Comma Diesel Magic Fuel Treatment

I had started to notice a bit of apprehension and reluctance to pull off when the car was cold, it was also feeling like the engine was a little rough.

I did a bit of looking around and decided I should put some fuel treatment through the engine, I am 99% sure no one would have put any through before so it might make a nice difference.

After searching through the vast array of choices I settled on Comma Diesel Magic, its a one shot usage i.e. you put all of the contents of the bottle into one full tank of fuel (diesel). I had used a similar product in the past on my old car, but it didn't make much difference so I wasn't expecting much.

Luckily when I went and bought it I was about ready for a full tank fill up, so I emptied the bottle into the tank then went round to the pumps and filled up. This should have allowed it to mix in well with the new diesel, rather than sitting on top if I'd have filled up before putting it in.

After doing over 100 miles I can happily say that the stuff has worked er.. magic, the car feels so much smoother, there is no hesitation now when cold at all. So far this tank the fuel consumption appears to be well up on previous tanks. For every quarter tank I'd get around 110miles at best out of it, I just achieved 130miles with the first tank with this treatment in.

I cannot recommend the stuff more highly, at the bargain cost of £6.50, this stuff has made the biggest difference to my car out of any of the changes I have made. I will be putting this stuff in every third or forth tank of fuel from now on, to keep things crystal clear.

EGR Valve Bypass

This post also serves as a mini guide on how to bypass an E46 3 series 330d EGR valve, although you do so at your own risk, I will accept no responsibility for damage caused.

When I was doing the thermostat replacement I noticed that the EGR valve had started to coke up quite heavily again. Considering the time and mileage since I had cleaned it, I was quite surprised and concerned.

I did some reading around on bimmerforums.co.uk, and the general consensus is to bypass the valve altogether.  There is an extensive write up on the forum and a considerable amount who have had the valve bypass for several thousand miles without problems.

Just to show how quickly the build up forms in the EGR, here is a picture from my EGR Cleanout post I wrote in September showing the valve freshly cleaned.

Now here's two photos just 2-3 months later, around 2000 miles.

Already it is looking a lot worse.

It is quite easy to bypass the EGR valve, as I will now explain.

Remove the engine plastics until the EGR valve is revealed, then locate the small vacuum pipe on the right hand side and pull it off.

I then rummaged through a tin of assorted bolts and set screws until I found one about the right size to plug the vacuum pipe just removed. I used a bolt so that I could cut the thread off and just use the smooth shank (to avoid splitting the pipe).

Next I found something to cover up the tube on the EGR valve. For this I used a bit of silicone hose that was a real tight fit. Then plugged it with another bolt cut down.

With everything now plugged, I took the EGR valve off and gave it another clean in a bath of petrol. It's a messy job but the results were good.

Finally I just replaced the EGR valve, ensured both plugs were in tight, then cable tied the two together so that neither flapped around and could easily be located if I wanted to re-enable the EGR valve.

So far I've noticed no adverse effects, only positive ones. The car seems to rev more freely and pulls slightly better. I will update in a few months if there is any developments.