Continuous fuel pump run is often a sign there is an ECU issue. I would go ahead and pull the ecu and inspect the capacitors and test for continuity between pin 46 and 40/60.
I've seen the relay get stuck.
You could try replacing it or swapping it out.
Or whack it with the back end of a screw driver.
No idea if it still triggers a code. Back in the day i don't think anyone i knew actually looked at codes.
You could try replacing it or swapping it out.
Or whack it with the back end of a screw driver.
No idea if it still triggers a code. Back in the day i don't think anyone i knew actually looked at codes.
Good suggestion on stuck relay. It’s worth checking.
I’m not convinced the code is tied to this issue. It might be an old code and one worth erasing and verifying if it comes back.
Pin 19 on the ECU monitors the fuel pump circuit after the relay. If there’s no power on the wire that runs the pump, pin 19 won’t see voltage and will trip that code that says the fuel pump isn’t running.
In this case the fuel pump IS running. So under normal conditions that code shouldn’t appear. That suggests to me it’s an old code that just needs to be erased, or the circuit for pin 19 and the fuel pump circuit is compromised. However…the pump runs.
I guess the question to ask is OP, are you aware of any wiring changes or hackery to the fuel pump circuit (or any circuit) on this car?
I’m not convinced the code is tied to this issue. It might be an old code and one worth erasing and verifying if it comes back.
Pin 19 on the ECU monitors the fuel pump circuit after the relay. If there’s no power on the wire that runs the pump, pin 19 won’t see voltage and will trip that code that says the fuel pump isn’t running.
In this case the fuel pump IS running. So under normal conditions that code shouldn’t appear. That suggests to me it’s an old code that just needs to be erased, or the circuit for pin 19 and the fuel pump circuit is compromised. However…the pump runs.
I guess the question to ask is OP, are you aware of any wiring changes or hackery to the fuel pump circuit (or any circuit) on this car?
I’ve actually been digging around inside the A9L a bit in an attempt to study it.
I believe one way to test to see if this issue is the ECU is to perform a continuity test from pin 22 to pin 40 or 60 with the ECU disconnected. With a good ECU, you won’t have it, but on a bad one I believe you will have continuity.
The fuel pump is driven internally by a transistor with a few resistors. A common way this setup blows is by wrongly applying 12v to the fuel pump test circuit on the sto test plug, or wrongly applying 12v to the fuel pump relay on the wrong side of the coil trying to manual activate it.
Either the resistor blows, or the transistor shorts. If the fuel pump doesn’t run, it’s the resistor. If it runs constantly, it’s usually the transistor that needs to be replaced.
I don’t have a bad ECU to test my test methods and repair on, but I’m fairly confident that short of any wiring issues, this is an ECU issue, specifically the fuel pump transistor.
If you get a chance, if you remove the ECU can you test continuity from pin 22 to pin 40 or 60?
I believe one way to test to see if this issue is the ECU is to perform a continuity test from pin 22 to pin 40 or 60 with the ECU disconnected. With a good ECU, you won’t have it, but on a bad one I believe you will have continuity.
The fuel pump is driven internally by a transistor with a few resistors. A common way this setup blows is by wrongly applying 12v to the fuel pump test circuit on the sto test plug, or wrongly applying 12v to the fuel pump relay on the wrong side of the coil trying to manual activate it.
Either the resistor blows, or the transistor shorts. If the fuel pump doesn’t run, it’s the resistor. If it runs constantly, it’s usually the transistor that needs to be replaced.
I don’t have a bad ECU to test my test methods and repair on, but I’m fairly confident that short of any wiring issues, this is an ECU issue, specifically the fuel pump transistor.
If you get a chance, if you remove the ECU can you test continuity from pin 22 to pin 40 or 60?
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Honestly, if you are going to crack it open, imo just repair those parts.
Some things can be tested in circuit some can't.
You could most likely test the transistor mike listed as the issue by just checking continuity at the legs, but as i said i've seen times on electronics that works and times it doesn't. So if you have to remove it you can test it vs a new one.
Me personally, i'd just do the caps and transistor while its apart.
That's assuming you are good at desoldering (soldering is kinda easy, desoldering, not so much). Personally i own a Hakko FR300 so i don't really shy away from the task like i used to.
Some things can be tested in circuit some can't.
You could most likely test the transistor mike listed as the issue by just checking continuity at the legs, but as i said i've seen times on electronics that works and times it doesn't. So if you have to remove it you can test it vs a new one.
Me personally, i'd just do the caps and transistor while its apart.
That's assuming you are good at desoldering (soldering is kinda easy, desoldering, not so much). Personally i own a Hakko FR300 so i don't really shy away from the task like i used to.
I agree. Testing some of these parts is tricky to do on an assembled board. If you can do soldering, this is a $10 repair to change out that transistor and replace the 3 caps.
The fuel pump transistor is this one I circled in red. It's pretty easy to identify which one as the center post of the transistor rings out when you test continuity from pin 22 to it. I think a MJF3055G transistor would be an acceptable substitute. The three capacitors are also an easy change out.
Of course i realize not everyone is comfortable doing this sort of thing
The fuel pump transistor is this one I circled in red. It's pretty easy to identify which one as the center post of the transistor rings out when you test continuity from pin 22 to it. I think a MJF3055G transistor would be an acceptable substitute. The three capacitors are also an easy change out.
Of course i realize not everyone is comfortable doing this sort of thing
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Code 85 and 97 don’t make sense here. Those codes pertain to the pump not running when they clearly are. Generally the lack of power on pin 19 will trip this code. With the pump running this should not be the case.
Are you absolutely sure the fuel pump relay wiring has not been tampered with? Have you pulled back the carpet to check? Any chance a PO installed a fuel pump kill switch.
With the car running, can you check for voltage on pin 19 to ground?
Are you absolutely sure the fuel pump relay wiring has not been tampered with? Have you pulled back the carpet to check? Any chance a PO installed a fuel pump kill switch.
With the car running, can you check for voltage on pin 19 to ground?
was having same issue all of a sudden (had my car at the track 2 weeks ago and the engine ran well,
(yesterday car would start but was running really rough misfiring and smelled like gas, had to keep feathering the throttle just to keep it running, something was definitely wrong)
one thing to check if your running a moates quarterhorse, definitely check the 2032 battery on the device it should read 3v or close to it, mine was reading 1.7v and fuel pump was running continous, replaced the battery, re flashed my tune file and fuel pump is operating correctly now.
I checked pin 22, both fuel pump and eec relays and was thinking my eec was bad, decided to check the battery on the moates and it was low so I think the tune was corrupted or something
I will fire the car tonight to make sure it's running proper, wife is taking a nap right now.
anyways hope it helps someone!
(yesterday car would start but was running really rough misfiring and smelled like gas, had to keep feathering the throttle just to keep it running, something was definitely wrong)
one thing to check if your running a moates quarterhorse, definitely check the 2032 battery on the device it should read 3v or close to it, mine was reading 1.7v and fuel pump was running continous, replaced the battery, re flashed my tune file and fuel pump is operating correctly now.
I checked pin 22, both fuel pump and eec relays and was thinking my eec was bad, decided to check the battery on the moates and it was low so I think the tune was corrupted or something
I will fire the car tonight to make sure it's running proper, wife is taking a nap right now.
anyways hope it helps someone!