Intermittent CEL, poor mileage. - Page 3 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat
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1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 08-10-2006, 11:00 PM   #21
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Its been consuming under my watch for the last 3 tanks so I was careful to watch my foot. It may not be an issue at all if what BrownBuick says is true so I could be over-reacting but I dotn have another SSEi to compare it to. No other symptoms. Mechanic who did an alignment yesterday checked everything out ok but it was just one opinion.

But, I will tell you this. While I was driving today, it seems that there were 2 occasions where it was "spirited", where I would just step on the gas and it would just go. But it could be just in my head and not used to the stiffer throttle spring and the SSEi in general. Or mayby the engine cooled down when I did it, I dont remember exactly. Were taking it on our vacation starting tomorrow, I just hope nothing breaks down, I can tolerate the gas consumption. It will be a better ride than our Seville who'* suspensions got a leak so not a good idea to load the back with luggage.

Also, the boost gauge at idle when the A/C is on fluctuates very slightly, but I assume thats normal, right? I just want to make sure I got all these SSEi related nuances down.

Oh yea, didnt have a chance to check and wont be able to replace the cat with a high flow one since im going on vacation, but that is a definate once I come back. I do remember now that the previous owner (douchebag that he was) had the "seafoam" procedure done at the dealer, and the cat is still original, and now that I think about it that could be the source of the issue. Will report back once I 'git er done' as they say.
1993 Bonnieville SE "Old Ironsides" 211,xxx mi
Mods: Drilled 180 T-Stat, Carsound Cat, 8mm Beldin wires, NGK-TR55 Plugs, CAI with K&N RX-4750 and ghetto cardboard heatshield, Michelin Harmony tires.
---------------My Car Site---------------
1996 Bonneville SSEi "Double Trouble" 139,xxx
AC Delco 12-Disc Changer, Drilled 180* T-stat, NGK TR-55.
TBI: K&N RX-4750, Magnaflow Cat, Res, and Muffler
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Old 08-14-2006, 11:04 PM   #22
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Well, I got my log book and here are my fuel mileage numbers since the car has been supercharged.

16.77 mpg
19.22 mpg (some highway)
15.90 mpg
18.00 mpg
18.80 mpg
17.47 mpg
16.87 mpg
15.10 mpg (heavy driving, lots of whining)

I think the 4T60-E get worse gas mileage than 4T65-E. I've got a 60 and my friend has a supercharged 97 LSS with a 65. I've noticed that it seems that my car'* torque convertor is a little looser than his. Accelerating normally, when my car shifts, my rpms only drop about 200-300 rpm, while his car drops 500 rpm plus. I'm also not positive, but I think that his 65 will lock the torque convertor in 3rd gear around 35 mph. (not sure on this one, but I think it does) Also, his car shifts out of 1st gear at 45 mph under full throttle (can any '97+ SSEi driver confirm?) while my car shifts out of 1st at 39-40 mph. That would support that my trans has a slightly higher stall torque convertor that requires my car to shift sooner. And, we all know a higher stall torque convertor means worse gas mileage.

And, on the subject of torque convertor lock-up, I know my car will NEVER lock to torque convertor unless I travel over 45 mph. There'* a dead spot around 38 mph where it won't shift into 4th, and won't lock-up, so I'm stuck at about 2,000 rpm to do 38 mph. I'm sure that really kills gas mileage. The 60HD also has a 2.97 ratio, compared to the 65HD which got a 2.93 (not that it'* even a noticable differeance, but it'* still a differeance.)

I think you're fine. You can't but an SSEi and expect it to get Civic gas mileage. The car is rated at 17 or 18 city, how much more do you expect?
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