I have a 6th Gen DX which came without a tach so i put one in. For the most part I am satisfied, idle appears accurate, and I have confirmed various cruising speeds in different gears at 3000rpm and they are at what they should be. But whenever I try and take it to redline (only actually done it in first and second) it wont. The revlimiter kicks in at what appears to be ~6000rpm, but my speed in second when this happens is like 65mph which I know should be higher than 6000rpm, like 7100 or 7200rpm if the revlimiter is actually accurate. So my question...is there any reason my tach would not keep up with my engine in 1st and 2nd or is there anything else you can think of?

Oh and while we are at it, does havin the AC on decrease how high you can take your engine? One time I had the AC on and was merging onto a really busy highway in second, and it only got to 60mph before it jerked and I felt something like a revlimiter

Yes I know hitting the revlimiter is bad for your engine, no i do not try to do it or constantly drive near redline (I enjoy my gas mileage, not to mention my car in working order), its just something that has happened 2 or 3 times and I was wondering about it

 

The rev limit for the D16Y7 is 6,900 rpm, which is higher than the 6,000 rpm limit you are experiencing. Maybe you should hook up a scan tool and compare the rpm reading between the tach and scan tool.

The A/C definitely sumps a lot of engine power, so the reduced power may be normal.

 

Yeah thanks, thats a good suggestion. Can you rent scan tools/how expensive are they to buy? 6900rpm is rev limit? Redline is 6800 and I had always read that revlimit is 7100, in some places I've seen it say 7200

Yeah I barely use AC cuz it drains both power and gas mileage, it was almost 100 that day I experienced the weird "revlimit" tho, and a semi-broken (doesnt roll down properly) driver's side window and no AC was just too much. It was actually one of the first times i'd bothered to use it

 

I found the 6900 rpm rev limit in the Civic service manual.

AutoZone should let you borrow a scan tool free of charge (refundable deposit).

Are you saying that the A/C doesn't work? Is the CEL ON?

 

Well seeing as you have the serive manual I would be inclined to trust you lol, but I just did a search and found a bunch of places/ppl sayin 7100/7200 for the stock rev limit on a Y7. You're sure you looked at the figures for a Y7?

Autozone huh? I might have to head down there tomorrow or so if no one else happens to know what the issue is.

No sorry for the confusion, the AC DOES work and the CEL is NOT on. I was just saying I never use the AC cuz it saps engine power and reduces gas mileage a bit.

 

Here it is directly from the 96-00 Civic service manual:

 

Yup haha, that sure looks like 6900. I dunno why so many people are saying 7100, even the Y8 isn't 7100 so they couldn't be confusing it with that. Thanks for clearing that up tho

Has anyone experienced anything similar with their tach? or there any reason that my rev limit could have been lowered or anything that would make my engine not rev as high as it should be ablt to to? I haven't had any engine problems and the oil was just changed less than 400 miles ago

 

It might be your tach that it's reading incorrectly.. because I have a little one that reads about 300-500rpm different than my stock one. Then again, mine's a cheap ebay one

 

So you have 2 tachs in the car and they read different?

 

^^^ Yeah.