W124 300TD power loss

[immoral]

Hi, my W124 300TD '92 suddenly lost it's power. In the morning everything was OK but after few hours it all started. I got back to the car, started engine, foot on the gas pedal and the car is barely moving When the engine reached it's working temperature i noticed that it got little more power, but not even close to how it should be
So after few days one person told me that i need to change ALDA unit. According to him this part "controls fuel pressure".

Can you tell me your opinion if changing alda would fix the problem, or i need to check something else to get my W124 running as it should be...

[bobodaclown]

Check your fuel filters first. When was the last time they were changed? How does the clear one look? Black with specks? Can you post a picture of the filter? Also what about the air filter.
Before you mess with the ALDA the engine should run fine. The ALDA only adds fuel under boost conditions.

[immoral]

both fuel filters were changed and air filter was cleaned next day after the problem appeared, it made no change.

[vstech]

Originally Posted by bobodaclown

Check your fuel filters first. When was the last time they were changed? How does the clear one look? Black with specks? Can you post a picture of the filter? Also what about the air filter.
Before you mess with the ALDA the engine should run fine. The ALDA only adds fuel under boost conditions.

this is incorrect~!

the alda REDUCES fuel under pre boost conditions, so it could easily account for the lack of power.

another issue with this car is the catalytic converter. they soot up, and REALLY reduce the engine power. you can test this by removing the small brass plug in the #1 exhaust port!

Fuel filters would be my first choice for the problem, then cat, then alda.
simple test of the alda would be take it off. see if the car instantly has TONS of power. if so, put it back on, and adjust the alda screw out 1 turn and try again.
if the 1 screw out makes no difference, then likely the alda aneroid has burst, and needs replacement, (or just leave it off, and adjust fueling with your foot)

[bobodaclown]

Check the bolt that connects the canister fuel filter. You may be getting air into the fuel system. I don't remember if its an o-ring or crush washer on that connector. How's the engine run at idle? Does the exhaust have excessive smoke?

Could you be more specific on "lost of power". Does the engine not rev up? Or does it rev up but with no power?

The tank strainer may be clogged. I believe you can swap the intake and return lines to check. Also how full is the tank? When was the last time it was filled?
(Just trying to cover the bases)

[immoral]

Originally Posted by bobodaclown

Check the bolt that connects the canister fuel filter. You may be getting air into the fuel system. I don't remember if its an o-ring or crush washer on that connector. How's the engine run at idle? Does the exhaust have excessive smoke?

Could you be more specific on "lost of power". Does the engine not rev up? Or does it rev up but with no power?

The tank strainer may be clogged. I believe you can swap the intake and return lines to check. Also how full is the tank? When was the last time it was filled?
(Just trying to cover the bases)

At idle engine runs perfect, no background noise and no smoke (only on high revs).
With cold engine car just doesn't rev up, i must push gas pedal to the end just to start moving.
I have a bad habit to drive with ~20 liters of fuel in tank, sometimes it happens that i go to the gas station only when warning light lights up

[1stbenznc]

Originally Posted by immoral

At idle engine runs perfect, no background noise and no smoke (only on high revs).
With cold engine car just doesn't rev up, i must push gas pedal to the end just to start moving.
I have a bad habit to drive with ~20 liters of fuel in tank, sometimes it happens that i go to the gas station only when warning light lights up

If it doesn't even rev up I don't think it's a turbo thing.

Like John said, remove the alda and see if it make a huge difference, and unplug the bolt on the exhaust manifold to release some pressure if you do indeed have a clogged CAT (first "muffler" down). One at a time....

You can try running your fuel lines from a can of clean diesel in the engine compartment to eliminate the fuel tank and strainer as the issue.

May want to do a "diesel purge" while you are at it to clean up the injection pump and injectors.

Is this a sedan or euro wagon (TD)?

[bobodaclown]

http://www.peachparts.com/shopforum/showthread.php?t=203907&highlight=alda+function
http://www.peachparts.com/shopforum/showthread.php?t=296234&highlight=ALDA

Those more knowlegable than me will chime in.

[babymog]

I believe that the '92 has the dreaded vacuum-actuated wastegate which relies on a couple of signals/parameters in the ECU to allow boost.

[jltcasper3]

When your driving it and it has no power, Is it running smooth and not miss fireing?? If u have a miss u probably have a fuel supply issue. If it is running smooth but no power, u most likley are having a boosting issue. U can hook a guage up to intake manifold to see if thats ur problem, and then we can go from there.


Search for gsxr's wastegate conversion.

[vstech]

oof, I missed the 92 part... likely the "TD" he's talking about is not a wagon...

[vstech]

Saw you deleted this figured it was a mistake

[biopete]

What does your alda look like? Is it the new style that looks like a tin can with little nipple coming out of it ? Or old style that is tougher and you can't open it with a screwdriver? If new, i've had two of those clog up and make car have no power.
You can chisel it off with a screw driver and hammer like you are opening a tin can around the bottom circumference. Worst case, it does'nt cause you trouble later. Best case, problem solved in 5 minutes. You can always put better old style alda back on. I have one from a 90 2.5T that works good if interested.

[jltcasper3]

just remove alda and cap of ports, thats what i did. Also maybe check lift pump pressure and yes run it off a can of diesel to eliminate bad duel or plugged suction line/screen.

[jfikentscher]

Make sure the vacuum line that goes to the manifold is not blocked. Run a wire in the hole to clear it. Also the vacuum valve on the firewall can get plugged. Bypass the firewall valve and go direct to the manifold. If this works replace the valve.