Djetronic pressure and injectors control

[GGR]

Hi all,

I would need to know what the fuel pressure should be in psi (measured at the cold start valve) in the Djetronic system of a 3.5 M116 engine.

I would also like to have the injectors controlled. Where shouls I bring them in the Washington DC area?

Thanks in advance

[ctaylor738]

You want to see 2 bar (30-31 psi) fuel pressure.

I don't know what you mean by having the injectors "controlled."

[230/8]

Maybe he means cleaned and flow tested?? I suspect either of these shops can clean/test his injectors.

http://www.cruzinperformance.com/

http://www.witchhunter.com/index.php4

This may help with maintenance issues.

[http://members.rennlist.com/pbanders/djetfund.htm

230/8

[ctaylor738]

I long ago stopped guessing at what people were asking.

[GGR]

Sorry, English is not my native language and I'm new in the US. Yes 230/8, this is exactly what I need. Thank you very much. In the meantime I checked the pressure: it was 26 psi. I raised it to 30 psi and there is a great improvement. The car is more powerful, less noisy and idle is much more steady. I also talked to the previous owner who told me he had the injectors checked. So I may wait a bit for that. I was told that putting ATF liquid in the fuel tank (1%) for a while will help cleaning the injectors. I plan to drive to Ohio from DC next week, I will try that on that occasion.

One more question: The previous owner gave me some spare injectors: some are with a yellow ring, the others with a blue ring. Do they have the same specs? Are they interchangeable? The ones on my car are all with a yellow ring.

[Graham]

Originally Posted by GGR

One more question: The previous owner gave me some spare injectors: some are with a yellow ring, the others with a blue ring. Do they have the same specs? Are they interchangeable? The ones on my car are all with a yellow ring.

Yellow ones are for the M116 engine. Blue ones for M117. They are different. Yellow are rated at 317 cc/min and blue at 485 cc/min.

I have just set up a test rig to check spray pattern and flow rate from my own M117 injectors. Cost practically nothing to do and it works fine! I should post about it separately. I have a jewelery ultrasonic cleaner to clean the injectors and will also pass Techron through them in the test rig.

I don't know about putting ATF in fuel, but a couple of those bottles of injector cleaner won't do any harm.

[Gurunutkins]

Mercedes dealerships in the 70's always told you to run about 200ml of atf through every third or fourth tank of gas to act as a head lubricant
cheers
barri

[Graham]

Originally Posted by Gurunutkins

Mercedes dealerships in the 70's always told you to run about 200ml of atf through every third or fourth tank of gas to act as a head lubricant
cheers
barri

barri - ATF probably has some additives designed to prevent varnish and other deposits. But, it also has a lot of other stuff in it to improve it's performance as a lubricant. The base is probably just a low viscosity oil like SAE 30. Not all ATFs are the same either - some are synthetic and others have different formulations.

I don't think I would put ATF in my tank to clean injectors. The various types of injector cleaners available probably are better suited if the DIY in-tank method is used. But, for cars with O2 sensors and Catalysts, there is a danger of messing them up even with the proper cleaners, never mind ATF! Same can be true for the on-car injector cleaning services offered by garages.

Seems to me that removing injectors is best way to go, but having said that, I have often put a few bottles of STP or Wynns injector cleaner through my old SL, especially in Spring after it has been sitting.

I have some questions about injectors that you may be able to answer - see separate topic.

Cheers

[ctaylor738]

As to your other question, there is no one in the DC area that I know of that will test or otherwise mess with these injectors. They might agree to replace them, but even that's tough to find. Nobody in this area wants to mess with these cars. You can try Don Pool or JCP Motorsports.

germanstar.net sells rebuilt injectors for $50 apiece. IMO that's the best deal going. Not cheap, but you will at least have a good set of injectors when you're done. I had a set "cleaned" and "tested" by Cruisin and they came back in worse shape than when they left and it took them three weeks to do that.

[mbgingerbread]

Another product for routine fuel system cleaning goes by the name of Seafoam. It comes in a metal canister similar to the old types which I used to see which had two-cycle oil in them. Seafoam is probably like most of the fuel additives but for me it has served to improve idling, etc. in the fuel injected engines I have owned over the years..

[Graham]

Originally Posted by mbgingerbread

Another product for routine fuel system cleaning goes by the name of Seafoam. It comes in a metal canister similar to the old types which I used to see which had two-cycle oil in them. Seafoam is probably like most of the fuel additives but for me it has served to improve idling, etc. in the fuel injected engines I have owned over the years..

I see lot's of stuff on the net about Seafoam. But have never seen it sold in Canada. The MSD sheets say it is a light napthhenic oil (40-60%), Naptha 24-35% and Isopropylalcohol 10-20%. Should be a good solvent!

I am looking for something like that here in Canada to clean my injectors in (off-car).

[winecountryone]

Have you checked at places other than auto parts stores?
Here in California,I can get seafoam at my local Wal-Mart.Runs about $5.00 for a 32 oz. can.
The first time I used this on my mazda miata I had a pile of carbon soot under the exhaust pipe about 2 feet in diameter!
It really made a difference in how my car ran.
Another of my favorite injector cleaners is made by Redline oil here in northern CA.
Their SL-1 looks kinda like ATF.It's supposed to be 100% synthetic like their motor oils.

[Graham]

Originally Posted by winecountryone

Have you checked at places other than auto parts stores?
Here in California,I can get seafoam at my local Wal-Mart.Runs about $5.00 for a 32 oz. can.
The first time I used this on my mazda miata I had a pile of carbon soot under the exhaust pipe about 2 feet in diameter!
It really made a difference in how my car ran.
Another of my favorite injector cleaners is made by Redline oil here in northern CA.
Their SL-1 looks kinda like ATF.It's supposed to be 100% synthetic like their motor oils.

I just read on another forum that it is now available at NAPA. Luckily a new store opened here recently. Will have to give it a try!

[Graham]

Originally Posted by Graham

I just read on another forum that it is now available at NAPA. Luckily a new store opened here recently. Will have to give it a try!

Picked up two cans at NAPA today - C$16.74 each for a 1 pint can! Paid same for a gallon of carb cleaner.

But, I will try using it to clean up the injectors.

I took a picture of my test bench. That's a fancy name for this crude set-up (By the way, the injectors are actually better secured in the bottle cap! Masking tape still needs to be calibrated (using kitchen measuring jug!)

Crude, I know, but it does work and it is easy to measure flow and observe the jet pattern. By the way, the brake bleeder is home-made and similar to the one in this link:

http://www.bmw-m.net/TechProc/bleeder.htm

[GaryF]

Cool, I guess the bottle holds the pressure at a steady rate for long enough to get a decent run.