Would a bad MAF only show signs with load?

[Robb]

OBDII KA24DE
Auto trans


So, I'm pretty sure we've got a MAF issue this time.

I checked voltages on the white wire of the MAF, 1.7 at idle, 2.6-2.8 at 4000RPM. Obviously not right, right?

So there are not issue while the car is in Park, but once on the road, I definitely have issues with sputtering and such when getting on the pedal even in the slightest.

Input?



Edit: Not the MAF, see post 14 for updated information.

[PoorMans180SX]

Check your distributor cap for water.

[Banana_Cute]

I couldnt smog my car due to that. I cleaned MAF. IACV. TB. Still had it.

Smog guy told me i might have a dead spot on a TPS. pretty much the connection is worn inside. Got a new one and its gone.

It happens between 3500-4000 RPM. and in granny style driving. but when i floor it you cant feel nothing.

[Robb]

Cap, Rotor, Plus, Plug wires were all replaced when trying to troubleshoot this.

It was running like crap at idle, unplugged the MAF, plugged it back in, and there was no longer an issue at idle. Only happens when actually driving.

[AlexSR]

Same problem! need help always please!

Problem goes away when MAF is unplugged then plugged back in, but comes back a few miles later with no codes present at all! Only does it when under load at idle.

[Robb]

I'm throwing an EVAP code, but that's unrelated.

I also cleaned the MAF with no luck.


Alex, seems as if your problem is different than mine. I do not have an issue at idle, only when actually driving down the road.

[PoorMans180SX]

Yup, replace maf.

[AlexSR]

Talking to me or Robb? I clean the MAF and everything, it looks like its in excellent condition

[Robb]

Alex, mine did too, the only thing that was a bit dark is the mesh. Are you running an aftermarket filter or intake setup?

[PoorMans180SX]

They always look in good shape.

[BrokenLynkz]

just had the same problem change the MAF. I have a s14 and it would sputter like that then it finally stopped working. Order one from online you should be good after that unless you have a vacuum leak

[Robb]

Just had a friend pull a MAF and EVAP Purge Solenoid (my vacuum leak) for me. Let's see if it solves the problem. It seems like bad MAFs are all too common on these cars.

[Robb]

Welp, said MAF did not work. Read 2.6-2.8v, again.


Went out and bought a brand new MAF, 2.6-2.8v at 4000 RPM.


Engine grounds show continuity, TPS is checking out. I'm so lost. Ideas?

[Robb]

Yesterday I checked the injectors, replaced the fuel filter, replaced the distributor cap, checked for vacuum/intake leaks, cleaned the IACV, regapped the plugs with note of signs of fouling due to unburnt fuel on all four plugs, also noted that timing was a few degrees off. Retimed the motor and set idle but still having issues only when the motor is warm.

When the motor is cold, things run fine.

When the motor is warm...
Idle = misfire every 30 seconds - 1 minute
Press on the gas slightly = fine
Press on the gas 1/4-WOT = stumbles until 2500 RPM then takes off
Above 2500 RPM = Pulls nice and hard

The thing sounds like a Subaru when on the throttle until it gets going. I like the sound of a flat four, but not in this car, hah. Beginning to suspect a bad coil, but that's in the distributor since it's an s14, right? Ideas/Comments/Opinions? Really need some help here..

[PoorMans180SX]

Yes the coil is in the distributor on an S14 KA. It's hard to diagnose things over the internet. See if you can find a plug or injector that is not firing with a spark tester and noid light.

[Robb]

Bought a dizzy for a great price that will go in this weekend, CTS as well.

Seems to actually misfire all over the place, but is only terrible in low RPMs. I've stalled out once in reverse, but that's about it. When the car is cold it's not as bad, but as soon as it runs for a few minutes, the misfire comes into play.

[Robb]

Put in the new CTS and set timing again. No luck

Rev:
s14 Misfire Rev - YouTube

Drive:
s14 Misfire Drive - YouTube

[ska]

if it only happens when warm, check your o2 sensor.

[Robb]

It's also when cold now it seems, just not as bad

[Robb]

A friend dropped me a fuel rail with FPR I will swap out.

Backtracking to fuel, wouldn't it cause everything to lean out if the fuel pump was going bad? I've eliminated injectors/o-rings because ALL plugs are fouled, highly doubt all four would fail at once. So I would imagine FPR if anything involved with fuel.

I was also suggested O2 sensor. Recommendation on testing/thoughts?

[HIGHFIVEBETA]

Take the time to check your grounds on your maf wires. Mines would hesitate under load + higher boost. I took the wiring apart and one of the 2 ground wires on the connector was not connected to ground. I'm yet to have it running but i'm certain this might have been my issue.

[Robb]

You're saying on the actual harness connector?

I actually only have a 3 prong MAF harness connector, so, only 1 ground.

[HIGHFIVEBETA]

oh ok. thought you might have had a z32 maf

[Robb]

Replaced the FPR today - that wasn't it

[PoorMans180SX]

What kind of plug wires are you running? I get my aftermarket wires warrantied about every 6 months because they melt the insides out.

[Robb]

I picked up some Autozone brand wires because they were all I could find and I needed them that day. The NGK wires were like $120, nuts.

Replaced the O2 sensor for good measure, noted it was white like lean deposits. But the plugs are fouled with carbon as if it's not burning all the fuel.

[HellaflushS14]

Hey man, im having this exact same problem. Every time i pull up to a stoplight i have to feather the gas to keep the rpm's from dropping...the engine sounds like it's going to die every time. Once in a while under consistant load (keeping the car at say 30mph) it will start to stutter and want to cut out like its not getting fuel... replacing the fuel filter helped it...but only for a few days. So tonight im droppin in a new pump and ill let you guys know how that goes..