Blistering 24 sec. 0-60mph in a 124
 

What would the 0-60 time be on a 124 if it was getting no boost? My new 124 is quite slow. The car is very slow 0-30 but pulls a little better 30-60. It may shift a little early too. I adjusted the alda on my other 124 and it made quite a difference. But I don't think it will cut the 0-60 time in half for the new car. I have a mity vac, can I check the boost by plugging into the line from the alda to the switch on the firewall? If not there where? What should I look for first if I find no boost?

PS: kickdown switch doesn't work either.

Well, gearing makes work easier, so I'd focus on the kickdown rather than the boost, or at least as much. While it doesn't effect 0-60, its huge in driving application, i.e. 30-60

If you're getting those times on one of those 87's in your sig, then something is definitely wrong. The 603 in the '87 doesn't use a vacuum controlled wastegate like the 602 in the 90-93 300D, it has the old pressure activated one. First off, check fuel and air filters. Second, be sure that your ALDA lines are clear and the overboost valve and switch are functioning properly. To test, just temporarily run a line from the manifold fitting to the ALDA directly. If that doesn't help, check the tank strainer, mine was pretty gunked after 100k. You also might want to check out the timing chain stretch since that can hurt your performance if it's really bad. Past that, unfortunately you're going to have to dig into the turbo or IP.

To test your boost, you're going to need a boost gauge, not a mityvac. Put a Y connector between the manifold and the ALDA and run a line to the boost gauge from the Y. You should be getting 12-14psi at full boost with the ALDA functioning.

My 602-powered '90 gets about an 18-19 second 0-60 when there's no boost.

Thanks all
 

2.5 turbo- Have changed filters, but not tank screen. Will check alda stuff today. My mityvac is supposed to measure pressure also, the guage shows both. Motor seems to run good, just lacking power. Could the wastegate be stuck open?

Stuck open wastegate is a possible as well.

Well if it is none of the above works then try removing the bolt that is in the exhaust manifold at front right of engine...Maybe you have a clogged CAT??? Same thing happened to me and then I had a no start situation. Check this out
http://www.peachparts.com/shopforum/diesel-discussion/170274-1987-300sdl-no-power.html

Almost guaranteed to be one or more of the following:

1) The boost signal may not be reaching the ALDA. Check boost at the ALDA with a "T" fitting using your MityVac set to "pressure". Go for a test drive, look for 10-12psi at full throttle in 2nd or 3rd gear above 4000rpm. Bypass the overboost protection for a quick test, see if that fixes things - the valve often gets gunked up inside, or the plastic tubes can be plugged or cracked.

2) The ALDA may need further adjustment. 1.0-1.5 turns CCW may help significantly. If the car doesn't leave a stop sign quickly, you need to adjust the ALDA.

3) You could have a plugged cat, but I doubt it. I'm assuming the trap oxidizer is removed already.

4) The car may need a couple thousand miles of Italian tuneups. My recently-purchased 1993 300D was kind of a slug when I bought it, despite 14psi of boost and tweaking the ALDA. After a 1000 mile trip with lots of high-rpm, full load driving (and Mobil-1 in the crankcase) the power improved significantly, especially at part throttle and leaving a stop.

5) Have you checked the chain stretch and IP timing yet?

6) If you haven't seen this yet, it's worth reading:
http://www.w124performance.com/docs/mb/articles/124.1x3_buying_tips.txt

:scholar:

To check for a stock open wastegate, test boost at the intake manifold. You will read ZERO boost while driving the car (you can't measure boost in park, in the driveway... has to be under load.) This would be unusual on a 603 engine. The wastegate is pressure operated, and if the hose breaks you'll get overboost, not zero boost. If it's a Garrett, you can connect the MityVac to the wastegate and pressurize it. You'll see the control rod start moving around 12-14psi and it should hold pressure. When you release the pressure, the rod will come back towards the wastegate pod. If you have a KKK turbo, you can't test it with a Mity-Vac.

