BF130 green light (oil pressure)

Hello,

My 2002 BF130a3 has a rev limiting or running problem and wont rev over 2000. I suspect something to do with the oil pressure rev limiter at 1800rpm.

I need some advice on how to troubleshoot.

According to the user manual:
The green oil pressure light should come on for 2 seconds when the key is turned on, but it does not come on.
The green light does not come on at all when the engine is running either, but it should be on when the engine is running if the oil pressure is good..
Again, the engine will not rev over about 2000rpm.

Maybe the ECU is bad and not controlling the light properly and throwing it into rev limited mode. I would like to test the light first to make sure the bulb is good and the wiring is good.

This is a beginner question but how can I test the green light and wiring without cutting the insulation and damaging the weatherproof sealing? The light pod on the dash is sealed. Also concerned I could damage the ECU if i test improperly.

Are there any other suggestions on how to figure out the problem?

It’s probably best to start with the basics.
1)Is the filament bulb ok (as In not burnt)?
2)Is the oil pressure sensor functioning correctly?
3)Are the wires/cabling functioning ok.
I had a 1999 BF130 until recently.
The oil pressure sensor is on the starboard side top rear behind the intake manifold.
Best to look into the above first.

Thank you for the advice, George. Per the service manual I will try the following and report back. Does this look correct? Anything else I should check while I am at it?

1)Is the filament bulb ok (as In not burnt)? Will connect 12V to the pin A-19 at the ECU and see if the light/wire are good.

2)Is the oil pressure sensor functioning correctly? Will check pin A-23 to see if the OPS has continuity to ground when engine not running. Will see if I can insert a wire to the circuit when the engine is running to check if the OPS switch opens or voltage goes to 0V (12v when not running)

3)Are the wires/cabling functioning ok. Hopefully this method will verify the harness cables, too.

Not sure how soon I can get to this, especially since I have to dunk it to test the OPS.

I don't know, maybe it's just me, but having over 3 decades of experience in the automotive repair business I was first and foremost always concerned about verifying actual oil pressure with a mechanical gauge before troubleshooting any lamp, switch or wiring in a situation like this.

I mean, after all, if low oil pressure turns out to be the culprit here, you could actually do irrevocable damage to the engine running it to test the switch.

I also would caution you about applying 12 volts in such a way as to be feeding it into the ECM. That testing should be done with the harness unplugged and volts applied to the bulb side of the connector leaving the computer "out of the loop". In addition, if you do it "my way" you may need to also supply a ground if that is also disconnected with the harness

Not criticizing your efforts or trying to cause confusion but do want to see you be safe and not sorry.

Good luck.

Thanks JGMO. I understand your logic completely and will do as you advise. I would update the post above with this but the website doesn't allow me to edit.

1)Is the filament bulb ok (as In not burnt)? Will connect 12V to the pin A-19 at the ECU (with ECU disconnected) and see if the light/wire are good.

2)Is the oil pressure sensor functioning correctly? Will check pin A-23 to see if the OPS has continuity to ground when engine not running. Will test oil pressure with a gauge. Will see if I can insert a wire to the circuit when the engine is running to check if the OPS switch opens or voltage goes to 0V (12v when not running)

PS. The engine was run for a considerable amount of time troubleshooting this. If it is low OP then it would have probably seized, but I will none the less check OP with a gauge. When the problem first occurred all of the advice I received pointed to a fuel system problem. I didn't discover the inoperable green light until well along in the troubleshooting process. Due to the age of the engine and lack or troubleshooting capabilities available, most shops won't work on this type of problem. It is one of the early fuel injected models with no computer diagnostic hookup. But t least the honda folks have a decent service manual. So here I am...

PSS: I have dealt with several 1980's cars with similar primitive ECU's.

It is in deed best to keep things simple and practical.
The bulbs can be removed and visually inspected or tested with 12 volts.
They are filament bulbs and might look blackish due to age.
There is no need to go through the ECU.
Correctly said an oil pressure gauge will do well.
The oil pressure sensor is an on off switch that is activated or deactivated according to the pressure.
I don’t know if continuity = green light on or off.
Basically it is an analog contact switch that changes state accordingly.

I don't know about the 4 cylinders but the 2 cylinder Hondas use BPT (British Pipe Thread) at the OP switch. Something I had to get via Amazon to adapt my gauge.

Good hunting.