why would you replace an eprom

[zr-1assassin]

here is the deal... i just got my 90 about 2-3 weeks ago and im looking over the paperwork that came with it and there is a receipt in there for an F-EPROM part#16163905 in 5/06. why?? was there a problem? why would a guy replace the eprom? surely this isnt routine maint. anyone had to replace theres for any reasons?

[tccrab]

Originally Posted by zr-1assassin

here is the deal... i just got my 90 about 2-3 weeks ago and im looking over the paperwork that came with it and there is a receipt in there for an F-EPROM part#16163905 in 5/06. why?? was there a problem? why would a guy replace the eprom? surely this isnt routine maint. anyone had to replace theres for any reasons?

There are drivability issues, notably a high idle in closed loop that was corrected by an updated prom (AYBK).

Aftermarket proms are available from tuners that provide better fuel maps, removal of CAGS, cooler engine operating temps by turning on the fans eariler, and timing adjustments to increase performance. They also provide custom tunes for modifications like headers, engine mods, etc.

TomC
'90ZR1 #792

[Aurora40]

Yeah, there were more than one programs released. I guess if the guy hadn't had it done under warranty, then he'd have bought the newer one himself.

This is true on new cars too, except that the dealer just programs your car with the latest stuff vs you installing a new chip.

[WB9MCW]

Originally Posted by tccrab

There are drivability issues, notably a high idle in closed loop that was corrected by an updated prom (AYBK).

Aftermarket proms are available from tuners that provide better fuel maps, removal of CAGS, cooler engine operating temps by turning on the fans eariler, and timing adjustments to increase performance. They also provide custom tunes for modifications like headers, engine mods, etc.

TomC
'90ZR1 #792

Best dawg gone single mod I have done to my ZR-1!!!

ESP the cooler op temp's and getting rid of the "STUPID CAGS"---

[tomtom72]

Just as a side note Assassin over at the netreg site there is a "recall" section that has some info and a better source is over at ZR1Specialist.com, Marc Haibeck's site.....he has a fairly good explaination of the PROM programming...at least Marc's write up was enlightening to me but I'm new to EEC!

I bought the update for my 90 as it still had the original version...net result was a bit better but the idle speed still "hangs" upon de-accleration but not as long as it did with the original program. I think, if I understood Marc's explaination correctly, that the idea was to use the program as a de-accel valve without actually having a de-accel valve. Something about emissions upon engine de-acceleration being too high or some such thing


Tom