Improving Mercedes OM603 engine efficiency

[cRiPpLe_rOoStEr]

Originally Posted by squirrl22

Are you saying there are flex fuel diesels? I've never heard of one, so why would an OEM bother with nicrome wires as a factory fit?

No, I was refering to gasoline and ethanol spark-ignited flexfuel cars.

[320touring]

Originally Posted by squirrl22

Couple things you can do, that I did with my 1.6 Jetta diesel: 1. wrap a nicrome wire around each injector, attach to your battery via a relay keyed to your ignition. Ignition on, the wires almost instantly warm up to 200 F(depending on wire type, length, thickness) which then warms your incoming fuel.
2. modify your rev limiter, so that it doesn't start cutting off your fuel @3000rpm, and lets you get full fueling all the way to your rev limit before cutting off the fuel.
Both create a big improvement in driveability, and preheating the oil will save you a LOT of engine damage (coking of injectors& combustion chamber, lubricating oil turning int sludge, etc)

Interesting ideas, I will have a look and see if they would work (I know you can adjust the fuelling rack so that it doesn't lean out as much higher in the rev range)

Originally Posted by ratgreen

I hope you've changed any o rings on the fuel pipes, if your engine has them that is. I'm not familiar with om603.

Not changed anything on the fuelling side yet - no leaks so leaving well alone ( apart from possible fuel filter changes

[pete c]

Originally Posted by cRiPpLe_rOoStEr

There is no cheap when it comes to Mercedes-Benz...

As the former owner of an old 300SD, I can attest to this.

You want cheap? But an old corolla.

[320touring]

Went out to this in the morning, and she just wound over and over and over. Battery got drained and not even a cough.

Luckily, my neighbour was performing a thorough* check of his Disco 2 before heading to Skye for the weekend.

He discovered a need for 2L of oil, but only had one. I swapped him a litre for a jumpstart.

Leads connected and away it went no bother.

This suggested to me that it was struggling to pull fuel through with just the battery in the car. The filters on the car had been on it since I got it, so no doubt overdue a swap.

Anyways, with it running, it was time to head to the unit.

Once there, I had a look at the pre-filter



Definitely got my monies worth out of it!

A new one was swapped on



Then it was time to check the main filter:


Who knows how this ever ran..

Anyways, a new Main filter was sorted, and the car fired up and taken for a test drive. All well, and possibly a slightly perceptible increase in performance..

Ever since the car has been mine it has been howling inside - I think previous owners have done over 200K on veg, and I reckon they could have done another 20K on the veg that was in the interior..

The plan was simple - a £10 valet


The attack was thus:
Hoover
Upholstery cleaners plus scrubby brush for seats and doorcards
Hoover again
Wipes for all the plastic/trim
Windows cleaned.

I used no less than 9 half buckets of water (changing it when dirty) and about 40 wipes.

An example - the back of the boot prior


And after


In total this took about 5 hours. It felt like I removed about 100kg of utter crud from it.

Whilst the fan heater whirred in the interior, I turned my craftsmanship to the exterior:

One crusty arch:


Exceptional surface preparation (handheld wire brush held somewhere near the panel)



Seamless


It'll do until I can be arsed.

I left it up at the unit with doors open to finish drying out, and brought the A2 loaner home..

Thoughts on that to be put elsewhere

[iikhod]

My god that trunk was in a hideous shape

Nice job on the cleaning, though

[320touring]

Originally Posted by iikhod

My god that trunk was in a hideous shape

Nice job on the cleaning, though

Cheers, it made a huge difference to the feel of the interior. It smells like a car now.

I also have febreze to spray on the upholstery - should help again.

In other news, the filter swap seems to have made it more responsive at partial throttle, which is encouraging.

I also treated it to a new 14" rear wiper - allowing me to wipe the smoke particles that settle on the screen more effectively.

It'll be off on a big old roadtrip this week - circa 800miles. Will be interesting to see how the MPG works out

[320touring]

The first tank of the roadtrip has been finished, and the next one should be done shortly.

The first tank saw 467.6 miles completed for 65L of zero cost WVO. A new best mpg of 27.23 (32.7imp)

However, it was no without incident!

As Hot Chocolate would say

"It started with an FTP" (Failure To Proceed = failure to start)

I had to jump through Merc with the Clio. I suspect the battery is on its last legs.

Down to Tebay ( a motorway service station), no bother.

Then it threw a low coolant light as we pulled in to park.

We scranned then found something for free at Tebay : Water


You can see the 3 part cap that shouldn't be 3 parts here



A new one has been ordered from Mercedes Benz (£8.50/$11.50) and will be fitted asap.

Switching on the heater caused the light to come back on, so e added a litre of coolant, and it remained off. We think it didn't bleed properly when the thermostat was replaced.

We arrived in to Wales, and set to work on the other car..



Much as done on the Golf, but we ran short on time and had to do a late night dash back home (arriving back at 3.05am on Saturday morning)

Here's the car getting the last of the WVO we had carried before the final stint up the road.




It does do sustained highish speed cruising with aplomb, and is a most comfortable mile muncher despite nearly 320K on the clock.

[cRiPpLe_rOoStEr]

I haven't seen a convertible Golf for a while.

[squirrl22]

Diesels like heat- they tend to run best when you put in the highest temp thermostat you can find. Raising the temp on any IC engine raises the thermal efficiency- Gas or diesel. I got my best MPG on my 1986 Jetta diesel by using this coolant https://www.evanscoolant.com/ and partially blocking the radiator.

[320touring]

Originally Posted by squirrl22

Diesels like heat- they tend to run best when you put in the highest temp thermostat you can find. Raising the temp on any IC engine raises the thermal efficiency- Gas or diesel. I got my best MPG on my 1986 Jetta diesel by using this coolant https://www.evanscoolant.com/ and partially blocking the radiator.

Having replaced the stat, I'm happy with how it heats up now, and the roadtrip served to bleed the system through well.

At the moment I'll leave her be - I think the more pressing work will be getting the autobox fluid changed as I think it's a bigger issue at the moment