Rep Power: 0

Hondudes,

Thank you for taking the time to read this and help out.

I have a 1995 Civic EX 1.6L MT. Stock, with the only mod being Chinese stainless headers (as they were cheaper than an aftermarket OE replacement). 236,xxx on the clock.

Cylinder 3 feels dead at idle and under 3500 RPM, irrespective of gear (neutral included.), hot or cold, it doesn't matter. I think I'm dealing with an electrical gremlin or a pissed off ECU. Car is old, so I wouldn't be surprised, so any help or feedback is greatly appreciated. I have outlined what I've done and seen with the car, including the parts replaced during a major service around 15,000 miles ago.

Here's the rundown:

I can pull the Fuel Injector connector or the spark plug wire from either the plug or the distributor on Cylinder 3 and nothing changes. Unless, I unplug the wire and rev the engine, then it continues to miss over 3500 rpm.

Once over 3500 rpm, no matter the gear, throttle position, or load, I have four cylinders again, everything is smooth, the engine note is true, and engine pulls with full power. Engine also smooths out when off-throttle (no matter the RPM), with or without the driveline engaged. But, once ANY throttle is applied there is the mis-fire and odd engine note.

I've had this EXACT same behavior happen once before. It was diagnosed on the side of the road, when I pulled the fuel injector connector for cylinder 3 with no change to the idle, and the spark plug wire (then nearly brand new) was arcing from the distributor side and the spark plug side. I had also replaced the spark plugs that were less than 1,000 miles old at the time as part of this diagnosis process. It was fixed with a can of BG 44k fuel system cleaner and about 70 miles of highway. No such luck this time.

So my first course of action this time around was to replace the cylinder 3 fuel injector. With a brand new unit, there was no change. I tried swapping injectors from a different cylinder. No change. Swapped spark plugs, and wires from cylinder to cylinder, no change. Spark plug wires on all cylinders were still arcing on both sides (distributor and spark plug) properly.

I'm inclined to rule out a vavletrain issue, as the engine would miss after 3,500 rpm with relative consistency. Timing belt was inspected and still tight with no visible damage or evidence of jumping. Usually if it's a fuel pressure, timing, or ignition issue it gets worse the faster the engine goes, not better.

I also ran it in this condition well over 400 miles (don't judge, it was better then being stuck in rural Pennsylvania). Over this time the condition hasn't changed (good or bad), nor has there been any other issue with the engine, or any obvious or evident damage.

I have been unable to pull codes, and will try again after the engine is run again.

Check the recent service done to the car, all of the tell tale suspects have very little time and mileage on them.

Engine Parts and service with less than 15,000 miles on them:

Timing belt
Water Pump
Head Gasket
Valve cover gasket
Head and valve train was machined and inspected by certified Honda tech (and Honda geek)
NGK Iridium Spark Plugs
Spark Plug Wires
Bosch Distributor Cap
All V-Belts
Engine mounts
Clutch
IAC Valve
O2 sensor
Fuel Filter
Air Filter (still looks brand new, and free of debris)
Exhaust Headers (OE Manifold was cracked right down the middle)

Car has run, as you'd expect, problem free since the service (with the exception of the aforementioned hiccup), and have had no issue or concern driving it to and from Toronto from Virginia. No overheating issues after all this service, and the old girl will use 1 qt. of oil every 1,200 miles or so. Always had synthetic oil changed at or before proper intervals. Average mileage still well in the 30's mpg.

Thanks in advance for your help.

-T

 
Rep Power: 518

Step #1: Compression test.