Tech Area > General Auto Tech
Failed upgrade to new 3"downpipe and resulting problems
kjhansen:
OK, so I have a 3" downpipe on my PTE 5858 turbo already. But the wastegate was stuck shut--good and hard. Rather than break it trying to fix it, then ordering a new downpipe, I figured I'd just order a new downpipe. Ordered one from RJC Racing. They seem to have a good reputation.
I had to wait 2 months to get it, but it came. Took it to my muffler guy and he could not make it fit. No matter how much he twisted and turned it, it would sit on the bushing on the passenger side A-Arm and contact the inner fender well where it's plastic. Plus he broke one wrench and three of the four bolts that attached it old downpipe to the turbo taking the old downpipe out.
So he went ahead and put the old downpipe back in after putting studs in the bolt holes on the turbo. He had worked and worked on the wastegate and said it should work... maybe. Only thing is, he accidently knocked the number 4 spark plug wire off. He didn't notice this because he just pulled the car out of the garage and into the driveway--just a few yards. This was late Friday night.
When I picked up the car and pulled out of his place of business I certainly noticed, but it was too late to do anything about it, so I went ahead and drove it home. It had no power, bucked and stuttered and almost died more than once. I immediately knew something was wrong of course, but I just had to get home. After leaving town the speed limit went up to 45 so I sped up. After it shifted gears into 4th it locked up the torque convertor, like it's supposed to do, and that caused the engine to lug and stutter. I got home all right, but was very unhappy.
The next morning (today, Saturday July 3rd) I inspected the car and found the disconnected spark plug wire. I hooked it back up and started the car. It ran much better and the wastegate seems to work--sort of. Supposedly it was set for 21psi of boost before it froze shut, but now that it's "working" the car will only hit about 18 psi of boost. The adjustable rod length hasn't been changed. It's as far back as it will go without cutting more threads. But it has a flat spot in second gear where it doesn't seem to have much power and doesn't increase rpm like it should. Then it hits third and pulls pretty good except that it backfires on the shift.
Anyway, I checked the TPS settings and they were pretty close, but I adjusted them to be spot-on. Then I reprogramed the Turbo Tweak chip to the settings the previous owner had told me for an alcohol injected car running 21 psi of boost. The battery had been disconnected so it needed that.
I'm at a loss. All that was done was to remove and replace the old downpipe (and accidently disconnect the spark plug wire). I know I was running 30psi of boost with the frozen-shut wastegate. Could just the change in boost have messed everything up so much? If so, what's to be done?
Keith
Shimy87:
At 30 lbs boost. How bad was the knock and how long did you run it that way?
kjhansen:
Actually knock wasn't that bad--you couldn't hear it anyway. Years ago. at a dragstrip, I had the boost control line pop off during a run and boost went up to 30psi+. It knocked very loudly and I backed off immediately. It was obvious what was happening. This time it never knocked loudly enough to announce its presence. I have a theory about that....
According to the previous owner, the stock valve springs have never been replaced on this engine and it has 190,000 miles on it. I think that saved the head gaskets. While the turbo pushed 30psi of boost, the valve springs were floating enough that a lot of it bled off. Just a theory. I didn't blow any head gaskets or break anything else with the few 30psi runs that I did. Car has been running smooth and strong for the past 9 months with no 30psi runs.
When I realized the boost was set at 30psi I checked O2 and retard on the ScanMaster (using the recall function). O2 was about 875 and retard was 4 degrees.
I ran with that boost setting for a long time because I couldn't change it (wastegate frozen shut) but quit doing WOT blasts immediately, i.e., as soon as I realized what was happening. I bought the car in September and made a few WOT runs but by October I had quit. The previous owner had told me the turbo was set at 21psi and I believed that. Let me tell you, there's a big difference in performance between 21psi and 30, boy howdy. When I punched it at 30psi I was too busy at first just staying on the road and going in a straight line to notice the boost gauge.
So that's why I ordered the new downpipe--to get a functioning wastegate. I didn't know what kind of downpipe the old one was or if I could get a replacement wastegate for it and if I did, I didn't know if anyone around here had the ability to install it. At 72 I'm not into getting down on the ground and working under the car anymore. But there are not exactly a lot of Turbo Regal cars around here, or mechanics who know anything about them.
So yes, I ran the car with boost set at 30psi for quite a long time, BUT I didn't RUN 30psi very many times. But I did run 20-24psi (watching the boost gauge) and didn't get any flat spots in second gear or any backfires on the shift into third. And the torque convertor clutch was locking up smoothly and running smoothly until this latest incident. I never did any WOT runs where I locked the torque converter manually either.
Long answer to a short question, but I wanted to cover all the bases.
Shimy87:
My best advise is read Steve's Vortex buicks site , beginning to end. If you have one of these and plan on running that kind of boost your life will be better if you understand the basics of these. You end up with 2 options, find a guy that knows these cars to work on it for you, or learn as much as you can and fix things yourself. The first option will be hard to find.
On your scanmaster readings, 875 is very rich to have a knock recall of 4 degrees.
Turn down the boost,, read the site, correct the basics. And go from there. People on here will help. Good luck!!
~JM~:
https://www.vortexbuicks-etc.com
http://www.vortexbuicks-etc.com/BeforeModifying.html
http://www.gnttype.org (Lot of info here. Difficult to navigate though. Look at the "Resources" drop down menu)
http://www.gnttype.org/techarea/techpage.html (Look at the drop down menu to the left) Do yourself a favor & Bookmark any of the articles you want to revisit so you can relocate them.
Turbobuick.com
Turbobuicks.co m (Note the "S" at the end. This forum appears inactive, but has many good posts with pictures intact)
(Hope it is not inappropriate to post links to other sites)
Sounds like you need a mechanic that is better acquainted with these cars. Also sounds like you may need new motor mounts & possibly new body bushings. If either, or both, are compressed due to age, exhaust parts alignment can suffer.
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