Moonan55

Okay I Know there has been a million questions about this but I'm still confused. My 85 has the 85mph speedo with the dummy lights and giant gas gauge, and I want to swap it with an 1988 one with a tach (110mph). I know the oil pressure sensors and water temp sensors are different, and was wondering if anyone knows which ones I need to replace the old ones with. There are like 4 different types, and I don't know which ones I need. My car is a 1985 Sport coupe with v8 305 and Vin number letter "G" if that helps. Any help is appreciated

fuchs

your '85 might have a cable driven speedo, the '88 will probably have an electronic speedometer.
The difference is obvious to see: the mechanical speed has a thick cable coming out of it.
Apart from that there's a few minor differences as well.

I didn't even know you could get a v8 with the base instrument cluster.

8t2 z-chev

Camaro speedos were cable drive up through '89(firebirds switched in '86-except base cluster stayed cable for a couple more years) IIRC,there is some changes in cluster plug pinouts between '82-86 and '87-89 Camaro clusters.82-85 sport coupe v8 should use gauge senders suitable for the cluster swap-later oil sender will have oil pressure switch built in for electric fuel pump control.

JCMaedl

My searching skills are probably not the greatest, but I haven't seen an answer for these questions. I have an 82 Firebird base 2.8 v6 with the giant speed and fuel gauges with telltale only, like OP I would just like a dash with decent gauges. I have found the service manual (official GM) to be painful to use.. stuff like 10 pages on the power antenna functionality, and half-mentions of things like the functionality of the instruments. I haven't purchased a new dash yet, want to make sure I'm getting the right stuff and know how to connect it.

1. Is the panel truly drop-in replacement? I noticed in the manual it says that both the wiring harness is the same, and then later shows different pinouts for the PCB.

2. what would need to be done to connect the tach? Does the extra board come with the cluster? Does the wire connect to the distributor?

3. I realize I need to change from switches to senders. In the service manual, for the V6 it does not show a distinct water sender, just 2 for oil. V8 and I4 have both. See pic.

fuchs

@@JCMaedl

Spend some time learning to use the GM service manual. It's really nice once you learn to work with it. Once you realize the components appear multiple times in the manual, and are discussed based on their context you'd probably appreciate it. The mechanical aspects are discussed in a different place than the electrical aspects. Maybe try section 8A-200 and further, it would should the location of many electrical components.

1] I doubt it. If you would be able to find a nice 82-84 rally gages cluster, you would be close. I'd still recommend checking the pinout. If you short it out, you would waste money and effort.

2] The tach connects directly to the ignition coil/distributor. There may not be a wire in place. I guess it should be white if there is one. You can look up the exact colors used in section 8A index, then Tachometer.


3] "Coolant Temperature Switch (VIN S) . . . . . . . . . . . . . . . . . . . . . . . Front LB side of engine, below valve cover.
Coolant Temperature Switch (VIN 2) ....................... Top LH rear of engine "

JCMaedl

Thanks for the reply!

I feel like I do have a decent understanding of how to use the manual, however the repair and part descriptions are not very thorough. It is the genuine GM manual.

Since my post I have acquired a genuine parts catalog as a supplement (PDF format). It is amazingly detailed and almost 1, 200 pages, so I sliced out all the pages that match my year and engine. I have gotten a hugely better result using the two together. I was able to locate the senders I need and find replacements. The service manual appears to leave out the coolant sensors but they are clearly shown in the parts manual.

The engine in your picture appears to be a V8 based on the illustrations I have seen... Can I ask where in the documents it came from?

As for the pinouts, it does seem as though drop in is possible with just a few mods. Hopefully it will turn out.

Thanks again!

1989karr

you'd need to replace the coolant temp sensor, the oil sensor.

if you go to like napa you can ask them and they wil lask you "light or gauge?"

I have seen some VERY nice 82 - 84 gauges on facebook...problem is, I don;t know if the V6 uses a different tach like the newer 87 up models supposedly do

JCMaedl

Yes, my car currently has only the "idiot lights" that just tell you when you are already done for, hah.

Indeed they need to be changed from "switches" to "senders" or "sensors." This language is similar to, but not the same as in the parts manual, but it is pretty easy to match up using both diagrams.

It refers to the same part in the diagram twice and lists the Oil one as "Oil pressure Sender w/gages" and "oil pressure switch." Same for Coolant, except it says "coolant sensor" and "coolant switch EXCL gages" - the opposite way. I found the replacements on RockAuto by using the part number found in the PDF. IMHO the parts manual is essential for effective use of the servicr manual.

Yes the tach calibration is different for v6 and v8. The service manual refers to a resistor bar that can be set depending on the engine. From what I have read on here tho, calibrating these things can be tricky, and does not improve with age, so am going to buy a custom digital replacement board mentioned here that can handle all that stuff with modern electronics attached to the original tach.

Thanks for the responses, I think I should be OK!