MikeF

I have a 96 Maxima that has a bad starting problem.

Just put in a new exhaust system and repainted it (new primer, paint, clear and buffed it out) and while in the garage, stopped starting.

Couple weeks ago, it would miss, so we changed plugs and fuel filter. (enter the garage for the new paint).

Starter went bad while in my garage for paint, so I changed the brushes. Turns over now great, but wouldn't start (what next?).

Tried:
Fuel pressure at the filter is ~40 psi
Spark OK (tested cylinder #1)
Camshaft sensor Ohms OK
Crankshaft sensor cleaned, Ohms OK.
Cleaned throttle body.
New Coolant temp sensor (thought it was bad, wrong range on the ohmeter)

Paint is done, pushed it down the driveway hill and it started (and smoked bad), runs rough, misses, stays running only with coaxing from the gas pedal.

Codes:
I had a P1320 code, but I think that was cleared up when it missed a few
weeks ago, pressed in one of the coil connectors and then it ran great).
There was also a Knock sensor code, but that is because of a cold lifter
knock.
I cleared the code, but no other's have shown up.

Is there an FAQ or something that give a bunch of "this" fixed "that", etc.?
Any words of wisdom?

I want to run my new black paint!!!
Mike

UPDATE: (There's 2 pages here), but the bottom line was that the starter wouldn't spin the engine over fast enough, I had changed the brushes on the old one. Put in a new starter and it works great. (This is why some guys will fix the start problem by adding ground wires!)
Mike 6/30/11

Product_Of_Korea

iTrader: (8)

Just cause there is pressure at the filter doesnt mean its gettting into the chamber. Id make sure you have fuel going into there.

FallenOne

iTrader: (17)

unplug MAF

Check Injector's.

Ohm Coils.

Check Fuel Pressure Regulator.

bobflood

You reported "crankshaft sensor cleaned." There are TWO crankshaft position sensors, one just above the crankshaft pulley and another at the junction between the engine and transmission. On my 97, it was the one between the engine and tranny that was bad; even though it ohmed out OK, it was erratic on the scope and replacing it cured the problem. Also, you said you did exhaust work and painting, so check your grounds - these engines seem particulaly sensitive to ground issues.

ls1forlife

Could you please explain your comment about the sensor that ohmed ok, but was actually faulty. I ohm sensors a lot, but if they come out ok, should i still dig further?

cashoit

The cam and crankshaft position sensors are magnetic. An OHM test on the sensor itself tells you NOTHING about the sensor. THe ohm test is done on the connector to test if the ground wire has shorted. The official FSM test for the actual CKPS is a voltage test for magnetism.

Check CKPS per FSM. Clean all ground points. You may have to add a few new ones as well.

Download the Factory Service Manual (FSM) from Fallenone's (a fellow orger) signature.

MikeF

Thanks for the replies. Here's some more detail.

Car ran fine for ~500 miles after the exhaust system, plugs and fuel filter were changed.
Ran a bit rough for my son, but he pushed the plug in on the #5 cylinder (coil plug), it snapped and then ran great.

It only quite when I worked on it to sand and repaint.

I don't think that it's crank or cam sensors, because it does run (when I push start it).
I'm getting fuel (when it runs, it smokes a lot, could be flooded and loaded up the exhaust system. When I was playing with the plugs out, I pulled the wrong fuse and there is fuel getting in the cylinders.

I tried unplugging the MAF, still didn't start.

HOWEVER, I did check each plug by removing all, removed fuel pump fuse and then put a plug in each coil and connected them up, one at a time.
Cranked it over and cylinders 1 (front passenger side) and 6 (rear drivers side) don't seem to spark like the other 4. I tried the coil/plug on another cylinder plug, it was OK. But putting another plug/coil from another (working) cylinder didn't work on the bad cylinder plug. Moving the #1 and #6 coil/plug to another cylinder sparked.

So, it appears that either the connections/wiring may be bad to the ECM or the ECM itself.

