1995 C3500 454 OBD1 questions - Chevelle Tech
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post #1 of 15 (permalink) Old Feb 4th, 19, 1:44 AM Thread Starter
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Greg
 
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1995 C3500 454 OBD1 questions

A little background- I’m familiar with RS232/422/485 and have a bag full of various network adapters (most have FTDI chipsets)..
Now my questions: I’d like to get into the ECM of my 95C3500 454 TBI. Long story short, about to put headers, a small cam, etc to try and get more towing power and want the ability to change timing maps, etc.
Looking on the interwebz, downloaded Tunerpro RT. Rigged up a cable to my OBD1 port per diagram (interestingly, interwebz indicated my 95 should have an OBD2 style plug but system is still OBD1. Mine has an OBD1 plug. Hasn’t been changed, I bought this truck brand new in ‘95..)
Now my Only problem is my usb>serial port RS232 converter won’t do 8192 baud..I can see it starts trying to communicate (LEDS) then drops out. ?? What baud rate do I set my Win7 serial port!? Tried setting port @ 9600 and TPSoftware @ 9600, didn’t work either.
Next, what’s needed to change parameters on the ECM chip? Am I going to have to drop $350 on all the EEPROM burning stuff (I.e. Moates) or what?
If that’s the route I have to go, TBI/intake/ignition will end up in the bottom of a lake and I’ll put a carb and HEI on it..
Anyone have some input?

Greg C.
1969 Chevelle Malibu
New 496 bullet under construction..
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post #2 of 15 (permalink) Old Feb 4th, 19, 7:27 AM Thread Starter
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After not being able to sleep because I couldn’t figure out what was happening, I got up and started researching.
Figured out why I couldn’t connect to it yesterday. Duh!
Also know about the EPROM that supposed to be in the ECM now, where and how to get a blank chip or emulator, and how to burn a new EPROM.
Biggest thing I learned is that the more I learn about EFI, and these automotive controls, the greater my love for a Holley carb and HEI becomes!!
And that’s coming from a fella that works as a Building Automation Systems Engineer!!!
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post #3 of 15 (permalink) Old Feb 4th, 19, 7:36 AM
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Rick
 
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Re: 1995 C3500 454 OBD1 questions

Some of those supposed FTDI chipsets in the adapters are often cheap Chinese clones of Prolific chipsets. And they are not particularly good copies.

I went through this problem a while back when computers stopped having real, no kidding hardware Comm ports for Comm 1. I need this so that my PC computer can talk with the computer inside my Icom HF radio - I'm a ham / amateur radio operator.

Rick

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post #4 of 15 (permalink) Old Feb 4th, 19, 7:44 AM
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Re: 1995 C3500 454 OBD1 questions

Quote:
Originally Posted by Iforgot View Post
After not being able to sleep because I couldnít figure out what was happening, I got up and started researching.
Figured out why I couldnít connect to it yesterday. Duh!
Also know about the EPROM that supposed to be in the ECM now, where and how to get a blank chip or emulator, and how to burn a new EPROM.
Biggest thing I learned is that the more I learn about EFI, and these automotive controls, the greater my love for a Holley carb and HEI becomes!!
And thatís coming from a fella that works as a Building Automation Systems Engineer!!!
What was the problem. I have fought many COM port battles in the past, but luckily not in quite a while. Last time was to console into an older smart networking switch. I think I used 3 different adapters and about 2 hours to get it to communicate.

1967 El Camino Malibu - Deepwater Blue
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post #5 of 15 (permalink) Old Feb 4th, 19, 9:46 AM Thread Starter
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Re: 1995 C3500 454 OBD1 questions

Quote:
Originally Posted by Pioneer4x4 View Post
What was the problem. I have fought many COM port battles in the past, but luckily not in quite a while. Last time was to console into an older smart networking switch. I think I used 3 different adapters and about 2 hours to get it to communicate.
Well, seems there wasn't one...forgot to connect everything THEN turn key to acc, etc...oops.



Also- using one of the RS232/422/485 converters we have here at work, VSCOM - USB to Serial: VScom USB-COMi-M is what we have. FTDI it's got external DIP switches to select RS232/422/485 and internal removable jumpers for pulldown-pullup-termination bias-3.3v power supply or 5v power supply on-off-etc. FTDI chipset, nice little device. Haven't found very many devices it WON'T talk to!
That said, there's probably more knockoffs out there that are not FTDI chipsets that wreak all kinda havoc. Haven't got a COMi-M device yet that was fake-or at least was fake and I didn't know it.

Even used one to fix the communication link at the dragstrip between the ET ticket printer and the Tower last year!

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post #6 of 15 (permalink) Old Feb 4th, 19, 10:15 AM
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Gary
 
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Re: 1995 C3500 454 OBD1 questions

I know what I would do if I were you. I would bolt some 96 and later Vortec l-29 cylinder heads on that thing with a q jet and an HEI. If I wanted fuel injection I would probably go with a new aftermarket system from Holley. easier to tune faster more capable ecm. i dont see why you couldnt use an aftermarket ecm to run the stock system as far as that goes as long as the injectors are compatable. If you still want to use the stock system there are people out there still burning proms. i would check with ed wright at fast chip
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post #7 of 15 (permalink) Old Feb 4th, 19, 10:33 AM
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Re: 1995 C3500 454 OBD1 questions

