Lost PSI on Turbo Boost

Post by **MadeInJapan** » 20 Mar 2010, 15:03

Hello everyone- long time no see.
I have been away- have had crisis after crisis in my life (I know that's no excuse) but after my son wrecked our 850 and my mom died, I went to her funeral in another state. On the way to the funeral home my S70 lost the cap over the tensioner pulley that keeps stuff from getting in the bearings (yes, it was an INA, switched out 3 years ago- 40K miles ago along with the TB change) and the timing jumped, so that left me with bent valves. Had the car towed home and had the engine rebuilt. So far so good. Anyway, now I have a problem (could be unrelated to the engine work but I don't know). My turbo has lost boost. I have an upgraded IPD ECU on my '98 S70 T5 and was boosting at 15PSI and peaking at 17 right before the TB incident. Now I'm back at stock...10 and peaking at 12...so I put in the original ECU and I get the same numbers, so I know it's not the ECU (or at least IPD tells me it's not- these don't just lose programming). I have checked all turbo hoses, vacuum hoses, TCV (even swapped it out to see if there's a difference) and no change. I'm running Dino oil for another 400 miles and I'll switch back to synthetic but don't think that would make a difference. Basically, besides what I've mentioned, nothing has changed. They didn't even unhook the battery to do the engine work but I did and reset adaptives hoping this would cure things, but it hasn't. The only part of the engine that was rebuilt was the top half with intake valves replaced. What could be going on here? If anyone knows, I'd appreciate you posting.

Post by **JDS60R** » 20 Mar 2010, 19:09

How is cam timing, compression, leakdown, leaks at turbo or exhasut manifold,wastegate operation?
Was your ECU labeled so you know you got the same one back? Possible someone swapped it?

If not, I would have IPD reflash it. Seems odd that you can only get stock performance from a upgraded ECU. Makes me wonder if you still have the same one.

Most importantly, I am sorry to hear about the misfortunes you have had to go through recently including your loss. It has been a tough year for many, myself included. I'll add you to my prayers.

John

Post by **MadeInJapan** » 21 Mar 2010, 06:15

Thanks John... The ECU that was flashed, I labeled with a sharpie... the shop I took it to would not know how to flash it down. All other numbers (compression, leak down, etc.) were tested by the shop and were good (so they say)...so I'm still stumped.

Post by **phils94850** » 21 Mar 2010, 06:52

MIJ... did u try unhooking the vac hose to your wastegate to see if the boost will increase. If it does, then you know its a mechnical prob. and not a electrical or ecu...

Post by **MadeInJapan** » 21 Mar 2010, 08:34

You mean the yellow line? Not the red one to the bottom of the turbo, right?

Post by **MadeInJapan** » 21 Mar 2010, 10:06

Checked with my mechanic- leak down and compression were both good when the engine was put back together- straight across 180 on each cylinder. Disconnected the hose to the wastegate, changed out spark plugs to new copper cores (Bosch) and no difference...any other ideas?

Post by **phils94850** » 21 Mar 2010, 11:22

Mij.. when you disconnected the line at the wastegate you should be able to get into higher boost with no problem. By disconnecting the line at the wastegate and not getting any higher boost is a problem...

You sure the wastegate isnt stuck open ? try a vacuum test on the wastegate...

Post by **MadeInJapan** » 21 Mar 2010, 12:27

If stuck open, would I get 12PSI? How do you test the wastegate vacuum?

Post by **phils94850** » 21 Mar 2010, 13:39

"usually" if your wastegate is stuck open you wouldnt get 12psi. So, id say thats not the prob. but, what makes me wonder is when you disconnected the vac line to the wastegate why you didnt get more than 12psi. When i disconnect mine and i have a stock ecu i can get 15psi very easy. I still think your problem is somewhere around there ( basically a mechanical prob. )

Im assuming you disconnected the correct line.. my vac lines have been replaced so im not sure the color code anymore, but, its the one easiest to get too and it comes off the wastegate nipple that sticks up.

here is a pic of the hose you need to remove to test the wastegate. I circled it for ya. Just be careful, cuz youll have no control over you boost and can blow a motor.

Post by **MadeInJapan** » 21 Mar 2010, 13:46

Yes, that's the one I disconnected. Same boost so, you're thinking the wastegate is the issue, if I'm reading you correctly. I'll check it out when I have more time. How about the rubber piece inside the triangular cover (lower than where you have circled- I know it's a bitch to get to)I have a spare one... if it is ripped what would happen?