Y2KevSE

iTrader: (13)

You are a very knowledgeable person and I would like to have your opinion on this if you don't mind. I'll be happy to provide more info if necessary. Thanks in advance...

http://forums.maxima.org/showthread.php?threadid=32465

Daniel B. Martin

I copied parts of your post in the cited thread to "set the stage." You said...

My hesitation started after the UDP install.

... A big wave of water splashed all over my car... When I gunned it the rpm needle hit 4K (I didn't know at that time), and the car hesitated and the Check Engine Light came on. I thought to myself, "Oh, no I might have ingested some water." ...

We drove home thinking everything was fine, then when 4K hit, *BOOM*! Check Engine Light and hesitation! Doh!

The error code the ECU throws out is the camshaft position sensor. The next week, we checked the sensor with a multimeter and that was within spec. To humor ourselves, I borrowed Turbo95Max's extra cam sensor assuming mine went bad. We drove home that night and guess what? Hesitation and Light again!

So far he's gone through all the troubleshooting steps in the 2k service manual but can't find anything. We've asked around and here's what we think the problem might be:

a) spark plugs or
b) ECU or
c) ignition coils or
d) cam gears

Now, I get hesitation once in a while and the "Light" is on. Help... anybody? Thanks.....

The fact that this problem arose immediately after that "bath" is an important clue. It would help if you provided the Diagnostic Trouble Code. What kind of fuel do you use? Please specify the Anti-Knock Index and also whether it is gasoline or gasohol.

My first impression is that your engine has sensor problems, and none of the four (a, b, c, d) possibilities is correct. That's only a first impression, as more information will be helpful.

Problems with spark plugs or ignition coils can cause an engine miss, but I think these parts are blameless.
Reason #1) A misfire is usually a random event, not something that occurs at one specific engine speed.
Reason #2) A misfire usually triggers the Service Engine Soon light and sets one of the Diagnostic Trouble Codes in the range 0603-0608 which identifies the cylinder which is misbehaving. You didn't get one of these DTCs... or did you?

I doubt the problem is with the Engine Control Module.
Reason #1) The ECM is in a sheltered environment, inside the passenger cabin. It didn't get splashed.
Reason #2) The ECM is often wrongly blamed for problems with sensors.

I doubt the problem is with the camshaft sprockets.
Reason #1) These parts are not exposed to the splash which started this failure scenario.
Reason #2) Cam sprockets seldom fail, and when they do fail the symptom is noise, not hesitation at a particular engine speed.

I cannot connect the UDP itself to this problem, but it could be connected with a slip-up in the UDP installation. The crankshaft pulley is in the same vicinity as the Crankshaft Position Sensor (REF). Maybe (and this is speculation) the insulation on the wiring for that sensor was damaged... and this didn't cause a problem until those exposed conductors got wet. That's something you could check.

Y2KevSE

iTrader: (13)

The DTC that came up was 1340 (camshaft position sensor). I use Chevron's or Shell's 92 octane (I live in Cali).

The only code the ECU threw out was that one, which I then borrowed Matthel's sensor and later buying a new one from Nissan. So, we believe 3 sensors can't go bad, thus eliminating the bad sensor theory.

Spark plugs or ignition coils:
We also thought it was weird that it only happens at 4K. This tidbit might be helpful to you so I'll spit it out... sometimes (after the problem of course) when I cruise with my foot of the accelerator, the car would feel like it's lunging back and forth when I'm in 1700 to 1900 rpms. I can actually see the needle jump and and down, +/- 200 rpms.

No we didn't get any other code besides 1340 (camshaft sensor).

ECU
A buddy of his and him checked the ECU and it seems to be fine, but his techs at work mentioned the ECU might be the problem. Since you're saying it's not at fault here, let's throw this theory out also.

Cams
None of the symptoms you've mentioned happens, so throw this theory out.

Yout theory
We haven't been around the crankshaft sensor (this is located near the tranny and to the front of the car, right?), but the ECU would've threw cranshaft and not camshaft.

Thanks for your help. I really, really appreciate it.

Still hoping to get this resolved soon.

Daniel B. Martin

My Maxima is a '99 and my service manual is for the '99. I'm working on the assumption that your 2K engine is similar in most respects. That could be a bad assumption.

On the '99 the Crankshaft Position Sensor (REF) is immediately below the crankshaft pulley and just to the right of the oil filter.

There is also a Crankshaft Position Sensor (POS) which is at the back end of the engine. The two sensors have similar names.

Y2KevSE

iTrader: (13)

Hmmm... I'm probably thinking of the wrong thing then. Let me check on it and I'll get back to you.

Why would it throw a 1340 if the Crankshaft Position Sensor (REF) is to blame?

Again, thanks for your help.

Daniel B. Martin

My '99 FSM doesn't list 1340 so I can't read up on this one.

I hit on the idea of damaged sensor CPS wiring by trying to figure out some kind of tie-in between the newly-installed UDP and the splash of water which triggered the SES light.

Y2KevSE

iTrader: (13)

Now that I think about it... it might be 0340 (I don't have my manual to look at), camshaft position sensor.

