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Discussion Starter #1
No power to the fuel pump. Jumpered the fuel pump relay socket (30 and 87), fuel pump whirs. No power at 85 and 86 in the fuel pump relay socket. No power at INJ and SNSR fuses. Main relay apparently rusted years ago, previous owner moved the main relay under the fusebox. Lifted the fusebox, swapped main relay for start relay. No difference. Swapped fuel pump relay for another same relay. Looked under the fusebox, moved a lot of wires to see better. Recently brake fluid spilled from the master cylinder. Where shoulders the teo fuses be getting their power from? They show some weird voltage like 0.33 v.
 

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From what you describe it sounds like either there is no power being supplied to the main relay or the main relay control circuit is open/broken. The main relay normally gets it's power supply from the main ECU fuselink....see below. But that might not be the case on your car if the relay circuit has been previously modified.

 

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Dont we have similar topic running already ??

Corroded wiring at underside of fuse box wiping out electric ?

Scan and find odd low voltage DTC that start out P05xx ?
 

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Discussion Starter #4
I was able to do a bit more probing before the dark today. I turned the key to on, and pulled out one relay at the time, then measured voltage at the pins. The ECU 30A link socket had 10.5 v. Fuel pump: 11.8v at 30, 85 gound ok, 86 had 0.35v (that is the problem). A/con relay had 11.75v at 85, and 0.34v at 86. IGN 30A relay had 11.9v. BATT #1 and BATT# 2 each had 11.74, at both pins (is this normal?). BLOWER had 11.7 v, one pin. INJ and SNSR fuses show 0.34v (weird). When I connect the red multimeter probe to the car battery positive terminal, and the black multimeter probe to the inj and snsr fuses, I get 0.34v. The others just show 0 when connected to battery +. CFAN relay had 11.74v and 0. I was clumsy yesterday and dropped one of the E18 joint connectors down into the engine bay, did not find it. Some schematics show that the first one after the gray (white) is not used, but others do not have it that way. Anyway, that slot is now empty, I do not know if I screwed anything else up.
 

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Discussion Starter #5
Sbr711, you are right, there is a very similar thread about a 2.7 L Tucson. I will try to read that again, but so far I was not able to figure out the problem just by reading that. Where does the ECU 30A link get its power from?
 

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Sbr711, you are right, there is a very similar thread about a 2.7 L Tucson. I will try to read that again, but so far I was not able to figure out the problem just by reading that. Where does the ECU 30A link get its power from?

ETM says "HOT ALL TIME"

Drawn out with cable to battery.. horn fuse, IGN 40, ECU 30 seen in first pic,, ABS 40, C/FAN 50, and host of hot links
 

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No check engine light on or anything unusual.
No check light is unusual when the engine isn't running and it's an indication that the ECU isn't being switched on/powered up.

You have power being supplied to the fuel pump & AC relays but none being supplied to INJ and SNSR fuses? Those circuits are all supplied with power from the MAIN relay, suggesting the relay is being switched on by the ECU but there is a problem with the wiring between the relay and the various circuits it's supposed to supply, possibly due to corrosion inside the fusebox as suggested by sbr711 earlier.

The E18 link that you dropped (missing in the photo I attached earlier?) shouldn't effect the engine. It's part of the headlamp circuit. The other E18 link I've highlighted below is the one on the output of the MAIN relay. You might want to pull that out (don't drop it :)) and take a look at the connections on the fusebox.

 

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Discussion Starter #9
Just to correct some errors; I said I dropped the "white" E18, but that was pink, as Autospark said. He still understood what I meant better than myself :(. Also, I said "no check engine light on" - I meant the opposite, sorry. At key-on, all of the usual lights come on, including the check engine light, and they stay on. Again, sorry to confuse everyone.

I attach the two schematics for a 2007 2.0 Tucson that I found online. The two black schematics are in conflict; according to one of them, the E18 I dropped is not used. But I think the other was is actually correct, because I did see some connectors in that slot. I can check when I remove and flip the fusebox again.

According to the wiring diagram, the ECU 30A fusible link powers the MAIN relay, 30 on the MAIN relay should be hot at all times. I will check that again, but it was okay the first time I checked. I believe 86 had power as well. My understanding of the diagram (I don't quite understand it though) is that when the engine control relay control opens ground to the MAIN relay, assuming there is power in 86 and ground in 85, then the 30 and 87 should click and send power to fuel pump etc. If the MAIN is good, then I should trace the white wire 99 to the E18 connector. White wire 100 should go from there to the IN and SNSR fuses, so I will check those carefully as well. (This should be on the third pink E18, not the second it seems). If there is no power to INJ and SNSR fuses, I should find a problem between MAIN, down to 99 W and 100 W before and after the E18.

On the fuel pump relay socket, my understanding is that 30 should be hot at all times, which comes again from the third e18 connector, white wire 103. That wire should power the 86 connector in the fuel pump relay socket, which now does not get power (I was surprised when Autospark that the FPR does get power - there is power only at 30, which I think comes from the ECU 30A link). Blower worked when I checked, so that would mean white wire 101 should have power.

I remember over time that the A/C knob adjuster inside would flicker and sometimes I would hear clicking, which would interrupt the A/C. When I flipped the engine bay fusebox, I could see corrosion in the FPR and A/C R sockets.

It seems to me the third pink E18 might have the key to the whole problem. I will have to try again tonight if possible. It is slow and tedious work though, especially for a clumsy guy who is bad with the multimeter :(.
 

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I was surprised when Autospark that the FPR does get power - there is power only at 30, which I think comes from the ECU 30A link
Sorry, your quite right. I must have misread your previous post about the FPR voltages. I just read it again and see you have no voltage on the FPR 86 terminal.

