Full Version: No Fuel At Idle?
So a few weeks ago I ran my tank down. Not intentionally, I just didn't have time to get gas. The next day when I filled up it started to idle like absolute garbage. I talked to the guy that does all the work on my car and he suggested filling up with premium and a bottle of dry gas thinking there might be water in the line. So I did and a couple days later after running marginally better the CEL comes on. When the codes get pulled I got, cyl 4 misfire, knock sensor, and transmission communication error. So, in the process of trying to figure this out we have checked spark in all 4 cylinders, checked for fuel in all 4 cylinders, changed the fuel filter, sprayed down for an intake leak, and cleared the CEL to see what comes back. Well now we have spark at all 4, no transmission code, and cyl 4 injector is not firing at idle. Off idle it fires just fine, but at idle it does not pulse. So after some brainstorming we come to the conclusion that the #4 injector is probably partially clogged and at idle there is not enough pressure for it to pulse. This morning the injector got changed out for a new one and no difference whatsoever. The only other thing we can think of is the ECU. For some reason it is telling cyl 4 not to fire at idle. I've already called Inskip and left a voicemail with there service manager, I've talked to Dj, and just about anyone else I can think of to call. Hopefully someone will read this and know what is going on because we are completely stumped.
that def sounds fucked up....do you know anyone with a similar Altima? Maybe plug their ECU into your car before you spend money on that and it ends up not being it.
QUOTE (Stangman_NB @ Jan 7 2010, 04:47 PM) 
that def sounds fucked up....do you know anyone with a similar Altima? Maybe plug their ECU into your car before you spend money on that and it ends up not being it.
Nope the only Altima I know of is mine. However after talking to Dj today apparently there is another 01 Altima that just went to the dealership with the exact same issue as me. So I'm hoping it gets resolved quickly and it can help me out.
If I had to guess I would say semi clogged injector from you running it low and picked up something in the tank
How the fuel PSI?
QUOTE (My84Z @ Jan 7 2010, 08:46 PM)
If I had to guess I would say semi clogged injector from you running it low and picked up something in the tank
The #4 injector and the fuel filter have been changed out.
QUOTE (NitrousJunkie406)
How the fuel PSI?
I don't remember off the top of my head.
talk to neil and ask him to ask Joe aka the nissan god he might have a opinion on it i belive i used my last call joe for advise lmfao for other peoples cars.
Try taking a test light and checking if the the injector is getting a signal at the connector. If it's not lighting up at all trace the wire back check for damage. If nothing it's prob a ECU problem.
QUOTE (My84Z @ Jan 7 2010, 08:46 PM)
If I had to guess I would say semi clogged injector from you running it low and picked up something in the tank
the tank always picks up off the bottom.... and it would have to pass through two filters one of which specificly filters to a level to keep shit from cloggin injectors. so a piece big enough to clog it enough to misfire didnt come from anywhere behind the fuel filter.
QUOTE (Nrw @ Jan 7 2010, 11:39 PM)
Try taking a test light and checking if the the injector is getting a signal at the connector. If it's not lighting up at all trace the wire back check for damage. If nothing it's prob a ECU problem.
It didn't light up at idle so we changed out the injector. With the new injector it doesn't light up either.
QUOTE (Fstrsn @ Jan 8 2010, 09:36 AM)
It didn't light up at idle so we changed out the injector. With the new injector it doesn't light up either.
I would definitely start back tracking looking for damaged wires. I had a crank sensor I could not figure out in a 91 Buick and we found one little spot that somehow melted and that was it. If everything traces back fine to the ECU then that be my next step. be nice if you could get one to test it ?
QUOTE (camarofreak72 @ Jan 8 2010, 09:40 AM)
I would definitely start back tracking looking for damaged wires. I had a crank sensor I could not figure out in a 91 Buick and we found one little spot that somehow melted and that was it. If everything traces back fine to the ECU then that be my next step. be nice if you could get one to test it ?
Mmmm. I'm hoping it's not the ECU and unfortunately I don't know of anyone else who has a 2.5 gen Altima.
QUOTE (Fstrsn @ Jan 8 2010, 09:46 AM)
Mmmm. I'm hoping it's not the ECU and unfortunately I don't know of anyone else who has a 2.5 gen Altima.
If you do end up going the ECU route let me know and I can get you some pricing I have the hook up at a local parts store and have been able to snag a few for a couple of different cars for around 100 bucks.
QUOTE (Stangman_NB @ Jan 8 2010, 10:11 AM)
If you do end up going the ECU route let me know and I can get you some pricing I have the hook up at a local parts store and have been able to snag a few for a couple of different cars for around 100 bucks.
