'93 300D 2.5T, 0-62 in 20 sec???
 

I'm am having a hard time believing this is normal for these cars, but if I listen to my dealer he says it is! I bought this car from them only two weeks ago and ever since I have got the run around. Took the car to an independent Bosch dealer that the dealer recommended and they said it was probably a worn out I.P....at 100K?? That seemed odd, so I've been doing my research on this site and think I my be closing in on the problem. When I disconnect and block off the pressure line from the intake to the ALDA there is NO change in performance at all. I adjusted the ALDA CCW about 1 turn to check for any change and none again. No matter what I adjust or change on this device it makes no difference. Could it be stuck at one position and unaffected by presuure or adjustment? Can it be replaced and adjusted properly on the car?

The car runs good and starts well, but it also has a noticable roughness and puffs of bluish white smoke if I hold the RPM at 2300 and slightly "tip in" the throttle in neutral.

By the way the economy is quite good. About 29 city and 35 or so Hwy.
Thanks in advance for any help!

Sounds like a turbo problem to me. I have a 91 300D and it runs very good with lots of power. Check all the vacuum hoses around the turbo and the vacuum valve in front of the air cleaner. On this car, it takes vacuum to close the waste gate on the turbo so it can make boost. This vacuum is controled by the EDS computer. You could also have a problem with the OVP relay. The EGR system has to work or the EDS system will kill the boost. The above rambling is just food for thought.

Just another thought. Remove the air intake hose from the turbo with the engine OFF. Turn the turbo shaft and make sure it turns free. Poor maintaince (oil changes) can make the turbo gum up and not produce the boost needed. I changed to Mobil 1 syn 15-40 and I could really feel the difference in power. I think this was because the Mobil 1 cleaned things up and as I could tell the turbo turned easer.

Clean out your ALDA line off the intake manifold. It most likely will be all gummed up with oil and EGR crud. Once those lines and fittings are cleared out, the ALDA will see the correct turbo pressure and increase the fuel as needed. Mine had the exact same problem when my grandmother handed it down. She never (and I mean never) drove it hard so nobody even knew something was wrong with it! That is until I got it at about 85,000 miles, looked up the specs, and found out that a 17 second 0-60 is not normal, and something needed to be done. It's a whole new car now, getting a 0-60 in 12-13 seconds. I can squeak tires accelerating through a turn now.

If you're not familiar on how the turbo should feel, floor it from a stop and note how it reacts. If it gives you a little kick in the pants at around 2000 RPM, your turbo and ALDA are working properly. If it's just slow all the way up past 3000 (like mine was), you need to do this fix ;)

If the line from the intake manifold to the ALDA goes through a switcover valve, bypass the switchover valve TEMPORARILY to see if it's clogged or stuck closed when the engine's running.

Plumb a boost gauge into the line leading to the ALDA. The turbo is good if you see 5 psi by 2500 rpm under load.

Does that model bleed boost if it detects a problem with the EGR system?

Sixto

What 2.5Turbo said.... http://www.mindspring.com/~houlihan/merc/banjo.htm

I should have mentioned that the boost is a solid 9 psi and the manifold pressure line and fitting have already been cleaned. The fact that I'm getting boost pressure at the ALDA is what is puzzling. With the hose on or off the ALDA seems to make no difference. It runs entirely the same way. I've checked the ALDA and it holds pressure, doesn't leak at all.

It's as if the ALDA is not moving when boost is applied and therefore no enrichment of fuel. If I were to replace the ALDA could it be adusted on the car or would the new one have to be calibrated on a bench?

Tom

So you got boost, but no fuel. Can we assume you checked the fuel lines and filters? You may want to get some codes ...http://www.peachparts.com/shopforum/diesel-discussion/77775-93-300d-2-5l-turbodiesel-power-loss.html?highlight=turbo
Check this thread too...http://www.peachparts.com/shopforum/diesel-discussion/140425-2-5-turbo-boost-problem.html?highlight=602

Yeah, I had the dealer replace the filter and checked for fuel line leaks or bubbles. There were none. The dealer ran codes and says there were none.
I am a little concerned however about the level of boost at 9 psi. I read on a post that the 2.5L should be no less than .95 bar or about 13.5psi. Is this correct? Obviously, with a lower boost comes lower power.
Thanks, Tom

20 secs is too long for sure. my mb buyer guide says it should do it in 10 sec to 60.

i would take the crossover off and look to see if it is tarred up.

tom w

If you're getting 9 psi my guess would be a defective ARV circuit. Either a problem with the actuator, an improperly seated or deformed valve, or a broken or weak spring. If you have a Garrett turbo you can dig into the ARV without removing the turbo.