Something here doesn't quite add up. Why the wiring or ECM go bad like that?

Is there a way to check the output of the plugs that go to the coils?

Cashoit, you said "Download the FSM from Fallenone's sig".
Can you explain what you mean?
Mike

njmaxseltd

iTrader: (19)

Check both crank position sensors again. Pay attention to (POS) which is located on the bell housing. You might try replacing it with a knows good sensor.

Also check your ignition switch, being the car started with a push, I suspect you may have a problem there too.

bobflood

On mine, the car ran great once it finally started. Still, CKPS POS sensor (crank sensor at junction of engine/transmission) was what was causing the hard start. Have had zero starting problem since replacing that sensor.

maxed_out_99

i think you have a leaking injector
pull th fuel pump relay and spry carb cleaner in the throttle body if you can get it to run plug in the relay if it immediatly quits you need an injector/injectors

FallenOne

iTrader: (17)

Here, download this. Its the Factory Service Manual and your new bible.

http://www.megaupload.com/?d=HRX0TLMH

MikeF

FallenOne,

Yes, I found the FSM yesterday!!! Thanks. You're right, it's GREAT. There are even signal diagrams for the ECU... (I'm like a kid in a candy shop, I'm an electronics tech/engineer, more software these days, but I know hardware.)

Can someone explain to me what a "Consult" is? I do have an ODB II connection and software for reading Trouble Codes from the car to a computer (PCMScan software).

BobFlood: I'm currently looking for the second Crank Sensor. Mine is a 96, yours is a 97. Would mine have the same second sensor? I can't find it!
It really seems to me that perhaps I'm not getting the spark on the 3 Coil/Plug sets because there is a signal missing (Crank/Cam sensor!!). (Hoping it's not the ECU). I can't find it in the Hanynes Manual that I have and so far, I haven't found it in the Service Manual that I downloaded (Reference above).

BY THE WAY, I've been working on adding grounds. I found that the front head is about 350 ohms to ground and the rear one is over 3k ohms!!!

MaxedOut99: It's not the injectors. It's ignition. I've determined that, thanks though.

MjMaxSelDt: Ignition switch isn't a problem. I did have a starter problem earlier, but changed the brushes and it now turns over just fine. It's just that it seems to be running on 3 cylinders and therefore won't start or when push started, runs very poorly.

Mike

njmaxseltd

iTrader: (19)

Mike CPS (POS) is located under the car on the bell housing. You can see it if you crawl under the front and look upwards at the bell housing.

luke95gxe

iTrader: (4)

all of our car 95-99 have that crank sensor its location is right on the bellhousing of the trans were it meets the engine

MikeF

GOT IT!!!

Thanks guys, just follow the wire down past the main battery ground on the block.
I'll check it out (or maybe just replace it.)

Mike

MikeF

OK, so I have the sensor out. I measure 4.0 Kohms between the outside two pins. The manual I have says to back probe pins 2 and 3 and measure the voltage when plugged in and switch on. Move a screw driver close and get 5 volts, and pull away slow, stay 5 v. Move the screwdriver away fast and the voltage drops to 0. But I don't get any voltage at all.

I'd sure like to make sure that this is bad, they're about $100.

What is the "Consult" (per the FSM)?

Mike

FallenOne

iTrader: (17)

The Consult is just a Nissan Specific Scanner. Your ODB II will do just fine, minus some basic functions such as venting AC, Controlling Rev's for testing (a Zip tie will do haha), and many other minuscule things.

Just get a junkyard sensor, NO NEED to spend 100$ If I was still hawkin parts I'd go get you one for cheap.. Make a WTB: thread in the Classifieds and have someone ship you one. Theres A Huge amount of Very good sellers, Maxima_Joe is your best place to start.

MikeF

FallenOne,

Thanks, I'll have to try that. Problem is, I'm running out of time to fix it this week (can't next week, have to put in a fence). Gonna be about 10 days, then I can get back at it.

