Hey there folks. Still trying to get my 91 300d 2.5 Turbo on the road. Currently have the intake off (what a PAIN in the neck!), just replaced delivery valve o-rings and crush washers, tested compression (350, 380, 390, 430, 400), removed and inspected injectors (no carbon buildup to speak of or nozzle dishing), replaced all cross-over lines and #5 injector end plug, reamed pre-chambers, and ordered 5 new glowplugs (only 2 bad but since the intake is off, I'm going to do everything possible to prevent having to do again!).

In the spirit of being thorough and avoiding the pain in the neck that is removing the intake, I decided to quickly test my ALDA with my MityVac hand activated vacuum pump. It won't even THINK about holding vacuum.

Regarding driveability, I found the 2.5 turbo (my first) to be underpowered compared to expectations. My expectations are reasonable, I'm a lifelong diesel owner. I would guess acceleration to be a shade faster than my 84 190d 2.2 and my 81 300d, but WAYYYY slower than my 97 jetta tdi. Also notable, NO smoke under any throttle conditions.

I've read forums and understand that camps are divided...some people say to throw it away, others say it's a valuable asset in some conditions.

Can someone explain to me what the alda does and how it does it (in layman's terms, I'm not real bright) and provide me options to proceed?Rebuild, replace, bypass?

Thank you all!

Best,
Brad

The reason that it won't "think" about holding vacuum is the fact that it's not a vacuum actuated device. In fact, applying vacuum to it will usually destroy it. Then, you have a device that won't "think" at all.

Do a search....tons of info on this forum.

If everything is working right, your car should be reasonably quick....0-60 in 12.8 seconds is factory spec.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
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