[Sausager]

Hey guys. I've been getting code 52 on my Japanese 1995 G16B LWB vitara for a while now. I am having trouble finding solid info on what actually causes the ECU to throw this code, and that makes it difficult to diagnose. There is some info about this code online that I have found, and it seems to be related to fuel/injectors/O2 sensor - but again, I don't know where to start since that is about all the info that I have. The Fixkick website has some info, but I find it really hard to follow the author's rabblings. I can't find mention of any code 52 in any FSMs that I have found

Other info that may/may not be relevant:
- Car does run rich. Exhaust stinks of fuel when idling and also when driving, both hot and cold.
- Unknown KMs on motor
- I recently pulled the 52 code from the ECU, and the time prior to that I checked for codes it wasn't there. Between then and now I have put a new exhaust and headers on it, with a different O2 sensor that came from a running car. Unknown if this is the cause or not, but I also want to know/test it is before swapping parts
- Vehicle has always seemed low on power, slow to build revs
- AW4, not manual

Any insight or some FSM pages would be super appreciated

[fordem]

Attachment:

Suz52.JPG

This is actually from an SV620 manual, but the code meanings are generally the same across vehicles, and it ties in with your complaint that the engine is running rich.

[Gwagensteve]

Snap, beaten by fordem - heated oxygen sensor model only....

Anyway, this is what I typed

I just checked my FSM but there is no code 52 for the early (cone AFM) EFI cars. In my early FSM code 13 is for the oxygen sensor.

However, there's a few confusing things going on here:

The oxygen sensor is only referenced under light load and constant rpm. if you unplug it I don't believe you will see a trouble code appear until those conditions are met and the ECU looks for a signal. However, being a JDM car it may have a heated oxygen sensor, (as per Ford's post above) not typically fitted to ADM cars it might be missing the correct signal for the heated O2 sensor. Note, early G16B's have four wires to the O2 sensor plug but only one wire is used to the sensor.

I don't believe there is any diagnostics associated with the injectors specifically. monitoring the injectors is pretty advanced EFI and not within the scope of 30 year old engine management - the injectors are on an output and are just switched on and off for as long as the computer decides. That's it. Note in the explanation of code 52 the stuck injector diagnosis will be coming from the O2 sensor reading rich constantly, not because the ECU is actually looking at the injectors. It could definitely be a stuck injector but that will normally hydrolock the engine. quick way to check (off the top of my head) - pull the spark plugs, turn the ignition on, sit it for a few seconds, and attempt to start the car, then just sit it wit the ignition on for a few seconds. if an injector is stuck there should be a heap of fuel in a cylinder if you crank the motor over again.

ECU's have sensor inputs (Camshaft position, air temperature, air mass, throttle position, Vehicle speed and O2 sensor) and the function of these are what the diagnostics covers.
The outputs (ignition signal, injector drive, IAC and EGR control) aren't subject to diagnostics, the ecu just switches them and hopes for the best.

This isn't the case with modern Euro 6 compliant ECUs where in-cylinder conditions are monitored through things like spark plug current draw but fortunately the G16B is pretty basic.

[Sausager]

Thanks for this guys, I appreciate your time.

For what it's worth, the O2 sensor on mine is the one Steve calls out - 4 wires to the plug but one to the actual sensor. I can't see how that can be a heated type sensor with one wire, so I am presuming it isn't. Does the above still apply then?

If not, I'm at a bit of a loss to what areas I target. In my head my list in priority is:
1. Injector function. Can that be done at home?
2. O2 sensor function - or swap with known good one
3. Fuel pressure
4. Failing those, I guess it is other things that cause incomplete fuel burn - spark, compression, timing, AFM, TPS, ECU and the list goes on...

Am I on the right track?

[Gwagensteve]

Firstly fit the correct oxygen sensor for the car. Code 52 only applies to vehicles with a heated oxygen sensor.
A non-heated oxygen sensor has been fitted.
The diagnostics won't recognise this as the cause of a problem as it can't anticipate that incorrect parts have been fitted.

If the car had the correct oxygen sensor fitted and it was operating correctly, it would be reporting a rich condition which is why it's suggesting to check the injectors. if you fit the correct oxygen sensor and still get code 52 then worry about injectors at that time.

I bet that will fix the issue.

To your other questions:

1) You can fire an injector with 12V - just some flying leads will do the job. you should hear it click open and shut. obviously it's harder to test with fuel/ fuel pressure but if you're creative it can be done.
2) Yes, swap to the correct, heater oxygen sensor as above
3) Yes, you can buy or adapt a fuel pressure gauge fairly easily. I have done this with a generic pressure gauge and some hose and fittings. What you're reporting would correspond with high fuel pressure, the most common reason would be a pinched/fouled return line.
4) Most likely not any of those things. TPS? AFM? No. The big one would be significantly retarded timing due to the old flogged out keyway issue. How can I be confident? you're not getting a TPS or AFM error code. Timing isn't monitored by diagnostics on this engine (it sort of is with the baleno engines as they have a crank AND cam position sensor. the early engines only have cam position in the distributor so the engine can't tell if the crank and cam aren't in phase.

[fordem]

Gwagensteve wrote:

3) Yes, you can buy or adapt a fuel pressure gauge fairly easily. I have done this with a generic pressure gauge and some hose and fittings. What you're reporting would correspond with high fuel pressure, the most common reason would be a pinched/fouled return line.

I don't know how common this is in Australia, but in the US, a "non-standard" fuel pump is another common cause of excessively high fuel pressure - it seems that someone on a forum somewhere suggested a pump from an Ford F150 could be used, without going into details on which F150, and one model has a pump with significantly higher pressure than the others.

[Gwagensteve]

Sorry if this seems overly pedantic Fordem, but it’s not that the pump produces more pressure, it’s that time flow rate of the pump overwhelms the pressure regulator and/or return line causing fuel pressure to exceed factory specs.

I’d be surprised if this is an issue in this case, however I do suspect it’s an issue when people use the generic Bosch 044 “Motorsport” pump in Suzuki applications as it flows flow far more fuel than the stock fuel system is designed for.

[Sausager]

Thanks guys.

Steve, how do I know for sure that my intended setup isn't as you describe above - 4 wires on the vehicle loom for the sensor but only one wire on the sensor? Are you saying that if this was the intention by Suzuki then the code 52 wouldn't be a "known" code that the ECU can throw? IE, the presence of code 52 proves that the ECU's expected sensor is a heated type?

I'll also inspect fuel return line, because it is low-hanging fruit and yes that would bump up fuel pressure. I don't recall seeing the fuel pump having been replaced/tampered with when I had the tank out last, and this tank & pump came from a well-running car (original one was dented) so I am going to rule that out as a low chance of being incorrect.

[Gwagensteve]

Code 52 only applies to cars with a heated sensor.
JDM cars have heated sensors.
Your car does not have a heated sensor although the loom has provision for it.

My car runs an early g16b and while there are four wires to sensor plug the sensor only has one wire. Code 52 does not exist for my model (I have the correct FSM for my engine)