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Car Forum / Nissan / Nissan Altima / January 200492 maxima idling and jerky acceleration
Hi all, Recently my 92 maxima GXE idling speed suddenly dropped at the traffic signal. It seems to not want to go back up any more. Further the acceleration is jerky but seems to get better at higher speed. I had changed my air filter with one from Autozone, a few days ago. That's all. My car even passed the stringent emission test. After reading this forum I gather that an aftermarket air filter can damage the air flow meter, so I replaced the air filter again with a Nissan dealer air filter. The problem is still there. Could the AFM be damaged. I only drove the car with the aftermarket air filter for five days. Anything else I can look for. Any simple tips to further diagnose will be much appreciated. I am not much of a diy person for car repairs but I will try. Thanks, Rusa Hi all, Just wanted to clarify, "jerky acceleration". It is as if the car has a sore throat while accelerating. The acceleration is pulsating and not smooth. Also, I dont have a problem starting the car. Thanks again for any advice. Rusa > Hi all, > [quoted text clipped - 19 lines] > > Rusa >Hi all, > [quoted text clipped - 8 lines] >damage the air flow meter, so I replaced the air filter again with a >Nissan dealer air filter. Most unlikely for an air filter to do any damage, it may allow small particles though which could cause more wear over 10's of thousands of miles, it may clog quicker or be more restrictive to begin with in which case you lose a bit of power at high revs. >The problem is still there. Could the AFM be damaged. I only drove the >car with the aftermarket air filter for five days. Anything else I can [quoted text clipped - 6 lines] > >Rusa Check the AFM connector is properly connected and the inlet duct has no leaks. It it's a flat rectangular panel filter check you put it in the right way up. There do seem to be some claims that using carb cleaner to clean any lint or dust off the hot wire that can be seen in the small hole off to one side in the AFM works wonders. I would not advise any attempt at removal of the hot wire module from it's alloy body. NissTech says it should be heated after switch off to burn off any deposits but I can't find any mention of this in a '91 200SX turbo RS13 Nissan workshop manual or the supplement. Nor in the later '94 200SX S14 turbo manual, the bottom line in that manual says check the hot wire for damage or dust. If it was supposed to burn off by some means there would be a fault finding guide to whatever had gone wrong with that system to allow the accumulation of dust. -- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets! >>After reading this forum I gather that an aftermarket air filter can >>damage the air flow meter, so I replaced the air filter again with a [quoted text clipped - 4 lines] > miles, it may clog quicker or be more restrictive to begin with in > which case you lose a bit of power at high revs. snip. > There do seem to be some claims that using carb cleaner to clean any > lint or dust off the hot wire that can be seen in the small hole off > to one side in the AFM works wonders. So if his crap on the wire causes problems, why wouldn't a crappy air filter allow too much crap to get onto the wire and ruin the meter? I've seen a BUNCH of AFM's ruined from cheap airfilters and wouldn't be shocked if this one was ruined as well.  SignatureSteve http://www.atlantaracing.com >>>After reading this forum I gather that an aftermarket air filter can >>>damage the air flow meter, so I replaced the air filter again with a [quoted text clipped - 16 lines] >I've seen a BUNCH of AFM's ruined from cheap airfilters and wouldn't be >shocked if this one was ruined as well. and how many AFM's and other expensive electronic items have been junked to no effect, with the poor sap of a customer picking up the bill for the shops inablity to properly test and diagnose a fault? How often do I see someone posting to alt.autos.nissan with a tale of woe that some shop has charged them for the replacement of $100's of parts and still not fixed the fault? -- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets! >>>>After reading this forum I gather that an aftermarket air filter can >>>>damage the air flow meter, so I replaced the air filter again with a [quoted text clipped - 20 lines] > junked to no effect, with the poor sap of a customer picking up the > bill for the shops inablity to properly test and diagnose a fault? Given the shop manual test for an questionable AFM is "replace with known good unit", how is that a faulty way to test it? The shop manual test and codes only works with a totally dead meter. I've seen dozens (if not hundreds) that pass the basic test in the shop manual (blow through the meter and watch for a voltage change) and set no code yet were -the- problem with the car. > How often do I see someone posting to alt.autos.nissan with a tale of > woe that some shop has charged them for the replacement of $100's of > parts and still not fixed the fault? So? If I use a known good AFM to test a car and it doesn't fix the problem, the old one goes back on and I move onto something else. If some other shop just leaves every part the suspect on a car, they are butchers. That isn't how I work. It's like a bad ECU, the ONLY test for a flakey ECU is to replace it with a known good one. So you're saying if the ECU might be flakey and there is no test, it shouldn't ever be replaced? SignatureSteve http://www.atlantaracing.com > Hi all, > [quoted text clipped - 3 lines] > > The problem is still there. Could the AFM be