StreetzINC

Is there anyway i can tell if my ecu is bad in my 2000 5spd Max??????
Are there any test i can do myself????

SoonerFan

iTrader: (5)

huh??
we need more info.
do you have a check engine light?
is something else wrong?

if there is something wrong with the ECU you will have other problems that you should be more concerned about.

StreetzINC

Yeah i have a check engine light(P1320), no signal from ecu wire to coil packs, and the car is not starting up.

Puppetmaster

iTrader: (48)

No, P1320 is when the ignition signal from the coils is not sent to the ECU during cranking, not the other way round. The P1320 is the DTC for bad coils so you should be testing those first and not trying to test or replace the ECU.

StreetzINC

I know what P1320 means and that is why i went and bought all new coils and still have the same problem im getting fuel on the spark plugs but no spark u guys keep saying coils coils coils thats not it. There is no signal going to the coils. Unless i am missing something the coils r good.

MacGarnicle

iTrader: (1)

Well keep checking.. the ECU doesn't just die - and if it did there'd be more problems then a check engine light..

StreetzINC

Tell me what more problems i will have???? My car isnt cranking, not one of the spark plugs are getting spark but they have gas on them, and when the car was cranking it was misfiring @ idle but when the throttle was wide open no misfire im sorry but i need to know what you mean by more problems??????????

jkayca

Sounds like a problem with the wiring harness. If you are getting codes out of the ECU then the odds are that it is OK.

StreetzINC

Now that sounds more reasonable. Anyone know how to check the wire harness??? If it is the wire harness its not obvious to look at it and tell.

VaporHead

Get a multimeter and some wiring schematics and check voltage and OHMS. ECU and/or wire harness are pretty expensive I would believe.

P. Samson

Check the connector on the Crankshaft Position Sensor (the one adjacent to the oil filter). Could be this sensor also. First thing....I would pull the connector, remove the sensor, clean the business end and reinstall.

StreetzINC

Ok now i am getting spark from cylinders 1,2, and 3. But no spark signal from 4,5, and 6. What is up with that????

P. Samson

Are you sure about the cyl. no.s? Do you mean no spark all on either the rear bank or the front bank? The odd cylinders are at the firewall with no. 1 at the accessory/drive pulley end and the even cylinders are the front bank. How good is the spark? A good, fat, blue/whitish one or a thin, weak reddish one?

StreetzINC

Its a weak reddish one but its better than cyl 4,5,and 6. and i do know that 1,3, and 5 is on firewall side of motor and 2,4, and 6 are on the radiator side! And i am sure of the cylinder numbers. Does this sound like a wire harness problem or does this sound like a ecu problem i am leaning more towards a wire harness problem now. Can anyone help me ASAP?????????? ps crank and camshaft sensors are functioning.

P. Samson

Check the condenser. Pull the connector and check the condenser resistance. Should be more than a megaohmn. (The condenser is taped to the harness/raceway right behind the front camshaft cover towards the intake side.)

StreetzINC

Anyone have a pic of a condenser on a 2000 Maxima engine i cant find it on mines??????????

P. Samson

Locate the top row of attach bolts for the front camshaft cover. Right next to the second bolt from the left, taped (with clear tape) to the harness/raceway, is the condenser. It's about the size of your thumb.

StreetzINC

When you say megaohm do you mean 1 ohm and what does this condenser do??????

5thgenmaxima

iTrader: (1)

My original guess (as well as others) was ignition issue.. At least now we know that you are not getting spark...

First off F.Y.I. ----Firing order on our engines is 1-2-3-4-5-6.....my GUESS is that you have a sensor somewhere with 1/2 of it rusted or not sending a/c current.

Directly from alldata
NOTE: Unless you have someone who has a nissan specific scantool (dealership, certain specialized shops, and diy'ers who bought a hacked (legally) version off of the internet.), these codes will not show up as they are not emissions related and this shop will probably send you away or charge you hundreds of dollars in diag fees to pinpoint the problem. (doing pulse width, scope tests, reading schumatics, checking continuinity, etc.)