So you're thinking that it might be the crank PS that's faulty (or the wiring)?

Turbo95Max

iTrader: (25)

sucks huh Kev? still cant figure it out....take it to the dealer!!!! hehehe, no no but your a racer boy...

Y2KevSE

iTrader: (13)

I would take it to the dealer, but don't want to go through what I had to go through getting the new TCM.

Can you believe the service advisor told a tech not to fix my car because I was a "racer boy"? Someone in the parts department overheard their conversation.

Daniel B. Martin

The following information is based on the '99 Maxima factory service manual. As previously mentioned, I don't know how much of this applies to your '00 model.

Diagnostic Trouble Code 0304 points to a problem with the Camshaft Position Sensor (Phase). This sensor is located on the engine front cover facing the intake camshaft sprocket on the front engine bank. It detects the cylinder number signal.

This malfunction is detected when ...
A) The cylinder number signal is not entered to the Engine Control Module for the first few seconds during engine cranking.
B) The cylinder number signal is not entered to the Engine Control Module during engine running.
C) The cylinder number signal is not in the normal pattern during engine running.

The possible causes include ...
- The harness or connectors (The Camshaft Position Sensor (Phase) circuit is open or shorted.)
- The Camshaft Position Sensor (Phase)
- Starter motor
- Starting system circuit

The dealer can use his electronic CONSULT tester for diagnosis. The home mechanic may do a less-comprehensive series of tests.

1) With the engine off, loosen and retighten the engine electrical ground connections. There are two which are easily accessed, just to the right of fuel injector #2. There are two more which are more difficult to reach. Follow the thick cable from the battery negative terminal to the engine block. It connects to a metal plate, and that metal plate is bolted to the engine block.

2) Check the electrical and physical condition of the CPS(P). Disconnect the harness connector. Remove the one bolt which fastens the sensor to the timing chain cover. Remove the sensor. Visually check the tip of the sensor for signs of chipping. Use an ohmmeter to measure the resistance of the sensor. At 68 degrees F the resistance should be:
- Hitachi sensor: 1,440-1,760 ohms
- Mitsubishi sensor: 2,090-2,550 ohms

3) Before installing the sensor look through the timing chain cover hole and visually examine the surface of the camshaft sprocket. Rotate the engine very slowly to permit a thorough evaluation. Look for signs of chipping.

Daniel B. Martin

My idea concerning damaged insulation on the Crankshaft Position Sensor (Ref) wiring was speculative, and labeled as such. It was the only thing I could come up with which connects two clues: a newly-installed UnderDrive Pulley and a big splash of water.

If you hit a brick wall on the Camshaft Position Sensor investigation you might want to use your imagination to look elsewhere. The Diagnostic Trouble Codes are supposed to point us in the right direction. Sometimes they are misleading and the trouble is elsewhere.

Daniel B. Martin

I had a similar experience with my '99 Maxima while experimenting with 87 Anti-Knock Index gasoline. The engine started readily and idled smoothly. It performed normally up to a point. When pressed for maximum performance the engine pulled strongly to about 4K rpm, hiccuped once, and then continued to accelerate but not as strongly. I believe (but do not know for sure) that hiccup was caused by the Knock Sensor signalling "pinging" to the Engine Control Module, and the ECM responding by retarding the timing.

Perhaps your Knock Sensor is misbehaving, and has become too sensitive. It has not failed, so you get no Diagnostic Trouble Code to implicate it. Here is an idea for your consideration. Disconnect the KS and drive without it for a day or two. If the 4K hesitation symptom vanishes, and then comes back as soon as you reconnect the KS, you have a new and promising line of inquiry.

Disconnecting the KS will turn on the Service Engine Soon light, but you will know why and need not be concerned. If you care to, you could substitute a 500 ohm resistor for the KS and fool the ECM into thinking the KS was still connected.

Daniel B. Martin

Some of us will go to the dealer only as a last resort.

Y2KevSE

iTrader: (13)

2nd dash... that's fine because I bought a new sensor
3rd dash... that's fine.

There shouldn't be any problems with 1st and 4th.

1) We'll check that
2) The sensor is fine (Mitsubishi with correct resistance).
3) We'll were planning on checking that.

Thanks for the write-up!

Y2KevSE

iTrader: (13)

Thanks, we'll take your advice and check the Crankshaft Position Sensor.

Y2KevSE

iTrader: (13)

I really appreciate all your help on my problem. I'll disconnect the knock sensor for a few days to see if I still have the problem. My Service Engine Soon light is on right now anyways, so disconnecting it won't affect me a bit. Thanks for all your advice and I'll update you on this in a few days.

Thanks!

Cumalot

iTrader: (8)

Kev, are you lost? You're in the wrong forum! j/k Btw, isn't there a "Daniel B. Martin" in the 5th gen. forum? I think every forum needs a Daniel B. Martin. Kudos to you Mr.Martin for actually using your time to help a few members out.

Y2KevSE

iTrader: (13)

Yes, I'm in the wrong forum, but Daniel doesn't go into the 5th gen forum.

I agree with you Mr. ****-a-lot. He is a great asset to the Maxima community. Thanks again Daniel.