92 Z28 5.7 auto
ok guys removing the GM ecm & harness.. whats left working in dash?
its a lot to ask I know..just want to know.. going with another EFI set up..
fitech

have always kept the dash working (but thinking I need to move on)
will the stock dash still
gas gauge? (aftermarket aluminum gas tank) and sending unit GM

trans speedo (manual auto no kickdown needed in this unit)

tach stock will it still work?
what will it take to keep the stock dash gauges working? if not then..out it all comes...

 

I think the tach goes through c100 so it’s separate from the efi harness.
To keep the stock speedometer you need the ecm or a vss buffer from a tpi maf or tbi car.

 

I don't know the wiring in your Camaro but based on experience with my 89 Firebird, most gauges are wired to things in the engine bay thru C100 connector. I think the only gauge that won't work will be speedometer and the check engine light. And PASSkey won't work anymore either. You'll have to look at a wiring diagram for your car but I suspect one of the ground wires in the ECM harness that goes to engine bay needs to be retained (or rerouted). It would be the ground wire common to PASSkey, OBD1 diagnostics port, and maybe even speedometer buffer.

Your interior looks like hardcore rice had their way with it. That is horrible man.

 

its a bit busy
sorry ya dont like it...its not a girls car...
no holes drilled..anyplace..in the interior for the Gauges..all in GM screw locations.. have had the car from day one from GM..it can all be removed with out damage... this was done after the car came back from Lingenfelters. In 1992.
some guys just don't like to cut up there cars...and some guys just drive slow cars/birds....me I dont cut mine up..

have always kept the cars stock gauges and things working..
but that has been the last 25 years..
the 10s and 11s in the 90s they were Fun..but its time to go faster...

for 2018 this is the new eng (but with a aluminum block and dual TBs)no carb..


just taking the step of going away from the GM efi.. and want to know what to look forward/problems..

edit to add...its going to be a pain....

 

I am prepping for aftermarket gages but I don't want to hack up my original gage pod either, and still want stock gages to work if I pop that gage pod back in. I bought another stock gage pod that I cut up and fitted with aftermarket gages (Speedhut). My plan is to create dual pigtails in the wiring harness. Stock pigtails will plug into the stock gage pod and everything work. The custom pigtail will plug into the aftermarket gage pod and everything work. I think that kind of idea is along the lines of what might suit your fancy.

It's not quite as easy as it seems though, so you'll need the wiring diagrams for your year vehicle to get it right. Here is example of the prep work that I have done so far. It's not finished yet and some of the more important details are yet to be completed but I'll get there eventually. It's just a side project that has been sitting for a while.

https://www.thirdgen.org/forums/ltx-...ml#post6111293

 

Not true. The PASSkey module will still work. I've been running MegaSquirt for years now and wondered if it rendered the PASSkey setup null so I bought an ignition key with a different resistor and had it cut at an Ace/TruValue ($1.50!) Popped it in the ignition and nothing. It would unlock the steering wheel and the key would turn the cylinder but the PASSkey module was still doing it's job.

 

I thought PASSkey requires permission from engine ECM, but I can't remember if it enables crank (start relay) or enables fuel injectors?

When I modified my car I defeated PASSkey from the beginning so I don't have experience trying it any other way.

https://www.thirdgen.org/forums/ltx-...ml#post5963351

 

It does both.
http://www.austinthirdgen.org/mkport...m_pass-key.jpg
It sends a signal to the ecm for the injectors as well as grounding the microswitch in the relay of the starter circuit.

 

Zip your lip, your car hasn't driven anywhere in years.

I do hope you get it going though and I hope you have fun with it. But seriously, you're in smack talk jail until then.

(this is all in good fun, of course)

 

I don't understand the deep inner workings of the PASSkey. You are saying the "key resistor" portion enables start relay, while the "PWM" portion enables fuel, and they operate independently?

You've got me scratching my head wondering why everybody is concerned about defeating VATS with engine swaps... old wives tale?

 

I believe that the key enables (or disables) both functions of the system. One is a simple grounding function and the other is the function to the ecm.

If you have the same key and PASSkey module there is no need to go to the trouble of removing or disabling it for an engine swap. My PASSkey system worked fine for 17 years, it presided over my MegaSquirt I, II and now III swap with never a hiccup. Until the fire, but that is a story for a different time.

 

I'm just astonished that you're the first person I've ever seen point this out. If it is true then it needs to be in a VATS sticky.

 

its all in fun...

cars has set since 03...locked away..but the last 7 years just putting stuff together...did a small block 427..before install..wanted to go big block..so every thing stopped..no install..just a wall hanger now..

back when the car was new.. LPE did all the stage 5 upgrades.383. exhaust. gears. trans.
ecm w/chip. the car ran fantastic..for over 9 years..then a rod let go...so I parked it...pic is from 92/93


so now with the BBC I want to make things easy..if I can..just did not want to shut the dash down..and if I had to I can swap everything out to autometer gauges..

side note I do have the 3" think GM shop manual...

 

There's that old adage about a lie getting halfway around the globe before the truth can put it's pants on.
Maybe I'm wrong and my personal experience has been a lucky for me outlier but I don't think so. I remember trying it a few weeks ago when the module was disconnected and nothing turned over.

 

There should be a sticky about vats or a additional information on the how to thread.
https://www.thirdgen.org/vats/

 

Not sure about that one but my ecm and harness is in a box out in the garage on the shelf. All my gauges work in my TA except for the temp gauge. I/m still trying to figure that out. I put a quick fuel carb and a regular mechanical fuel pump. No problems, I also done this same thing to a 1985 Z28. My car is a 1985 TA

 

eng..10.0 lol(625cid)
kewl... hoping to make it easy...always like the fact all my stuff still worked..with all the after market parts.. even the dome light and CD player..its the small things that make ya smile... have about 10/12 auto meter gauges started with sport comp..then went with procomp to match the yellow in the dash..all the sport comp gauges in the pic above are coming out..and getting the procomp stuff..

switch panel in the pic is coming out and replacing the vents in the dash..
custom panel getting made to hold gauges in its place.
have a A piller mount for gauges..but ditched that..after seeing others...dont like the way they look.

so much stuff is going to be left over....lol

 

This should help a little !





http://berlinetta.info/C207.htm

 

To add to Post #2
If you get rid of the ecm b9 and b10 need to go to a buffer box to feed the ip .
Not sure what pin P is used for unless it’s the signal from the ecm to the ip speedometer.
Here is how you can rewire it if you want to get rid of the ecm.




The out to ecm is a brown wire at the ecm pin b11

 

this don't look so easy..lol..

 

I took the passenger side harness out of my '86,
I believe the only wire I kept was the heater motor wire from that harness.
I'll double check that, but everything on the dash still works.
Mine is a cable speedometer car though

 

I have the VSS..but good info thank you...

 

If you want to record mph in your data logs then you'll need to give your fuel injection system a signal it can understand.

I don't know how your set up works but my Holley HP EFI only understands a Hall Effect speed sensor. The transmission has a magnectic pickup speed sender. And the factory speedometer only understands a 4000 PPM (pulse per mile) signal. That is 3 different type of signals. Oh, and the cruise control needs a 2000 PPM signal.

The way I overcame this was to ditch the factory speed buffer box and use a Dakota Digital SGI-5 instead. The SGI-5 device accepts the transmission speed signal and converts it to 5 different output signals you can use. Output #4 will run the speedometer, there is another output that will run the cruise control, and Output #1 was good enough to fool the HP EFI into thinking it sees a Hall Effect sensor.

This is how i wired it, Post #178, https://www.thirdgen.org/forums/ltx-...ml#post5821648