ill

Ive got a 91 camaro with a strange issue and looking for a little assistance! My speedometer or odometer has not worked since i bought the car. Initially i figured it was the speed sensor however im not having any form of transmission troubles or check engine lights. The gauge itself seems to be funtional as i turn the key it bounces the needle up a tiny bit but will not move at all afterwards, could this be a faulty gauge or even just the circuit board?

Tuned Performance

iTrader: (92)

Automatic? Does tcc lock ?
tbi or 3.1 or tpi ?

sofakingdom

iTrader: (1)

Based on this post, your problem is, that someone has done something (or more likely, MANY somethings) to your car's wiring. All your posts are covered by the main piece of info contained in this one.

https://www.thirdgen.org/forums/elec...t-scratch.html

Unfortunately, no one out here is going to be able to look into your car FOR YOU and immediately tell you what they hacked up, and how. Every hack is different. Only you can inspect it and find all the places (quite numerous, obviously) that this individual destroyed stuff in their process of "improving" the car.

Best place to start is to get a copy of the FSM. (yeah I know) No other resource will do. Forget about Chilton's, Haynes, etc. You need the FSM, since ONLY THAT will have the exact wiring diagrams for your car. Then, once you have that, go over the whole harness in detail, finding and identifying all the cuts, splices, loose connectors, missing parts, add-ons, etc. etc. etc. ("improvements"). Only then will you know what forms of sodomy and butchery have been visited upon your poor car. Without FIRST figuring out what has happened to it, it's IMPOSSIBLE to figure out what you have to do to get it to work again.

ill

Its an automatic that was originally a 305 tpi which has since been converted to a carbed 383. The transmission is still the 700r4 slightly modified to handle more power however it does not lock

ill

Thank you very much for this! It is very unfortunate what the previous owener did to the car and im certainly trying my best to correct what he did wrong, I will pickup a copy of the fsm and go from there! To say he butchered the wiring harness is an understatement to be quite honest, with the amount of cut and damaged wires it genuinely shocks me that it still fires up!

OrangeBird

iTrader: (1)

When you start a "blind" thread like this, without providing this bit information that the car has been majorly effed with, how can anyone possibly provide the answer to why your speedometer is dead? If this was a bone stock unmolested car everyone would be on the same page, troubleshooting wise, but this car is anything but factory stock. Given your situation with how deep you are into this poor car's electrical needs the question has gotta be asked: What is an honest assessment of your automotive electrical understanding and abilities? I ask this because your gonna need to go over this car's circuits one by one to get your speedometer back, and your gonna need to understand how to electrically restore what's needed. While an on line chat board can be a great info resource, it'll ultimately come down to someone with fairly extensive automotive electrical skills actually laying hands on the car.

So, If I were to throw out a wild azzed guess, it would be that during the conversion to the carbed 383, the ECM and it's wiring that ran the 305 TPI got removed as being "not needed".

Well, unfortunately, for your poor speedometer, yeah it was needed (well, at least it's shared wiring, and if the VSS buffer is in the ECM then yeah that to.I just don't recall offhand if the buffer is in the ECM or not )....

Tuned Performance

iTrader: (92)

Yes the buffer is in the 1227730 ecm. First spot is look then get a Dakota digital sgi-100bt and see if lockup is wired in for the 700r4.

ill

I wasn’t asking someone to fix it for me or tell me the exact cause im more than capable of doing so i was just looking for pointers as to where i should start and what the most common cause is so i dont have to spend weeks searching 🤷🏻‍♂️, ive already gone and re-wired every gauge and got them working (speedometer aside) along with many many other electrical components so im certainly capable of tackling a speedometer. It still has the ecm and every bit of wiring aside from heat and ac the only hacked up wiring it has is in the bay around the c100 where it appears they just cut off every connector that the car wasnt using and was left that way, the car still functions and drives amazingly the speedometer and odometer is the only thing in the car that doesnt work

Tuned Performance

iTrader: (92)

This has a lockup converter ?

ill

It does not have a lockup converter, the car is bone stock aside from having the 383 put in the trans being built for more power and the ac/heat removed, it was originally a 5.0 tpi and still has the wiring harness and ecm in the car

Tuned Performance

iTrader: (92)

Okay if it’s a stock converter I’d address the lockup issues as well.You say it’s built, then you say bone stock other than 383 and carb so who knows.
id check the 2 constant powers at the ecm and turn on as well as grounds to make sure the ecm is powered up and working as a buffer. If it is then go for a drive and watch Vss voltage yellow and purple at pin b9 and b10 of the ecm.
if all that checks out I’d suspect something wrong in the ip cluster.

https://tpiparts.net/1227730_pinout_diagram

ill

Im not entirely sure on alot about the car as i sadly wasnt the one to do all the work on it. What i meant by its built is its a 383 cranking close to 500hp on dyno sheets, by stock i mean everything else on the car wiring wise.I did some testing and the ecm does turn on however and maybe a stupid question but should i be testing the vss ground? (Purple wire) or just every ground connected to the ecm? The needle of the gauge does move up a tiny bit when the car is started then just stops and drops back down when its shut off

Tuned Performance

iTrader: (92)

Here’s a video, you will backprobe the ecm yellow and purple and drive the car. Same concept.

sofakingdom

iTrader: (1)

And then of course, track down and repair all 532.7 other things the PO fornicated about the car with his dykes. One at a time.

All the crap about "383" and "500 HP" is MEANINGLESS. Some dipweed EFFFFFED UP the car, and at some level, that's all that really matters. You're the lucky victim that shouldn't have bought it, and like SO MANY others, come on here all about "I bought this car that..." instead of using common sense and asking "should I buy this car that..." Oh well, what's done is done, neither you nor the rest of us can go back and change the past, all we can do is help you recover from your mistake. Which our help is gonna be kinda limited since we DON'T KNOW and CAN'T TELL what the PO butchered.

ill

Just an fyi its not butchered ive had many people in and around me people who work at well respected shops beg me not to daily drive it because its so clean, i mentioned the power rating and other things because all of you guys are asking about what the car is and saying im not providing info for suggestions or opinions. AGAIN I AM NOT ASKING YOU GUYS TO FIX MY CAR!! I simply asked for suggestions and tips so no need to get all upset and call other peoples cars mistakes and so “effed up” when cleary they arent, i daily drive the car with 0 issue besides me not being able to see how fast im going and yes i would consider myself very lucky to have got such a deal on this car so if your just gonna flame me and say me buying a car i love dearly and take care of with the upmost respect than kindly take your opinion to a different thread

sofakingdom

iTrader: (1)

Get the FSM. Trace all the way through all your wiring. Find what the PO butchered and hacked. Un-butcher and un-hack it.

Not really so hard. So simple in fact, even I can do it, occasionally anyway. You're WWWWAAAAAAYYYYYYY smarter than I'll ever be, shouldn't be any challenge at all.

Good luck.

ill

And thats exactly what im gonna do already picked one up didnt know there was a difference between manuals and there diagrams was all plus someone has already gave me a few pointers on what to look for first (which is what this post was for) so i got what i needed and thank you for the compliment its gonna be a breeeezeeeee 😉