Could be a simpler problem like a misadjusted wastegate flapper but I'm not sure 2.5s have wastegates.

Not to mention a tired turbo :/

Sixto

Yes, the boost should be higher than 9 psi. My 91 runs 14 psi. I would also recommend you check the cross over and make sure it is not almost plugged up. Also make sure the air valve (or what ever it is called) on the other side of the cross over from the EGR valve is not closing under boost. If it is, that will also make the boost drop. You can temporarly unhood the vacuum line from it and then test drive and check boost. This may cause an error in the EDS system which will then turn off the boost, but it should work at least 1 time. If this happens, simply turn off the engine, reconnect the vacuum line, and you will be back where you were.
Good luck.

Thanks for the suggestions so far, but I have tried most of those things with no luck. I've removed the crossover and checked it for sludge, there was a little but it had not plugged the port for the ALDA. I think I will check the codes myself and see if any are present. If not, I really don't no where to go next. I do think now that the boost is where my problem lies, however it may go beyond my limited knowledge of these cars as to what to check for. BTW, what is an ARV anyway??

ARV = air recirculation valve. A stupidity MB started using in the mid 80s. It bleeds boost from the pressure side of the compressor to the intake side to soften the onset of boost. Like these cars produce so much thrust that more acceleration would be objectionable.

I don't know if a 2.5 has ARV but I found the ARV flap wasn't sealing properly in the SDL.

Sixto

Holy crap! Does anyone know if the 2.5 Turbo has this device? I can NOT get decent throttle response from my car... maybe this is why.

As for the original subject - 20 seconds is waaay too slow. My car does about 15 seconds to 60mph, which is probably not quite up to par, but not bad. I can't squeal the tires around corners though!

The difference between 15 and 20 seconds is huge - I would tend to agree with pmari that it is a fuel problem, but I'm no expert. I would lean on the dealer to fix the problem - you should be able to find the published 0-60 figures from Mercedes, I think it's 12.8 seconds. If you show them that, they will not have a leg to stand on IMO.

-David

The dealer here knows what the published acceleration is but not sure why it is not, "up to par" so to speak. I don't think they have a clue. What is really scary is I also bought an E350 from them! I sure hope it doesn't develop any unusual issues or I may be living with it forever!
Any how, I will speak to them about this one more time as I believe I have exhausted the usual culprits. I will keep you all informed if they are successful in diagnosing and repairing this car. Maybe it will be of value to all who have tried to help me.
Thank you gentleman for all of your help.

**Update from the dealer. Now he tells me there are no "published" performance specs from Mercedes. Hmmm, that sounds like more of what I am coming to expect from this dealer....NOTHING! If anyone knows what I should check for as far as the lack of boost (9 PSI max), I will try anything. I checked codes today, nothing unless I'm doing it wrong. Turbo spins free. EGR is clean and operates freely. Hoses off the manifold, flapper, EGR are clean and not leaking. I'm seriously stumped. Vacuum transducers maybe? Or should I switch to Dilithium crystals, LOL. Thanks for any help!

they are full of it.

sorry.

if you bought it from the dealer you should just take it back and say fix it or take it back.

my 84 300sd was a turd slow too. the dealer tried to tell me it was working just fine. so i took the service manager out on the road. running sixty i floored it. it kicked down and just didnt accelerate, hardly at all. i said "see?" he said oh yeah. the turds hadnt even driven the car. they just took off the u tube and looked to see if the turbo was spinning.

it turned out to be a cracked line to the banjo fitting at the back of the valve cover.

it got great mileage that way though. 29 on the highway, best i ever got.

tom w

Have you checked the see if your dumpnig boost
 

EGR - Vacuum Transducer Leak Test

Date: August 1999

Order No.: P-SI-MBUSA-14.20/13

Supersedes:

Group: 14

SUBJECT:
ALL DIESEL MODELS
EGR VACUUM TRANSDUCER LEAK TEST

Following are procedures for an EGR vacuum transducer in-car characteristic curve test, internal leak test, and external leak test.

