2000 Sentra won't idle or rev, misses badly, PO300 etc
I've had a history of engine lights and PO171 and Po134 codes so I replace the O2 sensors and fuel pump.
But the engine never ran rough until I did a "learning procedure" after I cleaned the Mass Air Flow. I disconnected the MAF connector, did some pedal work and reconnected the MAF. Suddenly the engine wouldn't idle and was missing badly. The PO300 code appeared - multiple misfires.
At that point I replaced the front 02 sensor and it ran a little better.
When I start the engine, it runs for a few seconds and stalls. On the 3rd or 4th start, it begins to idle. But when I touch the gas the engine seems to flood. When I let off the gas, the engine surges a bit. I cannot get the engine to rev much past 3000 rpm. It sounds like it is starving for gas.
I have done the tap-test on the MAF but the engine sound doesn't change.
I have tried the idle re-learn procedure a few times, but the engine light won't blink.
what did u clean the MAF with? If the engine stalls when you push on the pedal quickly and won't rev past 3k then most likely the MAF is bad. That is its fail-safe, which is not to allow the motor to rev over 3k. If you here like a loud sucking noise when you push the pedal in at 3k then its def fail-safe. Is there a lot of black smoke when or does it smell really rich? If so then that also points towards the MAF being bad. So does the P0300 which is multi-cylinder misfire.
If you cleaned the MAF with brake cleaner or anything else not made specifically for MAFs, its done.
If you cleaned it with MAF cleaner then it should be OK, but depending on the condition of the wire may have caused damage.
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Thanks for the reply, Stich. I cleaned the MAF with CRC MAF cleaner.
There is another symptom that may or may not be related. The gas tank is very slow-fill. And the gas cap no longer "hisses" when I remove it. Does any of this restrict the flow of gas to engine? Today I pulled the fuel pump and gave it a bath with carb cleaner. Engine still misses.
Where would you reccomend buying a MAF? NAPA quoted me $900 for a factory replacement. I nearly choked.
The gas tank issue is most likely unrelated. Probably an evap line leaking or the vent control valve not sealing completely. All that is for the fuel tank and emission control. Yea the MAF's are expensive, Nissan's is probably about the same price as NAPA. Junkyard would probably be your best bet for a cheap one. Or going online and trying to locate one. Do u have any other codes?
I have had other codes. The ones that repeated were 171, 134 443 and most often PO300. I have seen a PO100 and 1320.
Most of the codes told me to look for an air leak. All I could find was a 1/4" hose coming out of the crankcase that dead-ends behind the MAF. Its open ended, connects to nothing. A second hose in the same harness goes into the MAF. I have tried plugging the end of the hose but if its venting something, I guess I should not plug it. Plugged or not, the engine still misfires.
I did a compression test looking for a blown head gasket. I do get a little white smoke from the tailpipe and some water in the pipe. I cant find anti-freeze in oil or oil in radiator.
The dry compression test was 185,180,188,and 191. The wet test gave me 205,205,195 and 195. I know that cylinder one and two look far apart. Factory specs allows a max difference of 14. But I wondered if I squirted too much oil into those pistons, accounting for the high reading. I immediately did a second test without additional oil and got 192 and 192, within the range. The point is, I'm unsure about the compression. I'm not an experienced motor head.
I wrote a letter to Nissan complaining that their shop manuals were written in dead-english, techinical gibberish no better than Greek with children's line drawings. I asked them how can anybody look up a problem when the table of contents is not in alphabetical order. A lady from Nissan called me today with all apologies. She said that the execs in Farmington Hills
were looking at it and wanted to 'help me out" but first i needed a dealership diagnosis. I told her that 'stealership" was a term I leaned on the web, and declined her offer. What good would it do for them to pay - lets say 10% - of a $900 MAF?? I told her the offer was too uncertain, a pig in a polk - and said thanks, but no.
What do you think about the compression numbers? Would you still install a new MAF?
those compression numbers sound perfect. If i recall correctly 185 is what the FSM states the nominal value to be. Also a P0100 is for MAF circ i believe. (too many code numbers wander around in my head so forgive me if i haven't memorized them all heh). The other numbers I can't recall right now except the 443, which I think (again) is evap small or very small leak which would explain your gas tank issue.
