cylinder 1 misfiring during warm-up

Summary:
Tried:
>Moisture in number 1 igniter hole
(igniter was dry when I checked this morning)
>Faulty igniter.
(-switched #1, and #2 igniter coil. Did not help )
>MAF clean (CRC product)
(removed MAF and spray cleaned it with MAF cleaner and reinstalled. Did not help)
>Throttle body clean (CRC product)
(Did not help)
>Ohmed out the injectors.
(all injectors have same resistance)


Todo:
-switch #1, and #2 spark plug ( dealer has done this)
-does it make sense to switch the injector? Is there a procedure somewhere?(letting dealer do one more diagnostic this week)

​

 

The dealer did do a compression test. At this point I am kind of at a loss for ideas. Here it is what has been done so far:
None have helped:

Dealer:
"swapped plug to #2"
"swapped coil to #4"
"performed compression test. OK"

Me:
>check for Moisture in number 1 igniter hole (igniter was dry when I checked this morning)
>check for Faulty igniter (-switched #1, and #2 igniter coil. Did not help )
>MAF clean (CRC product)(removed MAF and spray cleaned it with MAF cleaner and reinstalled. Did not help)
>Throttle body clean (CRC product)(Did not help)
>Ohmed out the injectors(all injectors have same resistance)

So thinking about:
1)Faulty injector(clogged, intermittently clogged?? but no misfire going up hill with good throttle on it. Several times now)
2)Wiring (I think it would be more persistent)

3)Have seen posting on the Internet about intake manifold leak ( rough idle warm-up)
4)Dealership/Toyota suggestion: fuel rail (??)​

​

 

I read my data from the on-board diagnostic. And refresh the read periodically during the drive.

The car goes back to the dealer on Wednesday for another shot. If they don't diagnose it this time around. I will take it to another set of eyes. $1400 is a little rich for a "maybe" solution on a fairly new 2009.

Here is a log of my daily commutes. Note at the end of the trip each way I have a good ~1 min uphill, where I have to give good throttle at (one city speed, one highway speed). Rarely ever misfires there(engine is good an warm by then also).

misfiresthese are approximate rounded off numbers)
the other cylinders, 2,3,4 have the odd very rare misfire. Maybe 1 or 2 misfires(<5) across the board on a 45 min commute

Date | 10 min | 20 min | 30 min | total
+-------------+-------+--------+-------+-------------
nov 29pm | 630 | 100 | <10 | 740
+-------------+-------+--------+-------+-------------
nov 30am | 1100 | 100 | <10 | 1210
+-------------+-------+--------+-------+-------------
nov 30pm | 900 | 100 | <10 | 1110
+-------------+-------+--------+-------+-------------
dec 01 am | 1000 | 100 | <10 | 1110
+-------------+-------+--------+-------+-------------
dec 03 am | 1000 | 100 | <10 | 1110


This post has my attention:
Capturing atmosphere in today's vehicles - Keeping the air moving through intake manifolds keeps your customers rolling. - Spectroscopy

"Then there was the Toyota with a misfire on number one cylinder. A brief shot of carb spray at the front runner smoothed the skip and a smoke test revealed the problem for what it was. The paper gasket had failed and had opened up a channel for outside air to come in."

What happens if the rubber seal on the injector is letting air in?



Regards
Joey

 

Is there a test I can do to test if the o-ring is failing? Cold engine(rubber contracts), air gets in. Warm engine, (rubber expands) and acts like a seal(misfire goes away)? (shoot carb spray at it? won't that hurt the o-ring in the long run? )

This guy is using brake cleaner? less harmful to the rubber?

PS: If I go through the trouble of re/re the rail. Should I replace all the injectors to be future safe?

From Toyota in Canada they are close to $200 a pop.



Thanks
Joey

 

K,

I will pick up some carb cleaner on the way home. I went through the can of throttle body cleaner(small can instructions said to use it all). I have some of the MAF cleaner left over. Will that work?

 

Looks like we might have something. I will get the Dealership to look into it on after I drop it off Wednesday.

(Note: this is a warm engine after getting home)
MAF in the injector well:
-evaporates quickly so effect does not last long at all.
-appears to raise the Max RPM reading by about +20 RPM.

Brake cleaner in the injector well:
-does not evaporate quickly.
-appears to seep through and causes the the exhaust to come out like smoke. Clear the garage smoke and fumes.

Regards
Joey

 

That is a nice doc. Just did a quick scan but will read a little more comprehensively tonight

 

The car is still at the dealership. They have replaced the injector seals, but are still seeing some ( a lot less misfires ). They are not sure if this is normal or not for a 2009 Prius. Does anyone have a nicely running Prius that has recently tracked misfires from warm-up and misfires after warm? Should there be any?

Regards
Joey

 

The Dealership informed me that they also tried swapping the injector. Also did not fix the issue. I got the car back this afternoon. Still shows misfires on cylinder #1. They took some logs from the car and want to analyze them then will call me back in. Hope they find it.

They have a fancy scanner. Shows the misfires in real-time. In my software I have to do a manual refresh. We could see the misfire increment in real-time, take a break and then increment again.

This link in VW forums seems to have the same symptoms. Points to a cylinder head failure. No closure yet on the thread. So Don't know for sure:
VWVortex.com - Cylinder 1 misfire when cold, once warmed up it goes away (AWP)

 

This is a pretty nice write-up.

I get to learn a thing or two.

Detecting Misfires in OBD II Engines:


Tech Feature: Detecting Misfires in OBD II Engines: Underhood Service


Interpreting Generic OBD-II Scan Data:

'http://obdcon.sourceforge.net/2010/06/interpreting-generic-obd-ii-scan-data/'