RPM not reading, cluster good
Thread Starter
Honda-Tech Member
iTrader: (2)
Joined: Jun 2007
Posts: 3,648
Likes: 0
From: pocatello, idaho, u.s.a.
I got my car running and tuned about a two weeks ago. Since that day the tach has not worked. I though that it was the cluster itself, so I tried to change it out. Upon changing it out, nothing different happened. Which wire should I be checking for signal? Is there a way that I can jump it straight to the ECU? Any help would be appreciated. Thanks in advance.
the rpm signal is the blue wire in the distributor harness. check for voltage to make sure there is not a short or something else. If you changed the guage cluster and the tach is still not working the problem is likely in the harness connector plug or wire
Trending Topics
Thread Starter
Honda-Tech Member
iTrader: (2)
Joined: Jun 2007
Posts: 3,648
Likes: 0
From: pocatello, idaho, u.s.a.
Ya, I just found out that the tach wire is the blue one. I have a hard time thinking that it's the harness because it's a Rywire harness in the car and; like I said before, the car runs great. I will be checking the pins in the clip for voltage tomorrow. I hope I don't have to track it through the interior harness!
Thread Starter
Honda-Tech Member
iTrader: (2)
Joined: Jun 2007
Posts: 3,648
Likes: 0
From: pocatello, idaho, u.s.a.
Alright, so I checked the cluster plug for voltage, and nothing. Checked the Blue(#8) wire. Then I went to the distributor, there are three different blue wires there. Two of them are in the bigger plug, and on of them is in the small two wire plug. Which one should I be checking? Also which setting should the volt meter be on? I am testing it with the straight voltage selection. Should I be using the ohm selection? I am no good with wiring man. Help a brotha out! Please!
Thread Starter
Honda-Tech Member
iTrader: (2)
Joined: Jun 2007
Posts: 3,648
Likes: 0
From: pocatello, idaho, u.s.a.
O.k. so I have found numerous diagrams of the pins in the plugs. I found one that says the blue wire in the small plug is the RPM lead signal, other called it TDC lead. That plug on my dizzy gives out no voltage, but my tuner's software read RPM. Meaning that it has to be giving out some type of signal right?
I have a 95 RHD EG hatch with a GsR swap and I have thhate same issue, my tach doesn't work. My cluster is the JDM CTR white face and i have checked every connection on the rear with no luck. The car has a wire tuck and has an OBD2 motor with an OBD2 distributor but I soldered the OBD2 plug to the engine harness myself, I have also checked it several times. My car has a p28 and runs awesome, I have been a master tech for several years now and I cant find the problem. I am going to try a different distributor but I am doubtful that it will make a difference. I will keep you posted and please do tell if and when you get yours working. GOOD LUCK(by the way the blue wire you want to test is a solid royal blue that is found on the two wire plug of an OBD1 distributor, also known as the negative side of the coil)
Thread Starter
Honda-Tech Member
iTrader: (2)
Joined: Jun 2007
Posts: 3,648
Likes: 0
From: pocatello, idaho, u.s.a.
That is the one that I tested. It didn't read anything. I am also thinking that it is the dizzy itself. I think maybe the dizzy has a loose connection or a cold solder in it. That would make it not put out a signal, but still run fine. My only question is:
why would only one wire/signal go bad?
Thanks for the reply though.
why would only one wire/signal go bad?
Thanks for the reply though.
I can't offer much, but I'm pretty sure I can safely say that the VSS has nothing to do with the tach. When my VSS stopped working, I had to tell my speed from the tach.


