So here is my problem I have power to my coils ( all coils have been tested and were fine), but no spark at the plug my ecm is fine tested by dealer, new fuel pump, cams sensors, crank sensor. I have fuel my issue is no spark the dealer told me it is a wireing issue possible short they also tested the timing to see if it has jumped but it did not. So my question has anyone seen this problem. The orginal problem occured when i was driving the truck died, loss of power after that it just cranks and cranks and nothing
Its a 2002 pathfinder vq35de
starting problem need help cranks but no start
Re: starting problem need help cranks but no start
All coils have primary, but no high voltage at the spark plug. It is unlikely to have all high tension leads dump their voltage to a ground other than the plugs. If I can believe the dealer, but I question why they did not finish the diagnostics, as you have told us. The problem has to be a common part that signals the primary to switch off and on in order to induce the secondary of each coil.
That would lead to the switching transistor(s), but if they are good any other component in the primary circuit because the secondary voltage is not usually controlled except via the primary.
I don't have a 2002 book, so you are going to have to post a copy of the ignition diagram and then I could work through that.
Is there a cut off via an alarm or an accident cut off of fuel and spark in that vehicle?
Why did the dealer stop?
That would lead to the switching transistor(s), but if they are good any other component in the primary circuit because the secondary voltage is not usually controlled except via the primary.
I don't have a 2002 book, so you are going to have to post a copy of the ignition diagram and then I could work through that.
Is there a cut off via an alarm or an accident cut off of fuel and spark in that vehicle?
Why did the dealer stop?
Re: starting problem need help cranks but no start
I tested the power to all coils from the red power feed wires when caranking 10.6vv and when on battery the shown 12.1v when on battery with a charger on the battery it self. The dealer had the truck for three weeks and started it by jumping power from the battery to the ecu rely or directly to the 1 one coil ( they said i picked it up after hours with a tow truck)the wanted to charge me by the hour to trouble shoot the issue they told me possible break on the power feed from the ecm relay to the ecm it self so the truck does not know when to fire but they apprently had it running i pulled it out becasue cost was getting hidh with no guarntee of resolving the issue I orginally assumed it was the natv security system but the dealer confirm it was not I will post the ignition schematic
Re: starting problem need help cranks but no start
First by pass the alarm system so the car is able to work, look in your service manual, find the relay(s) and jump the contact(s) out of circuit.
Then find the ECU main cable and verify the plug connector so that the cable can be assured correctly installed. When looking at the cable harness look for frayed wires, I doubt you will locate any but from your report, I say this.
With the ECU known to be OK, from your report and the ECU known to have a good connection, after you checked, install an OBDII reader and leave it on, unless you have access to a recorder, then use a recorder.
If in your manual the firing plugs are controlled via an external transistor, find that switching device, but if the switching device is located within the ECU, you will have to swap it out.
You need to tell me, or locate a diagram of your ignition system, so I can further help you. I do not have the manual for your vehicle, but if you have a book or software send me a copy, PM me and possibly we can resolve this.
From your earlier repot the dealer claimed the plug wires were grounded. Yes they are but that ground is through a spark plug with its one electrode attached to ground. It is critical to verify that the engine block is in common with the negative side of the battery and all the ground straps from the main ground are all tied together.
If a ground strap is missing and the engine is not clearly and cleanly tied to the car frame and the car frame is not tied to the negative battery post there can be many problems with the engine and the electrical system.
You must verify everything, in order, start with the battery and its major connections. This includes cables, wires, joints, everything.
Then we can do the ignition circuit.
Then find the ECU main cable and verify the plug connector so that the cable can be assured correctly installed. When looking at the cable harness look for frayed wires, I doubt you will locate any but from your report, I say this.
With the ECU known to be OK, from your report and the ECU known to have a good connection, after you checked, install an OBDII reader and leave it on, unless you have access to a recorder, then use a recorder.
If in your manual the firing plugs are controlled via an external transistor, find that switching device, but if the switching device is located within the ECU, you will have to swap it out.
You need to tell me, or locate a diagram of your ignition system, so I can further help you. I do not have the manual for your vehicle, but if you have a book or software send me a copy, PM me and possibly we can resolve this.
From your earlier repot the dealer claimed the plug wires were grounded. Yes they are but that ground is through a spark plug with its one electrode attached to ground. It is critical to verify that the engine block is in common with the negative side of the battery and all the ground straps from the main ground are all tied together.
If a ground strap is missing and the engine is not clearly and cleanly tied to the car frame and the car frame is not tied to the negative battery post there can be many problems with the engine and the electrical system.
You must verify everything, in order, start with the battery and its major connections. This includes cables, wires, joints, everything.
Then we can do the ignition circuit.
Re: starting problem need help cranks but no start
Ok so this is where I am, The battery is new and seemed to be OK ( WIll load test ) plus i have a charger hooked up. The alarm is by passsed no NATS codes, it has been confirmed to be off when the chip key is present in the ignition the harness at the ecm is secure in the ecm. I have a sacn tool but i do not see how it is needed to be connected for the test? The spark is controled by the ecm relay gets the feed from the cranksensor to determine TDC. It seems to test good. I have the whole service manal dealer edition. send me email and i can froward you the pages. I broke and cleaned all the grounds and. change the enigine block ground strap to be safe it goes directly to the negitive post now. Currently disconnecting the whole harness to throughly check it. all fuses under the hood have been checked with a mutli meter to verify 12v at all of them they passed. now removing coils to clean plugs from being blasted with gas from no spark
Re: starting problem need help cranks but no start
Hello. I see this thread is a few years old but i am currently experiencing the same issue with my 02' Pathfinder. First thing i did was check all my fuses, relays, etc, and checked at fuel pump harness to see if i was receiving power which i was. Since i had power at the plug but didnt hear the pump prime when turning on ACC i jumped to conclusion that it was a bad fuel pump n removed current pump n installed a new one. When both fuel pumps were in my hand, and out of the tank, i tested them both to see if they were working with 12v from the battery directly and they were. I also checked fuel filter n fuel pump return line to make sure they weren't clogged n everything was good. I put everything back together assuming the truck should now start n i still have the same issue 
, I don't hear the fuel pump prime yet im receiving signal at the pump harness. Lastly, i read in some other post or forum that it might be a bad CRANKSHAFT POSITION SENSOR but im not sure n would like some feedback from anybody who might have had this problem before. The last test i performed was remove coil pack n plug from cylinder #3 n test for spark and i'm not receiving any spark. So in the end, do u guys/gals think this may be a bad crank pos. sensor or something more?? Once again, thanks for any feedback in advanced. 
, I don't hear the fuel pump prime yet im receiving signal at the pump harness. Lastly, i read in some other post or forum that it might be a bad CRANKSHAFT POSITION SENSOR but im not sure n would like some feedback from anybody who might have had this problem before. The last test i performed was remove coil pack n plug from cylinder #3 n test for spark and i'm not receiving any spark. So in the end, do u guys/gals think this may be a bad crank pos. sensor or something more?? Once again, thanks for any feedback in advanced.