Situation is this.

88 Camaro, was 305 is 350 now. Engine is 9.5 to 1 with a flat tappet hyd. cam 212/212 112 LSA. Other wise stock.

I have been considering a Megasquirt swap, but decided to try and tune what is here. I know this is not far from stock and should be no problem, but boost is in the future and is why I considered Megasquirt.

Anyhow, I have been fighting the 305 Prom in the stock 165 ECM to get the engine to stop stalling. I have taken care of a Code 33 with a MAF meter replacement which helped a bunch (code is gone now), and have set the timing to Spec of 6 deg with timing connector disconnected. I did the Min air idle setting and could only get it to idle at about 650 before it would stall. The TPS was set at .58 V after the Min idle setting.

As it is right now it runs great except the occasional stall at idle when shifting out of park into gear. And the idle warm at a stop sign is often unsteady.

I have seen BLM's as high as 150 and know this computer is fighting to keep the 350 running based on 305 data.

I have tried an actual 350 PROM but with the injectors still being 19's this will hardly run.

So the plan is to burn my own Prom and set up the proper Injector constants, engine CID, maybe bump the idle RPM in Gear up from 700 to 850, and take care of that TCC clutch lockup that occurs WAY to soon.

SO what do you all think... is it a plan?

 

It sounds like your on the right track

 

You can make a completly stock motor run better with a few changes.
You will find that as you tune the setup that you have the car will run better and will be a lot more fun to drive.

 

YES! ALL engines benefit from proper tuning of the eprom, even bone stock.

 

First thing I would recommend is getting some 22# injectors like the factory originally installed on 350 motors. Then use the 350 memcal you already have. Naturally burning your own prom would be the best, but probably not "needed" with a factory set up when using the correct injectors. You could raise your fuel pressure to make the 19's work like 22's, but that's a "band-aid" approach and could cause some idle problems that require a custom prom to correct.

 

Well I took Vernw's advice and installed the 350 injectors. And I installed the 350 PROM that I had. Unfortunatly the 350 PROM is no good. The engine runs a little rough with the 305 PROM and is rich as expected with the 350 injectors. If I installed the 350 PROM the Check engine light is on all the time and it barely runs. Sooooo.... anybody got a Stock PROM 88 Camaro 350 auto? I got a friend with a 89 GTA PROM, but it has antitheft and I don't think it will work.

 

Check out the Classifieds or go to a GM dealer. Most people just "re-use" the memcals.

 

I ran into a similar prom swap problem one time with the check engine light - you have to make sure you have the same year 350 prom (i.e., don't try to use a 350 prom from a MAF set-up on a system that uses a MAP, and vice-versa).

 

Contrary to popular belief (and the GM parts guy) the 305 and 350 EST modules are not the same. Get a module from a 350 car at the junk yard or go to a reputable TPI guy like TPIS or FIS. They can supply you the correct module.

The car should actually run fine with the 305 module, you just get this annoying CEL that comes on and stays on every thousand miles or so.....

The factory EPROM should be about $75 at the dealer. Be sure you know what your rearend gear ratio is. If you have the 3.45 gears you may not be able to get the correct chip for your car as these gears were not available with an automatic and a 350....

You might also want to try setting your timing up to 8-10 degrees. I base this on your duration, what is the lift of your cam?

 

Nothing a little re-programming of the eprom won't fix. That is why DIY Prom is here.

BTW, zapo if you ever drive by Kamloops, look me up. I would be happy to give you a 'hands-on' demo.