LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Engine bogs BAD on full throttle launch

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Old 09-13-2002, 07:18 PM
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Default Engine bogs BAD on full throttle launch

I've got a problem which has shown up recently where launching at full throttle results in a huge bog from my LT1. If I torque it up it doesn't bog (but I have to really torque it up) and if I ease the pedal down it doesn't bog. It never used to bog like this before, so I'm puzzled as to why this is happening. It has perfect driveability under all other circumstances, and makes excellent torque off idle when I give it normal throttle or even half throttle. Could my injectors be clogged?

In the last 10k it has gotten a new coil, new EGR valve, new plugs and wires and a new fuel filter.
Old 09-21-2002, 06:55 PM
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Default Re: Engine bogs BAD on full throttle launch

Today at the dragstrip the bog was super bad! So bad that I could only run 14.6s to 14.8s! The weather wasn't that hot either, others were only running 2-3 tenths slower than their best ETs. At one point I pulled back into the lanes and the idle dropped all of a sudden and it started running rough and the check engine light came on. A friend hooked up his Scanmaster and code 44 came up, a bad 02 sensor. We looked at the data and the 02 readings were both terrible and the block learn was insane! Both 02s are trashed! My car only has 73k on it too! It should be covered under GM's 8yr emissions warranty though.

What would cause my 02s to both be trashed so soon??
Old 09-22-2002, 08:29 PM
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Default Re: Engine bogs BAD on full throttle launch

A 44 & high block learn & intergrater check out your fuel pressure, filter& regulator.
Old 09-23-2002, 07:13 PM
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Default Re: Engine bogs BAD on full throttle launch

Took my car to the dealer and in their diagnostic check, they said the left o2 was bad. I told them to go ahead and replace both. I had bad traffic on the drive home though, so couldn't do a full throttle launch to test for the bog though. But the car does idle a lot better now.
Old 09-23-2002, 11:00 PM
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Default Re: Engine bogs BAD on full throttle launch

I heard high octane fuel is bad for o2 sensors, but I am not positive on that. My 95 Lt1 formula used to always bog on a full throttle punch. I always suspected it to be the optispark which is a big problem area on those cars. I had a after market coil and msd igniton and figured the spark on the car should be great. That is untill the MSD crapped on me and my car broke down. I ended up hooking the old igntion and coil back up to get the car running again and the car ran perfect(no bog). So you might wanna give that a try, you really don't need a high performance coil or igntion in those cars unless you have a blower under the hood or something to that effect.
Old 09-24-2002, 04:35 AM
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Default Re: Engine bogs BAD on full throttle launch

I still have the stock ignition, and an OEM type replacement coil was put in earlier this year (that couldn't have been the source of the bog, as the car ran great for a while right up until recently)
Old 10-11-2002, 03:38 PM
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Default Re: Engine bogs BAD on full throttle launch

I had the same problem with my 93 Z28. I noticed it more when the car would get hot though. It ended up being the opti-spark. It figures, I figured that out 3 days after I changed the water pump.
Old 10-11-2002, 07:06 PM
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Default Re: Engine bogs BAD on full throttle launch

I hope my optispark doesn't go out, it's $500 up here, and that's with our club discount too. Normal GM price is $800 up here!! <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
Old 11-09-2002, 04:39 AM
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Default Re: Engine bogs BAD on full throttle launch

I forgot to mention I got the bog problem fixed. It was a vacuum leak on the connection to the PCV valve. Car runs like a champ now!
Old 11-09-2002, 11:15 AM
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Default Re: Engine bogs BAD on full throttle launch

hehe, funny how it can be the stupidest thing sometimes huh?

$500-800 for an Opti???? We get them for about $185, and even with exchange rate you'd be at what... $325 tops plus PST/GST??? I feel for you north of the border guys sometimes....
Old 11-09-2002, 11:32 AM
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Default Re: Engine bogs BAD on full throttle launch

Anytime we order parts from the US, you can effectively almost double the cost. So a part that is $185 US would be closer to $400 CDN. Plus the hassle of waiting all that time for it too. If and when my opti goes, I won't have the luxury of waiting a week while my car is down, I'll need the part right away. If I had more spending money I'd pick up a new opti from the US and have it kicking around the house until I actually needed it.



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