Help me choose a pcm

[Shawn1989]

So, the 350 miata is alive and well!!!! :)

drove it yesterday and i spun all the way through 4th and couldnt grab 5th cause i didnt have enough room, but the fuel cut at 4500 is seriously pissin me off; really cant get the car to gallop with it, 4.10's and 15" wheels..... Lol
so
rather than getting a tune, a cheaper alternative is a new pcm..... is there a computer out at the junkyard that will eliminate this problem for me?

tune will come after vortec heads and a 454 throttle body

My dad has a 305 computer from my stepbrothers old 91 305 camaro..... I dont think the camaro has a fuel cut, BUT does it have the capability to trim the fuel enough for the 350?

wiring it to work wont be an issue.

[dave w]

Looking back at your older post, I get the idea you are using the 16196395 computer?

I did not plow through all your older threads, so maybe an update of the hardware / software you are currently using would be helpful in choosing a PCM?

The GM TBI PCM's, the TBI computers with red / blue connectors are a good option, if your not already using one. I'm thinking the 16196395 computer is a TBI PCM with red / blue connectors?

I doubt the 16196395 computer has rev limits @ 4500 RPM, considering the Spark table goes to 6000 RPM and Fuel Table goes to 6400 RPM's.

I eagerly await hearing back what you are currently using!

dave w

[Shawn1989]

Looking back at your older post, I get the idea you are using the 16196395 computer?

I did not plow through all your older threads, so maybe an update of the hardware / software you are currently using would be helpful in choosing a PCM?

The GM TBI PCM's, the TBI computers with red / blue connectors are a good option, if your not already using one. I'm thinking the 16196395 computer is a TBI PCM with red / blue connectors?

I doubt the 16196395 computer has rev limits @ 4500 RPM, considering the Spark table goes to 6000 RPM and Fuel Table goes to 6400 RPM's.

I eagerly await hearing back what you are currently using!

dave w

you sir are 100% correct about the pcm, it has the red and blue connectors. Thats exactly what i have, BUT when i rev/drive, it cuts fuel at 4500 or so.....

im at a loss on whats happening and what to do?

if you have instagram, go on there and search @princeshawn_ send me a request (my profile is private) and ill tag you in the video of it doing it.

i eliminated all the wiring stuff i didnt need such as transmission stuff since im running a manual t5 transmission. Also running blocked off throttle body with external regulator @16 psi.

it came from a 93gmc sierra.
from my understanding 88-92 didnt have rev limiters and 92-95 did @4800? Trucks that is....

[dave w]

Seems like to me the most likely cause is loss of spark or fuel. Let's assume for the moment the PCM is doing as programmed. Let's see if we can prove the spark is doing as commanded by the PCM. Let's see if we can prove the injectors are doing as commanded by the PCM. My tool of choice to figure what is happening would be a Wide Band O2 Sensor (WBO2) to see what is happening with the Air Fuel Ratio's. If for say the WBO2 shows an AFR greater than 15.5:1 @ 4500, it would indicate a lean mixture. If for example the WBO2 showed an AFR less than 12:1 @ 4500 it could indicate the spark is cutting out and causing unburned fuel into the exhaust. A rich WBO2 reading @ 4500 RPM could also mean the PE is lean.

Without a data log, or WBO2 data I'm only guessing what might be happening. Maybe toss a different PCM into the troubleshooting mix to see if maybe an injector driver is going out?

I have personal experience that a properly functioning 16196395 PCM can rev an engine to 6000 RPM and slightly beyond.

The 16196395 can be configured to show the WBO2 information in a data log. See attached monitors screen shot of a 16196395 PCM with WBO2 information in the data log. The monitors data can be a gold mine of information to troubleshoot with!

dave w

[Shawn1989]

http://www.pirate4x4.com/forum/chevy...v-limiter.html

post #8, he even says it does. Hmmmm would 88-92 pcm work if i repin it?

[Shawn1989]

Its definately cutting fuel. I watch it with my own eyes. No air filter, no cup around the injectors, i watch it dump fuel onto the throttle plates.......
No matter how fast or slow i rev, it cuts it at 4500 and resumes @+/-4100
when it cuts, fuel pressure is at about 13psi or so.

[dave w]

I think maybe a good option for your application would be a system from Dynamic EFI.
http://www.dynamicefi.com/EBL_Choice.php

dave w

[Fast355]

Its definately cutting fuel. I watch it with my own eyes. No air filter, no cup around the injectors, i watch it dump fuel onto the throttle plates.......
No matter how fast or slow i rev, it cuts it at 4500 and resumes @+/-4100
when it cuts, fuel pressure is at about 13psi or so.

The 93-98 TBI PCMs cut fuel injectors at 4,800 RPM or 98 MPH.

[dave w]

The 93-98 TBI PCMs cut fuel injectors at 4,800 RPM or 98 MPH.

What was I thinking? I agree, the stock parameters, see attached.

dave w

[Six_Shooter]

Your best bet is to tune the PCM you have.

The fact that you have simply removed the trans stuff without changing the bin file to reflect these changes will cause problems in the long run.

There are no other ECMs that will be as good of a choice as what you have.

[Shawn1989]

Perfect. If i send my chip to any of you guys, can you raise fuel cut to like 6500-7000 or does this require a new chip and how much will you guys do it for?

[Six_Shooter]

Why don't you buy the tuning equipment so that you can do it yourself? This way as you make changes you can tune it for each change.

[Shawn1989]

Cause honestly i hve no idea how to do it or what to download or what to buy lol.

no idea how to tune. Etc. if you can link me to a good source then maybe we can get started on the process ;)

[Six_Shooter]

www.gearhead-efi.com

;)

There was a time when we didn't know what we were doing and we had less support and instruction than is available today. Just take it in small steps. Research what equipment you need for your particular ECM, take a look at what other people are using, take a look at our sponsors. ;)

It's not really that difficult, you just have to make logical changes and steps.

[Shawn1989]

Are there any picture tutorials? Lol

and how much money do you think i will have invested by the time i buy all the hardwareand download all the software then get to tuning?