Please, I need some help here. I bought this 89 nissan 240sx a couple months ago and the car is having problems. It runs great and has no problems until it warms up or after driving on the freeway which tends to get things heated. At this point the car still idles ok except that every so often and with regularity the engine idle will drop suddenly to about 4 or 5 rpm and slowly work its way back up to 850 again and run there for a minute and then do it all over again. However, that is not the worst of it. When i step on the gas, especially when i do it quickly, the idle will drop to almost die and then a second later kick back to and rev up like normal. Also, if the engine does totaly die from a fast foot on the gas it will not start for about an hour. It will just keep turning over and over. I have no other problems, as it runs great and drives good down the freeway, although i have noticed that the fuel economy is low. Some things i have checked and replaced:Replaced the plugs, wires, fuel filter, air filter, and fuel injectors (mainly because these where all in bad shape to begin with and it has lots of miles.)Checked for vacuum leaks, the ignition timing, tps, O2, cap and rotor, and fuel pressure. All ok.
Does anyone have any other suggestions, i think that it could be either the map sensor or the dirstributor. Does anyone have any other suggestions in finding the problem? No one seems to have a clue so far. Should i just take it to someone with a scanner? Also i heard that since the check engine light does not come on that it should not be a problem with a sensor is that true?thanks much
hesitating 240sx
well let me be the savior for u. i had that kind of problem in my 93 and it baffled me, my dad, and the master technician at a dealership for about a year. we changed the egr valve, ran consult, o2 sensor...etc. At least for my car, the problem boiled down to a knock sensor. 180 dollars for the little thing. My car was hesitating when i would push the gas, and then it would pick up the revs like normal. Tended not to happen when engine was cold but when your driving normally, it would happen. Knock sensor is something you should look into. hope this helps
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yellow_jacket
- Posts: 1355
- Joined: Mon Jan 13, 2003 4:43 pm
- Car: 95 240sx
also, you don't have a MAP sensor (manifold air pressur). You have a MAFS (Mass Air Flow Sensor).
If you have a friend with the same car you can swap the MAFS and see if it helps. You can also remove your MAFS and clean the elements within it with a q-tip and rubbing alcahol. Try cleaning it..it's free to do and you never know, it could solve you problem.
If you have a friend with the same car you can swap the MAFS and see if it helps. You can also remove your MAFS and clean the elements within it with a q-tip and rubbing alcahol. Try cleaning it..it's free to do and you never know, it could solve you problem.
Yeah, timing has nothign directly to do with running rich or lean. You could be dumping tons of fuel in and have your timing be dead on. Alot of these posts are bogus. Likely problems are of course incorrect timing (which could be a problem, but don't say "to check rich/lean use a timing gun"), bad MAFS, bad TPS, fuel pump, clogged filter, etc, but it appears you did all these except the MAFS. Bad sensors won't necessarily trigger a check engine light, my coolant temp sensor was out for months and it read nothing. Also, give it the twice over for vacuum leaks again.
Case in point, my O2 sensor was not malfunctioning to the point where it triggered a check engine light, but it was clogged with junk and it caused similar issues to what you are experiencing. Running rich, idle going up/down, hesitation, sucked gas, etc. A clogged O2 sensor won't necessarily trigger a code, but it can cause a lot of similar problems.
I had the same exact problem. Be carefull when the car decides not to start. Mine eventually had to be taken to the show to have the oil changed cause I had fuel in there.
Anyway, I changed my o2 sensor, coolant temp sensor, fuel filter, plugs (NGK--the Bosch ones are crap!) and put an Injen Intake on it and have not had the problem since.
You may have some cracks in the air intake tube closest to the intake box (where the ECCS is etched on top) in the ribs that thing has which is causing your engine to run very very rich and will eventually flood the engine and crankcase and not start.
Try replacing the o2 and coolant temp sensor. When your car won't start, take out a spark plug and check to see if it is soaked in fuel, if it is you are running rich and need to check your air flow.
Anyway, I changed my o2 sensor, coolant temp sensor, fuel filter, plugs (NGK--the Bosch ones are crap!) and put an Injen Intake on it and have not had the problem since.
You may have some cracks in the air intake tube closest to the intake box (where the ECCS is etched on top) in the ribs that thing has which is causing your engine to run very very rich and will eventually flood the engine and crankcase and not start.
Try replacing the o2 and coolant temp sensor. When your car won't start, take out a spark plug and check to see if it is soaked in fuel, if it is you are running rich and need to check your air flow.