I'll have to see what my ODB II system says again.

I did discover that the reason that I didn't have any voltage on the crank sensor was because I had disconnected my ECU.

Anyway, I really appreciate the help!!!

Mike

MikeF

Well guys, I tested the Crank Sensor (POS) and it tested bad so I replaced it ($100), still doesn't work. The new one tests good now, so it WAS bad.

I rechecked, still have fuel pressure (I did put in the fuel pressure pump fuse), measured it with a gauge.

I did get one or two pistons that fired, but for the most part, it just cranks over.

1. Coolant Sensor replaced (wasn't bad, just metered with the ohmmeter wrong!).
2. Fuel Pressure to the Rail, meaured with a gauge after the fuel filter.
Not certain that the fuel pressure regulator is right, but I do know that I'm getting gas into the cylinders (there was a lot of fuel smell when I removed the plugs).
3. Front Crank Sensor ohms out correctly and is connected.
4. Front Camshaft sensor ohms out correctly and is connected.
5. Rear Crank Sensor replaced (original was bad).
6. I did add a ground from the intake manifold to the body.
Heads both measure < 1 ohm to ground (it was the valve cover gaskets that were above ground!).
7. I did recheck the ECM, there are no codes after cranking.

I've gone over EVERYTHING for connectors and grounds (that I can find) that I may have disconnected in troubleshooting. All seems OK.

Guess I'll go back to the FSM and see what else I can try.

Mike

luke95gxe

iTrader: (4)

ground negative post on battery to a bolt on the trans and make sure u sand it very well

99zx2

iTrader: (3)

did you completely shrugged off your own observation? i'd go back and do more tests.
a car needs: fuel, spark, compression, and all of them at the right time. does it start if you spray some starting fluid in the intake?

MikeF

No, I've been retesting.

What I've found (like earlier) is that there is no spark to 3 of the 6 cylinders, not sure of the cylinder numbering, but front left 2 and rear right one. (tested with a scope on the Signal line from the ECU, no pulse on just these 3, the other 3 have a signal pulse)

I've checked continuity to the ECM for all 6 cylinders to the coils, 12v, ground all OK.


So, one of two things.
1. ECM is bad.
2. Signal input from another sensor is bad into the ECU.

I checked all continuity connections from:
Crank Sensor (POS)
Crank Sensor (REF)
Camshaft Sensor
for Ground, and all continuity connections to the ECU.

I did find (as I mentioned above) that the Crank Sensor (POS) tested bad, so I replaced it. Resistance through the Crank Sensor (REF) and Camshaft Sensor are correct, well within the range.

I measured 10V (or slightly higher) for the "Start Signal" at the ECU connector.

Ground connections to the different sensors and harness (including transmission) is less than 0.2 ohms. All grounds are correct.

Guess I'll try to figure out how to put the scope on the Crankshaft and Camshaft sensors at the sensors. I don't think that I can do this down at the ECU. The connections and wires aren't accessible.

Don't know what else to do...

Is there another sensor that's required for the ECU output pulse to the spark plugs other than the 2 crank sensors and the camshaft sensor? Can't find this info in the FSM.

Thanks for any thoughts...

Mike

Swazey

i call the starter STILL being the culprit even though you changed the brushes. have you tried a new starter? grab one from autozone or advance and see if that changes things. if not you can just return it.

i had a frayed wire on my cps (pos) and my tranny and engine grounds were completely corroded. after i cleaned them and fixed the frayed wire my car started better. i still have a hard start but it only takes 2-3 tries to fire up instead of not starting at all

MikeF

No, it's not the starter, Starter cranks over just fine. Ground for the starter is not frayed at all, very clean. I had added a bolt to the body on the wire from the battery - post just below the battery where it goes to the block. Ohmmeters shows that the grounds are tight, including when cranking is going on (no voltage drop across the grounds during cranking, which is more accurate than just the ohmmeter.)

