formulax4

iTrader: (1)

Hi,Awhile back i bought a 87 gta and it has been a can of worms ever sense.I'm almost finished getting every thing smoothed out but ran into a issue. I am using an auto xray scanner to view data and i see that the ecm is detecting 4th gear while its in park running or not.Also its detecting park and neutral in 1st second third and fourth gear!It also has the same behavior no matter the safety switch setting and have a couple new extra safety gear selector switches that all behave the exact same. The only gear it don't detect park and neutral in is reverse.I guess the questions would be: 1.Is it normal behavior for the ecm to detect park/neutral in 1-4 gear select positions? 2.Could someone share the knowledge of what component translates the gear selector setting?Is it the ecm? 3.I have the chip/prom/memcal out and was hoping to find info on the numbers on the chips. The 14pin chip has numbers 16055375 and 8716 on it. The 16 pin chip has numbers 16055376 and 8715 on it. Th large (prom chip) has Delco ABWT 8674 on it the smaller numbers are L8707,I606,980,9300,0182 on it. On a site i found i don't know if this is correct because it says the smaller resistor chips are for a tpi 5.0. Is this the correct chip/resistor combo? Useful information: It is the ecm 01227165. The car is a 1987 trans am gta with the 5.7 TPI l98 W/65k It is mostly stock minus the Flow master cat-back, headers and smog delete. It is a automatic 700r4 trans with the 3.27 gear ratio. Thanks guys cant wait to hear the results hope to take this baby out on the weekends sometime soon.T.I.A!

RBob

iTrader: (1)

ABWT is for an '87 5.7L Federal with a 700R4. So good to go there.

For the P/N to/from the ECM. It should show the proper P/N only when in park or neutral. The switch for this into the ECM is on the shifter assembly. Will have a wire (ORG/BLK) going to it. Grounded is P/N position, open is drive.

4th gear. This is a pressure switch in the transmission. When the trans shifts into 4th/OD it lets the ECM know. I didn't quite follow what you are saying about the 4th gear indicator. But if it is backwards then either Auto X-ray is incorrect or someone swapped in the wrong switch.

The switches are available in both N.O. and N.C. configurations.

RBob.

formulax4

iTrader: (1)

Hi Rbob,Thank you for the response! I have been having some transmission issues and have plans on going through it soon.As for the P/N switch it is for sure a good one,Though there is a possibility that wires could have been swapped it has a new pigtail tapped in im wondering if someone maybe confused the wires.Any idea of the polarity or color order for the wires to the P/N switch?I really don't want to throw parts at this.Also anyone know of a good place to send my ecm to have tested?
Im very grateful for the help thank you again thirdgen and Rbob.

formulax4

iTrader: (1)

Ohhh before i forget the autoxray reads fine on my 84 corvette.Just checked yesterday.

EagleMark

Here's a wiring diagram for the 7747 with 700R4 maybe it will help with wire colors and conections.

With the problem your having and seeing a new pigtail has been installed maybe stripping back tape or whatever will show the origanal wires and colors...

formulax4

iTrader: (1)

Hi there eaglemark.Thank you for the post but that schematic dont have the information for the park/neutral switch.I was hoping to find the polarity's of the wires that plug to it.I have the book on the car but see nothing in the diagrams for this.The wires are color coded and all match the original wire colors but im wondering if maybe someone confused the wires in the plug as you can slide them in or out.Im really leaning towards a new ecu the TCC in the trans locks like it should tho.Ima keep digging around .Its a conspiracy!(lawlz kiddn)Information comes by way to hard tho.Thank you guys for the help i am grateful.

EagleMark

ECMs rarly go bad and when they do you get a rapidly flashing CEL. There's always an exception.

I would spend some time trying to find correct wiring diagram or even purchase correct service manual with them before I spent the money on a new ECM. They are not cheap. The service manual will always be handy as well.

Do you have any error codes? Do you have any driveability issues? Or is it just the data information in the Scan Tool?

formulax4

iTrader: (1)

I do have a service manual but there isn't a diagram for that P/N plug.I hear ya on the price of the ecm, definitely not lookn to throw cash out the window.The drivability issue is mainly idle it dies sometimes even in park.I know for sure the following is good coil,pickup coil,ignition module,timing,compression.good reference voltages to everything.The car seems to want to jump when its put in gear at any idle speed.Im pretty sure that the jumping is the transmission acting up.The tps is set at.54 currently and it makes no matter where else its set the trans still jumps.I have properly set the minimum idle like i should (disconnecting the iac after centering it spout plug ect).Also good vacuum and no vacuum leaks.I have proper fuel pressure and flow as well.I figured its ether the trans causing all of this or the ecm.The 4th gear detection will detect engaged when looking at the live data via the scan tool it pulses in a perfect rythm to the engaged disengaged on fourth gear while at the same time its detecting its in 1st gear as well.But for the P/N thing its just that its reading in park or neutral while in 1-4th gears but not in reverse. I was assumeing the timing is being changed by the cpu causing it to die because it detects park while in gear.It seems to do fine with the spout connector disconnected.Kinda just wanted to resolve this matter before i redo the trans and bullet proof it.No check engine light at all.
On the scan tool you have to press scan data and within that second turn on the key to get it to read the data.sometime gotta do that 3-4 times if i don't do it just right.I have two other gm-1 equipped vehicles here and they don't have that issue,Its kinda a main reason im suspecting the ecm.The one i have is a delco refurbished ecm and looks almost as old as the car.I think this is the reason i got a 64k mile car for 3k Anyone have a pigtail off the P/N switch to verify the wire color and order?On the plug it will have a-b-c-d-e-f ect and one of each color wire will be in one of those slots.Thanks again i hope this info helps some.

The car runs like a scalded dog except for the 2nd gear slippage.