My 1990 Honda Civic DX died in heavy rain. Diagnosis: Need new alternator. Got it. Car immediately started surging loudly whenever idling. Took it back to the shop. 3 mechanics huddled for 3 hours and couldn’t figure out what was wrong. Quick fix: Deactivate IAC. They said I should be good for a couple of months. Took one 25-mph drive around the neighborhood. Car ran very rough; panel under steering wheel jolted loose. Made it home but now car won’t start. Battery is fine. Wonderful Firestone manager is willing to look at car again. I’m broke after the alternator on top of paying the IRS in April and really want to keep my generally reliable car (only 255,000 miles), at least through the hot South Florida summer. What do you think is going on and what should I do? Thanks much!
This shop has no clue. Find a good shop that works on a lot of Honda’s.
First check is your distributor. If the cap cracks, it can cause all sorts of firing problems on humid/rainy days.
Old spark plug wires will also short out in wet weather. You may just need a new set of spark plug wires.
Rain usually wouldn’t affect an alternator. So it’s puzzling what has happened to your car. Did the alternator warning light come on the dashboard before it died the first time? Usually when an alternator goes kapuut, the car will continue to run for a few hours before the battery finally dies, but the warning light will be lit.
Also, has the check engine light come on during this period?
The IAC – “Idle Air Control” – shouldn’t be deactivated. That will cause drivability problems. If it is faulty, it should be replaced. It performs the same function as if you pressed on the gas pedal slightly. It functions when the car is cold, or you turn the headlights on, or some other function is putting a load on the engine, which would otherwise cause the engine to sputter or stall at idle and low speeds. It revs the engine up a little so this doesn’t happen.
There’s several things that could cause these symptoms, like the EGR system, the PCV system, and including those mentioned above. It’s not possible to diagnose from what you’ve said. Given that the car won’t even start, the best bet will be to have it towed to an independent mechanic who specializes in Hondas. Ask your family/friends/co-workers for Honda mechanic recommendations. You’re gonna have to decide at some point whether the repairs continue to make sense. At 255K, pretty much all cars will fail now and then. It’s just the lot of those of us who drive older high mileage cars. Best of luck.
Agreed with Jesmed, rain, no start, and spark plug wires, and or distributor cap first thing if applicable.
Skip the Wonderful Firestine Manager. These guys have no clue whatsoever.
Erratic operation in the rain and stalling in the rain is almost alwaysignition system components getting wet. The distributor cap, the coil, the ignition wires, end even the igniter are all candidates. The alternator is not.
Re: the surging, if that were happening before the work I’d suggest looking at (NOT disconnecting) the IAC, but in this case it adds the possibility of a leaky vacuum hose. Vacuum hoses can do this after 22 years on the job. Any 1st year automotive student would head straight for a vacuum gage. Me, I’d probably just grab a roll of hose and change the lines one at a time. $3 worth of hose and 20 minutes would eliminate vacuum hoses as a candidate…and might just fix the problem.
And, finally, any shop that sends the customer on his way with a disconnected IAC should hang up his wrenches.
Allso, try reconnecting the IAC and see if the car starts. Post back with the results.
At night crack the hood open just enough to be able to see the area around the spark plugs, coil, distributor cap and start the car, preferably when it hasn’t been warmed up. I’ll bet you’ll see what looks like a video replay of a distant thunderstorm at about 4X normal speed.
At 255K the pistons are probably swappin’ holes.
Thanks to all for your comments & suggestions. I found a good Honda mechanic and it turns out the main problem was the main relay. Replaced it for $133 and the Civic is running strong again. The horrible loud idling is down to a murmur although I will eventually need a new IAC. The Firestone people had been good to me under previous management and they were close to home but from now on I’ll gladly go a few extra miles to get maintenance & repairs from someone who really knows how to fix an old Civic!
Along with the other comments related to the wires and caps, arching, etc - take a spray bottle with water and mist the wires, coil(pack?) and distributor down with it.
If it starts dying, you’ve found your problem (wire, distributor, coilpack, etc).
Oops. Missed you got it fixed. Good for you.
Unless there are symptoms that you aren’t describing, that just doesn’t sound like main relay to me. I hope I’m wrong, but don’t be too surprised if you start having trouble again down the road.