Hello this is my first post. I have a 95 S10 running a stock 4.3 TBI and stock 4.3 16197427 PCM and harness. I have a 5.7 SBC in it, it has ported vortec heads with screw in studs and guide plates, it has a crane cam (Duration @ .050": 216° I/ 228° E, Lift w/1.6's: .484" I / .512" E, LSA:112°) and the CR is 9.7:1. I am still running the stock 4.3 4L60E and stock torque converter. I have modded the fuel pressure regulator to be adjustable. Also have a Edelbrock Performer RPM intake with the Holley TBI adapter AND a TBI spacer, full length headers, 2.5" exhaust (x-pipe, dumped before the axle) I have all of the ultimate TBI mods done. I don't currently have na O2 sensor hooked up.

I am having problems with leaning out during hard acceleration. Actually anything over about 50% throttle and it hesitates bad, completly cutting out and backfiring. I know it is having a major AE problem but once (if it can) overcome the original AE stumble it it still really lean.

I also am getting popping out the exhaust during decel but that's not a big concern.
Just today I started trying to fix this (just got the truck together 3 days ago) I didn't have a fuel pressure gauge hooked up, I just did that tonight and now I don't feel like going out and testing but I got it as good as I could by feel. At first I turned it up from stock and it got better so I turned it up higher but it actually made it worse so I have it back down now. I will get a gauge hooked up tomorrow, I have the gauge and adapter.

Without a tune what can I do to make this as good as I can till I can afford the equipment and have the knowledge to tune. What size injectors should I get in it, are the 55lb/h 5.7 injectors big enough or should I get 454 ones? I actually have a set of 5.7 injectors.

Is some of the problem that the 4.3 Memcal has the spark control in it and I need to at least get a 5.7 memcal and the knock sensors just to have the V8 spark control in the mean time.

Also I love the MAF conversion, I read a lot of the info about it but I never saw a diagram for how to wire it, is there one that I missed?

 

Drumer welcome to TGO

1) READ stickies in DIY PROM

2) What is your FUEL PRESSURE and idle vacuum level?

3) GET THAT O2 Functioning

4) To feed that engine you'll need 55LB injectors and play with fuel pressure / DIY tune to dial it in.

5) 7427 PCM was used on V6 and V8 engines. You'll need to get EPROM (or DIY) that corresponds to 5.7L V8 engine and modify it to suit what your engine wants. IRC MEMCAL spark control is different - search in DIY PROM or start new thread there - mention 7427 PCM.

Sounds like fun combo - MAF is a long ways away for you.
//RF