EFI ignition intermittent miss

[roundhouse]

Got a 90 mass air EFI, was getting an intermittent mis , when it misses, the tach loses signal, so that means its on the primary side, right?

Just in case I swapped the cap and rotor, cause I noticed the cap had a crack in it. no improvement.
I swapped the TFI module and this helped alot, but didnt totally get rid of the miss,

what else should I swap, the coil, the signal generator inside the dizzy?

 

[SaddleUp]

Clean all of your connections and use dielectric grease in them.

 

[roundhouse]

Are there any other connections related to this besides the ones on both ends the TFI module?

 

[SaddleUp]

Are there any other connections related to this besides the ones on both ends the TFI module?

Clean ALL of the EFI connections. That includes the ECM connector, the engine harness connectors, etc. That one thing may change it from running rough to a smooth idle. It did on mine anyway. If it has poor connections then the voltages go stray and the resistances don't read correctly to the ECM. You can put your hand over each exhaust pipe and determine if the miss is coming from one or both sides. If it is only on one side then it could be a bad O2 sensor. But that would be accompanied by a fuel related issue in addition to the miss. I.E. It will be running rich or lean on that bank. It sounds like yours is more related to spark though which leads me to think it is in the wiring connections. Also don't neglect to check the main power wiring. Mine would stumble when I drove it down the road and smooth out when I stopped. It bugged me for a few days before I figured out what it was. I simply hadn't tightened the nut on the starter relay where my power connections were tight enough.

 

[roundhouse]

Whats the best way to clean the connections?
hose it with electrical contact cleaner, and then apply the grease?

 

[edge4]

Quick dry electrical contact cleaner, then dielectric grease. Make sure you have a cleaner that is waferboard safe. Some cleaners will melt the connectors.
One of the worst offenders are the 2 big "Salt and Pepper shakers" injector harness plugs. I ended up cutting them off and directly soldering the wires based on what I read at Ryan's website.

 

[roundhouse]

WHile cleaning everything in the dizzy I noticed the black sensor that the stator ring passes through is a little loose and , is rubbing the ring,

I didnt see any missing screws, what holds this thing in, other than being hooked onto the vacuum advance blockoff?

And how do you get this thing out?
Looks like you have to slide the dizzy shaft out the bottom to get this thing out?

 

[ransil]

WHile cleaning everything in the dizzy I noticed the black sensor that the stator ring passes through is a little loose and , is rubbing the ring,

I didnt see any missing screws, what holds this thing in, other than being hooked onto the vacuum advance blockoff?

And how do you get this thing out?
Looks like you have to slide the dizzy shaft out the bottom to get this thing out?

Its a Hall sensor, not a stator. you will need to pull the gear off the shaft to replace it. if you can get a spare from a junk yard, last time I changed a hall sensor it was a PITA.

 

[roundhouse]

So what holds the sensor in the dizzy, just the hole in the center. thats the stupidest thing Ive ever seen!

one at a junkyard would be worn out too I think.

or is it my bearing in the dizzy worn out and causing the shaft to wobble and wear out the hole in the hall sensor?

wonder if I can enlarge the hole and install a bronze bushing so it wont happen again.?

 

[roundhouse]

Well cleaning the connections apparently fixed it, thanks.

I also am working on a small bracket that will hold the hall sensor properly.

 

[roundhouse]

I made a small bracket out of a hacksaw blade, that holds the sensor in position,
so if you have a miss that you cant figure, check the hall sensor.