ignition control ?
Thread Starter
Newbie
Joined: Dec 2006
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ignition control ?
Greetings to all,
I have got 1990 W124, 2.6l. When I push the accelerator and engine gets over 6000 RPM it loses the power. It looks like some thing switches the ignition off. When I release the pedal of the accelerator, the engine continuing to run.
Why do you thing it is like that?
Thanks,
I have got 1990 W124, 2.6l. When I push the accelerator and engine gets over 6000 RPM it loses the power. It looks like some thing switches the ignition off. When I release the pedal of the accelerator, the engine continuing to run.
Why do you thing it is like that?
Thanks,
Senior Member
Joined: Apr 2007
Posts: 351
Likes: 90
Because it's supposed to be. It keeps people like yourself from destroying the engine by over-revving. It is your fuel pump cut-off built into your fuel pump relay. Allow the transmission to shift before this happens.
Thread Starter
Newbie
Joined: Dec 2006
Posts: 13
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it does that at 4200 not at 6000 RPM
I was going to make a correction. Actually it does that by 4200 RPM. Recently I have placed second fuel pump. My car used to run with one fuel pump (a big one). And it often used to slow down and even stop when I wanted to harshly accelerate it like there is no gas. After restarting it was running as usual. I checked with MB and they told me that this car should be equipped with two small fuel pumps. So I added second pump- a small one, hoping that this will solve the problem. Now I am experiencing above mentioned problem.
Thanks for your input.
Thanks for your input.
Senior Member
Joined: Apr 2007
Posts: 351
Likes: 90
If it always cuts off at 4200 RPM everytime, I would suspect something is stepping in and limiting the RPM's. If it were a component that was failing or unable to keep up, like a weak fuel pump, I would think the cut-off point would be more random and softer. I know different engine size relays would work in each other. The problem was the limiter would step in at the wrong time because the relay was reading a different RPM than the engine was truly turning. I would think a 4 cyl. relay would cause this symptom on a 6 cyl. car.
Look at your relay and confirm it has "6 zyl" or something like that. I can't remember the correct stamping. It will also have the RPM limit marked as well.
I hope this didn't sound too confusing. It's the first place I would start. Good luck.
Look at your relay and confirm it has "6 zyl" or something like that. I can't remember the correct stamping. It will also have the RPM limit marked as well.
I hope this didn't sound too confusing. It's the first place I would start. Good luck.
MBWorld Fanatic!
Joined: Dec 2006
Posts: 1,042
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From: Bellevue, NE
1995 E320 SE, 162,000 Miles (Sold) 2007 CLK350 Cabriolet 2014 ML550
A long shot, but I wonder if something activates the second pump at 4200 RPM and it can't handle the current draw of the big and small pumps running together so it cuts power to both. Unplug the connector to the small pump and see what happens.
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Member
Joined: May 2005
Posts: 151
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From: Atlanta, Ga
'16 E350 ‘07 S550 ‘21 GLE580
I don't know if this is true for the m103 but the m104 in '93-'95 will cut out at 4200 rpm if the gear selector is in park or neutral. Does anyone know if the m103 also does this? If it does you may have a bad neutral safety switch.
Newbie
Joined: Apr 2007
Posts: 14
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From: Hong Kong
300E-24 ohne-kat
Cutting off at around 4000rpm in neutual (N) only occurs in M104.942 (2.8) and M104.992 (3.2) with HFM. The mechanical CIS-E equipped M103 and M104.980 (3.0) doesn't have this feature.
Sorry I've no solution to the problem with the 2.6.
Sorry I've no solution to the problem with the 2.6.
Senior Member
Joined: Mar 2007
Posts: 268
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1992 190E 2.6L
I've seen 2 pumps on a W124 260E, one in the tank and another insdie the left front fender well... where/how did you add another pump?
I'm curious to know, how did you just decide to add another fuel pump?
Senior Member
Joined: Mar 2007
Posts: 268
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1992 190E 2.6L
Originally Posted by vahagn
...I checked with MB and they told me that this car should be equipped with two small fuel pumps. So I added second pump- a small one, hoping that this will solve the problem. Now I am experiencing above mentioned problem.
Thanks for your input.
...I checked with MB and they told me that this car should be equipped with two small fuel pumps. So I added second pump- a small one, hoping that this will solve the problem. Now I am experiencing above mentioned problem.
Thanks for your input.
You never responded, how and where did you install the second(third) fuel pump on the car? Before the TBI, in the trunk, and maybe you're talking about a regulator?
I'm lost with this situation about your fuel pump.