Gearheadefi.com has a good bit of support for those who are going to work on the older stuff...
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post #8 of 15 (permalink) Old Feb 4th, 19, 3:46 PM Thread Starter
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Quote:
Originally Posted by gnicholson View Post
I know what I would do if I were you. I would bolt some 96 and later Vortec l-29 cylinder heads on that thing with a q jet and an HEI. If I wanted fuel injection I would probably go with a new aftermarket system from Holley. easier to tune faster more capable ecm. i dont see why you couldnt use an aftermarket ecm to run the stock system as far as that goes as long as the injectors are compatable. If you still want to use the stock system there are people out there still burning proms. i would check with ed wright at fast chip
That was my original plan!! Then I caught so much flack about taking off this wonderful fuel injection, figured what the heck. That said..
I was planning on burning my own chip, but honestly the deeper in this I dig the worse (expensive) it looks. Plus keeps getting more complicated!
I mess with enough sensors and “ecm’s” from 7-4 every weekday.
Sure leaning back towards throwing this fine TBI in the lake and following the KISS principle ESPECIALLY since it’s a NV4500 manual trans!!

Greg C.
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post #9 of 15 (permalink) Old Feb 4th, 19, 4:29 PM
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Gary
 
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Re: 1995 C3500 454 OBD1 questions

i wouldnt take it off if it was the newer port injection. its not that the 87 to 95 tbi systems are bad . i wouldnt want to burn a prom for every change i wanted to make for one thing. the tb doesnt flow alot of air. good ol qjet and hei are hard to beat
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post #10 of 15 (permalink) Old Feb 4th, 19, 4:51 PM
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Re: 1995 C3500 454 OBD1 questions

I did a lot of prom burning with my TPI third gen camaro, then started to with my 89 TBI stepside. While I made improvements tuning it, it wasn't worth the effort compared to doing a carb/HEI swap. I never looked back. It was a pita. Scan while driving, upload data, analyze, make changes, burn new chip, drive and scan, upload, analyze, make changes, burn another chip, repeat, repeat, repeat. TPI could get to light right up without excessive cranking, TBI always seemed like a dry carb first start of the day no matter what I did. That was my biggest complaint. I used to use Tunercat and a pocket programmer II, but I think Jet bought Tunercat out. Life is supposed to get easier as we get older, not harder.
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post #11 of 15 (permalink) Old Feb 4th, 19, 8:16 PM Thread Starter
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Re: 1995 C3500 454 OBD1 questions

Quote:
Originally Posted by ZZ69chevelle View Post
I did a lot of prom burning with my TPI third gen camaro, then started to with my 89 TBI stepside. While I made improvements tuning it, it wasn't worth the effort compared to doing a carb/HEI swap. I never looked back. It was a pita. Scan while driving, upload data, analyze, make changes, burn new chip, drive and scan, upload, analyze, make changes, burn another chip, repeat, repeat, repeat. TPI could get to light right up without excessive cranking, TBI always seemed like a dry carb first start of the day no matter what I did. That was my biggest complaint. I used to use Tunercat and a pocket programmer II, but I think Jet bought Tunercat out. Life is supposed to get easier as we get older, not harder.
You read my mind.

Been out here TWO AND A HALF HOURS. Got connected to it finally, but it's got so many variables that depend on other variables that depend on other variables..

Thought I fried it a few minutes ago. Turns out I didn't tighten th e negative battery cable good..

I could be inside the shop running valves on a restored 64 Impala SS 425/409/2 4's.

But NOOOOOOO I'm out here chasing 30+ year old tech that was no better than the 60 year old tech it replaced.

TBI WILL get thrown down the hill and used for target practice.
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post #12 of 15 (permalink) Old Feb 4th, 19, 8:27 PM
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Re: 1995 C3500 454 OBD1 questions

Don't shoot it up just yet. I got $125 for my 454's TB from a guy upgrading a small block TB.
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post #13 of 15 (permalink) Old Feb 4th, 19, 11:22 PM Thread Starter
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Heck with it. Impala sho is purtier!!
1964 SS, 425HP 409, 4 speed, two fours, got to run valves, little tune up, niiice car!
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post #14 of 15 (permalink) Old Feb 6th, 19, 11:31 AM
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Re: 1995 C3500 454 OBD1 questions

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Originally Posted by Iforgot View Post
Sure leaning back towards throwing this fine TBI in the lake and following the KISS principle ESPECIALLY since itís a NV4500 manual trans!!
Funny you should mention the nv4500, I didn't know they came behind gas burners in GM's. I have a couple of diesel spec 2wd 4500's sitting around, spares for my dually. They are truly the "little" transmission that could-I've laid down some decently stout torque through those with no breakage. I even have one with an aftermarket bellhousing adapter for use behind a chevy. I guess your factory bellhousing does that.

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post #15 of 15 (permalink) Old Feb 6th, 19, 3:55 PM
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Re: 1995 C3500 454 OBD1 questions

The nv4500s are very popular with the 4wd crowds. They bolt to anything and are dang near bullet proof.

I came in on the LT1 tuning, 92-95s, and had my fair share of fun with RS232 ports and adapters. One of the weirdest problems I ran into was my rs232 port on my laptop didn't have enough output to keep the MAX232 chip happy. Ended up having to add a voltage regulator and power the adapter off the cigarette outlet.

I've heard of some success stories w/ the Moates Ostrich cable but heard it could be a pain too. If you do decide to get into it, this may be a isolated case, but my buddy had Moates piggyback memcal board and kept having problems with it running. Brought it to me, found the piggyback board had bad solder joints.

Good luck!

*Jeff*

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