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Discussion Starter #42
I know where b+ fuse is. Should I check with dmm for voltage, blown fuse? Check it with key on, cranking or running? Thanks for your help.
 

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Discussion Starter #43
Had a mechanic look at it for a brief second and he commented that it seemed like it was getting to much fuel possibly? I say mechanic, actually a tire shop
 

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You need to check at the pump. If you have jumped 12 volts to bypass the relay and you don't have B+ at the pump the feed wire has a problem.
 

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Not really because his car is fitted with an inertia switch which should cut the power supply to the fuel pump if the car is in an accident. I don't see any real issue with bypassing the PCM control of the relay on this car.
Just hope there isn't a fuel leak that's not big enough to stop the engine but fill up the engine bay. It's OK for testing but best fix the real problem.
 

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Just hope there isn't a fuel leak that's not big enough to stop the engine
When was the last time you had that happen? I've never heard of it happening in 30 years in the motor trade, so I think it's a very small risk. I recon he'd be less likely to have an engine fire on his 2001 with a bypassed pump relay than someone driving a newer Hyundai with it's PCM controlling the fuel pump....
444569
 

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I suppose if you live in a place where the temp is less than 10 you don't see many cars catch alight but I have seen quiet a few but why they burnt I don't know but cars are designed that way for obvious reasons.
Getting back to the task.
Why not connect your MM to the pump and go for a drive till it stops and see if you still have power to the pump.
 

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Discussion Starter #48
I'm actually running the relay now. It stalls intermittently, but I'm able to drive it. Today it stalked on me with the relay in, I jumped it and it didn't make any difference, so I put relay back in. I'm going to check the voltage at the fuel pump tomorrow and post results.
 

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Hook up a test light and drive it and when it stalls see if the light went out.
 

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I'm actually running the relay now. It stalls intermittently, but I'm able to drive it....I'm going to check the voltage at the fuel pump tomorrow and post results.
While it is able to run I suggest removing the pump relay again and recheck those voltages. Like I said earlier, one of your measurements didn't seem right. If that voltage is different when the relay is working you know where the problem lies, and there wouldn't be much point to going back the pump.
 

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Discussion Starter #52
Those numbers don't seem right. The low voltage (2.5~3V) is missing, which probably means the control wire coming from the PCM is open circuit/broken.

Are these the readings you got?
View attachment 444556


Not really because his car is fitted with an inertia switch which should cut the power supply to the fuel pump if the car is in an accident. I don't see any real issue with bypassing the PCM control of the relay on this car.
30-12v, 87-0.0v, 86-0.0v, 85-12v
 

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30-12v, 87-0.0v, 86-0.0v, 85-12v
One of the coil terminals (the 85/86) should have that low voltage coming from the PCM when the relay is removed. Yours is missing suggesting that the control circuit is open/broken. That wouldn't prevent the pump from running if you bypass the relay with a wire link though.

It's odd that Hyundai have wired the relay coil the wrong way round. The 86 terminal is usually the coil power supply with the ground on 85. That doesn't have any effect on how the relay works but if you were to fit a relay with a flyback diode into the socket it would cause a short circuit and, hopefully, blow the supply fuse rather than the relay driver inside your PCM. Sorry, just an unhelpful observation.
 

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Discussion Starter #54
I'm on a run right now of about 100 miles and with relay in and about 1/2 tank of gas I was sputturing, pulled over and pulled relay and jumped relay socket and no real change. Made it to a gas station and overfilled gas tank and now there is no sputtering. I git the pull apart fuel pump out if a 2004 and had to change the sick back to my 2001 sock filter. 2004 was too long to go in tank. Seems like float may be having something to do with it? It's running normal now with relay jumped and gas tank overfilled? I'll try to put relay back in and see what happens.
 

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Discussion Starter #55
So relay back in, sputtering again. Also getting about 6 miles to the gallon. Used to get 25 mpg. No noticeable leaks anywhere, oil was just changed. Dipstick level is not increasing. Viscosity seems normal.
 

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Yea fix the code problem and I suggest you measure the fuel pressure and flow rate if none of the codes would cause a very rich mixture. The float will have nothing to do with your problems except inaccurate gauge readings.
 
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