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I just bought a 1997 acura Cl 2.2 5 speed. It wouldn’t stay running without a scanner plugged into the obd2 port when I bought it. I found a loose ground on the intake manifold and it started without the scanner. Problem was it was running very roughly and wouldn’t drive on its own power. I pulled the plugs and they were fully fouled with carbon. I replaced the plugs, after one start THEY were fully fouled in carbon. I found out the catalytic converter was fully restricted and had it replaced. Now it will run and move just fine but has a slight miss now. I tuned it up with new plugs, wires, cap, and rotor but the miss is still present. No CEL was ever present nor were there any codes found stored by my cheapo scanner. I am worried that whatever is causing this miss was the culprit in clogging the catalytic converter and I don’t want the new one to suffer the same fate $$$. Any advice on where to start to find the source of the miss would be greatly appreciated. It’s difficult to pinpoint without a MIL.
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Indeed, you need to find out what is causing carbon build up on plugs. That simple. Likely oil leak.
This here is good write up on how to handle no MIL situations:
http://autorepair.about.com/cs/faqs/l/aa042603a_1.htm
But it’s overkill. Yours should be quite simple.
Does your CEL come on when you first turn the key on? You may need to find a scanner that can read Pending codes. Is it still fouling the plugs? Does it smoke when you run it?
If the cheapo scanner has some PID data for you, you could look at fuel trims for a clue. You could also maybe do a power balance test if the miss is consistent. Compression testing and a leak down test are a couple viable options too.
Does the miss get better or worse if you load the engine up while driving?
Thank you all for your responses. The map sensor is all good, the egr valve is all good. Block test revealed no exhaust gasses in the coolant. I even bled the coolant. I suspect vacuum since it has fluctuating low vacuum when I hooked my gauge up. I did take the IACV off to inspect/clean and noticed there was a loose o ring inside of the valve. It seems that this o ring creates a seal when the valve is closed. Since mine was loose and out of place I am assuming that this is faulty and is most likely the source of my misfire at idle. Please correct me if you think I’m wrong.
I checked fuel pressure. It read 35 psi at idle. I am not sure what this means as I can find no source to tell me what the fuel pressure should be. I disconnected the fuel pressure regulator and the pressure went up 5 psi to 40. Can anyone tell me what this might mean? Is the fuel pressure high, low, or spot on?
With the regulator vacuum hose unhooked and plugged the fuel pressure specs are 38-46 psi. Now hook the hose back up to the regulator, then unhook it again and if the regulator is good the pressure will go up like you observed. Good regulator.
there may be a injector leaking or “hanging” up. check resistance on the injector, i believe 10-13ohms is the spec. what is the engine vaccum at idle and high speed (2000 rpm), should be 17-21 in/hg. and hold steady any flutter on the vaccum gauge can indicate worn valve train components. also check for vaccum leaks if you haven’t done so already.
best of luck to you.
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