DJET Issues Solved - Now the Rest of the Story - PeachParts Mercedes-Benz Forum

meltedpanda · #1 04-29-2011, 09:24 PM

Thought Id start a new thread to finish the story
As you all know I have had a rich running issue, surging , lumpy idle

I ruled out all of the temp sensors, ECU, injectors , timing ,points ( put in optic a few months back) , plugs ect, all things you chase to get to the cause.
My efforts , although improving the performance, was never , what I felt to be "just right"
I was left with trigger points and MPS. I tried to adjust both to no avail.
The search began
I was able to source NOS trigger points ( ebay) and a know good MPS.
I had to retrofit a plug to the new points ( thanks Rowdie and AL) and got the good MPS bench tested ( thanks Genbiltstein) and a few pointers from the fine folks here ( thanks Graham) and I am happy to report
SUCCESS

I was able to get a consistent 3.5 % CO at 3000 RPM , slight adjust to rich ( less than a 1/4 turn) , and 1.5% at idle. 2 clicks off center to rich on ECU
She purrs, and has a great pull off the line. No lumpy idle, really nice
So there you have it , Trigger points and MPS new and adjusted = a happy 450SL
I have to tell on myself , when I redid the wiring , I was looking at both plugs , male and female from a top view, consequently I had some back wards, my first start up was met with a very bad running engine. A few head scratches later I figured out my mistake.. lol
The only issue of the day other than that was the protective cover around the wires entering the new TP's disintegrated, I guess nearly 40 years of sitting in a bag will do it . I black taped them for now but will need to figure out something
BTW the new TP's stayed closed for approx 100 dergrees +/- 5-6
Thanks all - hope this helps someone down the road. I actually think I understand these Djet systems now
Now all I gotta do is drive !!!

Hey just noticed - 4000 posts for me lol

Graham · #2 04-29-2011, 11:07 PM

Quote:

Originally Posted by meltedpanda

Thought Id start a new thread to finish the story

SUCCESS

Congrats Ron! I know how great you feel (having gone through exactly same process).

I was told even by top notch mechanics that worn trigger points just couldn't be the cause of the run-rich problem, but ......

Time for some top-down driving!

Graham

rowdie · #3 04-30-2011, 02:57 PM

In the end do you think it was both the trigger points and the MPS? Or do you think it was just one of them?

Or do you care as long as it is working now?

meltedpanda · #4 04-30-2011, 07:56 PM

I think it was the TP, although my bench test of my MPS was OK , I think it still suspect.
I went out today , top down , with the better half , who has NO clue as to engines and cars and such , and she says - boy this thing is running good,what did you do?? lol

I got the tires to squeel off the line .....hahaha...love it
Now onto a good set of tires, the ones I have are not stable enough....

rowdie · #5 04-30-2011, 08:48 PM

Yes. Time for a set of AMG 5 spoke 16x8 with centers painted to match.

meltedpanda · #6 05-01-2011, 10:37 PM

umm, Pearl is all stock, she would feel overdressed in those

Although , Having a heck of a time finding speed rated ,good stable 14 inch tire

Graham · #7 05-02-2011, 01:19 PM

Quote:

Originally Posted by meltedpanda

umm, Pearl is all stock, she would feel overdressed in those

Although , Having a heck of a time finding speed rated ,good stable 14 inch tire

I was just looking at my tires. They only have 10k miles on them, but they are 10 years old! Hopefully still OK for my type of driving, but I should have Michelin dealer look at sidewalls for cracking. Is always garaged, so may be OK.

Checked Tirerack and only tires they come up with are:

http://www.tirerack.com/tires/TireSearchResults.jsp?tireIndex=0&autoMake=Mercedes-Benz&autoYear=1973&autoModel=450SL&autoModClar=&width=205/&ratio=70&diameter=14&sortCode=35000&skipOver=true&minSpeedRating=H&minLoadRating=S&tab=All

Price is right!

More choices if you go to "T" rating instead of "H". Probably OK if you don't exceed speed limit

meltedpanda · #8 05-02-2011, 04:18 PM

yes those look nice, I am in the same boat mine are probably 10 -12 years old as well, always garaged, no sun, but my main goal is stablity, mine feel "loose"

meltedpanda · #9 05-03-2011, 09:27 AM

what is the "original" tire size 205 70 or 215 70 ?

rowdie · #10 05-03-2011, 10:44 AM

205 70 VR 14.

Graham · #11 05-03-2011, 11:00 AM

Quote:

Originally Posted by meltedpanda

what is the "original" tire size 205 70 or 215 70 ?

Page 54 of owners manual

Tires (with tube) 205/70 VR 14 (radial)

As you can see here, this would be a V rated tire presumably aimed at Autobahn speeds.

This from Performance Products site seems to indicate that in order to use Michelins, you may have to go down to S rated tires.

http://www.performanceproducts4benz.com/mercedes-tire-michelin-harmony-205-70-r14.html

Looks like Michelin X-Radials are also S-rated. The tires on my car are X-Ones, probably no longer made. They are P205-70R14. Theoretically Euro cars shouldn't have the "P", but this is what Tirerack says:

"Euro-metric and P-metric tires in the same size (i.e. P225/60R16 & 225/60R16) are equivalent in their dimensions with just slight differences in their load capacity calculations and inflation pressure tables. So if Euro-metric and P-metric tires have the same numeric size, the same tire performance category and the same speed rating, the two are considered equivalent and interchangeable if used in axle pairs or sets of four. Simply continue to follow your vehicle manufacturer's recommended inflation pressures provided in the vehicle's owner's manual or on the vehicle tire placard (usually found on the door jamb or on the glovebox or counsel door) for either size tire."

meltedpanda · #12 05-03-2011, 12:01 PM

OK thanks, I put my manual up somewhere when I did the concours and have not "re found" it yet -

so mine has 215 on it , 205's would be have less rubber on the road?
but
I think in reading what you sent the load rating and speed rating ( side wall ?) will provide the best ride whether 205 or 215??

meltedpanda · #13 05-03-2011, 04:27 PM

leaning to Uniroyal tiger paw AWP II -- 93T rating? Anyone familiar? Just no whitewalls, did this car come with standard WW?

compu_85 · #14 05-03-2011, 06:42 PM

Putting Michelin tires on a German car is always a safe bet for a smooth, comfortable ride.

Graham · #15 05-03-2011, 08:05 PM

Quote:

Originally Posted by meltedpanda

leaning to Uniroyal tiger paw AWP II -- 93T rating? Anyone familiar? Just no whitewalls, did this car come with standard WW?

I have Uniroyal Tiger paw Touring on my E320 - 93H rating. Not same tire, but these have been fine for 10k km. Only use car for LD highway travel. Quiet and track well. Previous Dunlops were terrible. Prior to that Michelins were great but wore out early.

The Michelin X-Ones on my SL are T-rated. No longer sold.

I agree with compu_85. but unfortunately, Michelin no longer sell a 205/70R14 with a suitable rating. Both Harmony and X-Radials only have S rating as compared with V in original spec. I wouldn't go that low - T or H would be better for such a sporty car

Don't think WW were standard - most likely an option - If your car had them, there should be an option code on your data card - 64/1 or 641 or something like that. Tire make is in box 19 - Dunlop in 1972 for some cars. But Dunlop is now made by Goodyear, at least here in NA.