Quote:
Originally Posted by noquarter1
Thanks for the help. Please excuse my ignorance, I'm clearly new to this, despite having tried to do my research, which is why I confused the intake manifold to ALDA as being a vacuum, when it is pressure line.
I attached a pic that I drew on to show what I did. I ran a line (red in the pic) from the intake manifold nipple directly to the 'Y' connector which is also connected to the ALDA and goes on to something else (transmission related, I think). In that line from the intake manifold nipple to the 'Y' connector, I inserted a 'T' connector, with that line running to the Harbor Freight pressure gauge (represented in green). I then ran it inside the car, and, once warmed up, floored it to see how much pressure I'm getting (measured clockwise on the gauge).
At idle, it registered flatly at 0. The needle didn't move.
I then did a 0-60 run with the accelerator firmly against the floor. The highest psi it registered was 3.
So, this would suggest there's no boost at all, is that correct? I wasn't able to get to the turbo tonight to see if it spins or if the wastegate opens. Could a clogged cat converter also be a culprit?
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The turbo produces no boost at idle. It requires waste heat in the exhaust to function (meaning the engine is doing work). You should have no boost at idle and very little boost when cruising steady-state (maybe 3-5PSI). Foot to the floor should get you up 12-14PSI if everything is working.
The "mystery" hose on your ALDA goes to the blue "UFO" vacuum amplifier on the fender. For testing purposes, make sure your manifold line connects ONLY to the ALDA. If the line to the blue UFO is broken, or if the blue UFO itself is leaking internally, guess what.....your boost to the ALDA isn't pumping up the ALDA.
Speaking of the ALDA, they have rubber seals in them that fail over time. The result is that boost comes on late. Once you find and fix the issues with your car, consider opening it up and replacing them. There's a thread on this forum somewhere that gives sizing (do a search for ALDA reseal). It makes a HUGE difference in how the car drives. Leaky ALDAs will make the boost come on late and very suddenly.
Quote:
Originally Posted by Maxbumpo
This diagram appears to be for the vacuum-operated waste gate? I think it is wrong for the OP's car.
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Wrong. The '87 diagram shows the ARV (which is vacuum operated). Many if not most '87 124 cars had the ARV on the turbo. A vacuum operated wastegate would show a second vacuum connection to the turbo.
Quote:
Originally Posted by R.Diesel
This came up as a 1987 300D diagram. If you know which diagram is applicable to OP's car perhaps you could post it. Checking the ALDA is important in my opinion since insufficient fueling will cause insufficient boost in a Bootstrap like process. Besides, its a 5 minute check.
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You posted the correct diagram. Checking/Fixing the ALDA sense line is absolutely the first step in all of this. If the ALDA doesn't enrich fuel, the boost doesn't build. If the boost doesn't build, the ALDA can't enrich the fuel. The two functions are intrinsically related to each other.