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Car was running with an idle surge for a week, left it for a day and it wouldn't start. Wasn't getting fuel past the fuel filter, replaced. Wasn't getting fuel past the injectors, replaced. Cleaned the IAC and replaced the alternator because 300k mile civic.
So now it starts idles rough, runs rich and then pops a check engine light idles up to 3k rpm and dies. The ECU blinks 5 times (manifold pressure?).
I found a line with a broken boot that runs from the firewall into something under the intake manifold not sure what it is.
I really appreciate any advise you guys can gleam from all this I'm new to civics and auto repair in general Mystery line
Tha is again
The mystery line is the speedometer cable. It runs from the mechanical VSS (vehicle speed sensor) on the transmission, through the firewall, and into the back of the speedometer.
The check engine light is indicating an issue with the MAP sensor. If I recall correctly, your MAP sensor will be firewall mounted instead of directly mounted on the intake manifold. To see what the manifold pressure is, this remote sensor requires a vacuum line from the intake manifold to the sensor. If this line is broken/cracked/leaking, it can cause an idle surge. If the line completely comes off or the leak is bad enough, it can cause the engine to not run.
I suggest you carefully check all of your vacuum lines on the engine and replace any that may be brittle or are obviously damaged.
The mystery line is the speedometer cable. It runs from the mechanical VSS (vehicle speed sensor) on the transmission, through the firewall, and into the back of the speedometer.
The check engine light is indicating an issue with the MAP sensor. If I recall correctly, your MAP sensor will be firewall mounted instead of directly mounted on the intake manifold. To see what the manifold pressure is, this remote sensor requires a vacuum line from the intake manifold to the sensor. If this line is broken/cracked/leaking, it can cause an idle surge. If the line completely comes off or the leak is bad enough, it can cause the engine to not run.
I suggest you carefully check all of your vacuum lines on the engine and replace any that may be brittle or are obviously damaged.
Thank you so much for responding, it turns out this was half plugged in and when I was fiddling with the vacuum lines it was jiggling the connector around. Now my civic is feeling fine 😎
The coolant temp switch is a ground switch in which provides a path to ground to fire the fan relay (or just grounds the fan if you don't have AC). If you "short" a ground, all you do is complete the circuit and the fan would turn on. There is zero chance this had anything to do with the issue as described.
The coolant temp switch is a ground switch in which provides a path to ground to fire the fan relay (or just grounds the fan if you don't have AC). If you "short" a ground, all you do is complete the circuit and the fan would turn on. There is zero chance this had anything to do with the issue as described.
Thank you for the info I'm always happy to learn, I'll keep my eye out for anything else out of place then
1991 civic si running rough and dying
