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2000 Corolla Fuel Injector O-Rings Vacuum Leak

By tiptoes4, January 25, 2012



I will thank everyone (especially Fish - you rock!) in advance for all the information i gained on this site.

I have a 2000 Corolla with 142000. The check engine light came on a couple weeks ago - code P0107 - running lean. When I started the car, the idle moved around a bit, then settled. No idea what the RPM was as I do not have a tachometer. When I put the car in D or R, the idle dropped and the car stumbled unless I pumped the gas pedal a tad. Once I got moving a few yards, the car seemed to run fine, with little to no hesitation. I could hear what sounded like a vacuum leak coming from the intake manifold gasket region and around the throttle body. With the car in P, I opened the hood and manually opened the throttle a bit and the leak became more pronounced. I did not think it was the IAC valve as when I turned on the air conditioning, it did what it should.

Hoping to fix the situation, I did all of the following yesterday: Cleaned MAF, cleaned throttle body, changed throttle body gasket, changed intake manifold gasket, changed OCV filter and visually checked all tubes. When I started the car it stumbled until I gave it a little gas - I assume the ECU was just figuring things out. Once the car warmed up (still parked) it sounded fine. I took it for a easy drive - all seemed fine. I parked the car for an hour and then came back to start - all fine - until I needed to accelerate and the car stumbled. I backed off the gas and pumped the peddle and it recovered and took off like there was no problem. However, the CEL came on.

I still hear what seems like a vacuum leak from the intake manifold - but specifically (with use of stethoscope) from tube that comes out from the 4th cylinder. Is it possible that an o-ring from the 4th cylinder fuel injector has been the vacuum leak all along? Fuel economy has not changed anything significant during all of this. I used fuel injector cleaner before doing any of the above and still no results.

If it is the o-ring (worth changing I would guess) - does the injector just drop in and only held in place by the o-ring, thread to screw in etc?? Is it better to replace the grommet at the same time, or can I get away with just the o-ring? Am I on the right track?

Thanks in advance - first post for me here.

Is there any dark oilyish residue around the injector? How about the intake manifold gasket? You could have the injectors' metric O-rings matched at a local hydraulics supply distributor. They should have some that are resistant to gasoline/oil.

I will have to pull the injectors to see about the residue. The intake manifold gasket was relatively clean as well as the mating surface on the engine. The intake ports (the four tubes - not sure of the proper name) on the manifold were pretty dark with residue. I cleaned a lot of it, but concentrated more on making sure the mating surfaces were spotless.

So I pulled the fuel rail with injectors attached. Now I'm a little stumped.

1) I got the o-rings from the dealership, but where do they go? I'm assuming on the top of the fuel injector where it connects to the fuel rail.

2) How on earth do I remove the injector from the fuel rail?

3) Could the actual leak be the rubber ring that is on the cylinder head where the injector is inserted? Is this also called an o-ring?

Sorry for so many questions, but frustrated after not finding the answers online.

The O-rings are in fact for top of injector to seal in the fuel rail. Looking in the repair manual, I see there is only one insulator per injector at the bottom. Did they stay in the head?

"Injector vibration insulator" # 23291-73010 Retail $8.68 each.

http://www.toyotapartszone.com/oem/toyota~insulator~injector~vibration~23291-73010.html

Fuel injector seal kits- including O-ring, insulator, and grommet (order 4 sets- only a couple bucks each):

GB REMANUFACTURING Part # 8024A

BECK/ARNLEY Part # 1580894

http://www.rockauto.com/catalog/x,carcode,1432903,parttype,13679,a,www.google.ca%2BSearch%2Bfor%2B2000%2BTOYOTA%2BCOROLLA%2B1.8L%2BL4

7. REMOVE FUEL DELIVERY PIPE SUB–ASSY

Remove the 3 bolts and fuel delivery pipe together with the 4 fuel injectors.

NOTICE:

Be careful not to drop the fuel injectors when removing the fuel delivery pipe.

8. REMOVE FUEL INJECTOR ASSY

Pull out the 4 fuel injectors from the fuel delivery pipe.

9. INSTALL FUEL INJECTOR ASSY

Install a new insulator to the each fuel injector.

Apply a light coat of spindle oil or gasoline to a new O– ring, and install it to the each fuel injector.

NOTICE:

Never use engine, gear or brake oil.

Apply a light coat of spindle oil or gasoline on the place where the fuel delivery pipe touches on the O–ring.

