T6 Sudden loss of compression :(

Post by **JDS60R** » 20 Apr 2010, 14:12

Pull the plugs and put two capfulls or so into the cylinders(so it goes over the edge of the piston onto the rings).Let it soak for 1/2 hour and then turn it over to blow out the excess (I put a towle across the head to soak up the seafoam while turning it over without plugs blows out most of the seafoam). Replace plugs and run for 20 minutes.

If not better then - add 1 can 6cyl Restore and drive 300 mies. Save up for rebuild or use Restore once every year until compression numbers are unacceptable. I've been a restoration mechanic for 27 years and we have brought back a lot worse than you have with these same techniques.

Restore will take about 300 miles until results are there. We have also seen folks with ridges in the surface where the spark pllug washer seals. These ridges allow some air to blow by and the compression readings are flawed. Try a secondoring and make sure your plug mating surface is flat

Post by **boosted5cyl** » 21 Apr 2010, 07:24

Thanks for all the tips guys. Ill work though all of them and keep you posted on progress...I think ill start with the seafoam in plughole route and go from there. The spark plug mating surface look good, but ill take a second look to be sure....

Since I already have seafoam in the oil, should I change the oil before I add the restore or can I add it to the existing oil?

Post by **JDS60R** » 21 Apr 2010, 07:29

Best to change the oil after the seafoam in the plug event. Remember to drive for 20 minutes after restarting it and then change the oil. Add the Restore to fresh oil and expect a 300/500 mile wait until you retest for compression numbers.

Post by **boosted5cyl** » 21 Apr 2010, 08:31

JDS60R wrote:Best to change the oil after the seafoam in the plug event. Remember to drive for 20 minutes after restarting it and then change the oil. Add the Restore to fresh oil and expect a 300/500 mile wait until you retest for compression numbers.

Sounds good, ill get on this this weekend...

Post by **boosted5cyl** » 24 Apr 2010, 19:51

Some interesting developments today.......

* My compression gauge took a dump, it no longer sticks at the highest reading.
* Spark plug on cylinder #5 was completely clean, i.e. no combustion happening in that cylinder. It wasn't flooded with fuel either.
* I dropped some Seafoam into the cylinders, turned it over a couple of times, dropped in some some and let it sit for about 20mins.
* After clearing the seafoam out, looking with (now dud) compression gauge all 6 cylinders seem to build and drop pressure in a similar pattern. For sure I could hear the starter motor loading up a little on the compression stroke on #4 which wasnt happening two weeks ago.
* I through impatience I mixed up the coils, so I'm not 100% sure what coil was on cylinder #5....however...
* I started up the motor and removed and replaced the injector cables in sequence, the motor note changed on on every cylinder EXCEPT #1
* After going through the injector connectors, I cleared the OBD codes and after a while a Cyl #1 misfire code was pending.

Its hard to say, but I have a gut feeling that the compression has improved. The idle seems to be a little smoother, like it was a couple of weeks ago and the car doesnt judder as much when I put it into drive.
I "think" I might have had a combo of bad compression AND a dud coil which appears to be in cyl #1 right now.
Next step is to take all that damn turbo piping off again and swap coil #1 with another and see if the misfire moves with it. At a later stage I hope to get a compression gauge that works.

Post by **JDS60R** » 24 Apr 2010, 20:52

glad to hear you are making progress. If the cylinder readings are changing then repeat the seafoam on top of the cylinders again. make sure to put in enough to overflow the piston so it truly soaks the rings.

Thanks for the update. Please keep us informed

Post by **boosted5cyl** » 25 Apr 2010, 06:23

JDS60R wrote:glad to hear you are making progress. If the cylinder readings are changing then repeat the seafoam on top of the cylinders again. make sure to put in enough to overflow the piston so it truly soaks the rings.

Thanks for the update. Please keep us informed

Thanks. I should know more when I swap the coil and\or get a compression gauge. Heres a pic of the plug that came from cyl#5. It has about 400 miles on it. What interesting is that the low compression reading was on #4 so frankly im confused.

: Plug from cyl#5

Post by **vegasjetskier** » 25 Apr 2010, 09:16

Perhaps the low compression readings were due to your malfunctioning gauge all along?

Post by **boosted5cyl** » 25 Apr 2010, 10:19

vegasjetskier wrote:Perhaps the low compression readings were due to your malfunctioning gauge all along?

That would be nice, but I dont think thats the case. The gauge still measures pressure, it just doesnt telltale the highest reading. In the original tests, I went back and forth between the good and bad cylinders and got consistant results.

Time will tell, I hope to have time to swap the coil on Cyl#1 tonight. Ive pulled the injector cable off in the meantime, I dont need that fuel eating up my cats!

Post by **boosted5cyl** » 29 Apr 2010, 06:58

Summary: Coil dead

OK, got around to testing the coil on #1 last night. For sure it is dead. I pulled out the coil, put a plug in it, grounded it to the valve cover and started the motor. There was no spark whatsoever at idle. Swapped it with coil in cyl #2 (same plug) and spark appeared. Finally, swapped coils #1 & 2 in their respective cylinders, pulled the power from the injector in cyl #2 and as expected, no change in engine note, however a notciable dip when I pull #1.

So at this stage I dont know where the compression is exactly, but I have a good feeling its better than before. Now to get a coil. I ordered stuff for the V70 from autohaus last week, damn!

I feel like I'm in the matrix with all the bullets I'm dodging!

T6 Sudden loss of compression :(

Re: T6 Sudden loss of compression :(