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Two dead Cylinders

9K views 29 replies 7 participants last post by  eodgator  
#1 ·
Have a 97 with a 2.0 and 175k miles giving me all I can handle. It has a cylinder 2 & 3 misfire code. It was overdue for plugs, wires, cap so did those to no avail. Ran quick spark check and at least getting some spark on all four cylinders, compression at or close to 185 on all four then tested for power going to injectors with noid lights and all four of those flashed. Now the cylinder 2 plug is wet with fuel, no signs of being fired, cylinder 3 plug only slight signs of firing and wet as well. I did clear the codes with a scan tool ad odd thing is after running for half hour or so no lights back on but definitely still misfiring, barely enough power to get moving and takes about two minutes but maxes out at 35mph. Any ideas of what I'm missing? Next plans is to see how much of a gap the spark will jump then pull injectors and rail to see if the two are plugged and just dribbling out. Would oxygen sensors make this much trouble, it did have a pending code for bank 1 sensor 1 not responding, but has not returned after clearing.
 
#3 ·
I am new to the Rav4 and it is my wife's car, and it is a 2014 so haven't need to dig yet. Doesn't the Rav4 have individual ignition coil packs? All is pointing to that, 175,000 miles is a bit past the point of reliability for those.
 
#10 ·
I forgot, you have a distributor, take it off and look for carbon tracks and/or moisture in the cap, replace the rotor and the distributor if you haven't done it in a while.
 
#11 ·
The coil, particularly if it has more than 200,000 miles is also a suspect, it could be weak.

Lastly (only because it is a chore to get to them), you could have a fuel injector issue. If they are remaining open they would flood the chambers.
 
#12 ·
Wouldn't suspect a jumped belt since that would affect all cylinders.

His initial post notes the list or parts replaced including plugs, wires & cap. However that doesn't mean he couldn't have gotten bad ones.

Injectors are a possibility but they would have to be extremely rich to cause a non-fire. And two going at the same time?

I'd check the relative spark at each cylinder by laying a good spark plug on the valve cover and rotating thru the four plug wires.

Unless the engine has two O2 sensors, one for 1&4 and a second for 2&3 that couldn't do it.
 
#13 ·
Correct, it does have new distributor cap, checked with gap tool, spark jumps a half inch gap and good looking spark as well. I did pull the injectors and getting them cleaned at the moment. One thing I'll be double checking this evening is a leak down test, had a tech buddy that ran into something similar where the headgasket was only leaking compression between cylinder 2 & 3, said it ran different when this was going on but might make sense of what's going on but I sure hope that's not the case with this thing.
 
#14 ·
Also as far as the o2 sensors, I believe just has one before the cat and one after. Speaking of cats, that's also original, I can't see if getting plugged up in a way to only effect two cylinders either but anything is possible.
 
#15 ·
My first thought was a head gasket failure between 2 & 3 but you said compression was good in all four. Maybe redo the test again when you're seeing the symptoms. Could also be bad valve clearance adjustments but that would show up on the compression test.
 
#17 ·
Check out Engine Misfire | Fix it yourself! some good info there.

Is it possible the cap is cracked or was seated improperly? I had a cap for a Ford that had a missing contact and it was a quality cap, just a bad one got past quality control.

Running too rich and good spark, check compression wet and dry that will tell you about rings/blown gasket or other more serious issues. The compression check is an invaluable diagnostic tool.

When you checked the fuel injectors, did you swap them around to see if the issue moved to a new cylinder. Fuel injectors can get stuck open or can stay open too long.

And, the site pointed out that a restricted exhaust system can cause cylinder specific misfires.
 
#19 ·
I always wondered what method the system used to detect a misfire. I originally thought that it was just monitoring the quality of the spark itself. I figured it used a sensor that picked up an induced voltage from the plug. This would be similar to the way old timing lights clamped onto a spark plug wire in order to fire at the correct time.

This site seems to be very informative ( and reliable). It says a misfire is determined by using the crankshaft sensor to determine the speed of the crankshaft between cylinder firings. In other words, anytime a cylinder doesn't produce power during the power stroke, it is considered a misfire, despite the fact that the spark plug DID NOT misfire.

The article contains a lot of troubleshooting ideas, but one idea that may be useful is "if one or more cylinders near the EGR port in the intake manifold are misfiring, a leaky EGR valve may be the culprit".
 
#20 ·
I don't know where the EGR valve is on a 4.1 but it would seem it would have to be stuck open to cause a significant problem and that should be diminished with engine rpm and throttle opening.
 
#21 ·
I don't know where the EGR it would seem it would have to be stuck open to cause a significant problem and that should be diminished with engine rpm and throttle opening.
I agree, a stuck EGR valve would result in a rough idle and even stalling at idle.

The OP has not complained of any drive-ability problems. It seems his only problem are the codes themselves, and a wet spark plug.
 
#24 ·
Check that the wires to 2 and 3 did not get crossed at the distributor, easy to do if you read the rotation wrong. Then you have 1 and 4 in the right place but 2 and 3 are 180 degrees out.
 
#25 ·
Yeah I thought of that but didn't get it posted. Could easily happen when changing ignition wires. To avoid it I always changed one at a time.
 
#28 ·
Figured this out on accident, running two heaters and over 1500 watts in lights popped my circuit breaker while the engine was running in the garage. Could see spark jumping at the cap, new cap was defective, replacement got it going. Wife was happy have her car back but I sure wasn't spending that much time on it.
 
#29 ·
New parts aren't always good parts.
Glad you figured it out before starting major surgery, especially since you'd have found nothing wrong internally.