Hey Smart guys , I have a good one and I really don't have a clue what can be wrong with my qx4.
I purchased it 6 months ago and was running perfect, no mil on etc. it has mileage on it 221k miles.
Sometimes the car wont startup , its turning over but wont fire the sparkplugs. But sometimes it fire up and there
wont be a check engine code whatsoever ! I have a scanner and see the input of cam and crank sensor which shows perfect.
So I have changed the following :
New Key , New engine Ecu , New Coilpacks, Crank sensor, Starter ,Cam sensors ( all oem from Nissan) New Nats receiver ( key security).
You see I spent a crap load of money. I spent a lot of time online to read all forums and come to ask your help.
When I turn over the engine the ecu don't sent signal to coils , the 12volt supply to coils is good, the ground supply is good and wont drop
during starting. All what it is doing is turning over and floods the cylinders until a spark ignites it and car fires up and again no check engine light , not running rough or skipping but slick as it can be.
I was wondering if the timing chain has stretched a little and because of it not being synchrome , the ecu wont allow to sent signal to coils. Is this a
possibility ?
Remember this tomorrow it can crank and fire right up . I really have no clue and hope one of you guys can help me.
01 Infinity qx4 wont fire, no signal to coilpacks
Re: 01 Infinity qx4 wont fire, no signal to coilpacks
The cam sensor supplies the signal for the fuel injectors so it seems that is fine since you have fuel.
There are two crank sensors - one up under the crankshaft pulley on the front of the engine, and the other back by the flywheel.
The front one provides what is called reference signal to the ecu. If you have not swapped it out, you might try that because crank sensors are known for going bad without setting codes. It is the cheaper of the two - you can get them on ebay.
When you start the vehicle, turn the key to "on", and stop there. Watch and make sure your security light goes off, and that the check engine light comes on. Then go ahead and try to start up. The relay supplying power to the engine computer is the same as a headlight relay I believe, so you can swap that if the check engine light is not coming on.
Try those ideas and see what happens!
There are two crank sensors - one up under the crankshaft pulley on the front of the engine, and the other back by the flywheel.
The front one provides what is called reference signal to the ecu. If you have not swapped it out, you might try that because crank sensors are known for going bad without setting codes. It is the cheaper of the two - you can get them on ebay.
When you start the vehicle, turn the key to "on", and stop there. Watch and make sure your security light goes off, and that the check engine light comes on. Then go ahead and try to start up. The relay supplying power to the engine computer is the same as a headlight relay I believe, so you can swap that if the check engine light is not coming on.
Try those ideas and see what happens!
Re: 01 Infinity qx4 wont fire, no signal to coilpacks
Thanks so much for your reply , I was giving up hope. I forgot to mention that I had that front sensor also replaced . The security light goes out , the power is there to the coils ( 3 wires Pos, Neg is ok but signal wire from ecu 0.2 volts and should be 3 volt during starting.
The fuel injectors are injecting fuel , but the fire isn't there. But sometimes it is and it will run like a new car ......
I am telling you I have no clue , hopefully maybe you have another solution . Thanks again for your help.
The fuel injectors are injecting fuel , but the fire isn't there. But sometimes it is and it will run like a new car ......
I am telling you I have no clue , hopefully maybe you have another solution . Thanks again for your help.
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Buzzman
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2023 Kia Stinger Elite V6 AWD.
Re: 01 Infinity qx4 wont fire, no signal to coilpacks
This may be far fetched, but it may be a grounding problem.
I seem to remember a thread a while back about poor grounding causing weird electrical problems.
There's even a ground check in the FSM, if memory serves me correctly.
I'll do a quick search to see if I can find it.
I seem to remember a thread a while back about poor grounding causing weird electrical problems.
There's even a ground check in the FSM, if memory serves me correctly.
I'll do a quick search to see if I can find it.
Re: 01 Infinity qx4 wont fire, no signal to coilpacks
Try swapping the ECM relay. That relay sends 12 volts to your coilpacks. The ECM grounds the power transistor in the coilpack to fire the plugs. But, there are two other wires that go from the ECM relay to the ECM.
Just need to be 100 % sure there is no problem with that relay.
Just need to be 100 % sure there is no problem with that relay.
Re: 01 Infinity qx4 wont fire, no signal to coilpacks
I have swapped the ECM relay , makes no difference . I have cleaned all ground on engine , the ones on the front of engine above the cam sensor.
When I am turning over the engine the power supplied to coils is constant no drops, the ground is the same way , only the ecm sents 0.2 volts to coils
which ain't right , it suppose to be 3-4 volts.
Yesterday eve I started it and cranked up and run perfectly , had scanner on it and shows crank signal and cam signal perfect . Then I shut off the car
and it wouldn't start up , no difference , all sensors are sending signal within specs.(cam/ Crank/ Temp sensor/TPS sensor.)
Its flooding and no spark. Is there anyway to check timing marks without taking the front plate off the engine ? I have set the crankshaft on mark and took the left front Cam sensor out and notice on the cam plate a somekind square with little bolts which I believe it the trigger for the sensor to sent signal.
But here I think it is : the sensor isn't straight with that mark , its almost in sight but not completely. Can anybody answer this question ? Or if anybody
has the same vehicle if they would set the engine on the crank mark and take the left cam sensor out and see if the cam has that square with little bolts (I think trigger) is direct in line with the sensor ?
Thank so much for you great help trying to help me with this.
When I am turning over the engine the power supplied to coils is constant no drops, the ground is the same way , only the ecm sents 0.2 volts to coils
which ain't right , it suppose to be 3-4 volts.
Yesterday eve I started it and cranked up and run perfectly , had scanner on it and shows crank signal and cam signal perfect . Then I shut off the car
and it wouldn't start up , no difference , all sensors are sending signal within specs.(cam/ Crank/ Temp sensor/TPS sensor.)
Its flooding and no spark. Is there anyway to check timing marks without taking the front plate off the engine ? I have set the crankshaft on mark and took the left front Cam sensor out and notice on the cam plate a somekind square with little bolts which I believe it the trigger for the sensor to sent signal.
But here I think it is : the sensor isn't straight with that mark , its almost in sight but not completely. Can anybody answer this question ? Or if anybody
has the same vehicle if they would set the engine on the crank mark and take the left cam sensor out and see if the cam has that square with little bolts (I think trigger) is direct in line with the sensor ?
Thank so much for you great help trying to help me with this.