'81 240D only going 74mph...

Mar 17, 2005 28 Replies

Now, guys, I've always known this was a slow car. But for the last month, my 81 240D with about 160,000 won't go faster than 74 mph. At that speed, she seems to be pushing against a wall.



What should I check? Ive replaced the airfilter. Winterfuel has never done this to me. Should I replace the fuel filter? It's less than 15,000 miles old. Also, I have a new clutch within the last 2 weeks. Would an improperly installed clutch cause to slip at high RPMs? My mechanic says injection pump but I suspect he just wants to throw parts at the problem.



Any ideas?



Paul


No, seriously, it does sound like fuel restriction. I'd definitely start with the filter(s) there are two, and a fresh tank of gas. Do you use Redline or other quality additive?

You would notice clutch slippage during normal driving.

This is either a power problem or a drag problem.

Check that when the accelerator is floored (w/ engine off) the throttle linkage is against the full throttle stop on the injection pump (look between the IP and the block). They may have jacked up the engine during the clutch work and so disturbed motor mounts and/or the throttle linkage.

If linkage is OK, adjust the valves for that's about all that's left other than recognizing that the engine may be below full power due to wear - less than optimal compression.

Check tire pressure and that there's not a dragging brake and the front wheels' toe-in.

Thanks Randall and T.G., I'll check out the things you mentioned first. Engine wear such as would cause this lack of power wouldn't happen over the course of a month, would it?

Paul

T.G. Lambach wrote:

From my experience I second that.

Juergen

I sure wouldn't think so, unless there's been a failure internally, which I've never experienced. More likely sluggish filters, bad fuel or both. Very common.

try going down hill.

don't expect much more than 80.

mine would hit 78 with the ac on

80 kinda with it off a good radio was required!

the filters should do it

the case, minus a few cans!

What max speed are you hoping for?

Note that Juergen has a 240D of broadly similar vintage.

DAS

For direct contact replace nospam with schmetterling

Takes me a while to get there but my '81 240D with only 124k on it will (eventually) get to 85 mph but that's really faster than I like to drive it. I want to get to 300k and 2025 if possible.

000000h!

huh! I've driven the new mb diesels at almost 150mph! :-)

only 300k?? at least 600k!! Is it manual?? My dream machine, I'm looking for a 1981-1983 MANUAL 240D, you know of any locally?

cp

Where is "locally". I know downtown, and the south side but....

Anywhere you are, as long as it's in the dry western states, preferably California, will be looking to get something in May, got three cars, have to get of 'em first...

cp

Find me a 240D that will do 150mph without a jato bottle and I'll buy it.

Still hasn't said what the target speed is...

DAS

For direct contact replace nospam with schmetterling

I have an '84 240D and it has a small prefilter in the fuel line towards the rear of the main filter, that has the cleanable cartridge. The prefilter is not really cleanable and should be replaced. It's quite small and low priced.

You may also have algae in your tank. Do you use additives, like Red line? I drove a 200D in Europe for about 12 years and never had a problem with algae, until I bought a 240 in California and had to use the well watered diesel they serve here. The gas stations here seem to think that a diesel tank should contain an aquarium ;-) My tank was almost full of what looked like seaweed in its worst state. I had to get it "boiled" out.

Cheers

JJ

I meant the OP of course... I trust you realised that.

In my 1980 200D I achieved a nominal 143 km/h, higher than that which my work colleagues with the same model achieved. I put all down to very careful running in.

DAS

For direct contact replace nospam with schmetterling

I currently have a '74 240D (Automatic) that can get to 80+ (downhill, of course) MPH. The single largest improvement in the engine's behavior came from using Lubro-Molly's Diesel Purge. I highly recommend it to anyone that drives an older Diesel-engined vehicle. I also use Lubro-Molly's Diesel "Hi-Test" when unable to fuel up at my local decent-quality station.

Regards,

- Bill

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