact that it is much lighter car, seems smoother and more responsive. The turbo seems to be boosting earlier and for longer across the 2000-3000rpm range (the engine's sweet spot). I thought the wastegate solenoid on the turbo may not be operating properly.
I took them both down to my local garage and they put a vacuum guage to the wastegate solenoid. On start up and idle the E-class was up to 10 mmHg almost immediately and the Gs got to 8 mmHg after about 10 secs. At about 2500 revs, the Es read 18 mmHg and the Gs struggled to hold 13mmHg. The Gs vacuum pressure seemed to wander around more and not be as responsive to revs. I think the vacuum pump on the G could be at fault as it may not be able to hold the wastegate shut and therefore 'leak' exhaust and thereby not giving the turbo enough 'air'. Is this correct?
My question is: are the vacuum pumps on these engines identical (they look it - the part numbers are hidden so I couldn't read them)? If so, are the Gs settings purposefully less responsive for durability to those of the Es?.........or is the vacuum pump/wastegate/solenoid on the G just not functioning properly?
All comments, as usually, highly appreciated because I'm stumped.
Thanks,
Phileas
Hello Phileas,
My knowledge on turbo-charging is basic and academic, I do not know much about the Mercedes set up but looking at the EPC, I learn that the system has at least two pressure converters that could be at fault.
Rather than guessing and picking at possible causes, the best advise I can suggest is to have the fault codes read and take it from there.
If picking at faults you want, then I would not have faulted the vacuum pump since you have not complained about poor braking effort on the pedal, for that is what would happen if the vacuum pumped was faulty. If the vacuum supply is to blame, then the fault would be before the solenoid, but after the pump. Try and swap the solenoid to see if the fault transfers as well, if so, you have an immediate diagnoses.
The WIS on the Mercedes Benz parts and service portal, charge a tariff of €4.00 per hour to get information and data from them.
Regards,
Hi
By my own admission my knowledge of turbo workings is somewhat behind Rakesh's however our EPC roles may be reversed, so between us we may help. Chassis numbers for both would be usefull if you want to PM me.
On first quick look both circa late 90's W210 E Class E300TD and W463 G300TD both run the same version of the 606a engine (606.912) They both show the same turbo and both show dual pressure accumalators/convertors/transducers. Simliar set up on the same era Sprinter van i am more used to and a common issue was a disloged vac pipe or the vac pipes swopped around. There are two types of transducer on the van i think for different boost setting for the wastegate...i.e same turbo different outputs. These were little square ish black boxes about 3"x3"x2" and have the part number on them...A0005450527 is the lower rating and A0005450427 the higher from memory. Both your vehicles (without chassis number) show dual A0005450427's.Could they have been swopped / changed / altered.
If i am talking rubbish please feel free to correct me no offense will be taken.
Hope this helps
Hi Gav,
Have one going through an MOT at the moment, so can not check. I'm going over the Gs vacuum hoses first to see that I haven't missed anything obvious. Thanks for your input. Will revert with findings.
Ph
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Hi Rakesh,
Thanks for your advice. I will take a look at the accumulators and revert with any findings.
Regards,
Phileas