'88 260E Stalls and Sputters - PeachParts Mercedes-Benz Forum

johnson · #1 09-12-2006, 12:13 PM

I have an ’88 260E with 92k miles

I've read the SSS thread and others. changed the Idle Control Valve, Fuel Filter(which was fairly dirty).

I just noticed that the stalling and sputtering seems to be related to the A/C compressor. I'll start up with the A/C on and the car will barely run, pull over turn the key off and restart (the A/C compressor doesn't restart) and the car runs flawlessly. The A/C compressor won’t engage until the car ignition is turned off and back on. The Car will then run badly again until the ignition is turned off and back on.

PS the A/C works when engaged.

johnson · #2 09-14-2006, 10:29 PM

I guess I don't know the secret handshake, I've posted several threads over 6-8 months asking for help and have gotten 1 response. I've searched and read lots of post and I cannot find a correlation between the A/C and the problem I'm having.

I'll just continue to lurk and with any luck some anointed one will ask the right question.

Mike Murrell · #3 09-14-2006, 10:54 PM

Having digested 1000's of posts here over the years, I've learned the following:

MBs from your era are equipped with what's known as the M103 motor. Many had a small elect. resistor that provided an additional 50-75 rpm(approx) with a/c on. Also, there was a speed sensor on the back of the a/c compressors fitted to cars of this era that when faulty required the ignition cycling you're employing. Make sure your serpentine belt is snug as well - just a side item.

I do not recall the name of the idle boost resistor(my words) but perhaps with this you'll be better equipped to do more useful searching.

Johnhef · #4 09-14-2006, 10:56 PM

If you don't use the a/c, how does it run then? still stall?

I had a 89 300SE beat my ass for a week before finally fixing its stalling out and crank and no start problem. probabaly a different issue than yours but I'l try to offer any insight.

Whats your lambda currently set at?

johnson · #5 09-14-2006, 11:28 PM

Thanks guys,

The car runs perfect with the A/C off. When the car runs badly with the A/C on I can pull over turn off the ignition and restart the car the A/C does not engage and the car runs perfect again. I can let it sit for a minute and restart with the A/C on it will run fine.

I replaced the Idle Control valve and the hoses for it. Looked at the fuses on the OVP Relay.

I have a '90 300e that is running perfect, it uses the same OVP Relay as the 260E does, tomorrow I plan to take the OVP out of the 300 and install it in the 260 and see if that's the clupret.

johnson · #6 09-14-2006, 11:30 PM

I have not learned how or tested "Lambda". I'll educate myself on that.

mctwin2kman · #7 09-15-2006, 08:36 AM

Check for vacuum leaks, give the AFM a thourough cleaning with Carb Cleaner, and check your plugs, wires, cap and rotor. I would even venture to guess that some healthy doses of fuel injector cleaner would also help. See it seems your idle is just not raising high enough to smooth out the engine when AC is engaged. Could be a weaker spark, clogging up injectors or just plain dirty AFM and intake. So check some things and hopefully you will get it worked out.

johnson · #8 09-15-2006, 09:56 AM

Let me clarify something. It's not just at idle the car acts like it's starved for fuel going down the road, wont get over 25 or 30 mph when floored. Stop, restart and it runs fine until I stop and restart with the A/C on then the problem reapears. With the A/C off and the car warm it runs like a scalded dog.

I've done the "in the dark" test for plug wires etc... nothing there. Not done a through test for vacume leaks, sprayed either on every vacume point but no engine change.

I've got some time today to work on it so I will try the sugestions. I'm off to Sears to get a #82139 meter as none of the 7 or 8 I own have a duty(%) circuit on them.

Thanks for the feedback, I'll report my findings.

johnson · #9 09-15-2006, 04:48 PM

OK, Went and got the correct Sears Meter. Put it on the 300e and read 81.35 with just the key on and 81.35 running.

Put it on the 260 and it read 0.0 key on 0.0 running.
there is voltage to the test pins 2 and 3 running 6.8 to 7.2. Voltage will go up to 11.6 when the Air Flow Flap is pushed open.

Mike Murrell · #10 09-15-2006, 06:55 PM

Three sources that may help you diagnose your situation:

http://www.landiss.com/mixture.htm

http://mb.braingears.com

Go to a section off the Home Page of this forum called "Diy Articles" - all sorts of "how to" stuff there and you may have seen already. Look for "Evaluating Electronics Engine Control". Click on it. Good stuff.

Last but not least, go to amazon.com or any book seller and purchase " Bosch Fuel Injection and Engine Management" - ISBN 0837603005 - great "theory" book.

psfred · #11 09-16-2006, 04:33 PM

Bad AC compressor or clogged expansion valve.

Check for difficulty in rotation of the AC compressor with the engine off. Should be fairly easy to rotate it using the clutch plate on the front. If very stiff or rough, it's shot and absorbing mucho horsepower.

If the belt slips, the AC relay will drop the AC compressor off line until you restart.

Peter

johnson · #12 10-07-2006, 11:16 PM

I appreciate everyone’s responses. I’ve had other more pressing problems, but finally got around to tearing the old girl apart. Turns out there was a hole about 1/4in in diameter on the underside of the hose that leads from the Idle Control Valve, to the base of the air flow manifold. $9 for both hoses , $5 shipping and 40hrs later she is fixed.

I thank everyone that gave suggestions. I bought more parts then I needed but I also have a ’90 300e that may need something down the road.

Thanks again,
Johnson