Lacking get up and go (87 300D 603)
 

My 87 300D runs great, shifts fine, but does not have the pep it should have. This all started on my trip to Florida for Christmas. I thought at first I had just gotten a bad tank of fuel. I replaced the filters, ran some diesel doctor through it, changed the filters again, and I am still having the same problem.

My car does not have the EGR disabled. I noticed a few months ago that the cross-over pipe was gunked up pretty bad. I cleaned most of this out but have not touched the intake manifold yet. Is it possible that the intake is clogged up so bad that I'm not getting the boost I should?

I have done some reading in the archives and have read a lot about stuck wastegates and such. Where exactly is the wastegate located on one of these cars and how do you check it for proper function?

If someone could possibly point me in the right direction, it would be appreciated.

Seems many of the 603s are becoming slow in this manner. Doen't make me wonder why I see more in the yards when I'm looking for SD bits. Some even with that evil TrapOx still attached! :eek:

I'd venture to guess bad switch over valve (my case), could be a plugged cat, plugged up line to the ALDA from the manifold.

Throttle linkage misadjusted (my case twice).

My intake manifold was FULL of junk, I posted the pics if you feel like searching for them. I pulled it off to install new GlowPlugs and was shocked. :D Also is the perfect time to tweak up the ALDA.

I would be really surprised if the cat was clogged since my entire exhaust system was replaced a year ago when the TO finally gave way and took out the turbo. The dealer replaced, for free, everything from the turbo to the tail pipe. If I tear into this, I'd like to disable the EGR at the same time. I have read numerous threads about tweaking the ALDA, and are there any negatives that can happen by doing this?

Oh okay! Good to hear it was replaced recently.

You can totally remove all that emission stuff that's there, vac lines and all. I did a long while back, even that AFM. I posted pics of that too. Heck, even my cat is gutted. :D To disable the fun EGR, simply remove the vac line. I have a kit from BC (member of the board) to eliminate the valve and tube. Looks quite nice.

I'd look at the tubes from the intake manifold to that switch over valve then to the ALDA. Mine were plugged in addition to that valve being bad.

My hands were too large to get the ALDA off with the intake manifold in place and I had to do glowplugs, so it was a no brainer while I was in there. I've had the ALDA on my SD cranked for a year now? No ill effects but more power off a dead stop. :)

I was told that there is no cat on my 87 300SDL, what's the deal?

Almost assuredly, there is a cat under there, if the trapox has been removed. Take a look underneath the vehicle, just behind the engine.

First, ever get that new oil sender in? :D

Well I don't think it's called a catalytic converter technically, it's an oxidizing catalyst or something on these diesels. 1987s had them (TrapOx, then moved to the downpipe), but I believe only CA Emission SDLs did in 1986.

I thought that was a cat. Someone said it's a resonator. I'd like to cut it out of there and just have a straight pipe, is that going to cause any problems?

I got the oil sender in but now I'm working on the timing chain and vacuum pump so I haven't filled it back up with oil to see how it works. I just keep taking things apart, who knows if it'll ever get put back together. :D

Luckily the trap ox is already gone, now I want that cat out of there!

do the 85 w123 D's have cats?

That's the cat. The resonator is further along the pipe.......just ahead of the rear axle.

If you cut it out, don't use a torch due to the potential of noxious fumes from the cat.

The only problem is with emission testing, if you have any.

Great, no emissions here.:D I'll use a hacksaw and a Popeye arm.

Get or rent yourself a Sawzall. It probably wont take more than 5 minutes with one.

I have yet to find a shop that will remove it for me. In California, it is against the law for a shop to do that - their license can be revoked if they are caught! Of course, if you are handy like a number of forum members, that's a different story:D .

if your in the south just take it to one of the red neck truck liftn and mud tire intalling places and ask them to cut out that cat so you can run a straight pipe in its place.. i bet theyd do it..bring a case of bud with you as a pre payment .. just make sure he doesnt drink the bud before cutting

I hope you all don't mind if I bring my post back to the original topic... How much power do you gain by disconnecting the EGR setup? I'll take a look at the tubes... How do you know if the switch over valve is bad? I have to say that the wife's 84 300D is much easier to work on than this jewel.

You gain no power at full rack position because the EGR is closed at that time. EGR is on in the midrange, above idle and below full power.

Bypass the switchover valve. Run the line directly from the manifold to the ALDA and see if you get any improvement in the times. Don't leave it this way permanently, however.

A boost gauge is nice to have...........to see what the turbo is actually doing.

:D I'm waiting on a fine deal for a vac pump, my T-chain is about 1.5° at the crank so maybe 0.75° chain. Great news for mine.

I did my cat and never looked back, one less potential problem.

You're in the market for vac pump? I might be able to get a good deal on one, let me know.

Yeah for an updated Pierburg, new OR used. My guy doesn't have them in stock currently so no pricing is available from him.

Shoot me a PM if you have some scoop I can use. :D