bb92RS350

I converted my 92 camaro rs from a v-6 to a v-8. I knew that a the tach would be off and so i bought a v-8 cluster on ebay and installed it figureing that it would fix the problem but the tach is still off can anyone help me? Thanks

camarogirl18

iTrader: (2)

maybe try posting this in the eletronics or engine swap forums...they might could help ya out more

onebinky

iTrader: (1)

Do you know for sure the guage pod is from a V8? So far as I know, if you changed the ECM and the guage it should be accurate. How do you know it's not reading right?

Something else to check would be all the grounds under the dash. There should be something like 3 of them. Also, find out what value the tach wire should be reading and verify it with a multimeter.

Good luck

bb92RS350

I know the gauges are from a V-8 car with a 110 speedo. I guy at work with a TBI RS has the exact same gauge cluster. When i'm going 60 it says I'm spinning about 2,600 RPM the guy at work's is like 1,700. I anothter thing that has me to believe it is still not right it that i can take it over 7,000 RPM Tell me how many basicly stock small-block chevy's rev to 7 grand. some one said that it might be in the ECM. Looking at a schematic in a haynes manual the tach wire comes straight off of the distributor to the cluster. O and the ECM in my car isn't doing anything. I have a 70's era Q-jet sitting on my intake.

onebinky

iTrader: (1)

It's possible that he has a really low gear ratio in the rear, and you have one of the higher ones available. Or, maybe a previous owner swapped a higher gearset in to your car and didn't tell you about it. That is wierd that it will spin to 7000 rpm on a stock bottom end. Maybe see if you can find out how many volts the tach wire should read at a given RPM and test it with a voltmeter. That would tell you where the problem lies.

Good luck

bb92RS350

Back in i think late may when i first got the car running with the 350/700R4 combo my uncle helped me get the car in time and the Carb tuned a little better. To set the timing he used a timing light and a hand held tach. Probably like the volt meter you are talking about but marked for RPM's Another thing that tells me that my tach is off is that my dad has an s-10 with a 350, turbo 400, and 3.42 gears and at 60 he spins around 3000 grand. My car has 3.23 gears and the 700R4 overdrive so it should be a lot lower. I've seen where other people have used a resistor to set it right but i dont know where or how or which type to get to fix it.

bb92RS350

Gonna sound funny but i still have this problem in one of the first posts there was a mention about the ecm. Does the tach signal go through to the ECM and then to the gauge. All of the wiring diagrams i have seen including the one in the 1992 Camaro Service Manual (yeah the beast from gm) has the wire going directly to the gauges. And if it goes to the ecm then to the gauge then changing to a tpi 305 or 350 prom would fix this?

BigBadLou

iTrader: (3)

The tach signal travels through a direct wire from the coil/dist to the tachometer. The ECM is not involved. So swapping PROM's won't do anything.

The culprit is most likely in the tach driver module. This is a very common problem in thirdgens. The fix is pretty involved. Some people can fix these things but it's not cheap. And I am not aware of any place where you can buy a new driver module.

Hope this helps.
Lou

bb92RS350

the driver module is in the cluster???? cause i have replaced the cluster with V8 gauges before and it was the same as V6 that i am currently using

BigBadLou

iTrader: (3)

Correct, the driver module is inside the cluster, under the tach. The V8 cluster might just by coincidence show the same deviation in the reading that the old cluster did.

Mine shows exactly 50% more so at let's say 4000rpm, I'm redlining at 6k. And it's a V8 tach.

There was a thread recently with detailed analysis of the cluster and the driver circuitry. It might help shine some light on your problem.

Lou