damaged. Yep, the symtoms you describe sound like AFM problems, hope you saved ~$500 on that air filter :-) Any other junky tuneup parts on the car? That's where I'd start... SignatureSteve http://www.atlantaracing.com Go to autozone and see if they will see if your ECCU (computer) has any codes that relate to this problem. If there are none I would take it to a shop for a diagnosis. There are several sensor circuits that have to do with the Idle. One being the sensor that tells the ECCU how hot the engine is for example. All will affect the idle. I am assuming that when you replaced the filter the first time you didn't pull and hoses or wires off. It could be assocated with the filter change or it could be something else decided to malfunction. When you take it in, choose a shop that is modern, fairly large and is known to have been around for several years. Ask your friends if the have one to recommend. Sorry but without codes its a crapshoot as to what signal is messed up. Even then it might not be the sensor itself but a bad connection or a bad ground somewhere. Or you might have got a bad tank of gas or something not even related to the filter. Pappa Ray Thanks all ! No, the check engine light does not come on. I havent changed any ignition-related parts on this car - spark plugs, distributor cap etc. I did not pull any hoses or wires. My car has 100K miles. I don't want to believe it was caused by the air-filter change since I had the aftermarket (STP) air-filter on for only 4-5 days before the problem started. I am guessing it is unrelated to the air-filter change. The way I understood the AFM damage was it was a gradual process? Any other way to determine it is the AFM. I read in this newsgroup that AFM damage will cause the RPM to cap off at 2K or so. I am hoping I can try to pull the trouble codes myself by using some of the other postings on this newsgroup Rusa > Go to autozone and see if they will see if your ECCU (computer) has > any codes that relate to this problem. If there are none I would take [quoted text clipped - 17 lines] > > Pappa Ray > Thanks all ! No, the check engine light does not come on. I havent > changed any ignition-related parts on this car - spark plugs, [quoted text clipped - 5 lines] > unrelated to the air-filter change. The way I understood the AFM > damage was it was a gradual process? Nope, throw a hand full of dirt into one and it's a done deal. ;-) Maybe it was close to the end and this filter finished it off? > Any other way to determine it is > the AFM. I read in this newsgroup that AFM damage will cause the RPM > to cap off at 2K or so. That's only if it's -totally- dead i.e. no signal whatsoever. One thing you can try, see how it runs with it unplugged. If it idles good, my money is on the AFM. SignatureSteve http://www.atlantaracing.com > > Thanks all ! No, the check engine light does not come on. I havent > > changed any ignition-related parts on this car - spark plugs, [quoted text clipped - 18 lines] > One thing you can try, see how it runs with it unplugged. If it idles good, > my money is on the AFM. Any precautions in unplugging the AFM? I havent done it before. Do I just pull the connector that plugs onto the AFM square box and then start the car ? I attempted to pull the ECU trouble codes. When I did the ECU procedure, I got 5 long flashes. No short ones. That didnt make sense. So, I attempted it again and no pulses, nada, the second time. I think I followed the procedure correctly. i.e. Turn the ECU screw clockwise to extreme position, wait 2 sec and then anticlockwise to original position. Is this procedure correct? I also read that a bad TPS can exhibit similar symptoms. Is there a way to tell that it is the TPS and not the AFM or vice versa ? I could not locate the TPS. I used the picture at this link below but couldnt locate it on my car. Is it placed differently on a 92 max than the one in the diagram. Any other pointers to locate it. Sorry if this is a dumb question http://vbxmaxima.8m.com/tps.html I am thinking of changing the distributor cap and rotor and see. Is this a good idea ? At the very least, this is something cheap that I think I can do before I down some big $$ >> > Thanks all ! No, the check engine light does not come on. I havent >> > changed any ignition-related parts on this car - spark plugs, [quoted text clipped - 22 lines] > just pull the connector that plugs onto the AFM square box and then > start the car ? Yep. It should only rev to 2200 but you should be able to tell if it idles better etc. > I also read that a bad TPS can exhibit similar symptoms. Is there a > way to tell that it is the TPS and not the AFM or vice versa ? Simples tests in a good shop manual. All you need is a ohm meter. > I am thinking of changing the distributor cap and rotor and see. Is > this a good idea ? Can't hurt and is pretty cheap. I'd be surprised if that does anything.. Good luck! SignatureSteve http://www.atlantaracing.com >I attempted to pull the ECU trouble codes. When I did the ECU >procedure, I got 5 long flashes. No short ones. That didnt make sense. >So, I attempted it again and no pulses, nada, the second time. I think >I followed the procedure correctly. i.e. Turn the ECU screw clockwise >to extreme position, wait 2 sec and then anticlockwise to original >position. Is this procedure correct? How many LED's do see in the window next to the screw? >I also read that a bad TPS can exhibit similar symptoms. Is there a >way to tell that it is the TPS and not the AFM or vice versa ? I [quoted text clipped - 3 lines] >is a dumb question >http://vbxmaxima.8m.com/tps.html It's on the other end of throttle shaft to the end with the quadrant plates