Diagnosing a sporadic shift light/possible lack of lean burn

[dlee275]

I want to begin by saying how much I appreciate the information available on this forum, especially for the VX.

I own a 92 Civic VX with 572k miles. It is on its second engine/trans/clutch, all replaced at the same time due to a leaky head gasket (couple busted hoses) and a bad transmission bearing coming to a head and the same time, around the 400k mark. I am a courier, driving over 100k annually, so gas mileage is a high priority. Before the JDM engine, I was getting upper 40s to the gallon w/o any aero mods, and many highway miles where I have trouble going much less than 70-75. After the new engine, I have been getting a consistent, still respectable 43-45. I should add that my hood is quite crumpled due to a couple of deer collisions, so the aerodynamics are far from perfect as well. I have had dreams of testing my TPS and MAP sensors, checking my vacuum lines, cleaning my IACV, and maybe replacing some grounds, but am always so busy I haven't done it. The car runs perfectly and it has been amazingly trouble free over my several 100k miles. It has made me quite a bit of money. I just had the timing belt done and the mechanic commented how under the valve cover it looked as good as any he'd, regardless of age.

There a few threads referencing this subject, but none really fit my situation. So, my car has just a few issues. My SIL only works about 10% of the time. I bought a new O2 sensor a little while back (almost $200), and it didn't help. When the light isn't working I think I would swear the car isn't going into lean burn. It also feels quicker. One clue might be that my tachometer isn't accurate. At 60mph it reads around 1300 most of the time, occasionally it will read closer to what it should, but for the most part it reads really low. Winter before last, the tach was going crazy when I would first start the car. It wouldn't read anything for the first few miles, then it would break loose and fly all the way around. It even got hung on the other side of the stop once. For some reason, it just stopped doing that when the weather warmed, before I got around to replacing what I thought was probably a bad part in the distributor. It hasn't done that again in over a year and 100k more miles. Anyway, even before that (and since) it has read low. My idle seems to be pretty steady.

I have a feeling my car is rarely reaching lean burn, but don't have any indicator wired in to know for sure. I feel like it is always in open loop. I would love for the reason my SIL isn't working to also fix my possible lack of lean burn, but I doubt that will happen.

If you guys have any guesses I would love to hear them. Thank you so much!

[benfrogg]

My shift light started working better when I cleaned/tested the clutch switches. There are two located at the stops of the pedal. Count their revolutions out so you can put them back in the same position.
Test them with a multi-meter and replace/clean them if they are bad.

If you feel high power all the time it's likely not getting into lean burn much.

The tach problem is likely related too. There's a few threads on hondatech about them having issues with cold solider joints in the back and the like. Very fixable, but any 5th gen set of gauges from a 5spd will work in a VX. Mine has one of these and the upshift light is replaced by a cruise control light. It still works the same, it just says cruise control instead of an arrow.

That's a start, there's probably dozens of reasons why your lean burn might not work. Easy things first!
B

[dlee275]

Thank you. I will check out the switches on my clutch pedal. Didn't even realize there were 2.

I will have to check out the solder joints in the cluster. I am really proud of my 572k miles; I would hate to lose my odometer. I forgot to mention that my car has a short squeal on a cold start. It made the same noise before and after all the belts were changes. Could that possibly be the distributor? I know distributors do send information that the tachometer uses.

Thanks again.

[vxdude]

if and when you switch out your cluster you can take the odometer and put it with the new cluster

[dlee275]

Didn't realize that about the cluster. Thank you.

Still haven't had time to check the switches but I will post my results.