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Discussion Starter #1
Hello friends,

2007 Accent Manual Trans, my trusty sidekick. Recently the car would appear to energize normally and crank normally, but won't catch. Multiple start attempts, no luck.

My spidey senses noticed the fuel pump wasn't doing its normal two second prime before cranking. It is at best intermittent with start attempts, sometimes it primes, sometimes it does nothing. Occasionally the car will start right up, and runs in all phases completely normal without any symptoms. Other days it will crank normally but will not start even with healthy crank times and liberal mashing of the pedal (I know that's a carb trick only really, worth a shot). Q1 Does the pump prime before EVERY start attempt, or does a sensor detect there is enough pressure already in the line and forgoes the priming.

I swapped the pump relay with another matching on the board, no change. The pump runs when 12v is applied directly to the terminals at the pump connector. The car will not start even when I manually power the pump and crank. I tested the end of the connector with the key in ON, no volts during prime period. When I put the test leads on the pump relay CONTROL terminals, it read 8.4V steady from the time I turned the ignition to on, until 10 or so seconds after I pulled the key out and the main relay powered the whole car down. Q2 Is 8.4 volts the normal control voltage for these relays? If so, why is it applying 8.4 volts of control for the entire length the key is in the ON position and further until total shutdown?

At first I thought this was just a pump, or pump relay issue. The good driveability of the car when it does start leads me to believe there is nothing physically wrong between the tank and cylinders. I'm leaning toward something is not sensing or not deciding properly in the chain somewhere. It has thrown no codes and logged no misfires, etc. I almost wish it would get a little worse and log something.

Please send me your thoughts. Open to new ideas, criticisms of my tests, etc.
 

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Q1 Does the pump prime before EVERY start attempt, or does a sensor detect there is enough pressure already in the line and forgoes the priming.
There are no fuel pressure sensors on an MPi engine so it should prime every time the ignition is switched on. But I wouldn't get too excited about the prime. Not priming wont cause a non start. What you what to know is whether the pump is being switched on DURING CRANK. That's all that really matters.

Ohioflyer said:
Q2 Is 8.4 volts the normal control voltage for these relays?
Yes, that sounds normal to me for a relay that isn't being switched on by the PCM.

Ohioflyer said:
If so, why is it applying 8.4 volts of control for the entire length the key is in the ON position and further until total shutdown?
It's not actually applying 8.4V. The MAIN relay is applying approx 12V to one side of the relay coil, and the PCM is applying.....12 - 8.4 = 3.6V....to the other side of the coil. You can confirm that for yourself by connecting your black meter probe to battery negative then touch the red probe to the two relay control terminals. What voltage is on each relay terminal (ignition on)?

Ohioflyer said:
Please send me your thoughts. Open to new ideas, criticisms of my tests, etc.
I suggest checking that the fuel pump is being switched on during crank. There is usually a fuel pump test point on the engine bay fusebox on the Accent. Look at the label on the inside of the fusebox cover. The fuel pump check terminal is usually marked as "F/P CHK". Connect your voltmeter to the test terminal and monitor the voltage during crank. You should get approx 10V if the pump is being switched on by the PCM.

Let us know how you get on.
 

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Discussion Starter #3
This is why I turn to fine people like yourself. Thanks for the info Autospark. This is great information to lead on.

My challenge is I work in Chicago where the car is and live in Denver. Tools in Denver, naturally. It'll be a few days before I get back to you. I see the fuel pump check terminal in my pictures, and I'll send the answers to your follow ups. Thank God the pump and connector is under the rear seat.

Standby, and thanks again.
 

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My son had a problem with his 09 accent a year ago intermittent crank but no start for a couple of months finally a mechanic found a ground wire in the engine compartment somewhere that was frayed

Sent from my KYOCERA-E6560 using Tapatalk
 

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Got a question ...
Does the vehicle have an anti-theft system?
If it does then sometimes the key won't work??
Could it be possible that this is the issue??
 