:kid:

Did some more fiddling
 

this afternoon. Ran a line direct from the manifold to the alda, no change. Replaced a couple suspect vacuum hoses in and around the alda, vacuum switch etc. no change. Changed the kick down switch with a known good one from my other 124, no change. The car seems to upshift very quickly and never build significant RPM's. Even with foot to the floor I don't believe it tops 2000-2500 RPM's until 35+ MPH. (tach doesn't work) Idles well and shuts off immediatly. I need to buy some vac. tubing to check the boost, I only have about a foot left. Do I just plug the mityvac into the manifold nipple that normally leads to the alda switch?

Trap ox has been removed. I don't think I could build enough RPM's to do an IT. Revs fine in park but no guts in gear.

Hmmm. Will it rev to 5000rpm in park? Floor the pedal and listen, it should scream away (don't worry, it's governed, just don't hold it up there for more than a couple of seconds.) If it won't rev up freely without load, the exhaust could be plugged. It's rare, but it has happened.

Also check the fitting at the intake manifold where the ALDA pressure signal feeds from... make sure it's clear of oily soot. This fitting often plugs up with gunk from the EGR (which is why many people disable the EGR). You should be able to blow into the little hole. Use a paper clip, wire, or thin drill bit to clean it out. Also make sure the EGR is not stuck open, dumping exhaust back into the intake (not likely.)

The quick upshifting sounds like the Bowden cable is broken or misadjusted. Also, with the engine OFF, have a friend floor the accelerator pedal from inside the car. Make sure the linkage is going all the way to the "stop" on the pump. This is hard to see, you'll need a flashlight to peek through the intake runners at the back side of the pump.

The dead tach is either the OVP relay (which would also trigger the ABS lights) or the tach sensor at the flywheel. Both are pretty common failures. I'd get that fixed pronto. Swap the OVP relay from your other car, if that doesn't fix it, the sensor is suspect. They're about $50 new, or I've got a good used one I'll sell for $20 (long story, lol.)

:kid:

Where
 

is the OVP and how hard is the sensor to replace?

I never floored it in park, however it revs freely to above 3K (by ear). Its buttoned up for tonite so I'll try the 5K rev. and removing the alda tomorrow.

I also cleaned the nipple on the manifold. How do I check for a stuck EGR? The EGR/ARV have NOT been disabled on this car. I need to look up how to do that too. I am on the list for a "test plate" for the EGR.

Smooth idle and no ABS lights.

I'll keep the sensor you have in mind (accept paypal?)

Thanks for the help.

The OVP is next to the battery with a red top, with a GM-style fuse. It's pretty easy to access.

I wouldn't get too excited about yanking the ALDA entirely... some other people recommend this but I think it's better to solve the real problem first. ;)

To check for a stuck EGR, apply vacuum to the EGR so it opens, then yank the hose off. The valve should audibly "thunk" closed. This is a really vague test but it's easier than yanking the manifold apart. A quick disable consists of disconnecting and plugging the hoses at the EGR and ARV valves.

If you confirm the sensor is bad, yep, PayPal is fine. The connector for this sensor is near the OVP. Disconnect it and measure AC voltage with the engine running. The AC voltage should increase as RPM's increase. If no voltage is present, the sensor is bad. Here's a photo:

http://img.eautopartscatalog.com/live/P401338301OES.JPG

My intent
 

with the alda was to get it off so I could adjust it. It made a big difference on my other 124.

So tomorrow:

5K RPM rev test

Bowden cable travel check

Check for boost, use nipple on manifold plumbed directly to my mityvac set for pressure. Hopefully will see 10+ lbs. boost.

Remove/adjust alda

Swap OVP relays with other car, check tach

I hope I have enough time tomorrow for all this.

Thanks for the help tonite, I'll let you get to others now:D

I'm unfamiliar with the vacuum transducers, are they the same as the vacuum pods that control the air vents? How do I test them?

He meant the switchover valve for the overboost protection. You can bypass this and route the intake manifold fitting straight to the ALDA for test purposes. It was mentioned in an earlier post, I think this was already tested.

The 1990-up models have transducers related to the wastegate and other boost-related items, but those don't apply to the 1987 setup.

:scholar: