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Hi all... I'm new to the forums. .. and I got a problem. .. lol.
Few months ago the tucson died... had the fuel pump replaced... worked great.
Had the tucson parked for a few day as I waited for winter tires to come... got them.. out them on... it won't start. OK so I pulled fuel pump... hooked it direct... works great. .. took out the relay... hooked it up to power source... it engages... no power get back to the pump... well power isn't getting to the relay to engage it... i put power direct to pump and almost started ... probably a bit of air. So... with fuse panel apart and light tester and multimeter... let's call the prongs on the relay 1 2 3 4 ... 1 being closest to windshield. .. then 2 then 3 on passenger side the 4 on driver
1 _
2 _
3.4[ ]
With key turned to on... i have
12v at 1
0V at 2
3v at 4
0V at 3
3 has white wire that goes to back of fuse panel. .. the to front where there it is connected to another ... hmm nothing. .. looks like there was a wire here but not now... and I don't see any broken wires....
All I can say... any suggestions
Thx.
 

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So I should have 12v at prong. .. 3 or 4... but dont
What you should have is 12V on 1 & 3 with the ignition on. No power on 3 then remove the yellow relay marked on the photo below and bridge the two terminals on the relay socket as shown on the 1st diagram.

Now recheck the voltage on 3 of the fuel pump relay. If you have voltage on 3 now, connect a voltmeter across the yellow relay coil terminals (2nd diagram) and check for 12V.

Scottie.





 

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Discussion Starter #8
Ok did all you said... shunted the main relay got power on 3... notice corrosion on main relay flipped fuse box and number 86 wire on main fuse fell out... gotta fix that and see if that's all it is... gonna be fun with all them wires and no room to work
 

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Discussion Starter #9
Ok added wire on brought it up to top of relay... secured it... Car now runs... awesome... thank.... happy holidays
 

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Glad I was able to help get you going again.

Just out of interest..where do you live? Just wondering if it's the climate where you live has caused all that corrosion under the fusebox.

Merry xmas.

Scottie.

PS...the yellow relay is the main engine control relay that powers up the engine PCM, fuel injectors, etc.
 

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Auto Spark

I am having same Issue as Zandermack.

I followed your steps Listed. I get 12.35 v power to #3 when I jump 30 and 87

BUT there is NO voltage when I test 86 to 85 0 Volts what does that mean?

2006 Hyundai tucson 2.7 2WD limited.

Also Note #3 has .70 volts on it and #4 has 4.07 Volts on it with the key on and BOTH main and Fuel relays removed ?
 

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85 and 86 are the coil terminals. One should have 12v to engine/body ground when the key is on as well as 30. The coil ground (I think it is 85) looking at the pictures orientation. That ground is supplied by the ECU and the only time you would get 12v across 85 and 86 is if the ECU is commanding the pump to be on.
 

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BUT there is NO voltage when I test 86 to 85 0 Volts what does that mean?
It could mean a couple of things. Either there is no power supply to the relay coil or the coil ground that comes from the PCM is open circuit.

I assume we're talking about the main engine control relay here (the yellow one in the photo in post #5)? If that's the case remove the relay and switch the ignition on. Now measure the voltage between ground and terminals 30 & 85. Both those terminals should have 12V.

If that checks out OK, connect your red meter probe to battery + and touch the black probe to the 86 terminal and you should get approx 12V if the ground from the PCM is good. If you don't get 12V on the 86 terminal, probe the black orange wire on the fusebox connector as shown below. If you get 12V on the connector but nothing on 86 at the relay, the wire inside the fusebox is probably broken/open.

Relay Socket Pinout



 

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FIXED. It is running.

I had same issue as Zander. the 86 wire was corroded right OFF re attached Wire. Not an easy fix. But the the car starts and runs.

Thank you SO SO SO SO much for all this helpful info.
 

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It could mean a couple of things. Either there is no power supply to the relay coil or the coil ground that comes from the PCM is open circuit.

I assume we're talking about the main engine control relay here (the yellow one in the photo in post #5)? If that's the case remove the relay and switch the ignition on. Now measure the voltage between ground and terminals 30 & 85. Both those terminals should have 12V.