Water in the exhaust is normal at start-up and so is white smoke (steam). I've even seen blow out steam 15min after idle. Just depends where the water condensed in the exhaust. If its still blowing out white smoke at operating temp (190 degrees F) then yea, it shouldn't still be in there.
That tube your seeing that isn't plugged into anything is supposed to be there. Its a breather for the transmission.
Ok, this is where things are going to get hairy. Theres a good chance this is 1 of 2 things. It can be a pain to diag and both are expensive so getting it wrong..sucks. I've seen this a few times. Its either a MAF, or an ECM. Have you checked the ECM for the foam recall? Or do u know if the recall was done?
If not, the foam inside the case for the ECM holds in heat/moisture and cooks the ECM. Which a common problem is a MAF issue. Its a logic error that forms and the car misses and acts like a bad MAF, but you can put in a new one and will still do the same thing.
Typically the easy way to check it would be to unplug the MAF. If your idle and throttle get better (it will not rev above 3k still) then 90% its your MAF. If it doesn't get better, then I would do further diag but its quite possibly the ECM. I don't how good you are at electrical but you will need to verify you have voltage, and ground to the MAF at least if we/your suspecting the ECM.
Your not the only one that is frustrated by the FSM. I use them daily and the lack of organization is astounding. But i've gotten used to it for the most part. My favorites are the explanations on how to remove something which goes like this:
Remove [insert part name here]
Reverse of Removal
So anyway, basically your gonna need to get into some electrical to find out exactly what is going on. Unplug the MAF and tell me what happens.
When I unplug the MAF connector the engine dies immediately. What does that tell you?
I don't know where the Electronic Control Module is. I heard it was somewhere under the dash?? I have digital multi-meter but not much knowledge. I'm really to learn.........
How do we know if the ECM is fried?
I know that the engine ran fine for 10 years......no misfires......until I did a 'relearn' procedure that some guy suggested, which is:
Warm engine, Turn off, wait 10 sec, then disconnect MAF connector, restart engine for.... 3 seconds.... stop engine.Reconnect MAF harness. Look for codes. possibly PO100 (had it) then erase codes. Start engine, run 10 min, then off. Look for codes. If engine is difficult to start, it said, then the fuel injection has a problem. The end.
I did the above procedure and the Sentra missed badly ever since.
You're right..........that I don't want to throw money into a MAF if the ECM is fried. Can I test the MAF with my multi-meter?
Stitch....My car was not part of the recall for ECM/foam. I just double checked and read the procedure for removing foam from the ECM. I think I will inspect it for debris anyway. At least I found the ECM!
I have never heard of that relearn procedure. You should never have to mess with the MAF to relearn something. I've seen disconnecting the throttle body to do idle adjustments but not MAF. The only thing i can think of is that the MAF disconnected forces the motor to run full rich, which would keep the injectors open longer. But can't seem to recall this procedure. Theres other ways to diag injector/fuel issues than disconnecting the MAF. unplugging injectors to isolate a missing one or using an engine stethescope to hear the "ticking" to make sure the plunger is working.
As for disconnecting the MAF, sorry i meant to specify. Disconnect it before starting the motor. If you disconnect while its running it will normally die.
Yes you can check the MAF with a multimeter. Well you can check to make sure the ECM is sending power and you can check to make sure the ground is good on the MAF. Red wire "should" be power. Black should be ground. Don't quote me though don't have a wiring diagram infront of me right now heh. There should be another signal that is what the MAF is sending to the ECM. I "think" its yellow(just look for a pin that has 1-5V). Its a 5v ref signal. At idle is normally around 1.3V and should rise steadily with RPM. If thats at something like 3V or .5v at idle then the MAF is probably bad.
Back probing the connector would be the best thing to do with T-pins or thin needles.
To find out if the ECM is fried will be difficult and will require a manual. You'll have to test the entire MAF circuit. But thats where this can be tricky. This is a logic issue in the ECM. Its not a simple "no power" or "bad ground". The ECM is not interpreting the signals correctly. So basically check power,ground,signal (within specs) and continuity to the ECM.
Could of sworn the 00-01 sentra's had the recall.. maybe it was 2002. Idk its been awhile since any of those have come in. Anyway yea its still a good idea to check. And doesn't mean the ECM isn't toast.
