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S13_conv · 10-14-2018, 09:51 PM

I need help please. Original owner bone stock 94 S13 DOHC convertible. 160K mi. No oil leaks. It’s OBD I.

It started running very rough, a rough violent shaky idle and no power on acceleration. No CELs. It is time for a tuneup so I replaced cap, rotor, plugs, plug wires, fuel filter, and a few vacuum hoses. Topped it off with good fuel. Same condition however. Remote ign coil and ign control module seem ok. Both getting power and ground and secondary resistance is 16K ohms. Sprayed carb cleaner at many places and don’t find any broken vacuum points. Throttle body is clean. Air filter clean. Getting strong spark from all four plugs wires.

I did a compression and cylinder leakdown tests. Hot compression is a bit low: 170-165-170-165 but still fair and leak down results show ok at 20% loss in all cylinders at 100psi so the head and the bottom end of the motor are sound.

Head gasket is not leaking since oil is clear and the leak down test would have discovered a cracked water jacket. So it’s not this.

Disconnecting the maf connector while idling does nothing to change the behavior.

Crank and cam position sensors must be ok since it starts and runs. And since I have spark, the ign coil and ign control module must be sound, right? How would I test the distributor? What am I missing?

Yes, I’m new here.

10-14-2018, 09:51 PM	#1
S13_conv Join Date: Oct 2018 Location: WA Age: 65 Posts: 6 Trader Rating: (0)	S13: rough idle, no power I need help please. Original owner bone stock 94 S13 DOHC convertible. 160K mi. No oil leaks. It’s OBD I. It started running very rough, a rough violent shaky idle and no power on acceleration. No CELs. It is time for a tuneup so I replaced cap, rotor, plugs, plug wires, fuel filter, and a few vacuum hoses. Topped it off with good fuel. Same condition however. Remote ign coil and ign control module seem ok. Both getting power and ground and secondary resistance is 16K ohms. Sprayed carb cleaner at many places and don’t find any broken vacuum points. Throttle body is clean. Air filter clean. Getting strong spark from all four plugs wires. I did a compression and cylinder leakdown tests. Hot compression is a bit low: 170-165-170-165 but still fair and leak down results show ok at 20% loss in all cylinders at 100psi so the head and the bottom end of the motor are sound. Head gasket is not leaking since oil is clear and the leak down test would have discovered a cracked water jacket. So it’s not this. Disconnecting the maf connector while idling does nothing to change the behavior. Crank and cam position sensors must be ok since it starts and runs. And since I have spark, the ign coil and ign control module must be sound, right? How would I test the distributor? What am I missing? Yes, I’m new here.