Thats not a bad price Thats my guess if a wires not damaged
QUOTE (Stangman_NB @ Jan 8 2010, 10:11 AM)
If you do end up going the ECU route let me know and I can get you some pricing I have the hook up at a local parts store and have been able to snag a few for a couple of different cars for around 100 bucks.
Thanks Nelson, I'll let you know. I posted this on a national nissan board and thankfully one of the wiring gurus replied with this. . .
QUOTE (jserrano)
Its very rare for the ECU to behave that way but it's possible. Here is what I'm thinking it might be.
The circuit for injector #4, which includes power, injector, wiring, ground, and ECU, is weak. Ruling out the injector was the first best bet.
After that, you could be dealing with a weak connection somewhere. Imagine for instance that the power wire strands to injector #4 is hanging on by just one thread - or it could have been just a very loose male/female harness terminal connector. In either case, there might be enough wiring for the injector to get some amps flowing to drive the injector at idle. But as soon as the injector goes into a higher duty cycle then there won't be enough current flow to drive the injector, so it will remain closed. If you had a dual-trace o'scope probing the bad injector, and an adjacent good one, you would clearly see if this is the case since the signal amplitude would be very reduced in the "bad injector" only.
Now since ground is common it should had affected all the injectors equally. So you could just about theoretically rule that out. The system ground BTW comes from those two grounding straps on the intake manifold.
To rule out the power, you could try putting a jumper wire between the battery +12V terminal and #4 injector power wire, just make sure you jumper the correct wire. Disconnect the injector harness and measure it for +12V to be sure.
If the above two tests comes back negative, then the next one on my list would be a weak wiring in between the ECU pinout (pin 109) and the #4 injector. Again if you have a long wire you could do a jumper test.
Finally, the last thing on my list would be a bad ECU. And the way it would likely have failed is that there is a cold solder joint somewhere in the injector #4 circuit inside the ECU. Cold solder joints behave just like loose connectors like I mentioned above. A solder reflow will easily fix that if it were the case.
For 2nd gens, if you have a 98-99 Altima then stick with the 98-99 ECUs. Same with 00-01, try to stick with 00-01 ECUs, though there are some variants that can throw you off.
Hope you can locate something solid, if not keep posting, and let us know the final outcome. GL.
The circuit for injector #4, which includes power, injector, wiring, ground, and ECU, is weak. Ruling out the injector was the first best bet.
After that, you could be dealing with a weak connection somewhere. Imagine for instance that the power wire strands to injector #4 is hanging on by just one thread - or it could have been just a very loose male/female harness terminal connector. In either case, there might be enough wiring for the injector to get some amps flowing to drive the injector at idle. But as soon as the injector goes into a higher duty cycle then there won't be enough current flow to drive the injector, so it will remain closed. If you had a dual-trace o'scope probing the bad injector, and an adjacent good one, you would clearly see if this is the case since the signal amplitude would be very reduced in the "bad injector" only.
Now since ground is common it should had affected all the injectors equally. So you could just about theoretically rule that out. The system ground BTW comes from those two grounding straps on the intake manifold.
To rule out the power, you could try putting a jumper wire between the battery +12V terminal and #4 injector power wire, just make sure you jumper the correct wire. Disconnect the injector harness and measure it for +12V to be sure.
If the above two tests comes back negative, then the next one on my list would be a weak wiring in between the ECU pinout (pin 109) and the #4 injector. Again if you have a long wire you could do a jumper test.
Finally, the last thing on my list would be a bad ECU. And the way it would likely have failed is that there is a cold solder joint somewhere in the injector #4 circuit inside the ECU. Cold solder joints behave just like loose connectors like I mentioned above. A solder reflow will easily fix that if it were the case.
For 2nd gens, if you have a 98-99 Altima then stick with the 98-99 ECUs. Same with 00-01, try to stick with 00-01 ECUs, though there are some variants that can throw you off.
Hope you can locate something solid, if not keep posting, and let us know the final outcome. GL.
A little update for curious minds,
The best way I can describe it is a pistol grip with about a foot and a half rod on the end that when it vibrates it triggers a light. I have a hard start condition on really cold mornings which I had on my old Altima as well. From what I've read on it, it's due to the valve cover gasket going and oil leaking onto the starter. Which isn't an issue in warm weather, but in cold weather it damages the starter. I don't know how true it is, it's just what I've heard from a few mechanics who have been around for a bit. Even though it passed the spray down test the IM gasket got done over the weekend and now it's running better but the idle is still a little bouncy. So before I cleared the CEL I pulled the codes one last time. Now we have a new code. The crankshaft position sensor. So I have 4 codes total now, cylinder 4 misfire, knock sensor, automatic transmission communication error, and crankshaft sensor. Hopefully once I do a little more research on the crankshaft sensor and replace it that will solve that issue and I can move on to the transmission code.
