99 e300 td sluggish with major turbo lag
 

Hi all,

I have my 99 e300 diesel and I had chasers fuel problem for over a year. The lines in the tank were pittedand leaking at certain spots in the tank. This quieted it down a lot. However I believe this problem is fuel related. There is a fuel leak coming from the plate on the side of the IP also there are bubbles in the lines after the fuel filter. I have new genuine mb filters brand new and all new lines from the tank to the pre filter all new. And new gas tank as well. Recently the clamps that hold the muffler together right before the cat busted apart and bent the clamp. Possible too much pressure? I'm curious As to what diagnostic route I should be goin on? Anything I should check? Thanks my symptom is extreme power loss under heavy acceleration until the turbo kicks In way late and then it will go. It so sluggish it's almost dangerous when first taking off

Have you checked your vaccuum lines going to the turbo? A leaking vaccuum line can cause your turbo to engage later in the RPM band.

Vacuum lines are good. Could it be a bad turbo. I'm working on a Volvo xc90 twon turbo at work And the turbo leaks so much it smokes like hell. Mine doesn't smoke that much but how can I check/test the turbo?

Check transducer and wastegate, then for a plugged/restricted cat.

One problem that this model car has experienced is a plugged cat. This will slow the turbo by quite a bit. The only way I know to test the theory is to remove the V band clamp so there's a gap between the turbo exit and the pipe an drive it that way for a test run.

Yes it'll be kind of loud and soot up under the hood a little but if it goes like a scalded dog, there's your answer.

Also need to eliminate all the bubbles.

The clamps at the cat busted it off so it already had that gap, so to further prove that I took the cat back exhaust off including cat. Still no change. How do I check the transducer or waste gate and where are they? Thanks

Can the ip itself leak? Not the delivery valves, sov or lines but the actual pump itself? I Ask because it leaks a thin black fluid around there looks like a mixture of oil and fuel smells like it too. But I still can't figure that out. Also the line from pre filter to fuel thermostat leaks down and is empty immediately after turning the car off. So it has to be leaking down somewhere. What about a faulty ip what are this symptoms?

There are 2 transducers, one for the turbo and one for EGR. They are identical so you can swap them for testing. The turbo transducer is located near the turbo inlet and the EGR transducer is located on the left side of the car, near the shock/spring tower.

The black valve with the vacuum lines to it and the turbo? Or is that something else?

Black valve, 3 vacuum lines and an electrical connector. One line is a vent, one goes to the wastegate and the other to the vacuum source.

Ill try tomorrow and post results

Hey Evan do later manuals have a test procedure for the transducers? I've thought about using them to control vents.

FYI - The prefilter fuel line draining back to the fuel thermo is normal. Ignore it.

Ok is there anything else I can check for the source of the sluggish acceleration

If you have access to a scan gauge, you can connect it to verify the boost levels and the MAP sensor operation. Conversely, you can also "T" a standard pressure gauge into the MAP sensor feed to measure boost.

Also, when the car is idling, remove the vacuum line on the waste gate and connect a vacuum gauge to it to verify there is 100% vacuum present. As a test, you can also connect the vacuum supply line going to the transducer directly to the waste gate so you get 100% boost all the time. If you regain your performance doing this, you can take a closer look at the transducer.

Rolf,

The transducers are variable vacuum devices controlled by a PCM signal from the ECU. If you can do with a "on/off" control rather than variable one, you might do well with an EGR purge or "switchover" valve.

ok i hooked the two lines together no change. i cleaned the MAF from all the black smoke from the exhaust leak and it seemed to make a little difference but it could be all in my head. i have a snapon verus scan tool what should the MAF and boost numbers be and under what condition?

ok i smoke tested all the vaccuum lines and no leak transducers are good. maf numbers on the scantool were 400 mg/s and didnt change very much at all. what is good for this? anything else to test? still nails at idle can that be l;inked to the sluggishness?

Is it 12v or 5v max? I've considered this as a poor mans control for VNT's. The hella VNT controller is expensive.

Ok I believe i have finally come up with a diagnosis. when checking the scan tool, i noticed the mass air flow was at arounf 400mg/s and didnt really change even under full throttle, and according to mitchell, it should be 275-300mg/s idle and 1000-1200 at 30mph wide open throttle. i suspect faulty mass air flow, 300 dollar sensor will get it this week to confirm fix.

Don't be too quick to condemn the MAF. On these cars, I have always believed it is strictly for EGR flow validation but I can see it would be logical to use MAF to determine max fueling for a given air flow. I'd like to see readings taken from an identical working car for comparison. There is a simple electronic bypass for the MAF that I'm running on my car. I can't remember all the details but there's a thread about it on here somewhere.

On the scan gauge, you should be looking at a max of about 15-16 PSI (reads about 28-29 because it's absolute) or 1+ bar for boost. If you check the vacuum at the wastegate, you should see full vacuum at idle (same as whatever you read at the vacuum source)

You were right the mass air flow didn't change the sluggish very much at all. Didn't change the numbers either. I can't seem to find boost with my scan tool. But I did hook the vacuum lines together to eliminate the transducer with no change. I have a mitt vac can I use that to check vacuum on this waste gate. How so?

this might seem silly but have you checked the boot between the intercooler and turbo? when that sucker comes off you dont get boost at all and you will have a VERY sluggish car. It's happened to me... they should have a clamp on it but it's just a friction fitting. this would be the bottom right side of the car.

If you remove the vacuum line on the waste gate and hook it to the vacuum port on the mit-y-vac, it should register on the gauge how much vacuum is present.

Saturday I am removing the intake for inspection and cleaning and a search for the source of my bubbles! I'll inspect them while I'm in there. On a side note I swapped the transducers and now the car is even more sluggish, what could this mean?

I swapped transducers and the car accelerates worse. Could this be an egr transducer problem or is my thought process incorrect? How pricey are these suckers? Thanks TM