Hot answers tagged rough-idle
6
Most likely, one of the engine mounts are 'torqued'. You can try and neutralize the mounts. Loosen the through bolts of all mounts several (4-5) turns. Then start the car, and drive back and forth several feet (using quick taps on the gas and not just idling) over and over, and let it rest at idle a few seconds before turning off the engine. Now tighten all ...
5
I had this same issue. The PCM and fuel pressure regulator is the correct fix. It is not cheap, but it does address the problem.
If i recall, the issue has to do with ethanol having a lower boiling point than traditional gas. This causes it to vaporize on the fuel rail when the car's warm, but no long pumping gas because it's off. When you go to re-start ...
4
Looks like I may have answered my own question last night. I did a deep clean on the throttle body (and as far back in as I could access). The idle is HUGELY improved, though still not perfect on this 28° morning.
Is that really all it was? I'd love to hear your comments if you've had the same experience.
4
Ahh, cold starts. In the DIY ECU world, this is always the most difficult part of tuning a vehicle. One reason is that the engine is horribly inefficient at low temperatures, and requires a very narrowly defined amount of fuel. Too much and it eventually bogs down and dies. Too little and it dies as well. Then if the engine's warmed up at all during this, ...
3
It might be the intermittent failure of an idle speed solenoid. They go by a bazillion different names and have just as many variations. For example:
Fast Idle Valve
Idle-up solenoid
Accessory Valve/Solenoid
Auxiliary Air Valve
Et cetera...
It may also be, as noted in your comments, an air leak somewhere. Seeing as how it works fine above a certain RPM, ...
3
The factory plugs should be good for 100,000 miles / 160,000 km or so. They're ridiculously easy to change on a Zetec. If you can handle a screwdriver and a socket wrench, you can check / change them yourself. They're easily accessible from the top of the engine through holes in the valve cover. The plug wires are also easy to inspect, just keep track of ...
2
Could be many things, but I'd start with what it gives you. Have the alternator checked. It may not be putting out enough to keep the car powered at idle, slowly draining the battery, causing the idle to lower do to low sparking ability.
Just a wild stab in the dark, probably wrong. It could also be other problems that didn't trigger a code causing a low ...
1
I would suspect that this is the problem:
I have absolutely no idea what can be causing this. I recently cleaned the carb and rebuilt it with all new needles and everything. Any help is greatly appreciated.
Rebuilding your carb is a tricky thing that if you don't get right could lead to the types of problems you have. I would take it to a bike shop ...
1
the oxygen sensor needed replacing
You may have identified the root of all of your issues. Depending on exactly what is happening with your faulty O2 sensor, it could affect any aspect of the intake-combustion-exhaust cycle. I would expect exactly the sort of symptoms that you cite; specifically, rough idle and reduced performance are to be expected.
1
Given that this started when you replaced the exhaust, the likely culprit here seems to be that one of the o2 sensors starts to fail when it gets hot and your engine starts to use too much fuel. My second guess was going to be your MAS, but as you say, you don't have one.
Have a car shop scan for and OBD II code and see if there is a code being thrown, the ...
1
In my experience, this type of issue is usually related to the EGR system - EGR valve starting to fail perhaps.
There are some great videos on YouTube on how to test the valve.
I would almost think to check the MAF sensor or IAC valve but the operation of those shouldn't change much as the car warms - the EGR valve might have the clearance to operate ...
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