BMS ignition module

[buickGTP]

I went out to start the race car and nothing. FI is pulsing and no spark.
A. cam sensor voltage varies between 3 to 4.3 volts when cranking
B. crank sensor voltage varies between 2 and 3 volts when cranking
C. 12 .5 volts to the coil pak
D. jumping A to P B to P and C to P there is spark
E. the manual (Buick power source manual says 1 to 5 Volts for cam & crank sensors)
F . I would check and change the crank sensoe but I want to be sure before I do because
I have to pull body , rear suspension, tranaxle and motor to get to it.
G. The ignition module is similar to a GN but has adjustible timing and advance
Questions
A. If you have a faulty crank sensor would you still get spark
B. Does anyone know of persons that can repair this type of ignition module ( the car is a vintage
race car and I would like to keep it original)
C. have I missed something

Thanks for taking time to read this
Steve Rowan

 

[750H.P.V6]

Steve,

Based on your description and the assumption that the Motorsports ignition system is similar in function to the stock type ignition on the Turbo Buicks I'd suspect the crank sensor. If it's bad you won't get spark because there is no output from the sensor. You should get 3 pulses per revolution from the crank sensor and 1 per 2 revolutions from the cam sensor. If the module is bad I don't know of anyone that repairs them however I crossed paths with a guy in FL who had a bunch of old IMSA stuff and he had some of those ignition parts.

Neal

 

[750H.P.V6]

As a follow on to my first post I dug out my Buick Power Source manual when I got home from work and looked up the info that pertains to the BMS ignition system. You'll want to check out connector #5 for the crank sensor to make sure you have source voltage on pin A, a ground on pin D and that you get an output voltage on pin C. As you rotate the engine the voltage on pin C should rise and fall between 5 volts and 0.5 volts as the tabs of the reluctor pass thru the crankshaft sensor. If you have power and ground and no output I think you've found your culprit.

Neal

 

[buickGTP]

Neal
Thank you for the reply and help it is greatly appreciated
Steve

 

[buickGTP]

Neal
currently checking your suggestions
my multimeter is not a high quality one is it possible it does not react fast enough to the volt changes.
thanks
STEVE

 

[turbodave231]

If you are cranking the engine with the starter, you will not see the voltages toggle even with the best DVOM. You would need a lab scope to see the changes. Turn the engine by hand with a breaker bar and watch for the crank signal to toggle high and low. Then watch the cam signal the same way. The stock GN system toggles between .5v and 7.5V. Not sure what the BMS system should do but it is a Hall effect sensor and will toggle between 2 voltages (will do something very similar)

 

[buickGTP]

Turbo dave
thanks I will do that in the am
steve

 

[buickGTP]

I hand cranked the motor and the crank and cam sensor checked out .5 to 5 volts. so it must be the ignition module
If anyone knows of someone who can repair the BMS module i would like to hear from them
Steve

 

[BlownV6]

Sorry Im a bit handicapped on these parts. I have some BMS original ignition parts. What is the ignition module?? Any pics.??? Mike

 

[buickGTP]

Mike
this is what it looks like
thanks
Steve

 

[BlownV6]

I have 3 of them. How many do you want?? Mike

 

[buickGTP]

Mike
Thanks for the responce do you know if they are OK and what do you want for them.
Also I may have the valve covers you are looking for. I will get you pictures next day. The buick part# is 25500122
thanks
steve

 

[buickGTP]

Mike
Here are the photos of the valve covers
Steve

 

[BlownV6]

I will trade you my 3 boxes for your valve covers!! Any of the other stuff I have pictured that you might need ??
Let me know. Thanks Mike

 

[dr_frankenstein]

oh wow Mike.........

man you have tons of the neatest stuff.... I just want half a day with a 6 pack to look at your stuff!

 

[buickGTP]

sounds good ,let me know where to ship them to. I am going to need some standard valve covers to
put on the spare motor. I think you have some on ebay also Iam looking for pulleys for the mclaren
front cover

Steve Rowan
967 Camelia Dr
Henderson, Nevada 89011

702-564-3236

 

[BlownV6]

oh wow Mike.........

man you have tons of the neatest stuff.... I just want half a day with a 6 pack to look at your stuff!

Miller Lite!!!! Mike

 

[BlownV6]

I will get your boxes packed up and sent your way. Mike Booher 7632 Downing Street Dayton , Ohio 45414
I dont have the pulleys !! Would you know anyone that wants a billet alum front cover (Mclearen style)??

 

[buickGTP]

Mike
I sent the package this AM the tracking # is 1Z60W8770330143208 UPS
you might try derecklola a TB member he has a indy light car which uses that front cover also anyone
who has a Buick indy,Gtp & lights car.

 

[BlownV6]

Your modules went out today also via USPS priority mail conf. #0312 1430 0002 8133 2124 Thanks Mike