BesideTheBox

geolab - Thank you for the wonderful document. Cool! I am learning and I now know that there is one temperature sensor at cylinder 3.

I pulled the electrical connector to each cylinder injector while the engine was idling. Pulling any injector on the left bank resulted in rhythmic popping from the left exhaust. Pulling injector 4 or 5 on the right bank resulted in double popping, but irregular. Pulling 6 was just plain irregular. Maybe I am influencing the result because the CEL code tells me it is 6.

If all injectors were working equally well, I would expect the delta to be similar, but it was not.

If I can get the injectors pulled this evening, I am going to have them couriered out to a shop to have them cleaned and hopefully get them reinstalled tomorrow evening.

I've seen several places (rennlist, pcar, pcar workshop?) that say the 3.6 should get the triple electrode plug. My owner's manual states that the following plugs are acceptable:

Bosch FR 6 LDC
Bosch FR 5 DTC - 3 electrode
Beru 14 FR 5 DTU
Beru 14 FR 6 LDU - 2 electrode

I saw this in the owner's manual after that post. I did order a complete set of the Bosch 3 prong plugs to install at some point. The current plugs are only 9K miles old. The plugs in 6 are likely shot, but I don't want to install a new set until the injectors are cleaned out.

BesideTheBox

Got the fuel injectors out. Relatively straight forward. Taking out the aux fan and airbox were firsts for me.
Took me about an hour and a half as I was proceeding slowly.
Here are the injectors. Some are somewhat 'cleaner' than others.
On the right bank, you can clearly see that 6 is grungier than 5 and 4.

geolab

from the pictures:
please assure us you have the lost plastic bit of the injector #3 ?
your injectors show a concentration of gunk
Normally this is due to concentration of oil vapor and/or high concentration of alcohol/hydroxyl in gas. do you use regular gas ? if so, should be the ethanol
Keep your oil level at mid-range on the oil level manual gauge, and try to change gas station or fuel brand.

BesideTheBox

I looked again. Can't find it. I think if you look closely, there are deposits along the crack line. Looks to me like it may have run through the engine?

I will seek out non-oxygenated premium moving forward.

Engine oil is at mid range. Engine burned maybe a half quart in 6K miles last year.

An update on the injectors. It is NOT the injectors. They were all spraying good prior to cleaning. All that crud was not hindering their performance.

Moving forward with removing plug #6 topside as long as I can get the spark plug socket out of #5. Struggling with this.

Link to the report: Ravenworks Fuel Injector Report.pdf

BesideTheBox

Found this in I-6. So I'm pretty sure by the looks of things that this plug was not changed at 68K or 60K as the service records show. 77K on the car now.
The electrode is supposed to be round, not triangular.

I'd say this is a contributing factor if not the culprit.

Magdaddy

amazing isn't it? Changing all 12 plugs on these cars isn't that bad really. I had the worst time getting the engine metal off the pass side for access to the top side three...the other 9 took about 30 minutes to do. Since all the hardware has been anti-seezed upon reinstallation...I bet I could do all 12 in just about two hours again...

provided the tranny vent hose doesn't come off again, that is.

Hopefully, your "culprit" has been found, good luck!

BesideTheBox

This is a good idea. I pulled all the plugs last week and looked at II-6 with magnification. The ceramic insulator was not cracked.

BesideTheBox

The thread by JB911 (https://rennlist.com/forums/993-foru...ing-apart.html) inspired me to get the plugs changed without taking off the mufflers or engine tin.
I'm pretty sure that the muffler bolts are not coming apart without snapping, and I just really didn't want to deal with that.

Here is what worked for me to get the plug under the power steering pump.

Total extension length including plug socket is 6 1/8" long.
5/8" magnetic socket
1/2" drive to 3/8" drive conversion
3/8" universal joint
1" long extension

The stubby has a 3" handle on it.

I found that the tape sometimes caused binding when screwing the plug in or out. Anyone have a solution for that?

BesideTheBox

I uploaded a video to youtube that reflects the audio signature from the post above. The video is just a picture and an mp3 audio clip combined together. Just enough to meet youtube's 'video' requirement. Please listen and let me know if you have any thoughts about the popping (backfiring?).



Here is what I have addressed so far:

• cleaned injectors (turns out they didn't need it)
• replaced spark plugs with Bosch FR5 DTC (plug in I-6 was ancient, I-5 and I-4 were 30K miles old, the other 9 were likely changed at 68K as documented)
• rechecked plug and coil wire resistance (~3K ohm and ~1K ohm)
• verified no plug wire arcing in a pitch dark environment
• checked distributor rotor resistance (1K ohm)
• checked distributor caps - good
• checked battery voltage (14.12 volts)
• measured CHT at ambient and intermittently as engine warmed up

Yet to be addressed:

• Install new Porsche belts (shims should be here Thursday)
• Clean and inspect Idle Speed Adjuster
• Clean and inspect Mass Air Flow sensor
• Find the cause for the P0306 - hopefully it's one of these three things

BesideTheBox

Cleaned ISV and MAF yesterday. Went for a drive without letting the car idle for 10 minutes before driving it and the CEL came on 1/2 mile away from the house as the engine was warming up.

Symptoms are less power, CEL comes on. If I push on the gas, it hesitates more and the CEL starts flashing. Let up on the gas and the CEL stops flashing after a few seconds.

I pulled over and let the engine idle to finish warming up for a couple of minutes. Then the engine smoothed out a bit and I was off. Engine felt strong after that. Had the CEL checked and again it was P0306.

Put 3 new OEM belts on today. Started up the car afterward and let it idle until fully warm. After a minute or so, the idle gets rough and the entire car shakes. After a couple more minutes, the shaking subsides almost entirely.

Since the CEL always points to cylinder 6, someone suggested that I might want to do a compression test on all cylinders to see if I have a leaky valve. If I did have a leaky valve, could this cause the P0306 that occurs if I drive the car while it is warming up?

Any ideas would be greatly appreciated. I'm sure there are more things that can be checked. Whatever the issue, engine warmup is a primary contributing factor.

BesideTheBox

The engine warm up issue that was causing my P0306 CEL has been resolved. The issue appears to have been remedied by cleaning several grounding points.

I cleaned grounding points I, II, IV, V, X, XIV, and XXI. Click here to read about it. I also cleaned the power takeoff (was told that this goes to the DME) that is attached to the positive battery terminal, and also the battery ground strap where it attaches to the body.

Since the grounding points were cleaned at 77295 miles, I have had no hesitation, bucking, or check engine lights during engine warmup, or otherwise. Current mileage is 77680.

I still have light misfires at idle. A separate thread was started to track this issue and can be found here.

Thank you all for your help!