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miss from idle to about 2000 rpm


joyride
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Disconnect both of the fuel injector clips.

 

Remove #3 spark plug.

 

Reconnect the plug wire to #3 spark plug.

 

Ground the spark plug to the block, using an insulated set of pliers to hold it.

 

Roll the engine with the starter and see if the plug is sparking.

 

Let us know what you find.

 

For What It's Worth.

 

KEN

 

PS - what did you set the plug gaps, especially #3, at?

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Sorry it took so long to get back to you, but I've been busy moving out of a storage space.

 

Some questions:

 

How did you determine that it's only #3 mis-firing?

 

Are you losing any engine coolant or getting a puff of white "smoke"/vapor coming out of the tail pipe on initial cold engine start up? You may have a crack in the head at #3.

 

What are your hot and cold compression pressures in #3? How about the others?

 

Are the Jet valves still in the head? You may have a bad one in #3. If you have the jet valves, replace all of 'em with Dad's Jet Valve Eliminator Kit.

 

Are your spark plug wire runs spread so they are not touching each other. You may have a cross fire situation if they aren't. Unlikely cuz you just replaced 'em but it may be worth mentioning. Use the FSM Page 8 - 152 for how they should be run & separated.

 

Let us know what you find.

 

For What It's Worth.

 

KEN

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I determined it was the #3 because when I removed the spark plug wire from the distributor it didn't change how it ran. I'm not getting a puff of smoke on cold start. and I don't think I'm loosing coolant. compression is 115 on all of the cylinders. the car is completely stock so it still has jet valves.
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I determined it was the #3 because when I removed the spark plug wire from the distributor it didn't change how it ran. I'm not getting a puff of smoke on cold start. and I don't think I'm loosing coolant. compression is 115 on all of the cylinders. the car is completely stock so it still has jet valves.

 

How many miles does your Lady have on her clock?

 

115 PSIG is LOW compression pressure for the Mitsu G54B T engine. When you took the compression pressures, did you have all of the plugs removed, FI clips disconnected, and the TB throttle plate wide open? The reason I ask this is that is unusual for the cylinder compression pressure to be this LOW and the same across all 4 cylinders.

 

Is the 115 PSIG cold or hot compression pressure?

 

This may be off the wall - remove the CTS and test it per FSM Page 14 - 64. Are it's female electrical connector metal terminals clean and tight on the wires and the CTS's male metal terminals?

 

Let us know exactly what you found/did.

 

For What It's Worth.

 

KEN

 

PS - I'd recommend getting rid of the jet valves.

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it has just over 77000 miles.

when I checked the compression I had all the plugs out but I didn't disconnect the FI clips or have the throttle plate open. it was 115 cold.

 

what's the CTS

 

With the throttle plate at the idle position you are greatly restricting the air going into the air intake system, consequently you will get a lower compression pressure.. Put a big brick on the accelerator pedal to hold it wide open.

 

HHHHHHHMMMMMM!! CTS is the engine Coolant Temperature Sensor. I strongly suggest that you down load the FSM and read Chapter 14. ;)

 

You should disconnect the injector clips so you don't spray fuel into the cylinders and the air/fuel vapor gets blown out of the open spark plug holes as you're rolling the engine with the starter. That ain't too safe.

 

Take a hot and cold set of readings properly so you know what condition your engine's compression actually is under both operating conditions. If there is a problem with the cylinders compression boundaries, comparing the two sets of readings should reveal it.

 

One other thing - pull back the boot on #3 plug wire in the dizzy cap and make sure that that wire is fully seated all the way down into it's hole. I've done it in the past were I didn't seat the wire's metal terminal clip inside and had a engine miss.

 

For What It's Worth.

 

KEN

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