1991 850i limp more again. Help needed!

[Bigzzz850]

Hi guys, yet again I'm coming to you guys for advice . A couple days ago went for a drive with the car and while waiting in the drive thru I noticed that the car started sputtering and back fireing a bit. As I pulled out I realized that the car is down to 6 cylinder mode . I drove it home , parked it went back to it the next day to see if it would run ok cold but there was no change the driver side of the engine isint running .
I have no CEL or EML light on and the information center dost say limp mode or anything else . Did a stomp test the only code I got is a 1234 . Now what I tried with an other members help . I switched the coils , maf,switched the computer connections, checked fuel. No change of sides. Also checked #6 wire seems to be ok . I'm at the end of my ideas any suggestion appreciated guys.

[8eights]

Check for fuel and spark on the bad side. Could be a relay or a pump or...

[Dr. T]

Does the CEL bulb work?

[Bigzzz850]

Yes all the lights are working and I check the fuel was fine and I got spark coming out of the coil to the distributer but no spark at the spark plugs distributor cap and rotor are brand new on both sides

[duje]

You probably know which side is not working, to confirm that your cyl ID sensors are ok, switch the ignition wires on both sides. For me the easiest way to diagnose the LHM is to start from fuel lines, turn the key and squeeze the fuel lines on the back of the engine, if one is soft, fuel isn't coming to the injectors , than check if both pumps are working ( disconect the connector on the pumps and apply 12v directly on the pumps ), and if that is ok than start swapping things from one side to another (DK's, coils, DME, ignition wires, MAF's, FPS, fuel return valves, caps and rotors), and also check fuel filters if you didn't replace them recently.

[Talyinka]

The 850s aren't quite as good fun when running on six, are they? :-)

It is peculiar that you have sparks at the distributor level but not at the plugs?? Are you sure? Have you just checked a single plug, or several? You say that the rotor is new. Has it been installed correctly? Is the centre carbon inside the dist cap working, nicely sprung? I have never come across that but theoretically you could of course get a faulty rotor.

Apart from this I agree with duje - but your description of the fault is unusual.

[8isenuff]

try checking your cps sensors by switching them.its kinda involved but not difficult

[Talyinka]

try checking your cps sensors by switching them.its kinda involved but not difficult

I would agree at a higher level - but if you get spark at the dist cap but no sparks at all further down that is not the problem - it is more basic.

[8eights]

checked fuel.

What happened here? Were both pumps working?

[Bigzzz850]

I have done all the swap over side to a side already and nothing made it switch side. I pulled both fuel line of and switched sides no change that tells me that the fuel pumps are ok . Fuel filters are a few weeks old and I checked the rotor seems totally fine .I havent changed the cps yet I guess I can try that , but I don't know how that's done just change the wire with the donat or is there more to it?

[Talyinka]

Bigzzz,

You have no misfire - just no ignition at all? Have you actually removed a spark plug and ensured there is no spark across the gap (careful not to shock yourself)? After running the engine on a single bank, are the spark plugs on the non-firing bank wet? Do you get a 'Catalyst overheat' error message when starting? The thing is that if the engine management computer doesn't receive a sensor signal from the ignition it will not open the injectors - this will be stored as a fault message that can be read with a normal diags computer.

[starship1701a]

you said you checked #6 plug wire (with donut) but you also said it was the driver side that's out... i'm no genius but you should be checking #12 wire for that bank... i believe #6 wire is for the passenger side bank.

plus, check #12 spark plug to ensure it isn't fouled, it could shut down the entire bank if it's fouled and the donut on wire #12 cant get a good ignition signal...

good luck...

[Bigzzz850]

So just as an update. I replaced my spark plug wires just a couple of days ago. And it still didn't solve my problem with the car. So I talked to a very helpful friend from this forum (Wuffer) who recommended to me to check my distributor cap and rotor be purse in some cases issues with that could be a cause of my problems. So I did, and sure it is my rotor on the driver side was comet lay burned in. Even know I just replaced them recently. So anyways put my old rotor back on the car, and. That's it the driver side of the motor is running great again. Thank you for all the input , and ideas with my issue, and a special thank you for the guy that helped me putting it back running like new again.

Just re-read my earlier post....F*KING IPHONE!!! Hahaha, whatevs, it's running lol

[Omega man 1969]

Just re-read my earlier post....F*KING IPHONE!!! Hahaha, whatevs, it's running lol

Ha ha , it could be worse. My phone changed ....I have been on bimmerforum.com to bummerforum.com.