Forum Replies Created
- Replies
Do i check the sensors manually with a voltmeter? please explain this process.
Also the milage drop was fairly sudden. The intake manifold gaskets were recently replaced upper and lower. I have checked for vacuum leaks using choke cleaner and it appears everything is sealed up.
I also removed my heat shield from the resonater due to vibration (long middle muffler after cat).
Do i check the sensors manually with a voltmeter? please explain this process.
Also the milage drop was fairly sudden. The intake manifold gaskets were recently replaced upper and lower. I have checked for vacuum leaks using choke cleaner and it appears everything is sealed up.
I also removed my heat shield from the resonater due to vibration (long middle muffler after cat).
ok,
mileage is 174000 in a 1999 pontiac grand prix
PCV valve is new
MAF was just cleaned with MAF cleaner (not sure how to tell if the reading on my scan tool is accurate though)
The oil is new and has always been maintained with synthetic oil
Air filter is ok (could maybe go for a change but only cause its like 2 years old it still looks pretty clean)
Spark plugs are less than a year and wires are brand new
ok,
mileage is 174000 in a 1999 pontiac grand prix
PCV valve is new
MAF was just cleaned with MAF cleaner (not sure how to tell if the reading on my scan tool is accurate though)
The oil is new and has always been maintained with synthetic oil
Air filter is ok (could maybe go for a change but only cause its like 2 years old it still looks pretty clean)
Spark plugs are less than a year and wires are brand new
Here is a question why did my LTFT get back to zero with the MAF sensor disconnected. Could I be dealing with an inaccurate sensor?
Would a small leak around the brake booster cause the LTFT to get thrown off? When I shut the vehicle off I can hear a small hiss from around that area. It only last about 10-15 seconds. Your thoughts
Well,
It is looking like I have not corrected the LTFT from fixing the vacuum leak (at least not all the way). At idle my ltft is still 16.4. Im not really sure were to do rom here. I do not have any driveability issues just poor gas milage mainly in town. MY vacuum repair with the rtv should be solid as the crack were small but i may hook up my brake bleader onto a hose and see if it can maintain some negative pressure.
Is there anything else that can cause a lean condition like I am seeing.
LTFT = 16.4 at idle and about 11-13 on the road
ok, idle issue is fixed i forgot to plug in the MAF afer cleaning it.. oops
The LTFT did return to 16.4 but I think its still adjusting again with the MAF back in business. I appears to be moving closer to zero as my STFT is now running mostly negative. I have seen some reading where both readings are negative, at this point i should prolly drive for a few days to relearn the Fuel trims as im sure they are totally screwed up with the MAF off and taking a nice long test drive.
ok, I found a cracked vacuum fitting, after sealing it up with some RTV my fuel trim at idle made its way down to zero within 5 minutes, however.
At startup the idle is terrible jumps all over the palce ( did not do this prior to fixing leak).
LTFT at higher rpms also is adjusting but probably not done yet
When only the ignition is on the LTFT reads 14
Do I just need to leave the battery un hooked or awhile so the computer clears all the LTFT data??
this is the exact opposite of what I have seen in every other post, which is correct
does LTFT control STFT or does STFT control LTFT i thought it was the 2nd
I did notice a considerable drop in my mileage prior to fixing a leak around the throttle body and upper intake manifold. With the leak fixed i do believe that my mileage has improved now i am at 240 miles with about 1/4 tank to go still so I should get very close to 300 on a tank. The vast majority of my driving is in town so that puts me at around 22 mpg. I think this is acceptable for the GM 3800 engines. I used to get over 400 per tank but that was entirely interstate driving. Anyway im a bit off topic. I think ill just keep an eye on the ltft and see if it changes over time. Does anyone know of a reason why it changes as I am driving, not just small but fairly large changes. Here is what I am seeing.
Idle 16.4
Regular driving 8-14 (changes frequently and always goes to 16.4 at idle)Does it save memory for different engine RPMs???