ill

Hey all! Doing alot more digging into my 91 and im gonna start off by explaining what the car is and has had done to it and the issues ive been having so first off the car does start and drive just fine (it has a “built” 700r4 from what i was told however ive noticed my first gear shifts very quick unsure if thats normal) the car is no longer the factory 5.0 tpi the po installed a 383 crate so my ecm (a cardone 77-7730) is only controlling the speed sensor and my ses light currently and nothing else as its quite literally connected to nothing else as i have a new aeromotive tank, stealth wiring harness (which is wired on its own standalone system) and an aeromotive efi to carb fuel pressure regulator. The problems im having which is leading me to believe i have a possibly faulty ecm would be my speedometer odometer and cruise control do not work in the slightest, I have already tried pulling codes via grounding the aldl and i couldnt even get the ses light to come on at all. Ive already checked all grounds and fuses in the vehicle to no avail, i have even replaced the speedometer circuit board in hopes that maybe that was just dead and that did not help either. Im just at a complete loss here as to what my issue is as ive tried everything i could (ecm aside) on the site so i guess my only question is could it possibly be the ecm at fault here?

Tuned Performance

iTrader: (92)

You’re just using the ecm as a Vss buffer ? Is it powered up ?

ill

Correct i am indeed using it only as a vss buffer. All of the original wiring to the ecm is still intact so it certainly should be getting power, Oddly enough a few more things i figured out i also have a power draw coming from somewhere as when my car sits overnight the battery drains to around 12.1-12.2 the ecm itself also looks pretty rough the casing actually has rust on it somehow i presume from water damage as i noticed i had a damp passenger floor and water was getting in right at where the po installed a heater delete plate (right behind the ecm) and didnt put any sealer on the back (which i have since done) the random power draw, the lack of a ses light even when grounded and the couple of gauges i mentioned not working plus everything i have done to fix the issue has just led me to start thinking it could be a malfunctioning ecm

Tuned Performance

iTrader: (92)

If B1,c16 are hot all the time it’s normal to have an amp draw do a parasitic draw test. If they are hot and the turn on a6 is good and grounds verified the ecm is bad.

Tuned Performance

iTrader: (92)

If you unplug the connectors and ground e7 the mil will light if build is good and it has power from ip.

RBob

iTrader: (1)

Not sure why you even bother with an unreliable '7730 ECM just for a VSS buffer. Find yourself a stock 4_Out_Buffer box or even use a Dakota Digital buffer box. Be done with that ECM and go simple (the KISS approach)..

RBob.

ill

I actually have a sgi-100bt sitting aside for a project i never used im just unsure on how to wire it properly as i obviously have a 7730 ecm with the integrated buffer and havent seen anyone on here show how they wired one up on a 7730 without one of the yellow buffers. I was assuming i would remove the ecm and cut the vss wires right at the ecm connectors and place the dakota digital box there then connect the wire that runs to the gauge, if any of you can clear up if thats how i should wire it then ill just go that route and be done with the ecm entirely as i do not need it for anything besides my speedometer currently.

Tuned Performance

iTrader: (92)

https://www.thirdgen.org/forums/elec...c-instead.html

https://www.thirdgen.org/forums/elec...-question.html

seems like we have already covered this

ill

we indeed have however im still just slightly confused as i just stated i personally have never seen someone show pictures or anything about wiring in a dakota digital box when you have an ecm without the yellow buffer, i wanna avoid getting a new connector and wires for the vss nobody has quite answered whether its a good idea to cut the wires for the vss right before the ecm connector as again i do not want to get a new connector for the vss and run two new wires when theres two existing wires already

Tuned Performance

iTrader: (92)

If you don’t want to cut the wire and want slightly longer unpin then cut off the terminal.

ill

I dont mind cutting the wire before the ecm connector i dont wanna have to go through depinning it when i just gotta strip the wire anyway since the dakota digital box has screws to lock wires into it. I just need to know if it will work cutting the wires right there or if the vss wires run through the car somewhere else where it would be smarter to cut

Tuned Performance

iTrader: (92)

They go out the passenger side under the kick panel through a pass through connector. Then by the distributor down the transmission tunnel to the Vss. You’re overthinking it. Cars already not original so what does it matter.

ill

Ok so that answers my old threads original question then. I wouldnt have minded adding a new connector and new wires your correct it doesnt matter since the cars far from original, However it is just much easier imo using wires that are already there and routed into the cab of the car instead of having to jack the car up add a new connector then route new wires all the way through the tunnel and into the cab of the car

ill

Wanted to update this thread by saying i have since wired up my SGI-100BT and fixed my dead speedometer! Also wanna clarify i never found the exact cause of why my speedometer and odometer died in the first place, before installing the SGi i replaced my stock ecm (which i have also since removed) so if i had any guess it was definitely ecm/prom related. If anyone in the future needs help or just has some questions on how to install one of these then feel free to reply or send me a pm and ill try and help out as much as i can!