Knowing if you have one of these codes IS VITAL and will pinpoint your problem in seconds instead of hours. I.E. p0335 is a crankshaft position sensor (POS) fault, p1335 is POS REF signal fault, etc.)...

The problem is that you need to find out if your ecu is getting a signal from each of these sensors before following the flow chart. It is a waste of time pulling your ecu and testing continuinity to each of your coils before you first check to make sure your ecu is even suppossed to be sending a signal in the first place.

You wrote: [quote-StreetzINC]ps crank and camshaft sensors are functioning.[/quote]
How do you know this. Did you hook a scope to the sensor and check the graph. Or was it a pulse width test on a QUALITY multimeter? If it was a pulse width test are you sure you verified that the signal was not dropping to 0 for 1/2 of each revolution?

5thgenmaxima

iTrader: (1)

ALSO:POSSIBLE CAUSES (LISTED ABOVE AS WELL)
Harness or connectors (The ignition primary circuit is open or shorted. )
I find this unlikely since there are 3 in a row (firing order) that are not firing.. I find it hard to beleive that 3 cylinders are shorted. (not all on the same bank)
Power transistor unit built into ignition coil
not likely at all


That leaves these three..... All three of these will throw a code accessible only to nissan specific scantools... 90% chance one of the following 3 are your problem..

Condenser
Crankshaft position sensor (REF)
Crankshaft position sensor (REF) circuit

5thgenmaxima

iTrader: (1)

Also you said you are getting spark from 1, 2 and 3....(your camshaft position sensor detects which cylinder you are on...)
If I didn't have a scantool this would be what I would check first.

Also note just because you graph a sensor and the sensor reads correct at the sensor, that doesn't necessarily mean that the ecu is reading the sensor correct. (high resistance fault in anywire to/from ecu, etc.)

I'm curious as to how you decided those sensors are functioning. I would check for signal at the correct terminals at the ecu if it where me.
(Not just a signal, but the signal has to be functioning as a permanent marnet signal should be... I.E. One high signal indicating cylinder #1 then 5 medium signals with drop offs inbetween. Then one high signal for #1 again, then 5 low....etc,etc,etc.)

5thgenmaxima

iTrader: (1)

Ok, now what did you do to turn this...........

and this


into this...

Whatever you did, you may be on the right track.

P. Samson

The easiest thing right now is to check the condenser if you a have multimeter/ohmeter. The resistance should be HIGH if the condenser is good. If it is low, chuck it. Above you said that you had a weak spark on at least three cylinders. Condensers are notorious when failing for causing a weak spark. The condenser (a capacitor) is in the primary ignition circuit and it is this primary voltage which is used by each coil to develop the secondary high tension voltage for the spark plugs. Capacitors hold/build up voltage then quicky discharge it. Go for the simple things first. It is unlikely that it is the ECM, and the crank pos. sensors and the like are simple, have no moving parts and rarely fail. As mentioned above, check all the connectors associated with the ignition system that you can find, including the one on the Crank Pos. Sensor. I would remove it, make sure that it is clean, and reinstall it. It is sometimes quite oily down there.

5thgenmaxima

iTrader: (1)

Sorry to get off subject, but samson do you have a link to how these work? I've never heard of a condensor (capacitor) in the primary igniton system.

The way I understood it is that 12v high amps went to the primary coil windings. When the coil collapsed (ecu took away the ground) magnetic induction turned this energy into high volts low amps calculated by the amount of windings in each coil.

Anyhow, I don't want to get off subject so if you know of an article or something that explains where these condensors are located (and exactly how they work) I would appreciate it.

P. Samson

Sorry, the ONE capacitor/condenser is in the coil power supply circuit, not the primary circuit as I stated above. Per FSM (Euro) EC Page 371/372. And.......I did not mean to imply that this condenser was generating the secondary high tension voltage. (da spark) After having looked at the FSM, the other possibility is a fault with the ECM relay relating to the coil power supply circuit. There are a couple of troubleshooting checks dealing with this relay.

StreetzINC

Where is this relay and what are the troubleshooting checks ????????????

