quick90rs

iTrader: (3)

So I have a problem ,
My 90 Camaro has a B&M Megashifter thats been installed for years, lately my car will start and just die after a little while. Its very inconsistent because it stays running well for a long time sometimes and sometimes it won't even start. If I unplug 2 certain wires from the relay and touch them together, the car will start but still will not stay running. Touching the 2 wires together will solve the starting problem but not the running problem, when it does run it runs violently and shaky but at sometimes it runs very very smooth and with no problems (it has a new ignition system and the engine is a new install (A Vortec from a 99GMC 3500 van) so i think it is related to this relay or the wiring somewhere in there)

I am going to replace the relay tomorrow and see what happens but I would like to get some ideas on what else to check if that doesn't fix the problem. Where do these wires go anyway (I know the wires are from the stock harness and cut and spliced onto the relay but the B&M diagram only shows color, not function. I included pics of the relay guys, if anyone can help me out it would really help thanks everyone.

quick90rs

iTrader: (3)

quick90rs

iTrader: (3)

Rolling Thunder

Since that does not appear to be a factory relay we really need to know more about what its connected to. and you tell us what wires went where? I'm guessing its an issue with the N/P safety switch.

quick90rs

iTrader: (3)

When I installed the relay I followed the b&m instructions for the wires from the factory harness, if it was a problem with the wiring for the switches would the car still die while I'm driving it? I heard a few of the wires from the shifter deal with idle speed, I figured my problem may stem from that.

Rolling Thunder

You are correct it should not kill the car while its running. I believe you have two separate issues. I know the ECM does have an input for the transmission selector switch however I don't believe it would cause the issue you describe.

quick90rs

iTrader: (3)

My plan is to replace the first relay, from all the information on here and I understand that B&M recommends Radio Shack 275-206 the thing that confuses me with this really is that I have 6 plugs from the harness but the relay has 8 pins, so which pins do I leave off?

Rolling Thunder

Your relay has two terminals for the coil and then a set of normally open and normally closed contacts. Most likely the normally closed contacts are not used.

quick90rs

iTrader: (3)

It would be just my luck that the "typical" pin numbers on the B&M diagram don't match this relay would you be able to tell me what ones to use, i attached pictures to the thread of the relay diagram and the B&M one, thanks for all your help

quick90rs

iTrader: (3)

quick90rs

iTrader: (3)

quick90rs

iTrader: (3)

Just because I can't tell what ones are normally closed the diagram makes no sense to me

Joe Tag

iTrader: (4)

Pins 1 & 4 are closed, 5 & 8 are open on the relay you're holding in pic. On the diagram, the pins marked 24/6 and 14/2 are open.

quick90rs

iTrader: (3)

Thanks for the help , so I shouldn't use the 1 and 4 pins on the relay, got that. and does it matter what wire I connect to 5 and 8

Joe Tag

iTrader: (4)

They're both triggered by the same signal wire,(A2/1) so it won't matter. Providing they are just connecting a hot to the open connection. I can't tell from the pic you posted.

quick90rs

iTrader: (3)

ok so 5,8 correspond to pins marked 24/6 and 14/2, and 9 and 12 correspond to 21/8 and 11/4?? Think i got this now!

quick90rs

iTrader: (3)

Installed the relay from Radioshack and the car won't crank at all and now my radio won't work with the key in the on position either which seems like too much of a coincidence to me. All the fuses are good, I'm at a loss here

Joe Tag

iTrader: (4)

You said you had the diagram figured out. If one is for crank and the other is for the coil and they are reversed as stated earlier, that could be your problem. I'm not familiar with the megashifter NSS, but the factory NSS does not cut ignition power when not in neutral or park. At this point if the wires are not reversed, I would suspect the ignition switch.

Joe Tag

iTrader: (4)

OK I dug around and found a wiring diagram for the relay you are replacing on the megashifter. It enables/disables the starter and tells the ecm whether the trans is in gear or not so it can change the idle accordingly. If you put yellow and purple on 9 &5 and orange/black and black/white on 8 & 12 ( or the other way around with same colors matched to pins 9 & 5 or 8 & 12)it will work as the old one did. Power to this relay comes from the turn/backup fuse, check it out.
Here's the link to installation directions for others that may have this shifter with no manual, or someone to correct me if I have read this wrong.
http://www.bmracing.com/bmnew/pdf/9500452.pdf