posting for a friend of mine. his car isnt getting any spark. thoguht it could be the ECU, changed it and nothing. any ideas. i think he has replaced the crank sensor already also. any input at this point would be great!

 

There are two 15 amp fuses to check. They are located under the hood by the battery and are labeled ENG CONT 1 and ENG CONT 2.

On the coil pack, there are 3 wires. Every coil pack has a red and a black wire. The red is 12 volts and the black is ground. The 3rd wire is a different color on each coil pack and this is the signal from the ECU to fire. See if you have 12 volts on the red wire. If not, this could be a bad ECM Relay. If you have 12 volts on the red wire, you could try and see if there is a trigger signal on the ECU wire. I would not expect to see one, though.

If the engine is a 3.0, there is a 2nd crank sensor at the harmonic balancer.

Also, the camshaft sensors can play into this, check them out.

 

This is my car he posted about, I just changed the camshaft sensor and no luck....both of the 15amp fuses are fine but I'm gunna swap them out anyway. just outta curiosty where is the ECM relay located? I changed both cranksensors

 

The ECM relay is under the hood, in the box that is in front of the battery. On the cover, it is labelled "ENGINE CONTROL".

For future reference, what is the year of you car? There are differences between the 5th gen and the 5.5 gen.

 

2000 max se, 5spd, cali spec

 

I've checked every fuse and even checked the relays. This all started when I changed my crank sensors I sprayed the connectors with some electrical cleaner and when I put everything back the car wouldn't start. So I figured they might b defective sensors so I changed them again and still nothing. I changed the cam sensor still nothing. Then I swapped out ECU's, no change what so ever so now I'm stuck and have less than an idea what 2 do. Some ppl have sed that if u swap ecu's u have to bring it to the dealer 2 b reprogrammed but then I have heard plenty of ppl say that you don't. I put the original ECU back in as soon as I found that the new one didn't fix it.

 

I have heard that the sensor harness can go bad so even changing the CKPOS sensor may not fix the wiring issue...good luck though

 

New update: I think I ****ed it up worse.... I had brought my yellow top to advanced 2 get it recharged, brought it home and put it in and proceeded 2 c if the car would start. It was like it was trying to catch itself. I even had fluctuation in the tach slightly(which I didn't b4). Then I strted 2 smell fuel so I stopped and waited like 20mins or so and attempted again. Now I can't get n e response out of it, its as if I am not pushing the clutch in. I can hear the fuel pump but I'm not even getting n e response out of the motor what so ever....wtf....plz help lol

 

If this started when you changed the crank sensors, then maybe you need to verify if the ecu is getting the pulses from the sensors. You would want to check at the ecu, which will also check all connections in between.

This is a challenge on 2 points: getting to the wire connections at the ecu and then being able to see the signal pulses. A fall back would be to check at the sensor connector.

Ideally you need an oscilloscope for this, but sometimes you can get lucky by using a voltmeter on the AC Volts scale. The reading would not be accurate but if you get a reading, then the sensor is probably ok. The cheaper the voltmeter, the less your chances. The meter has to be fairly sensitive and fast acting.

 

Just discovered that the power wire that goes from the starter 2 the soliond broke(gotta love advanced auto) so imma go frm there once I can find the right tools

 

Update, 75% positive that its the coils. Only getting spark from like 2 coils even after swaping them the two good coils one front and one rear are the only ones that spark.....joy

 

Here are resistance readings I got from my coil packs.

Pin 1 different color on each coil pack
Pin 2 black wire on every coil pack
Pin 3 red wire on every coil pack

measuring between Pin 3 and Pin 2 connections:
positive lead on Pin 3 reads open (or infinity)
positive lead on Pin 2 reads 7.7 megaohms

measuring between Pin 2 and Pin 1 connections:
reads 1.5 kilohms (polarity doesn't matter).

measuring between Pin 3 and Pin 1 connections:
positive lead on Pin 3 reads open (or infinity)
positive lead on Pin 1 reads 7.7 megaohms

I measured between the spark plug lead and each ot the 3 connector pins and got an open (or infinity) reading trying both polarities.

 

What code(s) is it throwing?

On testing coil packs: http://forums.maxima.org/5th-generat...ow-w-pics.html

 

Don't have code reader, cel bulb blew so idk I just swapped around coils and now the car is trying to start itself but with only 2plugs getting spark its a little difficult. Nor do I have a multimeter. This is why this has been such a pain to do. Bu thanx for that bit of info for future refference

 

Having the right tool makes all the difference. G/L

 

Ain't that the truth, but I got my boy comin thru wit his multimeter n code reader, all I need now is decent weather lol