Sr20det struggle street

[Yikes]

Hey guys, I'm at my ends meet with this thing. My 180sx has both an idling and starting problem. When cold, the engine at times would just keep on cranking, when it cranks it idles like trash. However, when warmed up it goes alright and drives okay. The idle also drops insanely fast and almost stalls the engine when it gets revved, oh and there's like a metal ticking noise in the exhaust as well but I'm not sure if that's an exhaust leak or something greater (but good compression reflect a somewhat healthy engine doesn't it?).

So far I've checked my coils, my compression is good and even across all cylinders. It's getting fuel into it, I've gapped and changed sparkplugs twice now (first went with BKR6E then BKR7E). I've searched in almost all Sr20det related forums and surely I've found similar problems but never the exact (most have it when it's hot, or when they clutch in, or the car will stall when coming to a stop which doesn't reflect my issue) and most of them never really have a follow-up fix to their issue. Oh I've also already cleaned out my IACV, I tried to do the MAF (Z32 MAF) test but my engine cuts off immediately when I pull the plug so I'm not sure if that's damaged either or how else to test it (I also don't really want to spend 200+ dollars buying one just to test it).

I suspect it's either an o2 sensor, TPS sensor or crankshaft position sensor but I'm not even sure if I'm on the right track with that, so any pointers would be much appreciated.

I'm not super techy with engines and what not since I've only had the car for a few months and I'm learning on the go, so I'd like to apologise for the seeminly dumb and long post.

*Edit, new information*

[TheVinylKingz]

Sounds similar to mine. My problem has started a week ago. It had a hard time cranking. So I bought a new battery. Alternator is good as it was tested prior buying a new battery.

Problem continues*************

When coming off load it sometimes stalls when under 1000k ——500 RPM. I had to jump it with my jumper that I carry in my s13. I can avoid it by reving/giving gas when the car is coming on a complete STOP with my hand break on low speeds.

Can it be the Air Idle Control Valve that needs cleaning or??????

[Yikes]

I've only recently cleaned out the Idle control valve, problem still persists.

[samotage]

What is the condition of your MAF sensor? And are there leaks, and is there a BOV venting to aptmosphere?


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[Yikes]

I'm not running any BOVs on the car and as far as leaks go I only have a powersteering leak and a smidge of oil leak somewhere near the pan. I don't really know the condition of the MAF since I can't do the unplug test due to the car stalling immediately. Are there any other ways to test for a bad MAF?

[NukeKS14]

Anyone tried pulling codes from their ecu?

https://240sx.org/faq/articles/ecm_codes_doch.htm

Most Silvia/180sx/240 are similar.

Barring that, check/adjust TPS, and could be a bad coolant temp sensor as well. Start looking for codes and go from there.

[Yikes]

Ah I'll check the TPS when I have the time then. I'll change out the temp sensor as well then since that's one of the easier installs. Oh and I forgot to mention but the previous owner had a Power FC installed and I don't think they throw codes, do they?

[samotage]

Pull your maf out, take it apart, inspect it, clean with brake or carby cleaner, dry it and re-install.

Many times goop like k&n filter oil will build up and make them go haywire.

And a PowerFC! A museum piece! Maybe there are codes on its hand held controller?


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[Yikes]

I'll be sure to clean the MAF as well then since I haven't done that either. I never got the hand held controller from the owner but it does have a dash mounted control unit which I'll double check on later to see if I can get some codes out of, this engine is driving me insane.

[samotage]

It?s a typical thing to happen when the ecu does not know how much air is in its system, so it cuts ignition to failsafe limp mode


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[S14rebuild]

Coolant temp sensor-2 wire one

[Yikes]

I tried to set the car into limp mode a while ago by unplugging the MAF while the car was running and it just dies immediately. That's the issue I was having when I was trying to test if the MAF was broken or not. But I'll update you all with the coolant sensor, TPS adjust and MAF clean tomorrow and see how I go. Appreciate all the help guys, means a lot

[samotage]

This tells the ecu there is no maf, a different scenario to a dirty one


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[Kingtal0n]

If it has a pfc the answer is simple. Look at the hand-held controller to see what the issue is. all the details are there.

Sounds like it needs tuning and a bypass valve.

[Yikes]

Originally Posted by Kingtal0n

If it has a pfc the answer is simple. Look at the hand-held controller to see what the issue is. all the details are there.

Sounds like it needs tuning and a bypass valve.

I don't have the hand controller since the previous owner never passed it on, but I did send him a message to see if he still has it. I'm not sure if a tune or a bypass valve is needed since the car drove absolutely fine in the months I've owned it.

[Yikes]

Also, I've cleaned out the MAF, checked my TPS (Sits at 0.48, most places said 0.45 so I thought it was okay to leave it there). Nothing's really changed. Are there any other checks I can/should do before I start pulling out things like the coolant sensor? Because if I pull that out I might as well change every other sensor listed in my original post...

Oh and I also forgot to mention the heavy RPM drops (to the point of almost stalling) after revving only exists when the engine is cold, when it warms up the RPM still drops fairly fast but manages to catch itself around 800-900 or so and occasionally stutters like when it's cold, but rarely.