While turning the fuel injector clockwise and counterclockwise, push it in the fuel delivery pipe.

NOTICE:

Be careful not twist the O–ring.

After installing the fuel injectors, check that they turns smoothly. If the fuel injector does not, reinstall it with a new O–ring.

10. INSTALL FUEL DELIVERY PIPE SUB–ASSY

Install the fuel delivery pipe together with the 4 fuel injectors with the 3 bolts.

Torque:

Bolt A (2-front) 14 ft-lbf

Bolt B (1-side) 80 in.-lbf (6.67 ft-lbf)

NOTICE:

Be careful not drop the fuel injectors when installing the fuel delivery pipe.

Check that the fuel injectors rotate smoothly after installing the fuel delivery pipe.

11. CONNECT FUEL TUBE SUB–ASSY

Connect the fuel tube to the fuel delivery pipe.

NOTICE:

Check if there is any damage or foreign objects on the connected part of the fuel tube.

After connecting, check if the fuel tube and the connector are securely connected by pulling them.

Thanks for the reply's guys.

I pulled the fuel rail with injectors attached but did not pull the fuel injectors out. From what I have read, you just yank them out. Maybe I am too cautious, but I didn't feel 100% confident about pulling them out that way. I did replace the insulators though.

Anyway, the CEL just will not go off. I'm gonna break down and take it to a mechanic so they can do a better diagnosis.

Will up date later.

P0107 is a trouble code for MAP (manifold absolute pressure) sensor low input, but you don't have a MAP sensor... Is it not code P0171 (system too lean)?

Are you still on original MAF/IAT combined sensor? If so, it's most likely due for replacement. Same for your primary O2 sensor.

Took the car into a mechanic. They went over it and determined it was the MAF sensor. According to them, when they unplugged the MAF sensor, the O2 sensors would read rich/lean back and forth. So I bit the bullet and replaced the MAF - which was about 5 years old. I guess cleaning it didn't do the trick.

I unplugged the battery, put in the new MAF and started the car. It stumbled at first, but eventually found where it wanted to idle at. I took the car out for a spin for about 30 minutes on the highway and I have to admit it sounded and reacted a lot better than it has in a while. So took the car home and let it sit over night. When I started it in the morning, it stumbled so I hit the pedal a bit and seemed ok. After driving it for a few miles the CEL came on!

One question: After resetting the CEL and starting the car, there sounded like a massive amount of air was being sucked in from the intake hose (pre filter) as the car tried to find where to idle. Is this normal?

Any other ideas. I already cleaned the throttle, replaced gaskets, and can not find a leak if there is one.

BTW: Thanks for help on fuel injectors. The mechanic tested pressure and it was good and stable.

Dom, yes the code was P0171 - my bad.

Now that the CEL came back on, is it still P0171?

IAC valve? TPS?

Now that the CEL came back on, is it still P0171?

 

IAC valve? TPS?

I would recommend going back to the shop you had the sensor replaced at and grill them. Since you did NOT have a CEL code such as P0100 - P0105 indicating a fault with the MAF sensor or wiring, the only true way to determine that a MAF is the true problem is to have a "scanner" that will graph the voltage and/or grams/sec value readings from the MAFat idle and while driving it so you can see if they are within proper spec, but not triggering a code due to the threshold. My money is that they didn't do this. This testing can also be accomplished by having the blowing throw the MAF and measuring changing voltage, but using a "scanner" is a much more accurate way to monitor systems in today's cars.

Monitoring the voltages from the O2 sensor as well is important, because a "lazy" sensor that does not switch between lean and rich quickly enough can also cause a lean condition. This can also be done with a "scanner" or o-scope, but generally isn't because the independent garage don't have the technology, or don't understand how to use it correctly. So they'd rather recommend replacing it without knowing if that's the problem or not. You can't check fuel pressure yourself either unless you open up a line and add a t-fitting in line because there is no service port on this generation.

Word from experience, the pintle caps on fuel injectors (the end that goes into the cylinder head) do become brittle with age and crack, and can cause vacuum leaks there. This has happened before on my Miata, and I simply bought new caps and put them on. You can diagnose this properly with an Ultrasound Detector, or with a hose to your ear for a stethoscope if it's loud enough.

And if the mechanic says it's the EGR valve or system, walk away because they don't know what they are talking about, because your car doesn't have EGR due to the way the engine was created it eliminated the need.

Things to consider when speaking with your mechanic and considering to switching to a competent garage.



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