new coils

[oldsinner111]

I have a problem it seems with my 1998 m104. engine.When cold runs good.when reaches operating temp,it won't take much throttle pressure.I had bought new coils 1 year ago.Could it be one is shot.Feels like a electrical problem.

[mpolli]

When I had a bad coil it threw misfire codes. Crank sensors can fail at high temp. I don't know what code that would throw.

[oldsinner111]

I have no way to get codes pulled.Mines a 99,I wonder if a homemade code reader will work on this model m104.

[Stretch]

Seems to me the clue is the "when it reaches operating temperature" bit.

Check the resistance on the coolant sensor. My earlier M102 has a two in one sensor in the housing. You compare the resistances on the pins diagonally. Check the connections on the coolant sensor.

(It is a start if you can't get codes)

[oldsinner111]

Yes I will,good point.I also had a problem last year like this,and it was the crank sensor not fully plugged in.But I checked it.
I also replaced the wires last summer.I bought them and they were advertised as Bosch.However they were not.

[Hirnbeiss]

All cars after '96 needed OBD2, so your car should have a port.

[oldsinner111]

oh yes my port is under the hood.Just don't have money to get codes read.

[Stretch]

Don't pay for the reading of codes invest it in your own code reader. I've seen some really cheap ones but having never owned a car with electric windows let alone one with a OBD2 socket I've never tried one.

I did stumble on this kind of thing a few months back and it got me thinking

Best OBD car apps for Android: turn your phone into a black box

It is a cheap thing that connects via bloooo tooooof to an android smart phone - might be worth a gamble. (If you can afford it)

[JamesDean]

Originally Posted by oldsinner111

oh yes my port is under the hood.Just don't have money to get codes read.

Your local auto-parts store should be able to read them for free. It will at least get you the code values and what is going on

[oldsinner111]

unless they have a NAPA code reader,with round plug for port they cant read my w140.

[mpolli]

Although there is a round connector under the hood (my car also), the 16 pin OBDII connector is required to be under the dash on the drivers side and according to a quick web search in the W140 is described as being located "underneath the dash just above the driver's left foot." Might be behind a little plastic door.

[oldsinner111]

all you get from under the dash is mileage,model numbers,and such.I hooked up there before,and had to get soft wear,and round cable.

[Hirnbeiss]

When I had misfires (that felt electrical) with no codes on my M104, it turned out to be a bad MAF.

[oldsinner111]

yes I have new Maf,and I cleaned it to be safe.I'am wondering if Karlyn wires are no good.I will also look at fuel pump connections,and the coil near firewall.For some reason the other coil had green corrosion on it.

[oldsinner111]

also could be a sudder.which means not enough fuel taking off,then misses at idle at stoplights.when put into nuetral barely a miss.