QUOTE (jserrano)
So this pulse detector had four wires connecting up to each injectors? Or, it just had one wire and he ran through each injector one-at-a-time. I'd be interested in knowing how this behaves while cranking, with the ignition coil disconnected. In that state, all injectors should be firing simultaneously, and since it is below idle the injector #4 should not be firing. Sounds like you should've also been getting a bad hard start condition as well.
I would have said its the ECU but it just doesn't makes sense to me why it would fire just during the off-idle condition. No wonder its throwing everyone for a loop. Its a weird failure.
You can still try the "shotgun approach" and replace the ECU to see what happens. If anything, at least you'll be able to rule that out.
I would have said its the ECU but it just doesn't makes sense to me why it would fire just during the off-idle condition. No wonder its throwing everyone for a loop. Its a weird failure.
You can still try the "shotgun approach" and replace the ECU to see what happens. If anything, at least you'll be able to rule that out.
The best way I can describe it is a pistol grip with about a foot and a half rod on the end that when it vibrates it triggers a light. I have a hard start condition on really cold mornings which I had on my old Altima as well. From what I've read on it, it's due to the valve cover gasket going and oil leaking onto the starter. Which isn't an issue in warm weather, but in cold weather it damages the starter. I don't know how true it is, it's just what I've heard from a few mechanics who have been around for a bit. Even though it passed the spray down test the IM gasket got done over the weekend and now it's running better but the idle is still a little bouncy. So before I cleared the CEL I pulled the codes one last time. Now we have a new code. The crankshaft position sensor. So I have 4 codes total now, cylinder 4 misfire, knock sensor, automatic transmission communication error, and crankshaft sensor. Hopefully once I do a little more research on the crankshaft sensor and replace it that will solve that issue and I can move on to the transmission code.
Did you ever get cly4 injector firing?
Ok, so things have kinda stalled on my end, sorry folks. The guy who has been doing all the diagnostic and repair work was fired last week for a bunch of bullshit. But I did have the codes cleared and I only got two that came back. P0304 and P0340. 0304 is the cyl #4 misfire that I've had all along and 0340 is the Camshaft Position Sensor. The little bit of research I've done states that the crankshaft sensor could cause this code to throw, the car won't start if the camshaft sensor is bad, and obviously cyl # misfires or random misfires go hand in hand with this. Now like I stated before, I do have a hard start condition in cold weather but the car does start. Also to replace the camshaft sensor do I have to replace the distributor?
I don't see why you would have to replace the dizzy when you do that sensor? But I'm not too familiar with working with dizzys since I don't have one haha.
QUOTE (Fstrsn @ Jan 23 2010, 05:20 PM)
Ok, so things have kinda stalled on my end, sorry folks. The guy who has been doing all the diagnostic and repair work was fired last week for a bunch of bullshit. But I did have the codes cleared and I only got two that came back. P0304 and P0340. 0304 is the cyl #4 misfire that I've had all along and 0340 is the Camshaft Position Sensor. The little bit of research I've done states that the crankshaft sensor could cause this code to throw, the car won't start if the camshaft sensor is bad, and obviously cyl # misfires or random misfires go hand in hand with this. Now like I stated before, I do have a hard start condition in cold weather but the car does start. Also to replace the camshaft sensor do I have to replace the distributor?
No Just replace the sensor.
For some reason I had it stuck in my head that the camshaft sensor was built into the distributor on the 2nd generation Altima's and in order to replace the sensor the distributor had to be replaced as well.
BUMP 
no luck yet Sean?
looks like this is for 2002+, but if the engines are the same (or similar) you should be able to use:
Crankshaft and Camshaft sensor replacement for Altima
Crankshaft and Camshaft sensor replacement for Altima
QUOTE (jcat @ Jan 25 2010, 01:29 PM)
looks like this is for 2002+, but if the engines are the same (or similar) you should be able to use:
Crankshaft and Camshaft sensor replacement for Altima
Crankshaft and Camshaft sensor replacement for Altima
Nope, 01 was the last year the KA was used. The 02 has the QR or the VQ. I'm gonna give Dj a call and see if he can shed some light on it.
QUOTE (Stangman_NB)
no luck yet Sean?
Nope no luck. It's running better then before the IM gasket but it's still misfiring and surging.
BUMPITY BUMP BUMP. So finally after months of driving it with advanced timing to make it semi-driveable the intake manifold gasket is done and whatdya know, the car runs beautifully now. No skipping, missing, backfiring, and it starts right up hot or cold. So all of the issues I've been having are the result of a bad IM gasket. When we got the IM seperated from the head the gasket fell apart into SIX pieces. My theory on the fuel issue is that once the ECU saw the misfire it would pull fuel to that cylinder at idle to prevent a fuel build-up. :shrug:
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