So i have a coolant leak somewhere and i cant seem to find it. The other day after the car was started for a little bit the tachometer dropped down to 0 rpm but was still idling fine. Then today i started the car and I let it start to warm up, all the sudden RPM's started to idle ☟. Then started to get below opperating RPM's, where i also believe the leak is and began to steam behind the block and near the intake manifold location. Do I replace all of the hoses that are from the back of the block. How do you explain the drop in idle below opperating?
How do you explain the tachometer dropping down to zero at about three minutes when running.

Any help would be appreciated.
90r3x

 

Replace all of those hoses. They are probably really old.

Have you messed with the distributor. The tach signal wire is the blue wire from the 2 pin connector on the dizzy harness.

Possibly your tach is going bad. I've been troubling shooting my non functioning tach on an 89 DX hatch I just bought and haven't had any luck. I'm thinking they tach is just finished. Yours might be on the way out too.

 

What would explain the idle dropping after running for a bit and that coolant leak?

 

Just remembered i recently changed the coolent temp sensor could it be leaking from there because it leaks when cars off. I was told not to tighten it to tight.

 

Tighten the sensor a good bit. As far as trying to find the issue, drive the car like normal, and then let it sit for a while while being on. If it leaks, then you know its just because of a hose, or the sensor. If not, then you may be burning coolant. I dont think NOT having coolant will affect the motor. Did the car shut off when the tach hit 0?

 

No. The tachometer hit 0 long before idle lowred. Can a unsnug coolant temp sensor cause not function properly?

 

No, my civic sometimes hit 0rpms at idle. Never shut off or gave issues related to that. Op.since you dont have the ckf or knock sensor hooked up, how is the car running? I assume you have the stock b16a2 ecu? Any cel?cant be running perfect. Op. Get yourself a PERFECT harness and the adapter harness and see what happens. If you are fine with electronics, then follow hondapartshero, but if not, do as i say, and report back.

 

But what would cause the RPM's to drop?

 

The tach is controlled by the blue wire in the distributor. When my car hit 0 rpm, it was like the car would want to shut off. Does your car do this? When i came to complete stops, the car would shut off. This happened like 2-3 times since i had the car. Would start up again, and everythings fine lol.

 

No the tachometer will work for a bit then stop. But my main concern is when the car was running for a bit the idle began to get way lower than operating so i turned of the car due to that and the fact i saw steam come from the back of the block as if coolant hit the header.

 

Ignitor module in distributor sends the signal to the blue wire that feeds the tach.
The modules do fail over time and give hints that they are on their way out - bouncing tach, engine randomly cuts in and out, hard starts with several tries to start engine before it catches.
Completely failure will cause the engine to stop running.

 

Post pictures of your engine bay. The more the better.

 

Found leak bad hose on back of block and i will replace the dizzy to see if it fixes the idle problem.
Thanks

 

Great info! Had no idea.

 

If it's the hose I'm thinking of, it probably wetted your coil. Remove distributor cap and see if there is moisture in there.