1996 3800 series II, elusive Vaccuum leak
#32
#33
Member
Posts like a V-Tak
Thread Starter
Just checked on www.rockauto.com. could not find one.
Part # 24508516
Part is readily available.
#34
Member
Posts like a V-Tak
Thread Starter
Ran through a full tank of gas and got 25.5 MPG'*. That was a 50/50 Highway and back roads. Running like a champ with more power and no codes. Fuel trim numbers are running less than 4% in either direction. The rear o2 sensor is still running 99%. I'm thinking this is not a problem as I have checked two other vehicles with the same scanner and they both read 99% for the rear o2. Maybe my scanner is just not able to read the rear o2 as it'* just a cheap one. Dunno!
#35
I inquired about the EGR tube and found that the one for the supercharged engine is part #24504158 and so far the only parts stores that have it want too much money for it. Thanks for your help. Fred
#36
Senior Member
True Car Nut
If you start your own thread for your issue you will get a lot more attention. Also, we can help better if you tell us what car and engine you are working on.
#38
Senior Member
True Car Nut
First things first, read this thread:
https://www.gmforum.com/introductions-new-members-106/welcome-new-members-%7E-please-read-first-279711/
Create your signature and include information on the year and make of your car, including what engine you have if it not obvious. You might also want to list any mods you have. This information helps us to answer your questions.
To start a thread, click on "Forum Home" at the top of the page. Depending on what type of car you have, you then select "2000-2005" or "1999-1992" under the Pontiac Bonneville heading, or select the appropriate section for your car listed under the GM Brands and Mechanical - Maintenance section. Once you select the correct section, select the button that says "New Thread" and start your thread.
https://www.gmforum.com/introductions-new-members-106/welcome-new-members-%7E-please-read-first-279711/
Create your signature and include information on the year and make of your car, including what engine you have if it not obvious. You might also want to list any mods you have. This information helps us to answer your questions.
To start a thread, click on "Forum Home" at the top of the page. Depending on what type of car you have, you then select "2000-2005" or "1999-1992" under the Pontiac Bonneville heading, or select the appropriate section for your car listed under the GM Brands and Mechanical - Maintenance section. Once you select the correct section, select the button that says "New Thread" and start your thread.
#39
It was the front O2 sensor. Wish I would have replaced that sensor first. At least I got an education.
The last trip I took I got 2 codes, even though it was running better, both for the Bank 1 o2 sensor. Fuel trim numbers are now good except for the rear which is still 99%. Not sure where to go with that but the cat may be worn out. As long as it'* running well and my gas mileage is back I'll be satisfied. It'* running like it was prior to the intake job and the exhaust no longer stinks.
Never realised how important an O2 sensor really is. I will keep an eye out for high percentage fuel trim numbers in the future. Unbelievable how one sensor can make or brake the driveabilty of a vehicle.
The last trip I took I got 2 codes, even though it was running better, both for the Bank 1 o2 sensor. Fuel trim numbers are now good except for the rear which is still 99%. Not sure where to go with that but the cat may be worn out. As long as it'* running well and my gas mileage is back I'll be satisfied. It'* running like it was prior to the intake job and the exhaust no longer stinks.
Never realised how important an O2 sensor really is. I will keep an eye out for high percentage fuel trim numbers in the future. Unbelievable how one sensor can make or brake the driveabilty of a vehicle.
if your downstream cat. conv. is reading voltage and % that mirrors the upstream cat. readings, after it has warmed up and is in closed loop, that means your cat. conv. is either blocked, or not working, and the CO and HC gases are passing right through it, without being burned off. the CAT is defective. downstream o2 by design, should read low in voltage in closed loop, if it'* doing its job. in the .100-.400 range, while the upstream o2 reads .100 to .800 range.
do a backpressure test using the upstream o2 sensor fitting threaded hole.. if it'* more than zero, gut or change the CAT to a high efficiency aftermarket unit. my son has the IDENTICAL CAR and engine, but 2 years newer, with 166k miles, with new high quality CAT on it. the downstream o2 readings on his car, are much lower than the upstream readings. his CAT is working properly.
and his car runs smoother and gets 2-3mpg mileage in city.
today it'* all about the QUALITY OF THE PARTS. we are literally being flooded with low-quality car parts, that make diagnosing the problem more difficult. you bolt a new part on, and it'* defective already, and adds to the problem.
keep all your receipts, and don't be afraid to RETURN THIS STUFF if it'* junk. sorry to say to keep these old cars running, you have to ante up for high dollar NAPA or GM parts, or scrounge the junkyards for deals on the oem Delco sensors, etc. that are still good.
one more thing, the dipstick tube seal, if it breaks on the dipstick tube handle, will leak vacuum into the crankcase via the pcv system, and bypass the MAF and also give a problem. change the dipstick to a new one.
Last edited by no-EGR; 09-19-2015 at 06:16 AM.