Tried to drive it to work... - PeachParts Mercedes-Benz Forum

vandor · #1 05-16-2013, 04:56 PM

...but broke down 6 miles from home :-(
I was able to coast off the highway and into a mall parking lot. I called a tow truck then I messed with it some. I got no spark, but then I realized I had the coil wire sitting on the air cleaner, which is not grounded! So it could be fuel or spark. Then 20 minutes later it started. However since I did not trust it any more I had it towed home anyways. Not sure what to check, as it starts now... I'll put more electrical diagnostic tools in the car next time...
bye,

Csaba

Tomguy · #2 05-16-2013, 07:03 PM

That stinks! Hope you get it sorted. Also hope for your sake it isn't the electrical switchgear for the ignition. It happened to me before the box outright failed, as it got hot it just konked out.

Palolo · #3 05-16-2013, 08:52 PM

You look much younger than I expected.

What's the secret?

Tony H · #4 05-16-2013, 09:20 PM

Do you have a Pertronix Ignitor ignition? It is very simple, bypasses ALL the MB ignition stuff and fits in the distributor. If you use their coil you don't even need the resistors. dosen't get much simpler and you can rule out any ingition problems.

Adv_rider · #5 05-16-2013, 10:12 PM

Quote:

Originally Posted by Tony H

Do you have a Pertronix Ignitor ignition? It is very simple, bypasses ALL the MB ignition stuff and fits in the distributor. If you use their coil you don't even need the resistors. dosen't get much simpler and you can rule out any ingition problems.

+2 ... I couldn't be happier with mine.

vandor · #6 05-16-2013, 11:04 PM

Palolo, LOL, funny guy :-) That's junior, who was having a great time :-)

I do have a Pertronix ignition, but I was just thinking that maybe I should disconnect the wire that goes to the negative side of the coil from the car's harness. That way if the something happens with the stock 'box' it won't kill the ignition. Also, do I need to bypass the resistor to get full voltage to the coil? My car seems to have two resistors, FWIW.

This evening I put the coil wire on the air cleaner housing like I did when it quit running and I got spark, so there is a good chance that it was ignition related.

I also tested the distributor advance, and it would not go past 17 degrees BTDC! So the distributor is on the bench now, I lubed the advance weights with lithium grease and worked them back and fort a lot of times, I think they are free now.
BTW, the vacuum retard only works at idle, right?

The other things that could stop a car from running are the FI relay and the fuel pump relay, I think both would be pretty hard to diagnose on the side of the road. Do those go bad? Would it be worth replacing them with modern relays?
Thanks,

Csaba

Tony H · #7 05-17-2013, 12:43 AM

The stock box should not be in the system with the Pertronix-it is a stand alone ignition system. Here is the installation instructions so you can check your installation:

http://www.pertronix.com/support/manuals/pdf/ignitor12vneg.pdf

vandor · #8 05-18-2013, 12:10 AM

Tony,

Since the stock box is no longer receiving a signal it is not really in the system. The instructions do not say to disconnect it.

I still do not know why the car died. I looked at the fuses and they all looks good including the contacts. However, I cannot find any fuel injection fuses. The fusebox in the footwell only lists a fuel pump fuse and the fuses by the firewall are all for accessories according to the owners manual.

Yesterday I took the distributor out to free up the advance weights, I will reinstall tomorrow and will start driving the car again.
bye,

Csaba
72 280SEL 4.5

alabbasi · #9 05-18-2013, 12:43 AM

OK It happened. Fiats are now more reliable then Mercedes. Next will be sub zero temperatures in Dallas for June.

vandor · #10 05-18-2013, 11:49 PM

LOL! Actually my old Fiat has not stranded me in a long time. When I was in college I used AAA a lot :-)
Of course the new one better not strand me or I'll be rather upset.

Yesterday and today I've been trying to get the distributor to advance.
Even tho I soaked/lubed the weights I can only get ~10 degrees of mechanical advance out of it. I tried to get the shaft out, but the pin retaining the gear would not budge. I've removed these from other distributors by pressing them with a torx socket in a vice, but this one would not budge. Hm, we have a 20 ton press at work...

I installed the distributor with base timing at 10` BTDC with vacuum retard hooked up, so I should get a max of 30` at higher rpm. Not ideal, but better than what it was before. I may try to get another distributor if the salvage yard is open on Sunday.
bye,

Csaba

alabbasi · #11 05-18-2013, 11:53 PM

There's a salvage yard with a W108 in it?

vandor · #12 05-19-2013, 01:50 AM

Pick-n-pull by I-30 and loop 12 has a w108, but it's a 6 cyl.
There is a yard close to my house, by I-30 and Riverside Drive that has 2 r107s and a w116 that have D-jet, that's where I would go to get a distributor. I already took the D-jet point sets out of two of them.

I think it's called AB's.

Csaba

alabbasi · #13 05-19-2013, 01:58 AM

I'm not sure if it's the distributor or just the trigger points that are different on a W116 but they're not exactly the same.

Yeah, I've been to AB, they had a bunch of 107's back when I looked. Thanks for the lead on the W108. If it's an MFI car, I could probably scrounge some parts from it.

If you run out of options, hit me up. There's a shop owner that has a couple of W108 parts cars. He may not be junk yard cheap, but he's a good guy.

vandor · #14 05-19-2013, 11:38 AM

It was an MFI car, as I took the 280SE badge :-)

Thanks, I'll let you know if I can't find one or fix this one.

Csaba