and throttle cables. Early ones are rectangular with one three pin connector facing forwards for the idle / wide open switch and a well hidden lead coming out of the bottom to a connector for the TPS variable resistor. Just check the idle switch makes and breaks on closing / opening the throttle using a meter in continuity mode on the top two pins off the forward facing connector, V+ on the middle pin. If you don't get continuity when the throttle is closed moving the switch body until you do. On the TPS connector, pull the boot back so you can insert a thin wire into the back of the connector to make contact with the center pin, connect a voltmeter (analog pointer type is best 10 or 12v) to this wire and earth. Switch the ignition on and check you get between 0.5 (idle) and 4 volts this should be a smooth variation with no spikes or sudden drop offs as you open the throttle. >I am thinking of changing the distributor cap and rotor and see. Is >this a good idea ? At the very least, this is something cheap that I >think I can do before I down some big $$ I doubt it. The OEM Jap leads and cap are the best you can get. Only at very high mileage when the pickups in the cap are eroded hollow is it going to need replacing. -- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets! > I doubt it. The OEM Jap leads and cap are the best you can get. Only > at very high mileage when the pickups in the cap are eroded hollow is > it going to need replacing. Or burns through. Seen a few "leak" through to ground, especially the rotor button to the dist shaft. But his problem doesn't sound like a cap/rotor. SignatureSteve http://www.atlantaracing.com Sorry for my late responses. I use deja server and it takes 3-9 hrs for my post to appear. I dont know if there is a faster way. My ISP does not provided newsgroup access... > >I attempted to pull the ECU trouble codes. When I did the ECU > >procedure, I got 5 long flashes. No short ones. That didnt make sense. [quoted text clipped - 4 lines] > > How many LED's do see in the window next to the screw? I got hold of a Chiltons and followed the procedure mentioned. I think I got the procedure correct this time Diagnostic Mode 3 - flashes 5 red and 5 green = 55 (no trouble) Mode 4 and 5 also showed no problems. Changed distributor cap and rotor - it did not fix the problem. There is still lack of a healthy idle. But once I get the car in motion the problem is not noticeable. I am still holding off on the AFM test since both mode 3 and mode 5 did not indicate any problem with AFM. Chilton's says that the injectors cannot be diagnosed using the ECU for Non-California models. I wanted to try the resistance test for the injectors but I cant seem to locate them easily from the Chilton's diagram. Are they near the spark plugs area. Any pointers ? This is the first time I am working on a car myself !! I am happy to be making some progress though.. > >I also read that a bad TPS can exhibit similar symptoms. Is there a > >way to tell that it is the TPS and not the AFM or vice versa ? I [quoted text clipped - 18 lines] > check you get between 0.5 (idle) and 4 volts this should be a smooth > variation with no spikes or sudden drop offs as you open the throttle. I will try this. Thanks Peter! > >I am thinking of changing the distributor cap and rotor and see. Is > >this a good idea ? At the very least, this is something cheap that I [quoted text clipped - 3 lines] > at very high mileage when the pickups in the cap are eroded hollow is > it going to need replacing. > I got hold of a Chiltons and followed the procedure mentioned. I think > I got the procedure correct this time [quoted text clipped - 7 lines] > I am still holding off on the AFM test since both mode 3 and mode 5 > did not indicate any problem with AFM. It won't set a code unless the meter is -totally- dead i.e. in 2200rpm rev limiter mode. I've replaced tons of them that never set a code but caused the car to run poorly. > Chilton's says that the injectors cannot be diagnosed using the ECU > for Non-California models. I wanted to try the resistance test for the > injectors but I cant seem to locate them easily from the Chilton's > diagram. That isn't going to cause your problem. SignatureSteve http://www.atlantaracing.com > > I got hold of a Chiltons and followed the procedure mentioned. I think > > I got the procedure correct this time [quoted text clipped - 11 lines] > limiter mode. I've replaced tons of them that never set a code but caused > the car to run poorly. Thanks. I will try the AFM test then. I noticed that the car does rev past 2200 rpm (about 3K rmp) during normal driving, in the lower gears. > > Chilton's says that the injectors cannot be diagnosed using the ECU > > for Non-California models. I wanted to try the resistance test for the > > injectors but I cant seem to locate them easily from the Chilton's > > diagram. > > That isn't going to cause your problem. > It won't set a code unless the meter is -totally- dead i.e. in 2200rpm rev > limiter mode. I've replaced tons of them that never set a code but caused > the car to run poorly. Are there any do's and don'ts on the AFM replacement. Dealer parts only or aftermarket ok ? >> It won't set a code unless the meter is -totally- dead i.e. in 2200rpm >> rev limiter mode. I've replaced tons of them that never set a code but >> caused the car to run poorly. > > Are there any do's and don'ts on the AFM replacement. Dealer parts > only or aftermarket ok ? The python AFM's seem to work fairly well. I'd say they perform about 95% of what a new Nissan one will. SignatureSteve http://www.atlantaracing.com |
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