Not really camaro related but my S-10 is a TBI 4.3 i plan on keeping the TBI when i swap to the 350. will this cause any problems with the new motor?

 

For the most part yes, a V6 ECM will run a V8 engine provided the # of cylinders is changed, or the correct calibration is used.

 

Believe it or not it will be pretty drivable with the stock 4.3 calibration. Since a 4.3 is just a 350 with two cylincers lopped off a lot of the fuel calculations will be pretty close. What happens is the ecm will inject x amount of fuel at every reference pulse from the dissy. With the V-8 swapped in you are going to be getting two extra pulses, since each pulse of the fuel is calculated to the cylinder size it will work out pretty close.

Don't fool yourself into thinking you won't need to tune, the problem you will run into is that your pump shot is not "per cylinder" calculated and will be way off. Most trucks I've tuned had a nasty little backfire when you wacked the throttle. Also anything that has to do with engine speed will be off. You TCC will lock up sooner, and if you have a rev limiter it will come in sooner as well because the ECM is seeing the extra pulses and think the engine is turning faster than it is.

If you tell us what ECM you have we can tell you if your ECM was ever used with any V-8 engines. If so you may be able to run down to the GM dealership and get a factory chip that will get you up and running.

 

Where is the number for the ECM? I work at a chevy dealer so getting parts isn't a problem with the exception of price. granted i get a discount it's still over priced.

 

Onebad89

ECM service number is typically on the label. If it is completely missing remove the EPROM cover plate and record broadcast code BCC of EPROM chip. Most likely, since S10 (assuming model year 87-91) is a truck it uses 1227747 ECM or a close variant.
A used '7747 ECM can be had for $40 from most JY's

//RF

 

I did the 4.3 tune running the 350 TBI thing not all that long ago (Astro van). I set the cylinder count to 8 and the 350 ran almost perfectly. I don't even recall having to mess with the TPS/MAP AE. Just set the cylinder count to 8 and fly. I kept the small 46# injectors even. Ran fine around town and on the road, up to 3,500ish rpm where the injectors went static. I forced WOT high load async and it pulled fine up to 4,500ish. It was a work truck that rarely saw 3,000 rpm and the guy was too cheap to buy 350 injectors (I guess I won't mention it was my brother). So we left it at that.

 

Yeah. So long as its still a swirl port motor, it will be apples to apples. In the ECMs, the cylinder count is only for the RPM calculations for the most part. The RPMs will be miscalculated if you dont change the cylinder count. If you change the injectors, youll also need to change the BPWc.

Fast, I assume that was a PCM since you set it to use async at higher RPMs? I guess thats one way to get around the injectors going static How much more margin did it get you going to async?

 

It effects the timing as well. When running the V8 on the V6 ECM, it will run on the stock V6 chip, but the timing is WAY off. Thats perhaps the reason for the backfire that BMonteSS found running it that way.

Dimented, it was the PCM. In async mode the injector spend less time opening and closing than in sync above a certain RPM. The actual time the injector spends open is increased. This increases fuel delivery. I found that it richened things 10-15% above 3,000 rpm. That is just enough to eek a stockish 200 hp 350 on injectors meant for a 170 hp 4.3.

 

well i looked on my pcm, which is under the hood on my truck being a 95. the service number is 16184738. any thoughts if this one will work? And the engine i'm putting in the truck is a stock TBI 350 from an 89 gmc jimmy.

 

Bump! Anyone?