It's an ignition problem. I have spark to only 3 cylinders, and the 3 that are firing may be off in timing (this I'm not sure of).

I did put an oscilloscope on the Crank Sensors (POS and REF) as well as the Camshaft sensor. There is a signal on all, though the POS sensor (new sensor) is more of an oscillation than a pulse, which confuses me.

I've got 2 things that I'm going to try:
1. clean out the flywheel (for magnetic dust) through the Crank sensor (POS) hole. Suspecting the signal at the POS.
2. try to remove the ECM and test the output transistors for drive signal (if I can!). I'm expecting that they don't use discrete transistors, but rather some IC chip.

Wish me luck, I'm going to need it!

Mike

Swazey

mike have you had any luck cleaning the flywheel? im curious to know your results and am going to try and clean mine to see if it helps with my hard starts

ef9

iTrader: (8)

Wow, it just quit working after sitting for a while? No chance that mice or rats went into the engine bay and chewed up some wires?

michaelmaxima

man thats crazy

MikeF

Well, I've been working on it again...

Put in a different (salvage yard) ECM and it started, much to my surprise! I THINK what happened, is that I may have blown out the ECM when I was troubleshooting (pulled plugs and grounded them to the valve cover gasket and checked spark, not good idea!). Crank Sensor (POS) was definitely bad, that was changed about 10 days ago.

Drove it (got it good and hot), went into a store and then it wouldn't start again... ;-(
Would pop a bit, but like timing was way off.
Push started it and it ran GREAT again.

Read up on a "Hot Start" paper that I had, suggests injector leaking. Did the test, with a gauge after the fuel filter, squeeze off return line, pressurize the line and squeeze off the input line. If it bleeds down in 60 seconds, bad injector.
But the pressure held (long time!!). Not it...

So, I still have a VERY Hard Start problem...
Tried to start it this evening after testing the injector leak down, won't start!

Mike


Trouble is, once it's started, it runs VERY smooth.

ef9

iTrader: (8)

Maybe battery voltage dips below 10V during cranking?

MikeF

Nope, checked it out. Voltage goes to 11.0 volts during cranking (new battery, just a few months old). That's voltage at the battery.

I did try cleaning the flywheel, but looking at it (with a mirror through the hold) it was clean. Used some brake cleaner to spray while cranking. Then used a somewhat stiff bristled brush in the hole while cranking again. Didn't help at all. Still won't start on the crank.

Rechecked the "Start Signal" at pin 20 of the ECM. It jumps to +12v when cranked.

Damn, this is frustrating. I have no idea what to try next...

Mike

luke95gxe

iTrader: (4)

add a ground from the negative to abolt on the trans sand real well

ef9

iTrader: (8)

So, if you push start the car, it starts every time?

Your ignition switch may be to blame?

99zx2

iTrader: (3)

i've noticed that also. does it start every time with a push?

OC_Nooby

iTrader: (11)

Check your battery ground. I believe it attaches to the chassis then goes to the motor. Overtime they rust away. You can also try to take a set of jumper cables and put one end to the negative of your battery and another to the engine where you have bare metal exposed. Don't know if this was suggested as I skimmed through.

MikeF

I did go through the grounds to the starter -removed and cleaned all connections and surfaces (found a posting where someone said they "threw a starter at it" to fix it) and added a ground wire between the battery negative and the tranny (heavy braid copper). Also added other grounds.

Still won't start right.
Starts cold (not great but...), but not warm. Starts when pushed (Manual tranny) and runs great.
I rechecked the "start signal" to the ECM, it's OK, checked the connection to the coolant sensor at the ECM, it's OK. Tried cleaning the flywheel where the Crank Sensor (POS) gets it signal, no difference.

Knock sensor is open, new one on order. But according to the manual, that's not a "no/hard start" item.

Mike

ef9

iTrader: (8)

Replace your ignition switch. When you turn the ignition switch to crank, it may not be providing the proper voltage/current to other electronic items in the car.
Or it could be "shorting" the ignition system when trying to start.