P. Samson

The relay is in the elect. box in front of the battery. It is labelled. Do you have a multi-meter? Without one you are kinda screwed. One thing you can do is check the ground for coil power circuit. There are four grounds I think(one is the ground for this circuit) beside the oil filler. Loosen them off, check for corrosion and retighten.

StreetzINC

I see an engine control relay(thats it I guess??). And I do have a multi-meter just tell me what to do???

5thgenmaxima

iTrader: (1)

ok. Here are some diagrams..

I checked the connector F40. (located in f2 of the second to bottm picture posted) It is an engine ground on the passanger side of the motor. Looks to be near the top. The arrows are using the conventional flow theory. F34 in ign01 (the first one where f34 is next to the "condensor" is located) is located in d2 on the picture second to last.....Anyhow, This is the best I can do for you. Good luck.



connector for ign 01

connector for ign 02

5thgenmaxima

iTrader: (1)

connector for ign 03


and finally.....locations

P. Samson

FIRST: With the Ign. OFF remove the connector from the condenser. With Ign. ON, check DC VOLTS between the harness connector terminal 1 and ground. Should read about 12 volts. Does it?

P. Samson

http://jime.homeip.net/files/FSM/. This address for the Euro spec. FSM seems to be working again. Depending on your ISP speed you could try downloading the 2000 FSM in less than an hour. Then you've got all the info. Otherwise this is too tedius. Section EC pages 368 and subsequent is where you need to be.

StreetzINC

Im Checking now give me a few minutes

StreetzINC

Im getting 11.91 volts from terminal 2 terminal 1 is reading as a ground

P. Samson

That's perfect. Ign. OFF. Now with the ohmeter check the harness connector terminal 2 to a clean spot on the engine. Should have no resistance. This checks the circuit ground. Why your're at it, check between the two terminals on the condenser. With the ohmeter set to a high range, check that it has high resistance. More than the one Megaohm that I mentioned earlier. (Your meter will probably have a 1 or 2M and a 10M selection at the high end.) Jeez.....it's almost 01:00 your time!! WAIT!! I misread your previous terminal figures. You got the 11.91 at terminal 2?? That is a one piece connector on the condenser??

StreetzINC

Sorry for taking so long i was @ the relay but i checked the condenser like you said i got 12.24 volts and no resistance. I am picking up 0.483 resistance from the condenser itself. I took my 98 max condenser(which is working fine) and put it on the 2000 max. The car still did not start. My 98 max started up fine with no condenser on it @ all.

P. Samson

The battery voltage should be at condenser harness connector terminal 1. I can't see how you have it at terminal 2. Terminal 2 should be to ground. I didn't twig on the fact that you've got a '98. The next quick and dirty swap try could be the ECM relay. Check the terminals........if the same, try the swap. Same for the Crank Pos. Sensor (by the oil filter). Just make sure they have the same "business end" length/protrusion etc. Your condenser resistance reading confuses me but it shouldn't prevent a startup by the sound of it. When you're disconnecting/connectiong things just make sure the ignition is OFF! I'm going for coffee and to see if Leno is live tonight!

StreetzINC

I was @ the relay instead of the condenser but i am getting the correct voltage from terminal 1 of the condenser connecter. Thanks for all the help to.

StreetzINC

So today i switched cam sensor on my 98 max with the 2000. The 98 started up fine with the 2000 camshaft sensor. Then i went to the crankshaft sensor on the transmission not the one by the oil pan they looked a little different the 98 crankshaft sensor looks bigger but the 2000 crankshaft sensor fit on the 98 and tried to crank the 98 it didn't start with the 2000 crankshaft sensor. So i took the 98 sensor and put it on the 2000 it lined up but the car still didnt start. Still got the same result as before with the original sensor. I put the sensors back on the correct cars and the 98 cranked up fine, but the 2000 has the same result. Does this mean anything?????

P. Samson

The Crank Pos. Sensor and/or the circuit that could be the problem is the one under the accessory drive pulley. It was different than your '98s?? If they are different then swapping them would be a moot point. Did you think about "obtaining" the FSM copy? It would be far easier troubleshooting etc. for you now and probably in the future.