bec1488

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joelmatt89

wow you have covered everything i could think of this is a good one. Maybe it is your injectors have you tried running some sort of cleaner through them. Have you checked your timing?

Former User

I agree with your idea to troubleshoot the 2-wire coolant temperature sensor under the distributor. When the engine is hot, remove sensor connector, and then measure the resistance across the two terminals of the sensor itself. You should read 200-400 Ohms, otherwise the sensor is bad.

You might also want to check the fuel injectors.

Meoshe

iTrader: (3)

IACV? Cleaned it lately

honda.lioness

The oxygen sensor signal does not kick in until after warm up. A malfunctioning O2 sensor will not necessarily throw a code and can cause rough running problems. I would check it and the ECT sensor. Fortunately they both are cheap and cost about the same for OEM.

rocketdancer

hey you need to change the fuel filter because once the fuel heats up, itS more "free flowing" allowing the particles and crap get clogged in the filter, depriving your injectors, giving you a rough idle. GOOD LUCK!

joelmatt89

Seriously guys did you even bother to read his post where he clearly said he did both of these things

bec1488

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honda.lioness

The shop manual's diagnostics are for when a code is being thrown, meaning the wiring is amiss. So the shop manual is not very helpful when there is no code and we are just talking about a degraded O2 sensor. A lot of sites talk about connecting a high impedance multimeter to the oxygen sensor signal wire so that the sensor is still sending a signal to the ECU. You measure the voltage signal as it responds to the exhaust's changes in oxygen. A stock 93 Civic has a 4-wire sensor, so you'd have to rig up a special test harness and figure out which wire carries the signal to the ECU (not hard). The signal is supposed to bounce around 0.45 volts, 0.45 volts denoting the perfect oxygen concentration. Higher than this = rich; lower = lean. Google for {oxygen sensor test 0.45v} or similar and a lot of hits come up describing what to look for.

If your Civic's O2 sensor is old, I would just replace it. The cost for an OEM Denso make of O2 sensor is around $40 at Amazon. Look up the part number at densoproducts.com, first, then go to Amazon to buy it.

IntenseDriving00

I ran into the same problem before just last year when I picked up a 95 coupe. I replaced almost everything that you did. The cheapest way to start would be to replace the coolant temperature for the computer first. The problem I had was the timing belt was slightly off because the cam gear wasn't lined up correctly. Surprisingly enough, the engine was still in working condition. I was curious enough to take everything apart and just went ahead to replace the timing belt and water pump which was the only way I found that problem. Replaced it and it fixed the problem.

bec1488

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Pothole987

have you done a compression test? might be a bad headgasket.

bec1488

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Pothole987

Have you tried a different ECU (Computer) by chance? could be something wrong with it. also, Do you have any Check Engine Lights On?

OminousG2

I've been dealing with the same thing with my mom's del sol. I wish it would just give me a CEL. She won't let me swap it either...


Changed the Cap, Rotor, Plugs, Wires, Distributor (old one had a bad bearing), coil, fuel filter, and PCV.

Checked the timing, plug gap, and compression... all are good.

Cleaned the IACV and injectors, and put some injector cleaner in the car.

I am curious. If the O2 sensor is the issue and you unhook it, would it run the same just with a CEL? Or would it run smoother and in limp mode?

Edit: Put in a new ECT sensor, seems to be better. Now it seems to sputter/hesititate between 2000-3000 rpms, after that it accelerates pretty well. Will be searching the site for more info. At least all this stuff is getting fixed.