8 replies to this topic

[ofeargall]

My 86 Civic Si is running poorly under a load. If you keep it revved at 3500 + it'll run with a load on it. So, doing 60 in 3rd gear is possible. Shift to 4th or 5th and it feels like it's running on 1 or 2 cylinders and forces me to shift back down again.

Earlier in the summer I had a similar thing happen (occasionally) when the car was re-warming up - like if I drove to work (70 miles), parked for the day and then started my commute home. About the time that the temp would get to where the engine was half-way to operating temp it would chug and buck. If I shifted down and gave it the berries it would sputter a bit and then break free. After that I was fine for the rest of the commute.

Now, though, it's happening all the time. I can't get any power at all. It idles fine.

About this time last year I had to replace the ECU because the car flooded. They also had to replace the MAP sensor. They could only find a used one, so I don't know how good that was... But it would run fine 99% of the time.

I do have the 'surging-at-idle' problem too when the car first gets running after cooling down. I've heard that's a temp sensor of some sort, or a sticky throttle position sensor... Not sure which.

Adding insult to injury, the floorboard on the drivers' side has been getting wet. The whole car smells like a locker room and the humidity is pretty high inside the cabin. Not sure if that's contributing. I'm letting the rig idle in my driveway right now with the heater on full blast.

Any help or tips are appreciated.

[ofeargall]

Quick update. The car is idling and my wife says it smells like a mixture of varnish and alcohol, 'slightly' diesel-ish (she's actually babysitting the idling car as I'm at work 70 miles away...).

[letank]

How many miles, how many years have you own it?
Many things for chugging, but if the inside is wet and smell like !#%^, your ECU under the seat is probably getting compromised.... Pull the carpet, buy a space heater and dry the inside, using the car heater is not too fast, you can stuff newspaper sheets to absorb extra dampness and replace as needed.

Next could be fuel delivery, such as pressure or flow, when was the last time the fuel filter was replaced?

[chedda_j]

I'm suspecting fuel but if it seems to run really rich when it's at full load you should get a ecu light or two. Maybe your injectors, possibly your timing.

[ofeargall]

Okay, I finally had time to attend to this problem.

The engine actually had a very steady misfire. I pulled the plug wire from the plug furthest from the distributor and the metal snap ring stayed on the plug. Coincidentally, the engine trouble didn't change. I remembered from my shop days in High School that if you have a faulty plug or something you can get a hotter spark by putting a little gap between the plug and the terminal on the wire. I put the plug wire on slowly and it started to run. Sure enough, it started to run normal.

I ran down to the parts store and bought some new wires, put them in and - no difference! That one cylinder was still misfiring.

Next I pulled the plugs. Yikes. The offending cylinder's plug was heavily fouled (black and oily). I went back to the store and bought 4 new plugs gapped at .044 and we're good to go again. (the previous plugs and wires were about a year old.

This leads me to the obvious question about the condition of my engine. The engine has about 250K on it. There's no visible smoke while driving, and only an occasional smoke on start-up. It does burn oil over time as I'm adding a quart between oil changes. This is a highway car for me. I commute 140 miles a day so it's got a lot of time at 65MPH.

Does this sound like what you guys are seeing with your high-mile engines? I don't have a problem swapping in new plugs and burning a little oil I just want to make sure I'm not in the 'danger zone'.

[Mark L]

Do a compression check to see where you are at.

Hook up a vacuum gauge and see if you have 17-21 at idle and it is steady.

Worse case is just keep throwing plugs and oil at it until you can move.
A wet carpet on the drivers side is a leaky windshield gasket, a clogged drain for a sunroof, or there is a hole rusted though on the floor.

IS you can a SI ? Is it rusty?


Mark

[ofeargall]

Mark,

I'll run some tests this week and see where I'm at with compression/vacuum health.

It's an Si Civic, white, black interior with virtually no rust. It's a great little rig. Fun to drive, gets great mileage... Just a little old. I suspect the sunroof drain up front is probably the offender. My son pulled the passenger seat out for me the other day so I can keep an eye on the moisture condition around the ECU.

The floorboard flooded last year when the rear sunroof drain clogged (fried the ECU and had to get a refurb). The mechanic drilled a hole in the floor on the passenger side. I'm beginning to think some water is being wicked up through that hole on my commute. I'm in the Willamette Valley, Oregon where it rains a lot. My commute is pretty darn wet. Lots of water on the highway between home and the studio.

You looking to get into one of these gems? I sure love mine. I just put some winter tires on, sticks to the road pretty darn good now!

[letank]

Plug the drilled hole w a dab of silicone or any putty, plumber putty, and press a quarter or any piece of metal.

The windshield gasket can harden with time, cannot remember if the civic is glued and pressed on, or the older lock style, call a windshield place to figure it out.

[badpenny]

bad gas or fuel filter going out.