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Discussion Starter #7
The car, from my understanding, does have an immobilizer. I have no idea how to find if it's been activated, or how to reset it, or what components are affected when it is activated.
 

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I think avisitor is talking about a transponder key immobilizer. Cars built for the US market don't have those so it's not likely to be a factor...unless your car originated in Canada. Cars built for the Canadian market do have transponder keys, AFAIK.
 

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The car, from my understanding, does have an immobilizer. I have no idea how to find if it's been activated, or how to reset it, or what components are affected when it is activated.
First turn the key to on position and look at the dash.
Does it have a key symbol?
If it flashes or stays on when trying to start engine then the transponder is not being read correctly.
If you don't have the key symbol then probably a different issue.
 

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Discussion Starter #10
Here's what I've found.

The volts from each fuel pump relay terminal with the ignition on (and outside the two second prime) are 12V on one side and 3.6v on the other. Just as you suspected.

The car does not prime but DOES indicate 10v roughly at the fuel pump check terminal during cranking! II put my hand on the pump housing and I do think I feel some whirring etc. when I crank. Hard to tell physically. I was also able to power the pump via that terminal so I believe it is actually happening....

Based on my research, My car year does not have a transponder key immobilizer. Im not sure if the pcm has one. I keep reading "immobilizer must be reset" when I shop for used pcm units.

The pcm not priming is a confusing symptom to me. My logic tree is breaking down lol.
 

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The pcm not priming is a confusing symptom to me.
That is unusual but it doesn't seem likely to be the cause of your starting issue since it still doesn't start when you directly power the pump. I assume when you apply 12V to the pump it will be running for several seconds before you start to crank the engine over.
 

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Discussion Starter #12
That is unusual but it doesn't seem likely to be the cause of your starting issue since it still doesn't start when you directly power the pump. I assume when you apply 12V to the pump it will be running for several seconds before you start to crank the engine over.
Yes, I powered it for a few seconds, and continued to power it through the crank cycle. My understanding is that the pump runs continuously when the engine runs so I tried to mimic the same action.
 

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Is your engine a complete non start right now?
Since you know the fuel pump is running have you check that there is spark at the plugs? Injector control?
 

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Discussion Starter #14
Is your engine a complete non start right now?
Since you know the fuel pump is running have you check that there is spark at the plugs? Injector control?
Normal power up with typical cluster lights, normal crank, no catch/start. spark and injector impulse are next. Need more tools that aren't with me unfortunately. Still no codes. Everyone seems to throw the camshaft or crankshaft sensor on the recommended replacement list, but always seem to say it comes with a code first. I don't think its timing or fuel pressure/flow because when I was able to start the car on one of the intermittent successes, it drove totally normally with normal power. No sign of stall, hesitation, or other issue when it runs....

I don't have an injector impulse light (yet), is there a way I can test if an injector is opening with a power meter? Seems like too short of a burst to catch on a meter. Is one of the injectors powered open when the ignition is in ON?
 

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Discussion Starter #15 (Edited)
I got one of the injector connectors off, 12v to ground on one side (I understand this to be normal, one terminal is always hot with power on) and 3.6v on the other side. Both measured to ground. When I measure the lower voltage terminal during cranking, it jumped around between 3.7 and 3.3. The update rate on my meter is slow so I understand that test likely means nothing.

Need tools to get to the coils and plugs, more to come on that.

Also, I disconnected the crankshaft sensor and it threw a code when I did that. No codes when connected. 2.5v out of those connector terminals.
 

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I don't have an injector impulse light (yet)
Any 12V bulb works. If you don't have a proper test light you could just pop out your trunk light and add a couple of wires to the terminals and use that. With the wires attached, disconnect one of the injectors and push the free ends of the wires into the terminals of the injector connector. The bulb should blink during crank if the injector is being triggered by the PCM. The injector pulse is pretty short though so it wont be very bright.
 

