Subaru no start after headgaskets
Working on a subaru from our sister shop. They did a reseal on the engine down to the head gaskets. Got it together the first time and it would run but lacked power, they found they had left out the orings for the vvt on the front timing cover. Get it back together and still no power no vvt function, was still missing the o rings under the cam journal caps. Put it back together and it has been a crank no start ever since. This is how it was towed over to me. All cylinders are soaked in fuel, compression test in cylinder with wps … Verified with the scope the timing is correct to a known good I found on here. One intake scope pattern had an irregular pattern with the 3rd hump starting to early and being too long. And one exhaust cam had an inverted signal. I have since fixed the patterns (and was hopeful I had found the problem) Subaru has a tsb for no start with the same cam signal pattern tsb. I had to adjust the cam sensor air gap. Still a crank no start with back fires into the intake. If you crank on it for a bit you can feel intake runners 3 and 4 are warm to the touch. I had some time on friday, so I took the timing cover off and verified the timing was correct all arrows pointing at each other and crank key way at 6 o clock (what I was expecting to find with scope readings being what they were) verified all the cam phasers and cam shafts were on the correct bank and position. Also pulled the intake and exhaust manifolds and checked all valves are moving and look to be sealing. Leak down tested cylinder 3 because it has a weaker vacuum pull than the other cylinders and didnt find any problems. Last test I did friday was in cylinder with the coil trace also on screen. Looks like the coil is firing on the exhaust stroke. My work computer is at work, and we are closed today but I can upload some pico files as well. Thanks for any insight.
The VVT gears have been known to actually break while in service. I know it sucks that you have everything back together, but it may be worth physically trying to grab the gear while the chain is on and making sure that it does not move independently from the cam or the trigger wheel buy a large variation. Also if you removed the engine to do your recheck, the crank position sensor plate can be…
I should have checked the vvt gears when I had it apart (I guess luckily they come apart pretty quick). I did check and noted that all the alignment dowels were in the holes of the gears to the cams. I asked about the crank trigger, they said they didnt ever have the flex plate or crank reluctor off on any of the repairs. I will say though the pattern shown on alldata that subaru provides with…
Compression (fully open throttle): Standard 1,050 — 1,400 kPa (11 — 14 kgf/cm 2 , 152 — 203 psi) Difference between cylinders 100 kPa (1 kgf/cm 2 , 14 psi) or less Hmmm, did valve shim's go back to their original valves ?
I’ll start by saying, I have never had one of these engines out myself so I’m not familiar with what it actually takes, or how easily things can get switched around. Is it physically possible to accidentally switch Bank 1 and Bank 2 ignition coil connectors during the engine or intake removal? Are those legs of the harness similar in look and length? Just thinking about your comment on “coil…
It's possible, but one would really have to be trying I'd say.
On this engine it would be nearly impossible to swap any connectors bank to bank but slightly possible to swap connectors front to back but still unlikely.
Checked that it would be pretty hard to do that. Also non of the harness looks distributed like its been repaired.
Right here where you state, "Get it back together and still no power no vvt function, was still missing the o rings under the cam journal caps. Put it back together and it has been a crank no start ever since. " What do you think changed ? Has this car coded any AVCS (vvt) codes at all ? Have a look at scan data for ACVS & OCV (oil control valve) values if it will register while cranking…
I have a non turbo core engine sitting on my bench right now from a 2014 forester. I can pull the cover and take pictures of the alignment if it helps. the first one of these I had apart I had to take back apart and reset the timing because the instructions are not the easy to follow. I had both companion cylinders on compression together as a result. Would hardly crank and ran terribly.
If you have time that would be great as a reference. Right now all the small (hard to see) arrows point at eachother on the cams with the crank key at 6 o clock
"I had both companion cylinders on compression together as a result." That makes sense and I think it has come up here recently in a previous post for similar issues. Subaru instructions leave a lot to be desired :O)
Here is the crank key at 6 o’clock and all the arrow marks line up. FB25 engine
Some screen shots of some captures. Cam sensors before and after i got the signals fixed. Vacuum waveform and relative compression test, in cylinder 2 and ignition trace.
These Gifs are from a known good 2012 2.0 captured at idle. The first GIF is the driver side CH A ckp, CH B intake cmp, CH C exhaust cmp The second GIF is the passenger side CH A ckp, CH B intake cmp, CH C exhaust cmp
Looks like my cam signals are swapped from the 1 pulse and 2 pulse on the crank sensor. Only thing i can come up with is the crank reluctor is 180 out.
Compare the position of the 3 intake cmp toggles with the exhaust cmp toggles
Good that it wasn't something broken. You mentioned that the eengine was not removed for the reseal, so I was curious about the wheel being off
Nathan, I wonder how that happened if they never had the flex plate or crank reluctor off. Eric
Looks like they left out some key info on the repair. The reluctor was for sure taken off and installed wrong.
Wow. Because they "didn't ever have the flex plate or crank reluctor off on any of the repairs", I stayed out of this one, until now. Are you able to extract the alignment dowel from the crank? Installing the reluctor incorrectly that way drives it flush.
I wonder if the same person that didn't touch the flex/drive plate was the same person that reinstalled the valve shims, hmmmm. Hope the engine is still out of the car.
Leo, did you watch House? "rule number one, everybody lies" - LOL