Hello There,
I tried to get help on " another" forum and got ZERO results so maybe I can get some help or advice here.

91 Camaro RS (305 - 5.0) automatic with a rebuilt motor approx. 3 years old, after several months sitting in my driveway, I'm finally getting around to putting some time and money into this car. Paint was really getting bad, so I took it to maaco and let them paint it (was shocked at the excellent job they did IMO), replaced the cloudy driving lights, then did the routine maintenance (oil change, trans checked etc...). The car runs fine as is, however I do have a couple of questions I was hoping someone could answer and possibly point me in the right direction.
First question is about the tachometer, yes the infamous inaccurate tachometer issue. I saw a couple of threads here regarding this issue, but I wanted to ask again anyway. When the car is warm and I start it, all the gauges on the instrument panel read fine, but the tach reads around 1600 rpms, but I dont think it's actually running that high. I took the car to my brother-in-laws house (he is better mechanic than I am), and he said that it was not reading right. He attempted to connect a meter and see if the tach was accuarate or not. He swears it was connected in the right place, but he was unable to get any reading at all. The next day I found an identical tach at a salvage yard on a really decent looking camaro, so I bought it. Installed this other tach, all the gauges worked fine except......yes.....the tachometer, which reads slightly higher then the tach I had in there originally. I am assuming that the problem lies somewhere outside of the instrument panel, but I'm not sure where to look or what to try to fix next to resolve this issue. Whew.... ok, second issue

Second issue is the SES light..hehe...fun fun.... SES light comes on after I get out on the highway and drive for approx. 20 min at around 70-80 mph, then when I turn off the engine it resets, and does not come on again till I'm on the highway again at around 70 mph for 20 min. It does this almost everytime. I took the car over to my B-I-L house again, and we connected a code reader to it, and it comes up with code 32 (which I think is related to Fault in barometric pressure sensor circuit OR Fault in exhaust gas recirculation valve diagnostic switch OR Fault in electronic vacuum regulator valve) I did replace the egr valve, but I still have this same issue. Talked to another mecanic I know that advised me that it could be a vacuum leak. I haven't started to replace any vacuum hoses yet, but I wanted to ask in here and see if I could get some feedback and opinions on this. Any advice or opinions are welcome and appreciated

 

Wow!

Must be some tough questions, over a week and not one reply

 

Second issue I'd try torquing the intake manifold bolts. It gets hot causing things to expand and it could be opening a leak somewhere. When you turn off the car it gives it time to cool and thus, shutting off the SES light

With the tach I'd try going to autozone and buying the cheapest aftermarket tach they have and hooking that up. After you've found out if it's your instrument panel or something else I'd take it back. that should solve your problems. if the SES light still comes on let me know and we'll figure something else out.

 

Thanks For the suggestions SSV6!

I will try and torque the manifold bolts down and see if that changes anything with the SES issue; however, I'm not sure if it makes any difference, but the SES light will go off and stay off even if I turn the car off momentarily and restart it before it has had time to cool down. Then it will generate another code32 after around 20 min or so on the highway again . Torquing the manifold bolts is definitely a cheap and easy possible solution that I will try, but I'm actually leaning toward it being a computer or sensor issue. I ended up replacing alot of vacuum hoses and my TPS sensor yesterday so maybe that had some effect on this SES issue also. Haven't had a chance to get on the highway to test it, but I will soon.

Far as the tach RPM issue. Connecting a new tach is also not a bad idea to try, but I did connect a second instrument panel identical to the one I have now and it had the same readings. Guess there is a chance they were/are both "off "

Thanks for the reply, and I will surely let you know if things change.

 

That's why I suggested connecting another, you said the second read too high still yet it was higher than the first. Personally I think it's the instrument panel, but connecting a second one will disprove or confirm any suspicions. Not to mention the autozone tachs connect at the pigtail on the computer. One other thing with the sensors, It helped someone else, and I usually do this first with my car if I get an SES light on the intake. Try cleaning your IAT and see if that changes anything. Try the cheap fixes first before you go spending a ton of money.

 

I would add after market tac three wires to hook up or borrow one that will eliminate all wiring issues.ses light i would check arond to see if anyone has a old obd 1 tester and let him read codes.hope this info will help

 

Code 32 refers to the EGR valve, may want to check the wiring, and clean the valve and gas passages out.

 

Well, changing the TPS and the vacuum lines must have fixed or helped the situation. Haven't seen the SES light in awhile. Car runs really rich though. My buddy swears that it is normal, but it just seems kind of extreme to me. Start the car and you can smell the exhaust from 20 feet away. Was thinking about changing out the O2 sensors, but it seems like a real PITA to do. Looked in the chilton manual and it basicly says to use extreme caution removing the one on the manifold. Not sure how many there are either, some ppl say 1, some say 2, and some even say 3.