CUTLASS Replace TPS or Carb?

jiho

jiho

G-Body Guru
Jul 26, 2013
683
43
Now those are problems you LIKE to find! LOL
 
69hurstolds

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
4,007
113
Now to figure out this exhaust leak.
Thank goodness it was just fugged up wiring. Saved you hundreds! Plus a big PITA if you had to change out anything on the carb. Good job!

Now, as for the exhaust leak, I'm going to assume the pipes aren't rusted out.

If it's on the passenger side, it's very likely the donut gasket. The crossover pipe is unlikely, as there are metal flange seals there. Possible, but unlikely. The donut gasket is held on by 3 bolts with springs.

On the driver side, if it's coming from there, the most likely spot is the flat gasket between the EFE valve and the exhaust manifold. It's a simple gasket with 2 bolt holes. But this one is mounted with studs that go through the EFE valve and the crossover pipe flange. If you have to drop the pipes, use plenty of PB Blaster or similar penetrating fluid and let it soak in well. You twist off the bolts/studs you'll be taking off the exhaust manifold to fix it more than likely.

Donut- GM p/n 1262500. Or Felpro 60240 at the big box stores or Rockauto.com

1589975009041.png




EFE flange gasket- GM p/n 22526988, or Fel-Pro 60771 at the big box stores or Rockauto.com.

1589974904173.png
 
69hurstolds

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
4,007
113
Here's a set of used chassis service manuals, aka CSM, (3 in all) for your 1985 Cutlass for 30 bucks plus any applicable sales tax. If you pick one up, make sure it covers "CUTLASS SUPREME"... they have others out there that do not. They may cover others, but you want the one that encapsulates the Cutlass Supreme. Otherwise you'll be disappointed. The first time you have to use one of these to help you troubleshoot/fix your car, they will have paid for themselves.

https://rover.ebay.com/rover/1/711-...0001&campid=5335822911&icep_item=383467350430

You can also look for a Fisher Body manual for 1985 if you plan on messing with stuff like doors/windows, glass, or other body related items. It's usually a separate purchase to get a good deal, but ensure it includes "G" body.

Here's one- $12 plus any applicable sales tax to your door.

https://rover.ebay.com/rover/1/711-...0001&campid=5335822911&icep_item=184261412287

Good luck.

Here's something that may help you in the meantime if you have to change any exhaust gaskets. (From the 87 Cutlass Supreme Service Manual):

87 VIN Y Exhaust Pipe Boltup.JPG
 
Eddie Cutlass

Eddie Cutlass

Apprentice
May 3, 2020
74
18
San Diego
So, how long have you spent talking about it vs. how long it actually took to fix it? Sounds like a week vs. 15 minutes! :banana:
I like to ‘measure twice, cut once’ 😂
But believe me, I wish I had more time to work on the car everyday.
 
  • Haha
Reactions: fleming442
Eddie Cutlass

Eddie Cutlass

Apprentice
May 3, 2020
74
18
San Diego
Thank goodness it was just fugged up wiring. Saved you hundreds! Plus a big PITA if you had to change out anything on the carb. Good job!

Now, as for the exhaust leak, I'm going to assume the pipes aren't rusted out.

If it's on the passenger side, it's very likely the donut gasket. The crossover pipe is unlikely, as there are metal flange seals there. Possible, but unlikely. The donut gasket is held on by 3 bolts with springs.

On the driver side, if it's coming from there, the most likely spot is the flat gasket between the EFE valve and the exhaust manifold. It's a simple gasket with 2 bolt holes. But this one is mounted with studs that go through the EFE valve and the crossover pipe flange. If you have to drop the pipes, use plenty of PB Blaster or similar penetrating fluid and let it soak in well. You twist off the bolts/studs you'll be taking off the exhaust manifold to fix it more than likely.

Donut- GM p/n 1262500. Or Felpro 60240 at the big box stores or Rockauto.com

View attachment 146574



EFE flange gasket- GM p/n 22526988, or Fel-Pro 60771 at the big box stores or Rockauto.com.

View attachment 146573
Thank you for the info!!! Yes, the leak is coming from driver side, only when accelerating. I’ll check the gaskets at the efe valve/exhaust manifold. Thank you!!!💪🏽🤓💪🏽
 
ssn696

ssn696

Antique
Supporting Member
Jul 19, 2009
4,353
113
New Mexico
Just curious...is the exhaust leak a 'tap-tap-tap' sound? If you engine has them, it could be a cracked air injection reaction (AIR) tube on the manifold. It will be more pronounced under acceleration.
 
69hurstolds

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
4,007
113
Yeah, you really need to isolate the leak.

My guesses were based on no pipe rust throughs, but as ssn696 said, a bad/rusted through/cracked AIR line to the head could leak and cause spitting as well. Also, the check valves on those AIR pipes going to the heads LOVE to burn out and leak exhaust back through the AIR system. They're supposed to keep exhaust gases from getting back to the AIR pump, but if you feel the hoses from the valve behind the A/C compressor mounted on the head, those hoses should be relatively cool to the touch. If they're very hot when the engine is warm, you got at least ONE check valve not checking. There's 3. One to each head, and one to the cat converter. Check valve is located on a pipe next to the transmission dipstick. That diverter valve behind the A/C compressor is made of plastic/rubber diaphragms so it won't hold up to the exhaust heat for too long.
 
Eddie Cutlass

Eddie Cutlass

Apprentice
May 3, 2020
74
18
San Diego
Yeah, you really need to isolate the leak.

My guesses were based on no pipe rust throughs, but as ssn696 said, a bad/rusted through/cracked AIR line to the head could leak and cause spitting as well. Also, the check valves on those AIR pipes going to the heads LOVE to burn out and leak exhaust back through the AIR system. They're supposed to keep exhaust gases from getting back to the AIR pump, but if you feel the hoses from the valve behind the A/C compressor mounted on the head, those hoses should be relatively cool to the touch. If they're very hot when the engine is warm, you got at least ONE check valve not checking. There's 3. One to each head, and one to the cat converter. Check valve is located on a pipe next to the transmission dipstick. That diverter valve behind the A/C compressor is made of plastic/rubber diaphragms so it won't hold up to the exhaust heat for too long.
Thank you! I did check the vacuum hoses and one just broke off...one the hoses from valve behind AC compressor.
Before that, check engine light came on...but only after running for a minute and gives me the codes 21 and 34 now. This morning it only gave me code 34 and after driving to get tires slapped on and driving around town, came home and checked codes: 21 and 34.
So I’m back to checking wires and vacuum lines before replacing MAP and TPS.
 

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