How to wire a park/neutral feed

Okiedokie · March 24, 2012, 03:27:59 PM

I am trying to connect a feed to the park/neutral pinout on my 1227730 1990 Camaro speed density computer. It is in my 1940 Ford coupe with a TPI setup. I have a Flaming River column with Lokar linkage to trans with a Lokar neutral/safety switch. I thought I could do it thru a relay wired to close a ground to feed that pinout. Hot [from N/S switch side that is only hot in park and neutral] to 86 on relay, ground to 85, ground to 87, computer pinout for p/n to 30 on the relay. This accomplished nothing, scan tool still shows P/N not recognized. Can anyone shed any light on where I have gone wrong, or how you accomplished this. Thanks, Joe

wayne petty · March 24, 2012, 05:03:53 PM

hmm... thats strange...

the in park and neutral the orange and black wire from ECM PIN D16 is grounded by the switch...

there should be some voltage on the orange and black wire when the neutral safety switch is NOT grounded..

i looked up the neutral safety switch .. for the 90 camaro.. 82 to 01 the wells cross reference says it fits..

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/20/e2/2b/large/0996b43f8020e22b.gif

when you say you are using the neutral safety switch terminals to operate a relay... could you verify that you are using the closed in park and neutral terminals.. not the closed in reverse terminals..

post the part number of the locar switch and i will look at the wiring on it..

unless you need to be using pin 87A and pin 30

pin 30 and 87 are closed with the relay COIL NON POWERED

pin 30 and 87A are closed when the relay coil is powered..

can you use a different relay.. that you have removed the cover from and manually close the contacts while watching the scan tool...

?

have you spent 5 minutes reviewing this link.??

http://www.bcae1.com/relays.htm

can you also verify the wiring diagram and the numbers on the relay bottom..

i have seen a few ODD relays that had double 87A contacts..

those thru me for a loop.. now i am wondering where i put it.. .. i could have used it in a relay logic circuit i was working on a while back..

what prom is in the Computer.. if its a special prom.. or a stick shift prom.. it might not need the P/N wiring.. unless you are throwing a code 62 or something like that..

this is the 90 camaro TPI neutral safety switch..

http://contentinfo.autozone.com/znetcs/additional-prod-images/en/US/wl2/DR414/14/image/4/

orange and black wire from the ECM pin D16.,. whats strange is is shows from pin D11 from another source ...
goes to pin B on this neutral safety switch..

PIN A on the switch goes to ground..

pin B as described above to pin D16

Pin C is switched positive from the Back up light fuse..

pin D goes to the back up switch..

pin E to clutch switch and pass enable relay.

pin F to clutch switch

i am reading this off a L98 corvette diagram from bentley books..

https://wiki.bentleypublishers.com/display/tech/Wiring+Diagram+-+L98+Engine+1985-1991+%28GFCV%29

enjenjo · March 24, 2012, 06:35:32 PM

Are you using a stock or aftermarket PROM? Where did the harness come from?

I think I see your problem, you only have power on pin 86 when the engine is cranking, but not when it is running.

Okiedokie · March 24, 2012, 07:00:02 PM

Stock prom with the vats removed. It does not throw a code. I think that enjenjo is correct, no power to relay when the engine is running. Back to the drawing board.

enjenjo · March 24, 2012, 07:33:01 PM

Give me a little time. I think I have come up with a way to do it. I have to draw up a diagram for it.

enjenjo · March 25, 2012, 12:22:02 AM

This circuit should do it. You will need two relays

Okiedokie · March 25, 2012, 02:39:42 PM

Thanks enjenjo, but I am dumber than dirt sometimes [ok most of the time]. Are you showing this to come off of the "hot when in park or neutral" side of the switch? How will there be power in drive? Also, why would my original setup not indicate that the computer recognized p/n in park? I understand how it could not in drive, but it seems it would in park.

enjenjo · March 25, 2012, 04:08:44 PM

Quote from: "Okiedokie"Thanks enjenjo, but I am dumber than dirt sometimes [ok most of the time]. Are you showing this to come off of the "hot when in park or neutral" side of the switch? How will there be power in drive? Also, why would my original setup not indicate that the computer recognized p/n in park? I understand how it could not in drive, but it seems it would in park.

Disconnect everything from the neutral switch. There will be three wires going to it. A ground wire on one side, and one wire from each relay, terminal 85. The hot wire from the ignition that went to the neutral switch will now go to terminal 30 on the left relay. The other wire originally on the neutral switch will go to terminal 87 on the same relay. On both relays run a wire from the accessory circuit at the fuse box to terminal 86. This wire has to shut off with the ignition switch. The black/orange wire from the computer will connect to the 30 terminal on the right relay, and the 87 terminal will go to ground. On both relays 87a is not used.

What we have done is repurpose the original NSS to switch the relays. The left relay becomes the new NSS, and the right relay is the Neutral ground for the computer. Even with the ignition switch on, neither relay will be on unless it's in neutral or park.

In the original application, the NSS had an extra terminal for the Black/Orange wire that was grounded to the steering column. The computer is not looking for power, it's looking for a ground.

Another problem I have run into, some ignition switches will not supply power to the computer while the engine is cranking. This usually shows up by the engine not starting until you release the key. If you have this problem, we can fix that with a relay too.

Okiedokie · March 26, 2012, 01:14:28 PM

Thanks enjenjo, took awhile to grasp, but I think that I do. So what does he computer see when trans in drive? Why won't the computer recognize the ground if the orange/black wire is straight to ground? Thanks for your expertise. Wayne's also. Joe

enjenjo · March 26, 2012, 01:45:43 PM

Quote from: "Okiedokie"Thanks enjenjo, took awhile to grasp, but I think that I do. So what does he computer see when trans in drive? Why won't the computer recognize the ground if the orange/black wire is straight to ground? Thanks for your expertise. Wayne's also. Joe

When the trans is in drive, the computer sees no ground, so it sets the idle up to account for the load of the convertor. When it sees a ground in park or neutral, it sets the idle back down because there is no load. There is another circuit in the AC that does the same thing when the compressor comes on.