My s14 boggs, dies then runs great randomly.

[Sterlingaidenk]

So first off, I bought my s14 ka24de automatic and it ran super great for 3 months, then many problems came up and one after another a new problem would come up. Right now it runs great when it wants to, I could go on the highway and there are no unusual noises or anything and no bogging then out of the blue it dies, when I am able to get it going its extremely gutless and wont shift into second gear. It does not want to start when it dies, when I get it to fire up I gas it to keep it alive, black smoke comes out the back. The ignition timing is at 18-21btdc at 700rpm. So far i have replaced spark plugs, Idle air control valve and air regulator, a brand new engine harness from wiring specialties, tps, coolant sensors, all fuses(no relays), new 5 point grounding kit, and 02 sensor, no coolant leaks, no milky oil either. The owner before me did do a egr delete so some plugs on the harness are not used but no codes are thrown. The only code im getting is the IAT which i just ordered. Another thing that is odd with the motor now is that it does not die when i unplug the MAF, it used to die when I first got the car dont know if that matters. The only real thing i can think of is the distributor is going out, and a vacuum leak but there is little to none that are left after the egr delete which look good to me. I will not do a engine swap either. I hope its just one little dumb thing im looking over. If you need pictures of anything I will take some.

[Kingtal0n]

black smoke = fuel

as long as the sensors are working, (iat, cts etc...)
It goes
MAF -> ECU -> INJECTORS

its a very simple engine. So you are looking for something that has to do with one of those 3 things

If a sensor is bad that's different. So check your sensors, check compression, basic diagnostics, then look for an issue with the maf wiring or maf plumbing or fuel pressure or ecu grounds or ecu connection (the harness to ecu) stuff like that

the sudden onset makes me think wiring related. But a bad sensor can do that too (goes 'bad' internally is a wiring short)

[Sterlingaidenk]

Originally Posted by Kingtal0n

black smoke = fuel

as long as the sensors are working, (iat, cts etc...)
It goes
MAF -> ECU -> INJECTORS

its a very simple engine. So you are looking for something that has to do with one of those 3 things

If a sensor is bad that's different. So check your sensors, check compression, basic diagnostics, then look for an issue with the maf wiring or maf plumbing or fuel pressure or ecu grounds or ecu connection (the harness to ecu) stuff like that

the sudden onset makes me think wiring related. But a bad sensor can do that too (goes 'bad' internally is a wiring short)

I have replaced the maf more than once before, any sources that you recommend? I have also a isr fpr and gauge coming because i thought that was some of the problems with fuel pressure, like a bad fuel pump or even wiring to the pump.

[kyral]

Have you run the codes?
best place to start.
Ive also found that the plugging and unplugging the maf test isn't a gurantee the maf is actually the problem, just gurantees theres a problem
also have found when the distributor goes bad it doesn't like throttle. Breaking up under throttle and idling well, They may be able to fail in other ways IDK but from my experience that's how they generally fail
hows your fuel pump doing?

[Sterlingaidenk]

Originally Posted by kyral

Have you run the codes?
best place to start.
Ive also found that the plugging and unplugging the maf test isn't a gurantee the maf is actually the problem, just gurantees theres a problem
also have found when the distributor goes bad it doesn't like throttle. Breaking up under throttle and idling well, They may be able to fail in other ways IDK but from my experience that's how they generally fail
hows your fuel pump doing?

My fuel pump is good i just threw on the isr fuel pressure regulator and gauge today, the fuel pressure is consistent, when it gets up to temp it tends to jerk at a consistent pace and fuel pressure isnt affected. The rpms fluctuate between 500 and 900 at idle now, possibly a bad injector? I also just replaced the iat and the code still comes up no matter how many times i replace it, now im just thinking of running a wire from the bolts of the sensor to the body for a good ground since the bolt holes of the sensor are lined with brass. The throttle is good, nothing weird about it I revved it up to 3500 just fine many times, I get a good quick response, the timing is still good but that also fluctuates with the motor simultaneously with the jerking.

[kyral]

pretty much guessing at this point
maybe the ECU distributor or maf have failed

[rotbrap]

Have you replaced the dizzy cap and rotor?

This fixed mine.