Hi guys I own an 87 Iroc now and it has had a 350 swap from a 305 TPI.

I did some digging in the computer and found that it is still using the 305 LB9 EPROM.
I was wondering if this can cause any problems with the fuel calculations. Fuel Efficiency, Power etc.
Also worth noting that this car is most likely still using the 305 injectors.

Now to my real question.
I have an EPROM and ECM out of an 88 L98 GTA(it had the nifty digi dash).
Since I have a 350 EPROM Id like to use it and not have to hunt for another one.
Now 87 didnt use VATS but the 88 EPROM does.
Since the 88 EPROM is looking for a VATS signal it will not engage the injectors and the car just cranks. Is there a cheap DIY way to rig it to work? And by work I mean start the car. Ive read in the VATS tech article that if the ECM detects a VATS error (CODE 53) it will stop looking for a VATS signal. Now if it is not possible to rig it to work is it possible to artificially create the scenario where the EPROM thinks the VATS failed? Id prefer not to have to buy or hunt down kits and such as it would prolly be easier at that point to just get a 87 L98 EPROM

Thanks for any help

 

If the 19#/hr 305 injectors are in the engine, then the 305 PROM needs to be used.

If you change out the injectors for 22 #/hr units, then the 350 PROM is required.

For VATs, easiest to get a bypass module and wire it in.

RBob.

 

Thanks for the great info.

 

VATS did not show up until 89. I have never seen an 88 car with VATS in it.