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Discussion Starter #1
I've been experiencing a ton of misfires under boost lately and finally decided to get to the bottom of it.

I noticed the misfires soon after I changed the oil and cleaned out the engine bay with some cleaner and a garden hose. This was never an issue with other vehicles as the electrical connections are weather tight.

The misfires were only under boost over 7-8lbs at first. I was close to needing to fill up so I let the tank go really low and filled up with a fresh tank of Shell premium from another station just in case it was a fuel quality issue. After running about a 1/4 tank through it would tolerate 12-15lbs before misfiring. Then at half tank I could hit 25lbs on the highway and not notice anything but on the street it was still bad above 15lbs so today I went hunting for the real problem.

First I went looking for water in a connection since it started soon after cleaning out the engine compartment. I started by disconnecting the negative terminal on the battery as to not short anything.

Then I moved on to the PCM connections, they were dry but I sprayed them out with canned air just in case.

Next I disconnected all ignition coils and sprayed them out too, but they were also dry.

Not finding anything yet I moved onto removing the coils from the plugs starting at the firewall, #4. 4, dry, 3, dry, 2, dry, 1, SOAKED with water.

Being this far I decided to change the plugs while I was in there. 108s went back in, same as I pulled out and they had 50K on them anyway. I can't believe the dealership put 41K mile plugs back in after the rebuild, I figured you put that much into a rebuild, you put in new plugs....guess not.

Anyway, I took the #1 coil boot apart to make sure I got all the water out. There was corrosion on the internal spring so I cleaned it with a wire brush and hosed it all out with the canned air. A little anti-sieze on the threads of the plugs and dielectric grease on the tip and back together it all goes.

I reconnect all the coil and PCM connectors but notice the right PCM connector doesn't seem to go down as far as the left so I do it a couple times to make sure it's in tight.

Reconnect the negative battery terminal and try to start the car but it just cranks and cranks.

Recheck all electrical connections

Turn the key and just cranks and cranks

Rinse/repeat about 3 more times, nothing. Will NOT start

I pull all the plugs, and disassemble all coils but find nothing out of the ordinary so I wipe down any excess anti-seize lube and dielectric grease just in case they might be the culprit for some dumb reason.

Turn the key and nothing, just cranks.

I have a feeling it's all in the PCM connection now, nothing else makes sense and I already didn't like how that right connector went back on. I disconnect the negative battery terminal again, completely remove the PCM and look at the pins, all good here, all dry. Then I look at the lever mechanism for each of the two connectors the the right one doesn't close as far as the left does, remember I mentioned this earlier? I decide to forcefully close the lever and A-HA, it all goes back together same as the left.

I put everything back together, reconnected the battery and it fired right up!

There were a few issues here, old plugs, water in cylinder #1 coil pack, and a malfunctioning PCM connector.

I know it's a long read but I wanted to left folks know it could be a few different things when chasing a problem.
 

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Thanks for the write up, I appreciate it when someone takes the time to explain in detail how they solved an issue. Especially misfire issues since it seems like quite a few threads have been posted on them and then you never know if it was fixed or not.
 

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Not a good idea to hose the engine down IMHO, on a daily driver (new England) winter with salt I will light pressure spray the extreme outside of bay down, underside of hood and maybe the lower half of engine, but to me there are just too many electrical components and connections to risk soaking and or corrosion later.

The older sixties cars and beyond just had a coil, plug wires and battery/ voltage reg. basically. Our cars are now like sophisticated computers with countless sensors and components and a brain that wont tolerate a lot of moisture.

I dont know if you can find a steam cleaner station anymore, but if you can it is a little better than the hose.

Glad though that you found and solved your misfire issue.
 

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Not a good idea to hose the engine down IMHO, on a daily driver (new England) winter with salt I will light pressure spray the extreme outside of bay down, underside of hood and maybe the lower half of engine, but to me there are just too many electrical components and connections to risk soaking and or corrosion later.

The older sixties cars and beyond just had a coil, plug wires and battery/ voltage reg. basically. Our cars are now like sophisticated computers with countless sensors and components and a brain that wont tolerate a lot of moisture.

I dont know if you can find a steam cleaner station anymore, but if you can it is a little better than the hose.

Glad though that you found and solved your misfire issue.
ALL dealerships do this. And they use a pressure sprayer to do it. Sure a car here and there won't start occasionally...but it's no big deal. Take an airhose, blow it out and voila. I have NEVER seen any issue caused by washing a motor with a pressure sprayer...even when the motor is hot. As a matter of fact, our detail shop that we used at the dealership for our used cars preffered the engine to be operating temperature because it would "steam" the grease off that way. Then spray with degreasing and power spray again.... Then when they're done and it started, they would coat it with something akin to Armor All....but not flammable.

What do you think happens to all those sensors in a rain storm? They don't stay dry!!!
 

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I also clean my motors with higher water pressure, while warm. Never had an issue yet. Sometimes my Supra would misfire for like a little while right afterwards, but I'd just hit it with the leaf blower (no lie) and like an hour later she'd fire right up and purr smooth. If you are getting issues when the motor is wet, you have bad connections and other issues that need addressing. My issue on the supra was plug wires.
 

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Dry ice cleaning seems to be a safe way to clean an engine bay, and there's quite a few YT videos on it. It claimed to be safe for modern engine bays w/electrical components. Unfortunately, it's priced out of the range for most DIYs. Do a search for dry ice cleaning + your town, and a few commercial business's might come up that do services for local car dealerships.


I previously posted on this technology last year.
http://www.solsticeforum.com/forum/f62/dry-ice-engine-cleaning-machine-132793/
 

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Discussion Starter #7
I too have never had an issue hosing down an engine bay. If I were to do it again, and I probably will, I'll remove the DDM engine cover thingy so I can blow out the coil area with the leaf blower. Again, like I mentioned before, the connectors are SUPPOSED to be weather tight.
 

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Discussion Starter #8
Dry ice cleaning seems to be a safe way to clean an engine bay, and there's quite a few YT videos on it. It claimed to be safe for modern engine bays w/electrical components. Unfortunately, it's priced out of the range for most DIYs. Do a search for dry ice cleaning + your town, and a few commercial business's might come up that do services for local car dealerships.

http://www.youtube.com/watch?v=7gVm4Q2Ahs4

I previously posted on this technology last year.
http://www.solsticeforum.com/forum/f62/dry-ice-engine-cleaning-machine-132793/
I learned something new today.
 

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If you noticed in the first sentence of the video, they state that you should never high pressure spray your engine and engine bay down.

I realize that car dealers do this this to pretty up the bay to be more appealing to buyers, but

1. They are in the business of selling cars.

2. They are in the business to repair cars.

So no problem for them if they get more work down the road.

Also water and moisture normal to the engine bay is minimal unless you make it a habit to drive through 2 feet of water.

the water from puddles and rain put very little moisture into the area and what does get in quickly evaporates due to heat and air movement.

On the contrary introducing water @1500 -2500 PSI would tend to get moisture into areas that would never see it.

And respectfully yes, connections are "supposed" to be watertight, does not mean that they all are.

Because a person has not had a problem right after washing does not mean that components could not be compromised down the road.

Personally I keep my vehicles a long time, DDers I keep 10-12 yrs with 200 plus thousand miles on them.

Fun cars and collectables much longer and so I prefer not to flood the electrical components in hopes of extending their life.
 
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