1994 Camry Replace Injector?

[myersge1]

I have one cylinder (4 cylinder engine) that is not functioning. I pulled the spark plug wire and there was no change to the idling engine.

1) Spark? There is strong spark on that plug when grounded against engine.
2) Compression? Compression test showed 210 psi. The manual says anything over 178 psi. Probably a lot of carbon but from what I can see into the other cylinders, they all have a lot of carbon. I only did a compression test on the bad cylinder.

I assume the only thing left to check is the injector. From reading other posts, you guys say things like "remove and clean the injector" or "swap injectors with another cylinder and see if the problem follows the injector". My question: How hard is it to get to the injectors? When I look at my Camry repair manual, it says to take off the intake manifold, vacuum hoses, fuel lines, etc. just to get to the injectors. Is there a shortcut or a way to test the injectors in-place? Thanks.

[myersge1]

FYI, I found some old tubing to make a redneck sound scope and could hear all four injectors clicking. I then ohmed the suspect injector and it measured 13.8, which is what the manual says it should be.

I'm guessing the injector is working but clogged. So back to my original question, is there an easy way to remove, clean, and re-install an injector.

[Brian R.]

Not that I am aware of. Sorry I can't be of more help.

[artbuc]

Originally Posted by myersge1

FYI, I found some old tubing to make a redneck sound scope and could hear all four injectors clicking. I then ohmed the suspect injector and it measured 13.8, which is what the manual says it should be.

I'm guessing the injector is working but clogged. So back to my original question, is there an easy way to remove, clean, and re-install an injector.

I just went through a fuel injector issue. Clicking and good ohm reading do not necessarily mean it is functioning properly. Also, even though you remove and clean well, it still may not work properly. Taking it apart isn't that hard except you will need to buy new O rings. My advice would be to replace your injector if it isn't working correctly. BTW, another good way to check your injectors is to disconnect the wiring one injector at a time. Start with the good cylinders so you will know how the engine sounds when you lose one good cylinder. If an injector isn't working well, it will be obvious when you disconnect the power supply - minimal/no change in engine performance.

[danielsatur]

Any diesel shop can micro bath clean, and test the flow rate.

1) Pull the fuse or relay for the fuel pump, and run the engine out of fuel.
2) Remove the shrader valve on the fuel rail.
3) Pour some injector cleaner in the fuel rail + let soak.
4) Turn engine over a few time, but don't start.
5) Repeat steps 3 + 4.
6) Put the schrader valve back on the fuel rail.
7) Put fuse, or relay back in.
8) Put a new fuel flter on, and dump the rest of injector cleaner in tank.

If you use Sea Foam treatment for decarbonization, don't put any in the block.

[myersge1]

Update:

I replaced the suspect injector and got it all put back together but that cylinder is still not firing. I'm about out of things to check.

I have spark at the plug, fuel (presumably), and good compression (although a little high).

I'm grasping at straws here but would I get good compression on a cylinder with a valve stuck closed?

With the compression gauge installed and cranking the engine, the compression reaches 210 after about 4 incremental steps up the scale.

[Brian R.]

Did you check the distributor cap, plug wires for resistance, plug condition? It may still be a spark problem, even though you got spark outside of the cylinder.

As a general rule, valves don't stick closed.

[myersge1]

Thanks Brian. Initially the car wouldn't start and I replaced the plugs, cap, and rotor before eventually replacing the entire distributor (with a rebuilt one) that solved that problem. Now the car runs except for that cylinder. I did ohm the spark plug wires and they were all within spec. I guess a new set isn't that expensive to try.

I took the valve cover off just to see if there was anything obvious but it all looks sound although pretty dirty from 240k miles. While looking at it I realized that with two input valves and two output valves, both on one side would have to be stuck at the same time which isn't likely. Agreed, it's not likely that a valve would stick closed with that strong cam pressing down on it every revolution.

The spark plug is not wet when I pull it out of the bad cylinder. Would it be dripping wet with gas if the injector is indeed working?