Thanks alot guys for the suggestions. I have not had much time to try to fix this problem, but as most of you thought i am quite sure that it is running rich. I work at an auto parts store so i bought some bosh +4 plugs and i have not had the hesitating problem much at all. Probably because this plug is less likely to foul and burns hoter. However, it continues to get terrible gas milage, like 18 to 20 on the highway and the idle drops as it was before. Furthermore, i noticed that the oil smells like gas. When i pulled the old bosh single platinums out i noticed that they where coated with a white powdery buildup. Does this also indicate that it is running way too rich?I think i will double check for the vacuum leaks and carefully examine that intake tube for leaks. Since i work at an auto parts store, i will order the mafs and throw it on my intake to see if this helps. Also, i will replace the coolant temp sensor. Thanks again guys.
I have been told by several people, a couple of them mechanics, that the Bosch plugs are crap and should never be used in our cars (240's). One told me that he thought NGK were the stock ones (but that's yet to be determined!). Do your o2 sensor and coolant temp sensor and if you want to do a cool sounding upgrade, get a cold air intake like this one from Injen (which is what I have!)
The original 240 plug is either NGK or Denso, Nissan has used both. If you go to the Nissan dealership to get plugs I believe they give you an NGK unit, although the box will say Nissan. Not quite sure about that though. I AM sure that the Bosch plugs are CRAP, and definetly not suited for our cars.
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Gutacheese
- Posts: 8
- Joined: Wed Apr 30, 2003 6:27 pm
- Car: 1993 240sx Convertible
- Contact:
I had a very similar problem with my car. I brought it to a shop and they disconnected the EGR valve and it ran perfectly. Try disconnecting it and see if that solves the problem. Of course your going to want to disconnect that when the engine is warmed up.
Of course if you have to perfoem an emmissions test in your area that will have to be replaced before testing. Mine ran me about $380 cdn with labour included so I would hope thats not the problem for your wallets sake
I hope this helps out.
Of course if you have to perfoem an emmissions test in your area that will have to be replaced before testing. Mine ran me about $380 cdn with labour included so I would hope thats not the problem for your wallets sake
I hope this helps out.
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sdca240aaron
- Posts: 3
- Joined: Mon Apr 07, 2003 8:04 pm
- Car: cars, politics, philosophy, and video games
I had a simmilar problem with my '89 240. The idle would oscillate up and down between 600 and 1100 RPM at a stop. I couldn't figure out what it was for the life of me. After about a two weeks the car wouldn't start. I thought it was either the mass airflow sewnsor or the fuel pump. Eventually I broke down and took it into nissan. They told me that the fuel injectors were clogged and they flushed the injector rail. They replaced the fuel filter and told me that there was a 90% chance that the injectors were cleared up. If not it would require replacing the injectors at $120 dollars each. I would need to replace the filter again after 1000 miles. I got the car back repalced the filter after the thousand miles and haven't had any trouble since. Hope it helps.
Sounds like the same problem I fought with for weeks and several hundred dollars laterI finally fixed my problem thanks to this board. After new injectors, a new fuel pressure regulator, a new vacuum solenoid, new vacuum lines. I checked the malfunction codes on the cumputer and there was a temperature code. What was happening is the terminals on the temperature were corroded which created bad engine temperature being reported to the computer and the fuel mixture was being adjusted accordingly. I was running Very rich at times with very poor fuel milage, other times the car would run fine. I cleaned the terminals on the Temperature sensor and have not had abit of problem since. Does not sound right that something as simple as that could cause this kind of a problem but it does.
This seems common... i have an 89 240sx and i have a hesitating problem also .. my rpm's dont really change but it almost seems like something is clogging injectors and then it smooths out with more gas applied....but i know it is not clogged injectors.... have put in injector cleaner and also the injectors look new , I believe the previous owner replaced them and they are not larger because this problem just started occurring.
here is what i have done and it still is not fixed:
TPSdistributor cap and buttonbelts (all 3)spark plugsair cleaneroil changeO2 sensor new muffler (old was bad) and also had old.. bad.. gasket behind cadalitic changed, which was bad also.(also have checked for vaccuum leaks, none)
If anybody has any more suggestions i'd be eternally grateful!
Mark
here is what i have done and it still is not fixed:
TPSdistributor cap and buttonbelts (all 3)spark plugsair cleaneroil changeO2 sensor new muffler (old was bad) and also had old.. bad.. gasket behind cadalitic changed, which was bad also.(also have checked for vaccuum leaks, none)
If anybody has any more suggestions i'd be eternally grateful!
Mark