In-car characteristic curve test

The Mercedes-Benz Special Tool vacuum gauge (see below) is used to monitor the vacuum signal of the EGR vacuum transducer while operational in the vehicle. The leak test is performed at 25%, 50%, and 75% duty cycle (DC) using the Hand-Held Tester (HHT). Duty cycle is activated by way of the HHT 'activation' menu (the second screen of # 3 "EGR valve").

1. Check the vacuum pump for proper output. See appropriate diagnostic material for specifications.

2. Make sure the vacuum gauge needle reads "0".

3. Connect the vacuum gauge hose to the EGR vacuum transducer OUT cover port.

4. With the engine idling, activate the duty cycle using the HHT and observe the vacuum gauge readings.

5. The vacuum gauge should read steady, with no oscillation, within the below applicable tolerance ranges.

6. The vacuum reading should drop to its nominal value again once disconnecting the HHT.

7. If the vacuum reading is not within its applicable tolerance range, replace the vacuum transducer.


Tolerance Ranges

Note : The HHT can only access the duty cycle of the EGR vacuum transducer. To test the pressure flap/waste gate transducer, the electrical plug must be disconnected from the vacuum transducer and connected to the pressure flap/waste gate transducer. Make sure the electrical plug is connected back to its original position upon completion and all DTC's are erased after the test.

Internal leak test

1. Connect the vacuum gauge hose to the EGR vacuum transducer ATM cover port.

2. Leave the VAC and OUT cover ports open.

3. Pump up the vacuum until the gauge reads approximately 450 mbar (13").

4. If the vacuum gauge reading drops from 450 mbar to 400 mbar in less than 2 seconds, replace the EGR vacuum transducer.


External leak test

1. Cap-off the OUT and ATM cover ports.

2. Connect the vacuum gauge hose to the VAC cover port.

3. Pump up the vacuum until the gauge reads approximately 600 mbar (18").

4. If the vacuum gauge reading drops from 600 mbar to 500 mbar in less than 15 seconds, replace the EGR vacuum transducer.


In Case of Warranty

Operation: Replace EGR vacuum transducer

Damage Code Operation Number Time (hrs.) Model Indicator(s)

14398 04 14 8012 0.4 *

* see Microfiche for applicable model

Parts Information

Part Name Part Number

EGR vacuum transducer A 000 545 03 27
EGR vacuum transducer A 000 545 04 27

Well, had it at the dealer all day today and they tested the transducers as well as running the codes again that was suggested by PMARI (thank you, sir). Heres what they found. Car coded "15", (boost failure, vacuum transducer Y31/5). They tested it and said it passed the vacuum test. Other possibilities are the EDS controller or wiring problem. They said they checked the wiring and it was OK. So that leaves the controller, but they are not sure and its way $$$. All day there and the best they can come up with is "we're not sure"! This means, I think, that I should just start throwing parts on it and see what happens. I really can't believe that a dealer can't do a better job of diagnosing a problem that is not intermittent.

i would let them throw parts at it on their nickel.

tom w

How close is the next closest Mercedes dealer to you? Might be worth a drive as it sounds like yours is not willing to stand behind their company's products. My local dealership here in the Dallas area, though not perfect, would never stoop to such a level. If I could not get satisfaction from the dealer and there were no other dealers nearby, I would contact Mercedes Benz directly and complain. Good luck,

If you deside to investigate this problem some more on your own, this is how and what I did on mine. Remember, I have a 91 2.5, not a 93. I don't know what the differences are so if I say something that doesn't make sense, the blame it on the differences in the cars and not on my OLD and FEBLE brain.
First, you will need a vacuum guage and a boost guage.
With engine running, check the vacuum on the system at the vacuum transducer for the turbo. This will be the line suppling the vacuum to the transducer. I would think it will be 20 in or more. If not, find the vacuum leak, or repair the vacuum pump. If vacuum is good, connect this vacuum supply directly to the turbo waste gate. You possible will need some vacuum connectors, tee's, and hose. With the vacuum hooked to the turbo waste gate, go for a test drive, being very carefull not to overboost to much or for very long. If boost is good, you have proven the boost can work. If not good, look for bad or stuck wastgate actuator, partially pluged exhaust, or bad turbo. On mine, I found the vacuum transducer defective. Actually, all three of mine were leaking vacuum. (car has over 300K miles on it.)
I've got to go to work now so If you deside to investigate this problem and find something, maybe I can go into what I did to make mine work.

Thanks for the tip! I will try that this weekend.

Y/31-5 Or Y27/4, Y27/5