wrong chip in 89?? advice
 

First time hope I get it right

I went to install an after market chip(Jet stage 2 bought off forum member for 89 vette only) and on fitting found the wrong oem unit is currently fitted to the 89 with auto, (rear end ratio 2.59). which has annoyed me no end to say the least The unit currently fitted to my is Serv. no 1227165 ABIK 867801 M622278681 delco chip abtk 0739 with the details as below can you through me a few suggestions

1. Is it possible the whole ecu originally came from an 87 vette and some b#%@d changed it? I relise though the 1227165 was fitted to the 87-89 but has since been updated

2. what would the effect be, having an OEM CHIP abtk 0739 from an 87 fitted to my '89 apart from the cold start part" be having.

3. different diff ratios??

4. what will happen if i still fit this jet chip (18906-S) to the 87prom or do I need to find an oem 89 one??
P.S I dont have to meet the tough emission regulations that you fellas have to(eat your heart out)
I run 91 0ctane,2.5 inch hi flow exhaust,180 thermostat and k& n filter

I am having a bit of a hard time following your post, but what I can tell you is the 165 ECM was fitted to the many different year vettes. 86-89, they are all the same. What is different are the broadcast codes they used on the specific eproms.

You can take your VIN number to the local dealer and locate what eprom you should have and compare it to what you have. If its different, then you probably will have problems...if you need a new one you can order the right one or let me know and I will burn the broadcast code for you for free.

Just let me know if you need help. :cheers:

Thanks for the advice and sorry about confusing post.The current DELCO chip fitted is (abtk 0739 from an 87)and your offer much appreciated would be great to take you up on this however Im downunder(Australia)and use the vette daily.
I have contacted dealer in States given Vin IGIYY3182K5110 they have replyed with part#16134197 required (3536apza or 1374apkd or 4198arar) ??the guys at Jet chip state I require a arap chip gets all a bit confusing for us average guys

ABTK is from a 87, it will have the cold start, some different fan settings, and some other minor differences.. If you ran a 87 bin in a 89 you'll probally just see the fan running all the time (??) and hard starts.

ARAP is a pretty hot binary that GM. The ARAR is a bit more conservative. ARAR is also meant for a 2.59 gear and the ARAP is for a 3.07 so you may have some TCC issues and possibly wierd annoyances you've never delt with before like the shift light coming on.

The ABTK is from a 87 with a 2.73 ratio rear

IN a 89 you'll likely see fans running more than normal (??), and you'll have prolonged starts.

The ARAP is a more aggressive tune GM did for auto vettes with the 3.07 rear.

The ARAR is a bit more conservative meant for 2.59 gears.

If you mix up the two you'll likely see wierd problems like TCC setting screwed up and the shift light coming on when you've never seen it before.

Thanks for info,vette seems to perform satisfatory with the "87 chip" and the fan does not continually run just could not understand why the vehicle suffers when the jet chip is used.

Does it have a hard start issue?

No seems to work fine