[asdowdell]

It may very well just be your MAF. When mine went bad, it started out as a crazy idle and would bog when I pressed the gas at random times. It progressed into having a difficult time starting my car. When I did get it started, it would soon die. I bought an ISR MAF and have had no issues with it since.

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[Kingtal0n]

If it has a maf, it needs a bypass for most small turbos or the flow rate for the turbo overpowers the engine at low speeds causing air to flow backwards through the maf which stalls the engine. Which you would see if you had the controller.

[burnsauto]

I'm kind of leaning with the other guys suggesting you get a tune/diagnose the problem through the ECU. Having a professional take a deep look at exactly what's going on and pinpointing issues sounds way better than throwing parts/money at a problem that isn't fully understood. I wouldn't put too much faith into "some tune" from "some guy" when the engine is running poorly. It just needs checking, that way you know that end of things is good, and you don't have to assume that the tune is fine (because it very well may be not).

[samotage]

If a clean maf still fails, then get some real info from a tuner. What they said, it will be cheaper than a rebuild.


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[Yikes]

Yea, I'm taking the car into a shop tomorrow to see how I go. Hopefully I'll be able to come back and update the post with a real solution in case someone in the future finds themselves in a similar spot. Appreciate all the help so far guys.

[samotage]

Hope you find the answer! There will be a reason


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[brndck]

check for vacuum leaks as well, make sure you have adequate fuel pressure, fuel filter isn't clogged, sock on the fuel pump isn't clogged

[Kingtal0n]

A shop cant magically see inside the PFC. You need a commander. Bottom line is you are blind deaf and dumb without a commander to view variables. If you get commander simply post video here and we can see the variables on it, and tell you what is wrong.

well, I can

[burnsauto]

....i know some old heads on zilvia will know this...but what ever happened to steve shadows?

[S14rebuild]

I was lookn for him too not that long ago... was told he dissapeared..lol

[dorkidori_s13]

this sounds more like a tune based problem than anything else. youre gonna need to get into your PFC with a laptop and a wideband O2 sensor. trying to diagnose your PowerFCs tune with the commander will only drive you nuts due to how limited the stupid thing is (especially in screen size and resolution).

btw, pulling the plug from the MAF while the motor is running, even with a stock ECM, will instantly kill the car due to the ECM no longer being able to meter A/F. you are meant to unplug the MAF while the car is off, then start it. this puts the ECM into diagnostic mode where it will run without the MAF. there is a separate map in the ECM that runs when it detects the MAF is unplugged. on the factory ECM (i dont know about PFC LJetro ECMs, i have a DJetro), the car will only be able to rev to 2000-2500rpms... but, again, this is for the purposes of diagnosing whats going on with your motor only.

EDIT: i meant to ask... are you running a factory VG30 MAF? or is it aftermarket like an ISR unit?

[Kingtal0n]

If it has a maf its an L-jetro and a laptop is not important.

The D-jetro is where you really need the laptop

MAF tuning is incredibly simple, voltage based with a scalar easily accessed in the commander which removes the majority of difficulty

I can tune an FCLJ in like 1 hour done with just commander

DJ map based with laptop will take typical stand-alone times... 1 to 100 days depending how perfect you want the base map... its 100x the time consuming

[Yikes]

Oof, the shop I got recommended to by a friend is filled up today. Gotta go in tomorrow. But I definitely have enough fuel pressure, but I will make time today to double check my fuel filter and fuel pump to see how it goes. For a leak test Imma probably gunna have to do it at the shop since I don't have a compressor laying around but I might get that done first before an ECU read.

A shop cant magically see inside the PFC. You need a commander. Bottom line is you are blind deaf and dumb without a commander to view variables. If you get commander simply post video here and we can see the variables on it, and tell you what is wrong.

I'd love to post up the variables that can be obtained through the handheld unit but I simply just don't have it, I feel like it's not exactly worth it for me to spend 400 ~500 to buy a unit..it'll just be cheaper to do it in a shop. I do appreciate the recommendation though so no disrespect there.

btw, pulling the plug from the MAF while the motor is running, even with a stock ECM, will instantly kill the car due to the ECM no longer being able to meter A/F.you are meant to unplug the MAF while the car is off, then start it. this puts the ECM into diagnostic mode where it will run without the MAF.

A lot of videos I've seen, people pull the MAF while the motors is running and it jumps into limp mode immediately? I've also tried to launch the car with the MAF unplugged, it starts but dies pretty much immediately. So I'm not sure what's happening there of if it's just a Power FC thing.

i meant to ask... are you running a factory VG30 MAF? or is it aftermarket like an ISR unit?

I'm running a Bosch z32 MAF, it seems to have less pins than the VG30? Does that make a difference? (Sorry if this seems like an obvious question)


But all in all, I'm taking it into a recommended shop tomorrow noon, this time with a proper booking (since I was told to just rock up last time ahaha). If that doesn't work, I've also gotten a proper booking with a store that specifically dyno's imports. God I wish Nissan just made new 180s. Once again, thanks for everyone's input, issue isn't solved but at least I'm learning things on the go. Much appreciated.

[burnsauto]

i mean..they did make them for almost a decade....

hope your visit to the shop turns up something.