9 psi max boost - Page 4 - PeachParts Mercedes-Benz Forum

47dodge · #46 04-26-2011, 06:38 PM

If it does not hold pressure the diaphram may have a small leak. Not moving to start with sounds like it could well be most of your problem. Test drive and see how it is without it. It will hold back fuel being stuck, so you should see a noticable differance without it.

funola · #47 04-26-2011, 08:54 PM

With ALDA removed, I took it for a short drive and for the first time I was able to get smoke with the peddle to the metal from a standing start. Not black dense smoke but a gray haze. But the boost is still maxed at 9 psi. Is there a way to check if the wastegate is leaking w/o removing the cover or removing the turbo?

babymog · #48 04-26-2011, 10:09 PM

It's nearly 30 years old, the wastegate spring is probably weak and needs adjustment.

funola · #49 04-26-2011, 10:33 PM

Quote:

Originally Posted by babymog

It's nearly 30 years old, the wastegate spring is probably weak and needs adjustment.

Shouldn't he manual boost controller I have installed prevent the wastgate from opening? I would love to adjust the wastgate but I have been unsuccessful in getting the wastgate cover off. I will remove the MBC next and see if boost goes past 9 psi. With the ALDA removed and more fuel, boost should go up.

babymog · #50 04-27-2011, 09:40 AM

I missed the MBC part.

If the wastegate is not opening and you are only getting 9psi boost it could be air intake/exhaust or fuel or even rack travel. Do you get smoke?

funola · #51 04-27-2011, 10:48 AM

Quote:

Originally Posted by babymog

I missed the MBC part.

If the wastegate is not opening and you are only getting 9psi boost it could be air intake/exhaust or fuel or even rack travel. Do you get smoke?

You missed the smoke part also.

See post #47

Air filter is new

I should also check to make sure the over boost protection valve is not venting prematurely.

funola · #52 04-27-2011, 10:51 AM

I searched but did not find a post with pics on disassembling the ALDA capsule. If you know of such a post, please post a link. I want to open up the ALDA and see if it can be cleaned up and sealed. Are they rebuildable. There's 4 phillips head screws holding it together.

babymog · #53 04-27-2011, 11:40 AM

I don't think that you can buy the aneroid capsule for the ALDA, probably look for a used one.

The overboost is connected to the ALDA, you've disabled it.

If you can't get over 9psi without the ALDA, it is not ALDA related nor overboost protection.

Sorry to miss some of the earlier details. Does the boost get right to 9psi around 2500-3000rpm and just hang there or does it just lazily make it up in the vicinity at higher RPMs? If it seems to make all of its power and then peter out, with no smoke (other than the early off-boost smoke) with the ALDA removed I'd think that there is a fuel supply issue; plugged filter, tank vent plugged, plugged intake strainer, etc. Have you tried feeding it directly from a container of diesel fuel under the hood?

47dodge · #54 04-27-2011, 12:14 PM

ok getting closer. Seems like you should be getting enough fuel as you now have smoke. I would still want to know fuel pressure, just because. Wastegate spring is looking much more likely. I do not know of any easy way to check it.

Not sure if parts for the Alda are available, I have a spare(that works) if you do not find one.

funola · #55 04-27-2011, 12:38 PM

Right Jeff, cannot be the over boost solenoid.

I should be looking at a system diagram before spouting off.

Fuel pressure was set and adjusted to 20 psi a few months ago with my adjustable fuel pressure relief valve. The fuel pressure gauge is currently disconnected but I can hook it back up and check. I'll check out your other ideas also.

47Dodge, I have a spare IP, if the ALDA in it is also no good, I may need your's.

funola · #56 04-28-2011, 07:33 PM

Haven't done anymore to the car other than drive it. It feels peppier with ALDA removed. I pulled the ALDA from a spare IP and pressure tested it. It retracts with pressure and will hold pressure. The plunger on the bad ALDA sticks out more at rest and is probably the reason why I was not getting more fuel with the screw fully ccw. I will be putting the good ALDA in before any more testing.

funola · #57 04-30-2011, 06:41 PM

I got tired of having the boost gauge temporaily installed (hanging on rubber bands) and did something about it. I put it in the cluster between the speedo and tach. Seems like an ideal spot.

I checked the over boost relief valve and it leaks when pressure tested (no power to solenoid). I connected power to it, it drew 1/2 amp but I did not hear it click. So I bypassed the solenoid and still can't get it higher than 9 psi boost.

How easy (or hard) is it to reach 12 psi? The FSM says 12 psi at full load at 4000 rpm in first gear. I was in testing it while going up a hill in 4th and flooring the pedal. Is it possible 9 psi is normal for the way I was testing it? My transmission cannot be put into 1st.

47dodge · #58 04-30-2011, 09:04 PM

Once I adjusted mine it will hit 12psi floored, at anything above about 2500 rpms. It is not a slow climb. I feel your reluctance to really get into the spring especaily knowing that the snap ring is a pain, but think you really have exhausted all other reasonable avenues. Sorry no magic wand....

By the way I never did do anything to the IP on the 300. Now the 240 is a differant matter, full on tuning plus manifold change.

josha37 · #59 04-30-2011, 11:17 PM

for the love of god, just adjust the wastegate >.<

funola · #60 05-01-2011, 09:05 AM

Quote:

Originally Posted by josha37

for the love of god, just adjust the wastegate >.<

I tried and failed miserably trying to get the spring off. Couldn't even get purchase on it to get it started. Even if I got it off, getting it back on is even harder. Have you adjusted a Garrette in situ in a 617.952? Please post tips and tricks on how you did it, tools used etc. Pics very helpful