insomniac

iTrader: (3)

Question how can I get the speedo to work since my 91 is electronic and teh 87 ecm / motor being swapped in is from a 87?


Also if i work that out what kind of problems will it have now that the 87 computer has no speedo input and has no clue how fast the car is going?

the 87 also only uses the vss for lock up

ninetyone

iTrader: (2)

First of all,what color is the wire from the speedo to the buffer?

ninetyone

iTrader: (2)

Should be a tan wire from speedo to buffer .OK

ninetyone

iTrader: (2)

Ok, now connect the tan and the brown wires together after you unplug them from the buffer box,cut and splice of course. Now trace that brown wire (K) to the ecm(the 207 connector really) Ok,pause there. I was assuming you were swapping a tbi to a speed density tpi not a Maf car, sorry. Cause Speed density does not use a buffer box and i bypassed mine after my swap was done. I will let you know what i come up with man.

ninetyone

iTrader: (2)

http://home.earthlink.net/~gellett/89wiring.gif
there is a wiring diagram for your 165 ecm,looks like you may have a buffer still? Let me check further
https://www.thirdgen.org/forums/elec...blem-cant.html

check that link too,there is a guy on here by the name of "pocket" he may know more than i do on swapping to MAF and your speedo info. Good luck

ninetyone

iTrader: (2)

87 tpi may use a different buffer box than a 91 tbi too,im not sure man.

alex91z28

if your car was a tbi engine it came with a speed buffer that gave the speed signal to the ecm and the speedometer you might hook it up to that.
if your car was a tpi car they did not come with a buffer, since the speed sensor goes straight to the ecm and the ecm sends the signal to the speedometer. in this case you would need to get a buffer from a tbi car.

ninetyone

iTrader: (2)

ok that is your ecm pinouts. look at a10 the brown wire. that is a brown wire directly from your buffer box to the ecm. just trace the brown wire from a10 on your ecm. it should come out of ecm and stop at the c207 connector. make sure it leaves the c207 connector and goes to the buffer box correctly. so basically the other side of the c207 connector should also have a brown wire that goes to pin f on your buffer box. then it should work. then the signal should leave the buffer box on a tan wire that goes directly to speedo.

ninetyone

iTrader: (2)

the wiring looks the same on the 87 tpi and the 91 tbi concerning the buffer box, i am thinking maybe the 87 cars used the other type of buffer box.

ninetyone

iTrader: (2)

no, the earlier tpi cars used a buffer box too, now 90-92 tpi did not

ninetyone

iTrader: (2)

http://austinthirdgen.org/mkportal/m...ine_wiring.gif

look at that 1987 tpi used a buffer with a brown wire going to ecm and a black/wht ground wire

alex91z28

yes that right, but that was for the cable speedometer right. y think he is going to need a buffer from a 90 to 92 to get the electronic speedometer working and a vss signal for the older ecm.

ninetyone

iTrader: (2)

first of all have u re-pinned this car yet? and the speedo is the only problem?

ninetyone

iTrader: (2)

no, alex91z28. the 90-92 tpi did not use a buffer,but the 90-92 tbi did,but he already has a 91 ex-tbi car.so he has a 91 buffer box in there, its just a tbi box. the wiring at the 87 tpi ecm and the 91 tbi ecm look to accept the buffer output wire (a10) (brown wire) in the same spot tho (its A10) at the ecm.

ninetyone

iTrader: (2)

i think he needs to compare the 1987 buffer box against the 1991 tbi buffer box before anything, and remember be specific. look up 87 wiring not 88,not 1989 but 87'

Pocket

iTrader: (24)

All buffer boxes operate the same way. He needs to find the VSS pins for the 87 harness and move them to match his 91. Rest is taken care of

If all else fails he can wire the whole circuit external