Only getting spark when i let off the ignition

[bmwracing_6]

first off i had the hardest time to get a spark and have checked the cas and ignition module, and it has a new ignition coil and new ecu and this is what happens... i will turn the key and i do not get a spark and when i let off the ignition it will throw a spark.. i am lost and so confused to why this would happen.... somebody please help me thanks!

 

[freshlane]

Don't know if it will help but something similar happened to me. I ended up getting a new ignition switch.

 

[bmwracing_6]

i might try that but does anyone else have any suggestions

 

[bmwracing_6]

come on guys i need help fast my car has been disabled for 2 weeks now

 

[WOTDSM]

come on guys i need help fast my car has been disabled for 2 weeks now

Join the club. I'm betting ignition switch.

 

[bmwracing_6]

well i got the ignition out so how do i test it to see if it is bad or not and if a test is not possible does anyone know where i can get another.

 

[bmwracing_6]

so how can i test the ignition switch

 

[bmwracing_6]

come on guys i am stuck with this car out of service and it needs to be running soon.

 

[bmwracing_6]

please?

 

[Raph]

you can get a ignition contact switch from the dealer...

 

[toybreaker]

I'm actually thinking cas...or, maybe a bad m.f.i. relay

Please, check all the fuses before continuing...The ecu controls the mfi relay, and the mfi relay controls power to the cas, injectors, and etc. If you're missing a power supply to the ecu, it won't turn on the mfi relay, and you won't have any power in the engine compartment at the cas.

Since you're knee deep in the ignition switch, you should finish checking it out. With some contortion, you can reach the terminals directly at the back of the switch to test them. Or, You can just find something fed ignition power from the key, and test for power, key on. An easy, and helpfull place would be the black and white wire at the coil, as it's direct from the key.

Look around some while you're under the dash for an alarm brain/wires, or any modifications toobad: ) to the wiring harnesses. There could be an old alarm installed, and it could be interupting the ignition circuit. Most alarm installs will hit up the ignition harness from the switch, so it should be pretty obvious.

If you have another cas, you can test things easily, and quickly, by just substituting it for the one installed on the motor. Simply unplug the cas, and plug in another cas, turn the key on, and spin the cas in your hand. You should here a snap from the spark plugs, and the fuel pump will run for a couple of seconds.

If it doesn't spark, it's time to get more serious about checking powers and grounds at the mfi relay.

Good luck, and please let us know what you find, so we can better advise you.

 

[bmwracing_6]

ok this is what i have check and what is good so far the CAS took it off and put it on a running car (it works), the ignition coil (same thing with the CAS), replaced the ecu, and ignition module (again same thing with the CAS). i am going to check out the ignition i am going to do the same thing i did with the other just put it on my running car. but give me more information of the mfi relay... where is it and how do i test it? thanks guys for the feedback

 

[bmwracing_6]

anybody?

 

[bmwracing_6]

may car is in need of help its a dead project as of now

 

[toybreaker]

The m.f.i. relay is located under the radio on the dash/tranny tunnel sheetmetal brace.

The easiest way to access it to remove the right (passenger) side carpeted trim panel from the center console. There's some plastic buttons in the carpeted section, (three I think) Just pop them out, and then pull the screws out, and pull the trim panel.

You'll see the relay on the brace. It's the gold box with 9 wires going to it.

If you have a voltmeter, I can lead you through the troubleshooting procedure.

Have you checked all the fuses, with a testlight/voltmeter? Please do that first, the ecu is fed power several different ways, and a blown fuse will keep it from powering up and/or controlling the m.f.i. relay correctly correctly.

Also, please check for power at the black/white wire at the coil, with the key on. This will verify the igntition switch is working correctly.

Putting your components in another car is an excellent test, but it won't show you anything of value if your car has a power supply issue.

We are going to have to start testing things with a voltmeter, (or testlight) or we are just going to be guessing. A cheap one from autozone or wherever is fine.

I know you can get to the bottom of this problem, it's just going to take some patience, and a logical approach.

 

[bmwracing_6]

yes i do have a test light and all the fuses have been tested many times over and over and yes the black/white stripe wire is getting power... when have checked to wiring over and over to see if we made any mistakes and cannot find any however i have not checked to mfi relay so it is at the top of my list now. do you think that taking the mfi relay of and putting it on my running car will help i guess if it works than i have a wiring problem... i plan on getting a volt meter at some point too. thanks and i will let you know what happens when i switch the relays

 

[bmwracing_6]

also i have tested the wires to all of the sensors and parts i have tested with the other car... also i cannot find the ignition fuse where is it?

 

[toybreaker]

Specific fuses;

Ignition fuse, pink, 30 amp, on positive battery terminal

mpi fuse, blue, 20 amp, on positive battery terminal

mpi control unit, 10amp, #19, inside fuse box

 

[bmwracing_6]

ok well i have check all of those so they are all good

 

[95gs200k]

hey wanted to say good job on ## first serious problem with your dsm. this game isn't ever easy but it is rewarding when your done. I have a question for you do you have a haynes manual for your car yet? If not go get one imediaely. They have wiring diagrams for the entire car and you wii be able to see your power inputs and everything.

Now onto your problem, could be a power transistor ohms test it. if it reads infinity its bad I forget exactly what the reading should be But ill find out. Also go get that manual check for power ground and signal voltages at your cas, coil, and power transistors, after that ohms test each one. It is time concuming but everything with these cars is.

dj

 

[bmwracing_6]

haha well i am not really happy with this problem however it has help my knowledge with the engine. but i have chilton manuel and not a haynes. personally i hate this book because it has all the dsm models and not focus on a 2g or 1g... is the haynes like that? i have had bad weather down here today so i have not been able to work on it..however i will update when i do so

 

[bmwracing_6]

ok well i took the mfi relay off my running 92 gsx and put it on the one that i am trying to get running which is the 91... same thing no spark so it must be something in the wiring... i hear a clicking noise from either the mfi relay or the ecu but it is around the vicinity of them. i heard that it could be the mfi relay that is cutting off and on very quick thus prevent ing spark is this true and what could make this happen?

 

[bmwracing_6]

anybody have any advice?

 

[bmwracing_6]

someone has to know some info come on and post it

 

[sniver]

I'm willing to bet if you keep bumping your thread it will be put under lock down. Be patient everyone here knows how it is to have the dsm down for a while and I'm sure who ever can help will help. This is not a area of normal knowledge for most. Does It turn over while not sparking?