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Discussion Starter #17 (Edited)
Any 12V bulb works. If you don't have a proper test light you could just pop out your trunk light and add a couple of wires to the terminals and use that.
Thanks for the advice, I did exactly as described. During continuous strong cranking without start it went like this:

Flash
Flash
Flash

Flash


Flash





Flash

Then nothing.... Very interesting! I'd be very curious as to your thoughts on that! During those initial 3 flashes, I did hear one cylinder give a slight bark, but otherwise, nothing.

Something else is going on with the cluster that I'm now noticing...the fuel gauge stays up at the last indicated fuel level, even after key OFF, main relay off. And the digital mileage display above and between the tach and speedo fades away instead of just turning off.... I suppose this could be a symptom of the battery losing charge after all these attempts, but nevertheless another electrical symptom. I'm going to bring a charger next time out too.

Finally, I took a battery terminal off to give the hot bus items a full reset as well just because. When I reinstalled it, the fuel pump primed for two cycles of the ignition switch! and then of course went back to no primes.

(besides the lowish battery) Is something in the PCM preventing full electrical power delivery to the required relays and components? I've checked the pins and connector, looks mint inside. Looked all around the engine bay for anything else amiss. Its like everything is working for just for a moment and then dying out. Starter keeps cranking away constant strong revolutions.

Spark test to come next weekend. Crankshaft position sensor on order.
 

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If the engine is cranking at a constant RPM the frequency of the flashes should be constant too. If the cranking RPM starts to slow as the battery becomes discharged the frequency of the flashing would slow too, which kinda looks like what might be happening.

At least you know the PCM is controlling the injectors meaning fuel should be getting injected...assuming the fuel pressure is correct.
 

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Discussion Starter #19
If the engine is cranking at a constant RPM the frequency of the flashes should be constant too. If the cranking RPM starts to slow as the battery becomes discharged the frequency of the flashing would slow too, which kinda looks like what might be happening.
That's the thing... the starter was cranking at constant speed, not slowing down in any noticeable way. However, the fuel injector test flashes were coming more and more infrequently until they didn't at all (even with full cranking speed).

At least you know the PCM is controlling the injectors
Is it though lol? Intermittent triggering would be a generous adjective in my opinion. I consider the first 3 flashes I saw as the proper cadence and rate, after that it fell off the cliff. I actually thought the pcm triggered a code when the flashes became unpredictable and stopped. Like it detected misfiring and cut the cylinder ignition. No codes though.

...assuming the fuel pressure is correct.
This is one of the next tests I want to run next time I'm in town, and with a fresh charge. More results next Saturday or so.

I really want to thank you for hanging with me through this one, I'm sure you see a lot of newbies come and go. I appreciate your sharing advice very much. Get some sleep!
 

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Is it though lol?
The test maybe didn't produce the result we were expecting but it confirms the output side of the PCM is working, which was all we wanted to know at this point.

Ohioflyer said:
I actually thought the pcm triggered a code when the flashes became unpredictable and stopped. Like it detected misfiring and cut the cylinder ignition. No codes though.
If there is a misfire the PCM on most modern management systems will switch off the fuel injector control on the effected cylinder to prevent unburnt fuel from entering the catalytic converter. But that wouldn't effect the injector pulse during crank because misfire detection isn't active until after the engine is running.

Ohioflyer said:
This is one of the next tests I want to run next time I'm in town
Fuel pressure testing is a bit of a PITA on Hyundai engines. You usually need a special adaptor to plumb the pressure gauge in. No plug 'n' play Schrader valves on Hyundai engines, unfortunately.

Ohioflyer said:
I really want to thank you for hanging with me through this one
I'm happy to try and help.
Working with folk on the forum is actually pretty good fun. I get to just sit back with my tea and choccy bickies and tell you guys what to do without getting my own hands dirty :D
 
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