Hello, I'm a new member to the forum. I rescued a 1990 a few weeks ago - my first corvette! - and there's been no end to the surprises from the PO. But this is something else. I've heard you can fix a glitchy tach with the right resistor, but not like this. What do you suppose this person was trying to do here?

 

Radio ignition interference

 

When you need a certain value resistor they may not make one with that value, so you have to put several together in series to come up with the value you need. Say you need a 4k ohm resistor and can't find one but you can find 1K ohm resistors. You solder 4 1K ohm resistors in series (like in the picture) and that gives you a 4K ohm resistor. Now why he did what he did I have no idea. Usually, if you're going to make a filter you use a capacitor or a capacitor and a resistor together.

 

One more resister would have worked better.

 

Welcome to the Corvette Forum RescueVette!

I am probably not the first to suggest this but you need to get a set of the Factory Service Manuals for your particular year. They will be VERY helpful undoing the stuff "Bubba" did to your Corvette. On my 1988 C4 they had two manuals making up the set. One was for the mechanical stuff and the second has the electrical system completely covered. Don't trust any Chiltons, Haynes or whatever, get the original FSM in print or a bit cheaper on CD on Fleabay. The original FSM's were printed by HELM Publishers, they are a bit steep price-wise but worth every penny at times.

Get a Fuel Pressure Gauge and a good Volt Ohm Meter to start with your Corvette. Both will be used frequently in maintaining your Corvette. An OBD1 scanner is a helpful tool to have as well. I have an old Snap On MT 2500 which does a great job of showing what the ECM see's.

Good Luck and when you have questions We have ears and answers for you! Enjoy your Corvette, take good care of it and it will provide you with years of fun experiences.

Best regards,
Chris

 

I've been using Chiltons for 40 years with many classics and hot rods and just plain ol' cars. I now have an '85 Vette. I bought it 4 years ago, along with a Chilton's manual to go with it. I've updated, upgraded everything on the engine, sensors, switches, relays, wires, vacuum lines, and done a good amount of mods without tearing the engine apart. My Chilton's is filthy and in tatters with sticky notes, and all variety of page markers and such. But I know for a fact that my trusty Chilton's manual can get me through the toughest repairs and help me make whatever mods I can dream of. The Schematics are fantastic. I'm mechanically inclined and I'm also an excellent electronics technician. I always find the electronics data in the Chilton's to be dead on and easy to follow. It has a good dissertation on Pollution and what it's all about. All the emissions controls data is well described and all the codes are listed. It tells one how to read the codes. It tells one how to adjust things like the TPS and the IAC. The illustrations and photos are good.

The '85 is OBD-I so I don't have a scanner to read the ECM but the flashing codes work well enough for me... if I get any. The Chilton's still shows one how to read plugs and how to use one of the most important, least expensive, and hardly used anymore, tools: the vacuum gauge. I never see anyone using one. There's a lot you can learn about your engine, real quick, with that ol' timey diagnostic weapon. I can't think of anything that's not possible to do with a Chilton's and a Forum like this one. I do intend to get a FSM some day, probably on CD first. . I just recently picked up a "hardcover" Chilton's that was printed shortly after the C4 came out and it only covers '84 thru '86, and it's like brand new. It has a lot of color photos and illustrations in it. Got it on eBay.for $6 bucks, free shipping. The Haynes manual is short on data and you can see if you compare it to the Chiltons, it's about half the size. I guess it could make for a more robust owners manual if you know what I mean. Stick it under the seat of your car or something.. Don't be so hard on Chiltons. It's been helping shade tree low budget hot rodders for many decades. That's gotta mean something.

I believe there's a schematic for that Tach filter on this forum somewhere but if you like I can try to dig up the one I have and post it. Let me know.

 

is this for real?