1987 300td OM603 No Power under load, Low Boost Pressure - PeachParts Mercedes-Benz Forum

TheGolfTech · #1 03-08-2019, 02:08 PM

I ihave an 87 300td with the OM603 with a Garrett turbo. I have been driving the car for about a year daily thinking the car was just that slow. With everything I have done it is still taking 3/4 of a mile to get to 60 and max of 45 of hills. I have replaced all filters, blocked EGR, removed catalytic converter, removed ALDA for testing. With the ALDA removed it smokes like crazy with any load at all. It smokes just cruising on the highway but not at all revving. The engine just falls on its face when it has load. Removing the ALDA did improve the take off speed but then just falls on face again. Im going to check the wastegate today to see if disabling it will give me more than 5 psi boost. ANY suggestions on where to go from here I would greatly appreciate it. Pictures?

vstech · #2 03-08-2019, 02:55 PM

Try removing the fuel cap.

vstech · #3 03-08-2019, 02:58 PM

Also, under the air filter is a speed density flap for airflow and egr functions...

Verify it is connected to working vacuum hoses, or block it open...

Also also, the intake could be soot clogged from the old egr residue. I've seen completely blocked internal passages.

Maxbumpo · #4 03-08-2019, 04:31 PM

I like the idea of choked off air flow, check all the intake path from the air filter through the manifold.

Other things: I'm wondering if the IP timing is off, or the injectors are totally worn out. So many things to consider if you don't know the history of the car.

I'd say test the compression, check the IP timing. Put a boost gauge on it and check the boost. Consider pulling the injectors and sending them to be tested.

TheGolfTech · #5 03-08-2019, 06:23 PM

I have some new information. I pulled the crossover tube off and there was some oil but pretty clean otherwise. I put a T off of the intake manifold to test boost pressure. Instead of pressure I got 5 pounds of vacuum. I decided to check at the wastegate and it was the same result. checked the speed density flap, and it is fully functional. I cannot move the wastegate rod however. Best case scenario I think would be if the wastegate is stuck open, otherwise I'm thinking maybe a seized turbo.

TheGolfTech · #6 03-09-2019, 11:59 AM

The turbo is completely seized.... So I will be needing a new one, there is a brand new one on ebay for 400 shipped which seems pretty cheap. If anyone has another source of where to get these turbos I would appreciate it.

speednjay · #7 03-09-2019, 02:01 PM

Siezed turbo? So you can’t spin the impeller? Never heard of a siezed turbo on a normally driven car. It would smoke burn oil like a motha..make a high screeching noise long before it would sieze.

TheGolfTech · #8 03-09-2019, 06:23 PM

I have never seen it either. The car has 282k on it which isn't too much for these. The impeller will not move at all. No movement in ANY direction. This is my 5th turbo vehicle. Before I removed the alda there was very minimal smoke. I know that turbo has never been operational since I've owned it. I also spoke to the shop that worked on it for the original owner and they said it was always slow as well. I have no idea how long it has been driven like this, but it drives just like a normal N/A diesel would. If I give it 10 to 15 percent throttle it will accelerate with no smoke. I have seen plenty of seized superchargers back when I was a supercharger machinist, mostly from things going through the intake and grenading them. All the fins felt perfect on this turbo. The original owner took incredible care of the car so I am stumped as to how he didn't fix it. He put 2k in suspension on about 10k ago.

Maxbumpo · #9 03-11-2019, 10:23 AM

Wow, that is a rare occurrence. The turbo chargers are very robust and generally can last the life of the car. Thanks for letting us know the cause of the issue.

Search on Car-part -dot- com for a replacement.

barry12345 · #10 03-11-2019, 02:09 PM

That situation would be fairly restrictive overall as well. Serious issues with their turbos are not all that common. So a good used one might also be considered.

That accumulated milage you have indicated for example may or may not be accurate. You never want to go on the money pit trail unless factors make it in your favor.

I try to do things right overall. At the same time there are sane at least to me equations that dictate other options at times. It seems to work attempting to use reasonable judgement.

I never ever consider the odometers accurate on these cars anyways. . Unless some real proof exists. I think two of mine may be relatively accurate but I would not bet on it.

if6was9 · #11 03-11-2019, 10:00 PM

Quote:

Originally Posted by TheGolfTech

The turbo is completely seized.... So I will be needing a new one, there is a brand new one on ebay for 400 shipped which seems pretty cheap. If anyone has another source of where to get these turbos I would appreciate it.

$400 for a bolt in new turbo is a very good price.