If that checks out OK, connect your red meter probe to battery + and touch the black probe to the 86 terminal and you should get approx 12V if the ground from the PCM is good. If you don't get 12V on the 86 terminal, probe the black orange wire on the fusebox connector as shown below. If you get 12V on the connector but nothing on 86 at the relay, the wire inside the fusebox is probably broken/open.

Hello sir,


Yet another person with this ongoing issue :(


When I connect the red meter probe to battery + and touch the black probe to the 86 terminal, I do not get 12 V, i get about steady 9 sometimes 10.

The black orange wire on the fusebox connector gets about 13.65

Does this mean the wire inside the fusebox is definitely broken/open?

Thank you


PS: If so, any heads up, pictures or anything I could use to help me out with somehow fixing this? Do I have to remove the fuse box etc, (Or is there an easier way to fix it without removing the fuse box?)
 

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Does this mean the wire inside the fusebox is definitely broken/open?
Your getting some voltage so the wire can't be completely broken....yet.
But there certainly must be significant resistance inside the fusebox in the circuit between the connector (black/orange wire) and the MAIN relay.

kici said:
is there an easier way to fix it without removing the fuse box?
The proper way to repair this is to open the fusebox and cut the wires off the under side of the main relay socket. Then extend those wires and fit the relay somewhere outside the fusebox. There was another thread where someone had done that and posted some photos but the last time I checked the photos have now been removed.

The simple fix/workaround would be to splice a length of thin wire onto the black/orange wire at the connector, then jam the opposite end of the wire under the 85 terminal of the relay. In other words, lift the relay off of the fusebox and push the free end of the spliced wire into the 85 terminal of the relay socket then refit the relay back into the socket on top of the wire. Obviously that isn't fixing the corrosion inside the fusebox but it will likely get you mobile again inside 10~15mins.


You need to be careful that you place the spliced wire under the correct terminal of the relay if your going to do this workaround. The control terminal of the relay (the terminal the PCM grounds to switch the relay on) is the 85 terminal, not 86. The terminal on the relay socket that you want to push the wire into is the one nearest the engine bay bulkhead...see below :

 

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Thanks a lot, truly appreciate the swiftness and in depth response.


I will be back within the next day or two, attempt this and update with the outcome.


The other relay above it "Start" had one corroded pin as well but not nearly as bad as the Main one, if the Start one gives out, what would be the impact?



Again, Thank you really appreciated the response and well in depth with clear instructions.


PS: Even though my 86 Terminal has the issue with not going to 12 V, I splice the wire to 85 regardless? Can you help me explain how that wire to 85 will help the Terminal 86?
 

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if the Start one gives out, what would be the impact?
The engine probably wouldn't crank over when you attempt to start it.

kici said:
Even though my 86 Terminal has the issue with not going to 12 V, I splice the wire to 85 regardless? Can you help me explain how that wire to 85 will help the Terminal 86?
OK, we better just take a moment to make sure we get this bit right. Below is a photo showing the relay socket terminal numbers. Which one was it you probed with the voltmeter and got 9~10V relative to battery positive? I assume it was the 85 terminal (the one nearest the bulkhead)?

I think I might have caused some confusion with my earlier diagram. The little diagram I posted earlier (post #13) and said it was the relay socket actually shows the terminal positions as you look onto the base of the relay. When you turn the relay right way up to insert it into the fusebox the 85 & 86 swap over, if you see what I mean. So the relay socket on the fusebox is a mirror image of the base of the relay....follow?

Normally this isn't really significant which is why I never bothered to correct the previous diagram. But it is significant when we are jumping parts of the circuit. We need to make sure we're connecting our jump wire to the correct side of the relay. Getting it wrong could damage the PCM.




 

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Hello,



I'm attaching 2 images to show you which I think is terminal 86.




Testing 86, Red prone to Positive on battery and to 86 shows 0, and then tested to the 4th wire main relay ctrl wire shows 13 V



I tested ground with 86 shows 13



Let me know how to proceed or any other tests that I should conduct.






On the fuel pump (back seat is put up) I tested the black and red to see if anything goes to it when I turn the key - nothing, and i do not hear it.
 

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