Whats going on with my sparkplugs?

[lurtch]

Hello All - -

       I am guessing this is being caused by improper atomization at the injector nozzle on those two cylinders. The engine is healthy and powerful when up to temperature, but the startup and warmup period involves a lot of misses and snorts. This photo also seems to indicate that the WRD is leaning out just as it should.

  Anybody want to weigh in on this?   Also polling for  - - - how many of us had had partially plugged injectors in the past?

Larry in CA

[teahead]

Ya, #3 and #6 looks lean???

[Benz Dr.]

The two darker plugs seem to be too rich and the others are too lean. How long ( miles) have you been running those plugs?

[lurtch]

Hi Dan

I've got about 4K mile on them. They are NGK mid-heat range. The OEM Bosch plugs were more troublesome that these are.

Larry

[Benz Dr.]

Mid heat range doesn't tell me what you used. I used to install BP5ES which is a fairly hot non resistor plug. I can't get easy local supply any more so we are now using Auto Light 64.

4K miles and that bone white is too lean or running right on the edge of too lean. I like to see a bit more tan on the insulator.

Look on the ground electrode for the heat line. It should be right around the curve on the electrode if you have timing, heat range and mixture set right. For sure timing will show up as a moving line when adjustments are made.

[Pinder]

Just wondering what would cause this kind of variation. Is it the Injectors or is the fuel injection pump delivering different amounts of fuel?

[rwmastel]

Is fuel variation the only possibility?  What about oil getting into the cylinders with the "rich" condition? Or, maybe coolant getting into the cylinders with the "lean" condition?
I don't know, just asking.

[mdsalemi]

…I am guessing this is being caused by improper atomization at the injector nozzle…how many of us had had partially plugged injectors in the past…

Larry, at the last east coast event, hosted by Tom Sargeant in Charlottesville, Virginia, and the PUB before that in Blacklick, Jim Villers brought his injection pump tester. Since it is relatively quick and easy to remove the injection nozzles, lots of attendees with similar issues to yours and other runnability issues tested their nozzles. A good number of those with poor spray patterns were fixed by the tester.

The tester isn’t too difficult to build.

[rwmastel]

A good number of those with poor spray patterns were fixed by the tester.

How does the tester fix the injectors?

[Vander]

How does the tester fix the injectors?

It cleans them, and if there is a blockage or clog the pressure can blow it out.

[rwmastel]

So, it's just higher pressure than the FI pump normally uses.

[mdsalemi]

So, it's just higher pressure than the FI pump normally uses.

https://youtu.be/nmkiBz65Wjs

In concert with this you can clean the injectors in an ultrasonic bath…

And, BTW--once you have a confirmable "clean" and properly operating set of injectors, doesn't hurt to use Techron additive once or twice a year. I always did this prior to a long trip (usually to one of the PUBs) so that I'd burn the full tank of gas with the Techron in it all in one fell swoop. I used to buy the Techron at Costco in a 6-pak. Don't know if they still have it or not.

[yves]

Last year i used the mercedesource kit for injectors with succes . Diagnostic was obvious seeing the spray .
After around 20 pressures , the spray recovered a nice shape and a good spray noise too.
Now i should be confident with my injectors for some years ....i hope so !
BTW : the kit is available , let me know if ?

[Kevkeller]

Think we had this discussion before but even many brand new injectors have bad spray patterns from the start. I’ve run into that problem myself.
There’s more than one type of injector. Why and what’s the difference I don’t know.

[teahead]

https://www.witchhunter.com

[Lorsar]

Teahead, have you asked if they do mfi injectors because most of these companies only do newer electronic fuel injectors.  I have asked around to several companies in my area with no luck.

[dirkbalter]

Teahead, have you asked if they do mfi injectors because most of these companies only do newer electronic fuel injectors.  I have asked around to several companies in my area with no luck.

You should ask the known pump rebuilders. They usually offer to test / clean you injectors.

[Lorsar]

oh yeah, I know there are some on the supplier list.  At the time (about a year and a half ago) I was looking for something quicker. I ended up buying cleaned and tested used ones from ebay for $60 apiece at the time.

[Benz Dr.]

Think we had this discussion before but even many brand new injectors have bad spray patterns from the start. I’ve run into that problem myself.
There’s more than one type of injector. Why and what’s the difference I don’t know.

There are two types as you've noted.

R1  are used on 230SL and they have a very defined cone pattern. The preferred part if you can find good ones. It's what I have in my car.
R2 are the current edition. Different spray pattern, not bad and they will do the job.