When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I found the problem!!! Or at least most of it... Was working in my garage and heard a big PSHHHH come from the engine bay. I'm used to hearing some air escape after shutting off the car but this was 15-20 minutes after the fact? Checked all vacuum lines I could see without getting too invasive and turned my attention to the booster... The clamp holding the hose to the booster was not tight enough to create a good seal with the check valve! Have no idea if it was the factory clamp or not but with a little force I could wiggle the hose around pretty good and pull the line right off with no issues while the clamp was on! Put a fresh hose clamp on and drove it and the difference was NIGHT AND DAY. There is still a bit of drag but the car no longer bogs or drags after letting off the throttle. This also probably explains why the car was fine at idle but got leaner(vacuum leak) the more I pushed the rpms and the fact that everything tested fine for the vacuum test as I used that hose. I bet if I cleaned the MAF(cleaned MY maf but not the "loaner" on it now), and checked the other lines for improper fit/looseness the car would run flawlessly. Also want to run some techron through the system and change the fuel filter(probably not needed but it's cheap and might as well with 65k on the dash- the deeper I go into the car I realize how poorly it was taken care of by the old owner). Will give an update tomorrow after all this so I can verify my results with scan tool data!!
Don’t see how the car could have been running rich with a vacuum leak…it should have been positive.
Don’t see how the car could have been running rich with a vacuum leak…it should have been positive.
Right, I believe the vacuum hose problems fixed most of the problems I could FEEL(dragging/bogging on acceleration). When cruising it also feels more "freed up". Cannot say for certain but I bet my fuel trims will not lean out as hard or at all anymore when accelerating. That being said there is still a bit of drag and the idle still doesn't sound perfect. It is probably still running rich and ft's might even show up as more rich now but it's not something I can directly feel as much anymore. What would be the next diagnostic step? I assume since the VE was good the problem must be on the fueling side?? It's tough to run through probable causes in my head as the fuel pressure reads 58-60 while driving and the injector balance test checked out.
Last edited by Zsnyder5; Apr 24, 2023 at 06:41 PM.
Right, I believe the vacuum hose problems fixed most of the problems I could FEEL(dragging/bogging on acceleration). When cruising it also feels more "freed up". That being said there is still a bit of drag and the idle still doesn't sound perfect. It is probably still running rich and might be running even richer now but it's not something I can directly feel as much anymore. What would be the next diagnostic step? I assume since the VE was good the problem must be on the fueling side??
I had mentioned in my initial post about checking the EVAP purge valve…I’d remove the purge valve connector from the intake manifold and plug the intake manifold fitting and then look at your fuel trims…normally with a stuck open purge valve you will have rich AND lean codes…rich when the intake manifold is drawing in those fuel vapor from the EVAP canister and then lean once all those vapors are burned…you have basically a vacuum leak since the EVAP vent valve is open and vented to atmosphere…the purge valve is normally closed.
I had mentioned in my initial post about checking the EVAP purge valve…I’d remove the purge valve connector from the intake manifold and plug the intake manifold fitting and then look at your fuel trims…normally with a stuck open purge valve you will have rich AND lean codes…rich when the intake manifold is drawing in those fuel vapor from the EVAP canister and then lean once all those vapors are burned…you have basically a vacuum leak since the EVAP vent valve is open and vented to atmosphere…the purge valve is normally closed.
Removed the connection at the manifold and plugged the manifold and here is what I came up with. Same concept... Line represents idling at a stop sign, shifts every 3k, with another stop sign at at 1670(neutral coast). Something is definitely weird because plugging that line should have brought on a cel right? No codes and I'm no genius but bank 1 and 2 certainly seem different for this test...
Last edited by Zsnyder5; Apr 25, 2023 at 05:59 PM.
The code will not set because the PCM is not doing its test of the EVAP system…your “total fuel trims” look fine there !!…anything over plus or minus 10% you worry about…you are at minus 3%…that’s fine !!…I didn’t go back and read what numbers you had previously but these numbers are OK !!…if you watch the videos it will help you understand all this stuff !!
The code will not set because the PCM is not doing its test of the EVAP system…your “total fuel trims” look fine there !!…anything over plus or minus 10% you worry about…you are at minus 3%…that’s fine !!…I didn’t go back and read what numbers you had previously but these numbers are OK !!…if you watch the videos it will help you understand all this stuff !!
Numbers are a bit better than they were before and leaps and bounds ahead of where I was at during the beginning. Could the purge valve be the issue? Also I did watch the vides but a refresh wouldn't hurt... It was just odd to me that Bank 1 still showed Ft's getting more lean with acceleration then dropping while Bank 2 was more constant(during shifts) and that my long terms dive after letting of throttle or idling, but I could totally be second guessing myself here...
A purge valve issue would affect BOTH banks...if just bank 1 fuel trims are going lean (number increasing) I'd say you have an injector that is not flowing properly or a vacuum leak on one of the intake runners but if your long terms are sitting at minus 3 % I don't see an issue there...if you take a spin around for an hour and your short terms are sitting at 0 and the long terms at -3 at idle you're fine...on a rapid deceleration (decel fuel cut) the O2 sensors go lean and the injectors are shut off and your fuel trims will increase...on rapid acceleration the upstream O2 sensors go RICH so the fuel trims will decrease....you have to learn this stuff and you don't learn it by turning wrenches...that's why a majority of mechanics can't diagnose...they just replace parts until hopefully they fix the problem...a lot of times they don't and the car will go to another shop....a good diagnostian is worth their weight in gold.
