I recently purchased a a 1977 Triumph TR7 with a Buick V6 Turbo Conversion. I believe the engine to be out of a 1980 Regal. I'm running a T50 tranny as well. The car also has a 4 barrel Rochester Quadrajet carb. Here's my issue. The car idles erratically from 500-1500 rpms at will. No matter where I do set the idle in the beginning,but it still does this. Now my biggest issue : When the car is idling, the Boost gauge shows a 20 on the left side if the gauge. When I accelerate at full throttle in any gear, the boost hits 5-10 and the car cuts out until I let of the gas at least halfway. If I do this, the boost stays around 10 and functions fine. I can hear the trubo whine like normal, but the problem is driving me crazy. Is there a Buick
Turbo Nut out there that can help me ????
( PS- the car sat outside for 5 years, but I
did tune it up and get all old gas out )
Also, could you tell me the HP of this engine ?,and if the gauge should read on the left side when Idling. Thanks in advance. Ryan / Denver, CO
Left side of the gauge indicates vacuum, which is normal.
Right side indicates boost, which sounds like maybe it is overboosting and you don't have enough fuel (or octane) to support that level of boost. You should be able to turn the boost down until that problem clears up....
The idle problem sounds like you might need to look for a vacuum leak (does the gauge fluctuate as the idle changes?) or a carb rebuild. Spray some carb cleaner around the manifold CAREFULLY and see if the idle changes. If it does, you've found your leak. Also, might want to spray some in the carb itself and see if it's a stuck metering rod or partially clogged idle passage/jet.
Thanks Ken.
My gut has told me it's a carb issue, but this
is my first Buick Turbo and it's in the wrong
car. The guy who did the conversion was anal and
I have all the notes and paperwork. I was just
wondering if it could be something turbo related.
Have you had good luck with rebuilding the original carbs ? I thought of buying a new carb but I could use some advise on what to get ....
Any help would be greatly appreciated. Oh yeah, how do I adjust the boost ?????
Thanks....
Ryan / Denver, CO
Well, not much of a carbed turbo guy... last carb'ed car I had was my 430 Riv. The turbo carbs have a power valve that is unique that enriches the mixture under boost. Other than that, I think they are a typical Quadrajet? Freddie? Wanna step in here?
Check out:
http://www.gnttype.org/techarea/recipes/carb.html
for some tips.
I went ahead and replaced the plugs with new
Platinum plugs, new cap, rotor,wires, air
filter - It idles smoother, but high at
1500 rpms, it drops as low as 1K at times
now.
I went to buy a new carb today only to have
the local part stores that is a weird one
being a turbo - they claim the turbo was
a special carb - is this true ??? I did
find a vacuum leak between the main gasket
in between the two carb pieces. The parts
guys said the Quadrajets are better to just
replace if I can find one - Can I do an Edelbrock or Holley with it being a turbo ??
Here's the # off the carb - 17059243 , and
3198 CKD
Also, at idle I'm now at about 18 on the vac
gauge, at 30mph in 3rd gear I'm at 2K rpm and
about 12 on the vac gauge. It likes to boost
quick to +5 in high gears with lots of pedal - it starts cutting out at +7 until I
let off.
Any ideas - how do I do a wastegate check ?
Thanks,
Ryan
Hello;
Yes, the carb's on the turbo Buick are different. they have the power valve referencing the intake manifold , not under the carb.
The reason for this is that it is possible to be under boost at part throttle and still have a vacuum under the carb. this would close the power valve and cause a lean condition which may cause detention.
I have install a Holley 650 carb. on my car and had to plug the power valve hole in the bottom of the carb. and drill a hole to a external port and tied that to the intake. I also put a ball valve inline so boost pressure can not pop the holley power valve.
If you need parts I still have two Rochester's some where around here.
Thanks for the help Fred.
I finally decided to rebuild the carb, so I bought a kit and float. When I took the carb off, I noticed teh gasket underneath had a gap on one of the secondary holes. This was where I found the vacuum leak while spraying carb cleaner when
running. The kit cam with one just like it, and one
about 3 times as thick. Which one should I use ?
I should have it back up and going tomorrow night.
The carb looked really clean otherwise.
Ryan