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Thread ID: 74962	2006-12-11 21:53:00	Fuel Injector Cleaner	smithie 38 (6684)	PC World Chat

Post ID	Timestamp	Content	User
505976	2006-12-21 09:10:00	Well, I'm not sure at all. That's just what's left after they stung me for replacing everything else. It's could be anything, but short of paying SurferJoe's airfares to come and take a look, I don't know who can give me an honest assessment, so I'm doing the "cheap" things I can do ($20 for a bottle of STP Injector Cleaner). I know next to nothing about modern cars. In my youth I only had a passing knowledge of the carburetor type. Now electronics have taken over aspects of the engine management, so I'm ripe to be ripped off.	chainey (9225)
505977	2006-12-21 09:15:00	whats the symptoms? what have they done to it?	tweak'e (69)
505978	2006-12-21 09:38:00	The symptoms are that the idle is a bit "lumpy" -- even in neutral it's detectable from the sound, but in drive with a foot on the brake there's an occasional "push" as if someone behind the car had given it a quick shove. It's not regular, but probably on average every 3 to 5 seconds. Also, under load it falters badly. If I need to pass and I put my foot down and drop a gear it'll accelerate smoothly at first, but then become ragged and lose power. The Nissan tech told me that he pushed it hard in test driving and the power apparently smooths out again above certain revs, but that's not much use to me. At normal sedate driving it's fine. What they did (according to the job sheet) was: - Interrogated all fault memories and found no faults logged - Cleaned throttle body and carried out basic settings - Removed and replaced spark plugs - Replace fuel filter - Checked airflow meter voltage and it seems to fluctuate a bit - Test drove vehicle and found to be running as should That last bit is BS as the first thing the guy said to me when I picked it up was that he hadn't been able to figure it out. He said bring it back and they'll clean the injectors. That little lot had cost me a few buck under $500, so I wasn't exactly raring to go back, pull my pants down and bend over for another "servicing". I can pour a bottle into a gas tank, so why pay them $100 an hour (and no doubt it would take them an hour to find the fuel cap release).	chainey (9225)
505979	2006-12-21 11:05:00	this car has no turbo right? sounds like a fuel/air mix problem... perhaps the little computer has broken? if there is an air filter (which i assume there will be in some form), is it clean? blowing any smoke? sounds sick?	motorbyclist (188)
505980	2006-12-21 18:46:00	I can pour a bottle into a gas tank, so why pay them $100 an hour (and no doubt it would take them an hour to find the fuel cap release). Take it to another garage, one with a good reputation, if you don't know any try www.nocowboys.co.nz. Cleaning the injectors is exactly that, pulling it apart and cleaning, not tipping bottles of goo into your car.	pctek (84)
505981	2006-12-22 00:20:00	chainey . . . Just wait a little while for the injector cleaner to get it's work done . . . if it doesn't work then it's time to dig deeper . The air-fuel ratio is computer controlled and not readilly adjustable without some computer knowledge to reprogram it . You can buy a "Power Chip", but that isn't your problem at the moment . One thing you said is that the Mass Airflow Sensor had varying voltage . That may be normal if you're not talking about the base 5+vdc reference signal . Also, the ground integrity might be suspect too . That you had a scan on the system (I assume it's OBD-II compliant), then you know as much as the onboard system knows . One thing that pops into my mind, and one that will also NOT cause a code to set or a flag to come up is the TPS . It is a rheostat-like device that detects the throttle position and relays that info to the ECM to allow the event and timing of the injectors and ignition timing to move as programmed . If the TPS is slightly damaged or worn out, it might not pop a code . There is some values comparison to the MAF (Mass Airflow Sensor) to check it against known and adaptive values stored in the PROM or e-Cell . If the numbers are way out, then it'll turn on the CES light on the dashboard . What's the mileage of this vehicle? If it's over 40,000 miles then I'd change the Oxygen Sensor just for kicks and giggles . . . unless the dealership already did it . They are known to cause many "fleeting" problems that are hard to hammer down . On the minus side, they also usually set a hard code . . . some times they start flashing the CES to warn you that you are doing damage to your catalytic convertor . The oxygen sensor has to swing thru the "neutral gate" of . 5vdc, and might go to . 01 or all the way to . 9 volts during it's cycle . . . but it is mostly supposed to be around . 5vdc if all is working well . DO NOT USE AN ANALOG METER for this test!!!! You may also have pre- and post-cat oxygen sensors . Testing the post-cat sensors should be very boring . . . as they never move much from . 5vdc if all is well and the cat's actually cooking . The engine and sensors must be at normal operating temp for this test . . . and some systems drop into open loop if you allow it to idle for a few seconds . . . making this test hard to perform . These systems will probably also have electrically heated oxygen snesors to get them online rapidy . They will have more than 2 wires for identification . There is so much more to consider . . . but wait for a while . . . give it a good two tanks full to see . :cool:	SurferJoe46 (51)
505982	2006-12-22 00:29:00	Take it to another garage, one with a good reputation, if you don't know any try www . nocowboys . co . nz . Cleaning the injectors is exactly that, pulling it apart and cleaning, not tipping bottles of goo into your car . Modern gasoline injectors are not serviceable . They are hermetically sealed and have no serviceable components that a mechanic can access . Some older diesel-types are fully rebuildable and serviceable . . . albeit with a popping bench to set them to values . If you mean scraping off the deposits from the nozzle shields, then that's ok . . but there is nothing else to do for/to them at that point . Don't even think of scraping across the face of the injector! Instant junk! I like to run a very careful ohms test and a trigger voltage/amps test to see that they are equal in performance . . . but other than that . . . there's naught to do but replace any that are suspect . Chemicals will clean what is cleanable . . and that isn't a mechanic-in-a-can theory .	SurferJoe46 (51)
505983	2006-12-23 00:29:00	Thanks for all your suggestions. I'll wait and see what improvement I get (if any) from the injector cleaner. I'll post the results. That 'no cowboys' site looks like it'll be a good resource once the referrals build up. Right now there are only one or two for each mechanic (the owner and his buddy?), and they're a bit vague -- i.e. might be the result of a trusting nature rather than a knowledgeable assessment.	chainey (9225)
505984	2006-12-27 08:12:00	Well, I got to the end of the tankful of gas that had the STP in it, and maybe there was a bit of improvement -- hard to say because it varied day-to-day anyway. Next task was to find a Caltex station (for the Techron(TM) additive) and, as luck would have it, there was one on the way to work this morning. I'd never noticed it before (I usually gas up close to home). Exiting the station I put my foot down and before I knew it I'd run two red lights, plowed across a football field and was nose down in the gorse on the other side. I explained to the attending officers that it was the Techron(TM) what done it. They were very understanding, but I had to admit to myself afterwards that my jandal thong had got caught in the accelerator pedal.	chainey (9225)
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