You can test this by using an external starter switch, or by jumpering the starter wire to +12V while the ignition is in the "ON" position. Should start right up every time.

Swazey

i have the same problem and have tested everything. once it starts, it runs totally fine.

are you getting spark now on cyl 3 and 6? i know you said the starter cranks fine but have you put in a new one yet to try? just because it cranks fine doenst mean its not the culprit. my friends cranked fine and come to find out his hard start problem was his starter.

knock sensor shouldnt make a difference in how it starts

mine will start within 4 tries and usually takes 3 everytime but still doesnt start right. doesnt matter if i give it a little gas, wiggle the key, etc. etc. I do wait a few seconds for the fuel line to pressurize and try to start. the car will crank and sputter/pop and i only let it crank for 3 seconds or so. by the 3rd time it will turn over. if i let it crank it just cranks all day and wont turn over. ive burned though 3 starters letting it crank

i have replaced/tested everything you have and also had my car at a mechanic for 3 weeks where he couldnt figure it out. we tested every single wire, grounds and sensors in engine bay. everything was in spec. tested spark, compression, fuel pressure, timing, etc and all looked good. also added 3 ground wires.

the only other thing i could try is r&r the tranny and clean the mating surface. i did replace the clutch years ago and dont remember cleaning the mating surface which could have caused a bad ground (no matter how many grounds you add) and throw off the sensors causing a hard start.

ur not alone

MikeF

Well, I don't want to speak too soon, but I think that changing the Knock Sensor fixed it! Started right up (but there's still a studder in the crank of it). I took it for a drive and stopped on a hill (in case it didn't start) but it seems to fairly consistently. I'll write back here later this week, in either case.

Swazey, if you burn out another starter, don't just buy a new starter. If you're any good at all with mechanics, you could take it apart and just go down and have new brushes put in. I spent about $8 putting brushes in my starter. (burned it out when it first started having problems).

Things to check:

Make sure that the 2 ground lugs on the top of the engine at the intake manifold are clean. Remove them, and use some sandpaper to clean all the sides and bolts.

As for the grounds to the tranny, I wouldn't hesitate to put a good heavy ground from one of the starter bolts to the battery negative. Clean the bolts on the tranny, both of them very well before installing the grounds. I put a ground from the intake manifold to body as well.

Check the resistance of the front Crank sensor and front camshaft sensor, according to the FSM (Factory Service Manual). Also check the rear Crank sensor (POS) according to the FSM. There is a procedure where you watch the voltage as you use a screwdriver against it.

Might even be worthwhile adding a good ground connection to one of the ground wires that come out of the ECM.

If you have a hot start issue, check the injectors for leaking by putting a fuel pressure gauge after the fuel filter and pinching off the return line from the fuel rail, then turn the key to the ON position (not start) to pressurize the system) and then pinch off the input line after the fuel filter. If the pressure bleeds down in less than 1 min, then you have leaking injectors. Remove and retest to figure out which one.

I also found another post where some guy had a power steering belt break and his inner pulley where the crank gets it signal, was loose. Not sure what the full problem was, but I was going to check mine (if I still have problems).

Thinking back, I'm not sure why I waited so long to change the Knock Sensor, considering that I knew it was bad. However, all of the documentation says that the Knock sensor doesn't affect starting.

If you read some of the above, you'll see that I blew out the ECM by testing for spark by grounding the plugs to the valve covers. Turns out they aren't grounded!!! If you do try this, use a special ground from the plug threads to a solid ground. Be careful with this.

I'll try to add some more detail for others that are having problems.

Mike

MikeF

Went to start it this morning to try to take it to work, but it wouldn't start. So much different than last evening.

There is something very definitely intermittent. I'm going to connect an LED from the START SIGNAL wire and see if that is intermittent. It has to be something like that.

Mike

99zx2

iTrader: (3)

definitely keep us posted!