I know that with my multimeter I can't measure the full injector signal coming from the ECM since it is such a short duration. However, with the car running, I get 0.5V across that injector wire. I get the same measuring an injector wire on a different cylinder so I'm guessing there is correct signal at the injector.

I'll try a new set of spark plug wires and let you know. Thanks again for your ideas.

[Brian R.]

Originally Posted by myersge1

The spark plug is not wet when I pull it out of the bad cylinder. Would it be dripping wet with gas if the injector is indeed working?

No, plugs don't get dripping wet with gas in an engine with fuel injection unless the injector is leaking when the engine is shut off.

Try also replacing the plug. Make sure the plug wire connections are solid to the distributor and plug.

[myersge1]

Sorry for the long post.

Spark:

I swapped the #2 plug (i.e. the bad cylinder) with one from a different cylinder and #2 still doesn't fire so I think I can rule out the plug.

I haven't be able to get to the auto parts store to get a new set of plug wires. However, I did hook up my timing light to the #2 wire (with the plug in and wire connected) and it flashes steady with the engine running. It looks like the plug wire is okay but I'll replace it anyway just to be safe. They're relatively cheap.

Compression:

After running the earlier compression where I got 210 psi on #2 cylinder (the bad one), I ran SeaFoam through an intake vacuum line twice. I then ran a full compression test again on all cylinders and here are the results:

#1 - 130 psi
#2 - 135 psi (the bad cylinder)
#3 - 140 psi
#4 - 140 psi

To be thorough I added a little oil through the #2 spark plug hole and got 165 psi so the rings are worn which is expected for 240K miles. The manual says that the minimum should be 142 psi but since they are read about the same and the other three fire fine, I think I can rule out the rings and valves.

Fuel:

As I said earlier, I replaced the #2 injector with a rebuilt one from Advance Auto but still nothing. The delivery pipe was clear. I couldn't see well enough into the injector hole in the cylinder to see if there was carbon blocking it on that end.

I see from the manual that the ECM signals the #2 and #4 injectors from the same pin so I can rule out the ECM (since #4 is firing). There could be a short in the #2 injector line but I get the same 0.5V across all four of the injector plug terminals.

I'm stumped.

Is it possible that the injector hole/cavity in the cylinder is blocked with carbon? I guess I should have shoved something in there when I had the injector out.

[Brian R.]

Swap the plug wire to a different cylinder and see if the plug wire causes a problem with the new cylinder (2 vs 1 bad cylinder). See if the #1 wire fires #2 (again, 2 vs 1 bad cylinder). Check the spray pattern from the #2 injector with the injector out of the intake manifold. Swap an injector with #2 injector.

I don't see how the injector port could get clogged with carbon. Loosening debris in the intake manifold could cause more problems than it solves.

[artbuc]

I wonder if you have a problem in the wiring harness for #2 fuel injector? You measured voltage so supply isn't the problem but you may have a bad ground. I have a 99 Avalon which may be different from yours, but on mine, the injector always has a voltage supply and the injector fires when the ECM completes the ground. You can get a special strobe light very cheap which will allow you to make sure your injector is getting the right electrical signal. You can also make your own (do internet search) but they are so cheap you may not want to bother.

Noid Light http://www.amazon.com/OTC-7188-Bosch.../dp/B000P72CMW

[jdmccright]

I had this problem that I couldn't figure out for a long time. Turns out the spark plug wire boot was grounding through the plug end to the engine and not going to the plug. Look closely at the plastic part that goes down into the engine. If you see a whitish spot, then that is where the spark is jumping to ground. Here is the link to that thread:

http://www.automotiveforums.com/vbul....php?t=1048723

[myersge1]

That was it! I put on a new set of spark plug wires and all four cylinders are firing. Brian, thanks for telling me all along to replace the wires. JD, I think your theory is probably right on. You guys have been great. Thanks to all!

Now onto my parking brake light (in the dash) that won't go off but that's for another thread.