Also, go ahead and disconnect your battery for 5minutes. Then reconnect it to clear out self learn and any codes. Try starting it after that. If it still does the same thing, shut it off, then disconnect the MAF. That way your starting with a clean slate and its not being confused by anything else.
I appreciate the advice, Stitch. Some Sentra's had the ECM/foam recall but not my VIN number. I will test the MAF as you described it. I'm not sure how to put the meter on the MAF pins while its connected - if thats the plan. It sounds like testing the ECM is beyond my capability. I will try to borrow a stethoscope for the injectors. I will post any new info.
Stitch......Update. I disconnected MAF connector before starting. . Engine started much easier, no stalling, no restarts required....but....it idled very nice at 1000rpm but not much more. I touched the gas a little.....multiple misfires. I cant rev it to 3 or 4 k. It won't go that high.
I see how to 'back probe' the connector. I disconnected battery to clear memory. more later.
I thought I'd join the thread, I believe I have the exact same problem with my Sentra. Its a 2k Nissan sentra 2.0 se. I have the exact same symptoms, except I have no check engine light. Can I still have codes without an check engine light?
It had been having some slight hesitation issues for a while, about 10-20k miles, but bearable. The short story: I had my mechanic look at it, he ended up replacing both the front o2 and MAF, with it wouldn't work. My mechanics friend from a Nissan dealership came over to check it out, and said it was probably the ECU. They put the old o2 and MAF back in but the car still drives like crap, it sounds exactly like what your experiencing now bobby. I've done mostly the same tests with the same results (no compression check).
I read the same recall and it pointed to only the 1.8 or 2.5 engines, but the nissan guy insisted he'd had this before with these cars. I spoke with both of them personally. They suggested it might get better after driving it a while, which it has, but still nowhere near what i call drivable. Wont rev smooth, bucks, smells rich, misfires, Cant get it up beyond 50mph really.
Its seemed to get a bit better after I used the same MAF cleaner, and drove it a bit, I can get it to rev to 5-6k with the clutch in, gotten a little faster. Just not going to cut it with my 50mile commute.
Anyway, aside from no check engine light on my car (it does work, comes on at start-up), it seems we're in the same boat.
I've tried replugging in both the o2 and MAF, and disconnecting the battery. With no change, which surprised me, because I figured it would get worse.
I might try finding a MAF and o2, at a junk yard for now, worth a shot I think. If I have any luck one way or the other I'll post the info.
@Stitch, Would you happen to know any MAF and o2 sensors that might be compatible for a 2000 sentra with a sr20de engine?
Anyway, Thanks for listening, and any help. I hope we can figure this out.
Scott, I cant get past 2000rpm or about 20 mph. I'm off the road.
A woman at Nissan told me that the company 'frowns' on people trying to fix their own cars. I told her that I just learned the term "stealership" on the web.
That lady was just being a bitch. She just wants you to come in so they can make money off you. In case you may not have noticed i'm a tech for nissan. But I help ppl that come into the dealer with questions or whatever when they want to do it themselves. Mostly older vehicles.
Bobby, well thats looking good if its able to maintain idle and not stall with the MAF disconnected. Let it run and idle for a while and check to see if it stalls. This should have eliminated the ECM from the problem, since its running strictly off of what the ECM is saying by fixed parameters. I'll still say 90% its the MAF since i can never fully rule out the ECM until the problem is fixed heh. When you disconnected the battery and restarted with the connector on the MAF connected was the SES light on and did you pull any codes?
Anyway, Scott, MAF's will typically throw a code even if the ECM is bad. If you don't have a code, then most likely your MAF is ok. I don't have as much experience with the sr as say the 1.8 and 2.5's but i do know they still used a distributor on those. If i remember correctly the cam sensor is built into that. When that goes bad it may cause a stumble/hesitation misfire but won't show a code necessarily. The only way you can make it show a code is with Nissan's diag computer which I have to sit there while its acting up and hit record. Then it'll come up with another screen on what codes were found during the recording. Typically you'll find a P0335 Cam Sensor, maybe a multi cyl misfire (P0300). Also, have you changed spark plugs and wires and cap/rotor? A tune up may be in order. Fuel filter is also a good cause, which will def cause hesitation if it becomes clogged. Message back with what has been done maintenence wise and we'll go from there.
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