HELP! M104 missing on acceleration
10-23-2005, 12:56 AM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
HELP! M104 missing on acceleration
Hi .. I have a '93 with an M104. Its been running great until this week. Here are the symptoms:
Idles great.. smooth as silk in gear or neutral.
Up to quarter throttle it is good but if I go past that it starts to backfire and miss and runs really rough. I've read here about the bad engine harness but seems to have to do with throttle position or RPM. Any help would be greatly appreciated!!!
THanks,
Carl
Idles great.. smooth as silk in gear or neutral.
Up to quarter throttle it is good but if I go past that it starts to backfire and miss and runs really rough. I've read here about the bad engine harness but seems to have to do with throttle position or RPM. Any help would be greatly appreciated!!!
THanks,
Carl
10-23-2005, 02:34 AM
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1992 300e
A bad coil or ignition module can cut out at rpm, causing misfire & backfires. Most of the time this will happen under a Load, not just revving it up in neutral.
HTH,
Ron
HTH,
Ron
10-23-2005, 12:33 PM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
Help
Thanks for the replies.. no there are no trouble codes.. LED just flashes once.. I thought about the coils too but seems to really have something to do with throttle position.even in neutral in the driveway .. if I push the throttle past the 1/4 mark it will act up .. . read a little about the TBA but seems most have problems with the cruise control ... are there any other signs of the TBA going bad?.. could it be the the engine harness?.. is there a way to test the coils other than replacing them?.. sorry so many questions.. this is my first Mercedes .. My wife loves this car.. I did until this week.. starting to get frustrated!!..
10-23-2005, 01:22 PM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
Coils
Is there a way to OHM out the coils or some other sort of test for them?.. starting to explore that Doughboy.. thanks...
10-23-2005, 04:44 PM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
Harness
Look familiar to anyone?.. Looks like my harness is shot.. would that be the culprit?
Last edited by upsidedown_04; 10-23-2005 at 04:50 PM.
10-24-2005, 12:20 PM
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1992 300CE AMG Hammer Replica, 2004 C240, 2015 ML350
that doesn't look good...
If the harness has not been replaced and your car is a 93 - 95 model, then definately do it.
Install is not difficult... there is a DIY article on Mercedesshop in the DIY section on doing it.
Is that part of the main harness or just a small section?
If the harness has not been replaced and your car is a 93 - 95 model, then definately do it.
Install is not difficult... there is a DIY article on Mercedesshop in the DIY section on doing it.
Is that part of the main harness or just a small section?
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10-24-2005, 03:18 PM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
I believe its part of the main harness.. its the wires that go to the coils under the removable sevice plate on the valve cover. Yea from what Ive been reading that its a common thing for my year.. yeesh and dang expensive!!.. is there any where thats cheeper than another?.. any advice on where to get this bugger??
10-28-2005, 02:43 PM
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300TE
Advise & codes reading?
check also the fuel pressure at high rpm (around 3000)
if its appear only at high R.P.M in N position also it can be a blocked CAT
How can i read the codes from the 8 pin connector? i built a led with a resistor, but i don't know the steps to read that codes on pin nr.3
if its appear only at high R.P.M in N position also it can be a blocked CAT
How can i read the codes from the 8 pin connector? i built a led with a resistor, but i don't know the steps to read that codes on pin nr.3
10-29-2005, 05:21 AM
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W124
Change that harness ASAP. It's not uncommon for a bad harness to blow the coils or ECU (big$$$). It's mid nineties Mercedes cost cutting at it's finest. (Although Mercedes will claim it's biodegradable and designed like that!). Do a search for wiring harness and you'll have plenty of bedtime reading)
10-29-2005, 10:11 AM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
Thanks Capt'n.. Im going to order one this week... any idea where's the best place to get one? my part number is 124 440 8308
10-29-2005, 01:40 PM
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W124
Can't help you with where to buy one (I'm in the UK) but here is the article referred to earlier on how to do it
http://www.mercedesshop.com/Wikka/M104WireHarness
http://www.mercedesshop.com/Wikka/M104WireHarness
10-30-2005, 10:16 AM
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'93 300E 3.2, 55 Buick Super, 68 Dodge Dart, 65 BSA A65
Sorry.. didnt check your profile before.. hey can I order a 1/4lb Honolulu Burger sent to California?.. My wife wants to visit England next year.. art, history,culture,Big Ben.. blah blah blah.. but now a good burger! .. I could go for one of those!
Thanks for the link .. Im wondering now if the main harness is so bad, I wonder if the throtle actuator is also just as bad... should plan on that one too..
Thanks for the link .. Im wondering now if the main harness is so bad, I wonder if the throtle actuator is also just as bad... should plan on that one too..
