Suspected dirty injectors... what to do?? GOT NEW INJECTORS!

[MMamdouh]

Hi guys

I have been having this problem for a while now... some times when I start the car it takes a while of cranking then it starts, sputters for 2 or 3 seconds with black smoke form the exhaust then it runs perfectly.

I recon this is due to a dirty injector where the dirt prevents the injector from effectively sealing the fuel path... when the car is off and their is some fuel pressure, the injector leaks fuel into the intake and mess the air/fuel ratio at the start up... seems pretty logical HUH?

Here is the whole feedback on the issue along with my interpretation:

1- Problem occurs after turning the engine off for a period ranging from 10 min to 4 hours. less than that will not give the injector a chance to leak enough fuel to affect the startup... more time than that and all the fuel is evaporated from the intake.

2- Black smoke comes out associated with the sputtering black smoke---> too rich mixture ---> too much fuel.

3- After some 10 to 15 minuets with the engine off, all the fuel pressure in the engine is lost... you can take off the fuel filter with no fuel rushing out at all. the leaky injector depressurized the fuel system.

4- Some mild hesitation during idling bad injector not delivering the correct amount of fuel

5- already checked spark plugs, spark plugs cables, idling speed sensor and extensive throttle body and intake cleanup this has nothing to do with those parts... only thing left is the injectors

I think I got all items covered that the injectors are the ones responsible for the problem... my mechanic concurred with me but he also said a bad O2 sensor could cause that... I don't have a CEL and that doesn't explain the loss of fuel pressure after 10 to 15 min.

after all that I need to try cleaning my injectors... already tried some STP injector cleaner but it didn't help, some people say I have to use it concentrated (i.e. add the bottle to 1/2 or 1/4 tank of fuel rather than a full tank as instructed) but I am not sure if that can hurt my engine.

Also does anybody know of a really effective product to clean them injectors... better than the STP stuff I mean?

Mechanics around here are not so well equipped so I don't have access to an "off the engine" injector cleaner machine or so... if all the "on the engine" cleanup fails I will have to replace the injectors so I am willing to try everything I can to clean them up.

MMamdouh

[Fishbone]

A bad MAF sensor could also cause symptoms similar to what you're experiencing...except for the fuel pressure drop. So assuming it is the injectors (and you don't have access to a pressurized stand alone injector cleaning service - what I use once a year BTW) you can look for a fuel injector cleaner product made by Chevron called "Techron". I read a report in a car mag awhile back that compared several different bottled fuel injector cleaners and the Chevron was the ONLY one that actually worked (they did before and after tests of injector flow rates).

Here's a link with some info:

http://www.chevron.com/prodserv/nafl/au ... eladd.shtm

[Daniel]

I have had this problem some weeks ago on my Nubira 1.6 and I believe it was linked to the fact that I have tanked 3 times at a "cheap" gas station. So was the sketch:

1) End of first "cheap" gas, a little harder to crank.
2) Pouring injector cleaner at end of second tank.
3) End of third tank even harder to crank.
4) Switching to "good gas" (always 95oct) , starting better and better. Now it cranks like new.

Cheers,
Daniel

[MMamdouh]

i suspected gas too but that is not it.

tried different gas stations (Mobil, Esso and others), different gas graids (90 and 92) and nothing changed the engine's behaivour plus that doesn't explain why the car starts right up in the morning or losing fuel pressure or the black smoke.

i am still in the quest of finding out the real reason for that before spending money on pars... thanks for the help though, i really appreciate it man!

MMamdouh

[python235]

injector cleaning isnt an issue
but it can be just more than the injectors
1st take the car to a mechaninc
remove the gas tank and clean any prespitates in it
2nd if the fuel filter was never changed or is old change it
3rd cleaning the injectors can take place at some gas stations (NOT SURE ABOUT EYGPT BUT WE HAVE IT IN AMMAN) and it u find noplave take them of and clean them by pusing disel in them with a squirt bottle gently in both directions and then leave then in disel for a while then take them out use alchol and then LET THEM DRY VERY WELL then use them, if non of this helps then u got an ECU prob or a Sendor prob

HOPE ITS NOTHIN SERIOUS GOODLUCK

[Me]

could it be your timing because thats what im faced with right now. I am in the middle of the same problem and i thought it was the fuel filter but it didnt fix anything, dont know about the loss of feul pressure though.
and i heard you could use ATF to clean the injectors but your car will just smoke a tad for a day or two

[MMamdouh]

what is ATF?

MMamdouh

[MMamdouh]

any body knows what "ATF" refers to??

i don't suuppose it means Powersteering fluid aas i never heard that it works as injector cleaner... any body got a better idea?

MMamdouh

[BosnianLanos]

If you are set on cleaning your injectors, relieve fuel pressure and take out your fuel rail with the injectors still attached. It will take some tugging because the injectors are really wedged in there, but don't worry, nothing can break.

Once you get them out, you can see the tip that goes into the combustion chamber, mine were a little dirty, but I used a fine wire brush to clean them to like new condition.

It is a really easy job, there isn't potential to mess up too bad. Good luck

[Efratech]

ATF? Auto Transmision Fluid?

[MMamdouh]

ATF? Auto Transmision Fluid?

that what i thought too... how can ATF clean injectors??

MMamdouh

[MMamdouh]

If you are set on cleaning your injectors, relieve fuel pressure and take out your fuel rail with the injectors still attached. It will take some tugging because the injectors are really wedged in there, but don't worry, nothing can break.

Once you get them out, you can see the tip that goes into the combustion chamber, mine were a little dirty, but I used a fine wire brush to clean them to like new condition.

It is a really easy job, there isn't potential to mess up too bad. Good luck

.

Hmmm... seems fairly easy but i got a question, wouldn't the wire brush change the shape of the injector's tip?? i mean it can brush off some metal off the injector tip so that it changes the tip shape and accordingly spray pattern?

i guess you used a REALLY fine brush with extra caution during the process...right?

MMamdouh

[BosnianLanos]

IDK, my injector tip was metal, there wasn't any way that even hard brushing with a hard brush could have affected it.

I don't know if they if your injectors are different.

[Me]

ATF Auto tranny fluid it would clean the fuel injectors by all the additives that are in it. it is supposed to brake down any matter that has wandered its way on them. but im just going off of what ive heard from some hot rod guys

[KnightWalace]

IDK, my injector tip was metal, there wasn't any way that even hard brushing with a hard brush could have affected it.

I don't know if they if your injectors are different.

Wouldn't it depend on the type of metal?

If it's a soft metal it could scrape or such?

I'm not really knowledgable with this in depth of the engine as of yet.. during the summer i plan on ripping apart the block and fixing it up a good by while i have my lancer and vice versa when xmas time comes around.