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]

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]

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.

[Sterlingaidenk]

Have you replaced the dizzy cap and rotor?

This fixed mine.

Yes today i just replaced the cap and rotor and its running beet till it gets to temp then it dies. Ecu is also replaced with a rebuilt one and still dies. Also Is it a possible vacuum leak? I have my pcv and valve cover breather hose open to the atmosphere.

[collegekid]

Kind of a doozie without any codes. I feel like there would be codes.

When my brothers car kept randomly shutting off, it would not want to start again (I had it towed 2 times). He had no code originally. I thought fuel, so I replaced the fuel pump and sock. Same problem persisted. Later a code finally showed up for MAF and Knock sensor. Once those were done, problem fixed.

Does your car still have power to accessories? My truck had a bad battery connection (from main power wire being pinched).

[Sterlingaidenk]

Kind of a doozie without any codes. I feel like there would be codes.

When my brothers car kept randomly shutting off, it would not want to start again (I had it towed 2 times). He had no code originally. I thought fuel, so I replaced the fuel pump and sock. Same problem persisted. Later a code finally showed up for MAF and Knock sensor. Once those were done, problem fixed.

Does your car still have power to accessories? My truck had a bad battery connection (from main power wire being pinched).

A code for the maf and knock sensor showed up when i first got the car after replacing them they never showed up again. I have power to all my accessories besides the back defrost button is messed up. Still the code for the iat shows up, but this weekend im going to the junkyard and getting a oem maf, and possibly a iat sensor. Only one thing that i have replaced that is not oem nissan, is the maf, its a rebuilt napa autoparts one. I will inspect the main power lines also this weekend and double check the ecu grounds.

[mechanicalmoron]

A code for the maf and knock sensor showed up when i first got the car after replacing them they never showed up again. I have power to all my accessories besides the back defrost button is messed up. Still the code for the iat shows up, but this weekend im going to the junkyard and getting a oem maf, and possibly a iat sensor. Only one thing that i have replaced that is not oem nissan, is the maf, its a rebuilt napa autoparts one. I will inspect the main power lines also this weekend and double check the ecu grounds.

When you did the knock sensor, did you pull apart all the pcv and egr lines and ream everything out and replace the hoses that were crusted shut?

[Sterlingaidenk]

When you did the knock sensor, did you pull apart all the pcv and egr lines and ream everything out and replace the hoses that were crusted shut?

yes I have replaced every hose, and there is no cracks. I solved most of the prroblem by putting a oem maf from the junkyard into the car. Only problems are... CEL for iat will not go away still and somtimes shifting is delayed, its slow 0-40 mph after that it picks up speed fast, but tends to use up alot of gas.

[mechanicalmoron]

yes I have replaced every hose, and there is no cracks. I solved most of the prroblem by putting a oem maf from the junkyard into the car. Only problems are... CEL for iat will not go away still and somtimes shifting is delayed, its slow 0-40 mph after that it picks up speed fast, but tends to use up alot of gas.

...The ones under the intake manifold?

Like, you pulled the intake manifold?

What was wrong with your maf? Mafs fail pretty rarely, but are an obvious component that changes how the engine runs when you monkey with it, so people love fucking with it.

[Sterlingaidenk]

...The ones under the intake manifold?

Like, you pulled the intake manifold?

What was wrong with your maf? Mafs fail pretty rarely, but are an obvious component that changes how the engine runs when you monkey with it, so people love fucking with it.

Yes I have pulled the intake manifold out and replaced every hose and gasket got new hose clamps for everything too. Im not sure what was wrong with those mafs from napa autoparts but they didn't last very long especially if i dallied the car for a while, yes it does have a air filter and everything, everything is clean inside which didn't make any sense why those ones kept being trash. Putting on a oem maf was the trick for me. Today I saw that my carrier bearing for the drive shaft is about shot too, so I might also put on a 1 piece drive shaft on it, should hopefully help the ka pull the car better.

[Kingtal0n]

Yes I have pulled the intake manifold out and replaced every hose and gasket got new hose clamps for everything too. Im not sure what was wrong with those mafs from napa autoparts but they didn't last very long especially if i dallied the car for a while, yes it does have a air filter and everything, everything is clean inside which didn't make any sense why those ones kept being trash. Putting on a oem maf was the trick for me. Today I saw that my carrier bearing for the drive shaft is about shot too, so I might also put on a 1 piece drive shaft on it, should hopefully help the ka pull the car better.

try to keep the oem shaft 2piece design

its safer, like if you crash it will fold up instead of rip through the floorboard and impale you

Its also more likely to drive right,
In other words it seems like 40% of the time someone buys a 1piece driveshaft it isn't balanced or phased right and the car picks up an annoying vibrations

Just don't...

[mechanicalmoron]

try to keep the oem shaft 2piece design

its safer, like if you crash it will fold up instead of rip through the floorboard and impale you

Its also more likely to drive right,
In other words it seems like 40% of the time someone buys a 1piece driveshaft it isn't balanced or phased right and the car picks up an annoying vibrations

Just don't...

Agree.

Carriers also deflect and absorb impact when you dump the clutch or hop a wheel or something.

It's good to have softer systems that fail more gently, so you know before it happens. A carrier is the maximum benefit from the minimum compliance, keep it.