Started running like it was missing, fuel pressure verified, spark from both old and new coil orange.
New battery
new coil
new plugs
new wires
have tried 3 different CPS all with the same results
cleaned grounds

Where do I start now?

92 4.0 auto

 

You should perform a voltage drop test between battery terminal positive and the 12v positive feed that goes into the coil via the connector. With a multimeter, you would place your probes at those two points, and the number the meter shows you (in volts DC mode) is the number of volts being lost between those two points (due to corrosion, poor connections, resistance). Cleaning up the ground connections was a good first step, but the positive sides can get corroded as well.

If you want to start with something more accessible, you can perform the voltage drop test between battery terminal positive and the ASD relay fuse. However, doing it the way a suggested above will make sure to measure the entire primary ignition system (the part of your ignition system that is still 12v).

Also have you opened the distributor cap and inspected in there?

 

ill try both of those tomorrow.

I suppose i forgot to throw in that the cap and rotor are new as well. Distributor is newer as well and seems to be indexed properly( was running perfectly for months when the missing started). Now it won’t even start hence I started with checking fuel pressure and spark finding that the spark seems weak.

 

Primary and secondary ignition really depend a lot on the engine block being grounded properly. One way you can rule out a weak ground connection is to fashion your own jumper between the block (at the studs below the coil) and the negative battery terminal. If things come back to life doing that, then it tells you that the block is not getting sufficient ground back to battery negative. (I've even used a set of jumper cables laying around to do this test)

An improperly indexed distributor would cause problems more like backfiring, sputters, no spark at all, etc.

A present, but weak, spark is more of a hallmark of a general electrical problem.

How is the overall system voltage doing?

 

Ok so I’ve got 12 volts running to the coil, it got dark before I could pull the coil itself to test it.
the map sensor tested 5.1 volts and 4.7 on the two leads and .13 ohms on the ground lead.

So so what would cause having fuel and spark but still no start. I’ve researched and Don’t really know where to go from here.

 

Ok you started off saying you had weak spark but your last post asks what causes no start. Which it be?

 

Started off as what felt like a misfire, got worse and worse,eventually requiring a lot of gas to get it to start, dark smoke and gas smelling exhaust. Found and fixed some vacuum leaks and now won’t start at all.

Ive got 30 psi at the rail with the key on and 45 or so when cranking. Plugs smell like gas when I pull them. New plugs rotor cap and wires. Replaced the coil and map sensor since they tested iffy and the coil housing had cracks.

Ive checked intake/exhaust manifold for tightness cleaned the aic and replaced the tps. Ive also swapped in and out 3 different CPS. Distributor and cam sensor are less than 3 months old and ran great until these recent troubles.

Im at a loss.

 

One possible problem is the PCM gives earth to the coil, so if the wire is bad there, or the connector, that may lead to an issue ?

couple of cases recently where PCM failed, no spark

There must be high current semi conductors in the PCM that handle these relatively high earth currents, ignition, alternator etc

 

Fuel pressure regulator is blown from what you telling me. Next step are there any codes.

 

My reference (sadly a website) stated 31 with key on and 45 while cranking. The pressure jumps quite a bit when cranking, if memory serves it jumped a bit higher than that. Is this incorrect? I’ll test again when I get home.

also, no codes.

 

Ok. Found a cracked vacuum boot going to the pressure regulator. Replaced. Still hitting 45+ Psi when cranking and plugs are drenched in gas. Also the oil dipstick smells like gas as well.

Does the regulator need to be replaced? I’m thinking yes. 31 should be where I need to be

Also thinking the constantly drenched plugs might be fouled as they are black and have been cleaned multiple times during this process.

Any feedback before fore I go buy a regulator and plugs?

 

feedback is, first find the problem then buy the parts

 

YES, the diaphragm in your fuel pressure regulator has likely failed. You should have 31 psi at idle, then about 39 psi with the vacuum line to the fuel pressure regulator disconnected.

 

You need a FAT BLUE spark. If you have a white spark no good, get a new coil

 

Nope, that isn't his problem and the only thing fat and blue you need is a wallet or cigar.