Just__Curious said:
30 on the MAIN relay should be hot at all times. I will check that again, but it was okay the first time I checked. I believe 86 had power as well.
If you have power to the 30 & 86 terminals of the main relay, what you want to check next is that the relay switches on (clicks) when you turn the ignition on. If the relay switches on but you have no power to the INJ and SNSR fuses that means either the relay is faulty or there is a problem with the wiring between the 87 terminal and the fuses. If the relay doesn't switch on you have a problem with the relay control wiring between the engine PCM and the relay 85 terminal.

Just__Curious said:
My understanding of the diagram (I don't quite understand it though) is that when the engine control relay control opens ground to the MAIN relay, assuming there is power in 86 and ground in 85, then the 30 and 87 should click and send power to fuel pump etc.
Yeah, that's pretty much how it works. When you switch the ignition on power is sent to the PCM. This is really just a signal to tell the PCM that you have turned the key on. When the PCM sees that the ignition has be switched on it outputs a ground to the 85 terminal of the MAIN relay, switching the relay on. The MAIN relay then sends power to the other circuits (FP Relay, engine sensors, etc).

BTW, here's a little sparkie trick you can try just for a giggle :
Switch the ignition on then remove the A/C relay from the fusebox. Next, use a link wire to bridge the 30 & 86 terminals on the relay socket on the fusebox as shown below. With all the other relays and the E18 links in place, try and start the engine and see if it will fire up. Don't run it long like that but see if it will start. If it does E18 isn't likely to be your problem.


A/C Relay Socket
 

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Discussion Starter #11
Yesterday it was raining like crazy, so I did not touch anything, but today I got 1-2 hours after work.

I dismounted the fusebox again and flipped it and checked the main relay (which was placed under the fusebox by the previous owner, if you remember). The connections are pretty bad and they slip off, so I double checked. I have power at 30, and also at 85 and 86, at key on. So the relay and the wire to ECU 30A link seems fine. No power at fuel pump and A/C. I did swap the ECU 30A and the blower links at the beginning. At the end, the blower was just clicking. But that might have been because I tried the sparkie trick that Autospark suggested, and the car started, but it stalled and died after 2-3 seconds. Might be the car battery, the voltages were around 9.5 V, so I will have to charge the battery. After connecting 30 and 85 on A/C relay socket and starting the car briefly, I could smell some smoke, but did not see where. The main relay wires did not seem to have been altered by the previous owner, he just had the main relay moved out of the box. I remember seeing blue corrosion on the A/C and FPR sockets, on the underside, so I think I will cut off the wires, extend out and connect the two relays directly to the wires. Wire W 99, between MAIN telay and e18 connector was badly corroded on the main relay side, so I cut it off closer to e18, extended and put a new connector on. Might be wise to fix the other MAIN wires as well. If thus fixing wires does not resolve the no start issue, then I might just have to get a new box and move all the wires. No that would take a week, judging by the number of wires - so hoping moving a few relays out of the box will do it.
 

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checked the main relay. I have power at 30, and also at 85 and 86, at key on.
If you have power on both the 85 & 86 terminals that's telling you the MAIN relay isn't switching on. Remember, when you switch the ignition on the PCM sends a ground out to one side of the relay coil, normally the 85 terminal, to switch the relay on. If you have power on both those terminals the ground control from the PCM is missing, either because the PCM isn't sending the signal or (more likely) the control wire is open circuit.

The relay control signal enters the fusebox on the black/orange wire shown below. With the connector plugged in, back probe the black/orange wire and see if it has voltage or a ground. If it has a ground you know the PCM is sending the ground signal meaning the wire must be open/broken inside the fusebox.

 

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Discussion Starter #13
I think I fixed the problem, but not 100% sure yet. I was able to start the car, had to jump start it because the battery was drained. After Autospark suggested checking for ground between main relay and connector EC11, I started checking again. I think my multimeter died (new but $25 at Home Depot) - beeps continuously on the continuity mode, probes apart; but I was able to get some work done before it. I carefully looked at the ground between the main relay and EC11 (point 11 in the diagram) and I could see that the wire had been connected together at one spot, and they just put electrical tape around it. Upon closer examination, it broke off because it disintegrated, looked like dust. So I cut it off close to ec11, made a butt splice to extend, and then put a new female disconnect at the other end, which I then connected to main relay. Turned the key to on, and I could hear the fuel pump whirring (an unnecessary, brand new pump, you will remember). Tried to start, battery too weak. Got jumper cables and another car, it started right away. Left it on for about 20 minutes to charge, now it is fine. Blower not working, the 30 amp fuse is blown, will buy that at NAPA ($4.99). When I replace that, I will check if A/C is working. Drove around a bit (rotors rusty, so had to scrape the rust off by braking - my neighbors prob'ly think I am a looney). All that hard braking did not dislodge the E18 connector, and I kind of do not want to dig for it. Does anybody know the Hyndai p/n for the pink one? Might just buy a new one and be done with it. The 30 amp slow blow fuse is 918304A000. Might be a good idea to buy a FPR/ A/CR also. So the bad ground to MAIN relay seems to have been the culprit. I attach some photos to help others who might have the same problem. Autospark, you are a gentleman and a scholar - thank you ?!
 

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If I was you I'd invest in some fully insulated terminals for the relay connections. I don't know the part number of the E18 link but I'm sure your local Hyundai dealer would be able to order you one. Or stop by your local breakers yard and see if you can find one. The Tucson shares the same fusebox with the XD Elantra and the GK Coupe/Tiburon, so look for one of those if you can't find a scrap Tucson.

Great to hear you got it running. Glad I was able to help.
 
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