97 Camry Poor Idle
Hey gentleman and ladies,
Yes I know I should be ashamed and I am for this one being so basic but I feel like I am losing focus and was maybe looking for something I am missing.
This Car was taken to another shop for a "Tune up" where ignition plugs and wires were replaced and some how missed the fact that she was 4 quarts low on oil. The lady drove it about 10 miles and it started bucking and loosing power and stalling. When she called the shop back they told her it was probably her catalytic converter at which point she lost faith and a friend recommended our shop to her.
I pulled codes none were found I found that MAP was reading erratic and lean trims so unplugged it to get it in the shop it leveled out.
With map sensor connected vacuum, as measured with a gauge, and map are erratic 13-17 sometimes down to 10,not rhythmic like a burnt valve more like hunting. When map is unplugged vacuum levels off to 19 inhg but runs very rich obviously, Hose from map sensor to intake is clear
My first gut feeling was a vacuum leak smoked the intake minimal smoke came from the egr valve in line with what I have seen on other cars without issue. pinched off every hose I could find going to the intake with no change. lifting the egr will stall the engine but I ended up blocking it off to make sure, no change.
Performed a relative compression vs firing event to see if some reason timing was off. didn't save the capture but it is where I expected.
Getting desperate I ended up going in cylinder anyway and got this diag.net/file/f46porwjs…
I looked up the specs in service info and the valve closings look almost perfect but there is a hump near the end of the exhaust stroke that had me concerned because I haven't seen it on a non vvt engine but I guess it is.
I obviously have to be missing something simple but I for the life of me I can't think of what it might be any help would be appreciated. You can tell me I'm dumb and smack me in the back of the head as long as you explain why :)
Hi Joseph, on the exhaust stroke the piston is pushing gas out. If the exhaust valve closes early, that gas becomes trapped and the pressure goes up, creating the “hump” on the waveform. How can you confirm timing of the exhaust valve? On unrelated topic, how do you add all of the ignition spikes to your pressure waveform. Possibly unintended, but it’s pretty cool — no need for the sync…
That 2.2L engine is very easy to pop the timing cover off the cams and inspect cam timing.
I can't help with your valve timing waveform, but if you do end up pulling the timing covers to check cam timing. If you don't find the timing marks off, don't forget to check for a sheared cam gear locating pin. If you find the timing off, or a sheared pin, I would be pulling several cam bearing caps to check for galling and seizing. 4 Qts low on oil and suddenly started running poorly makes me…
I believe the map sensor vacuum hose runs to a check valve/ filter that gets carbon restricted creating false map readings.
Okay everyone thank you for all the advice. It never fails when I post I always go back to it and something clicks. Eventually after letting it run on for about 30 min LTFT went from 25% correction over 40 and everything leveled out but it will fall on its face so now I am chasing a fuel issue which now makes sense. It didn't connect with me that on this system if I had a vacuum leak I should…
JT, I had a 4Runner one time, I looked up the fuel pressure spec for the wrong year, or the wrong model, or wrong engine or something, I still dunno....but it ran like it had serious mechanical damage, so I punted it. Nope, it just needed a fuel pump. I didn't have the interwebs (yet) for help that time. :-)
I looked in AD. It shows that the 5s-fe is VVT. I never did find the cam timing specs but the exhaust opening and intake closing look close to usual. I don’t know why an ECM should take 30 minutes to sort out a fuel shortage problem. Unless there is barely enough when the engine is warm and not enough when the engine is cold.
I don’t know if it figures into this issue. I see the base timing at about 4*btdc. Spec is 10*. Cyls 2&3(if the sensor is in 1) are at TDC or a little after.
Is the coolant temp reading correctly? I didn't see any mention of it.
Sorry everyone I wanted to make sure this one left and stayed gone. Thanks everyone for all of their help. A fuel pump fixed this one. Initially with the LTFT at 25 the STFT were close to 25 as well so it seemed like to me that the PCM was adding all the adaptations it could. Strangely to me at the time when LTFT went to 40 it leveled off with around 0 STFT so if figured the LTFT might have a…
Hi Joseph: Thinking about it simply, what is LTFT's job? (Disregard cold starting for the purposes of this example.) To give you a hint, this is one of the reasons that Total Fuel Trim can be helpful. Guido
Anthony As simply as it has been stated to me LTFT's job is to keep STFT as close to zero as possible. Maybe to basic?
Hi Joseph: Right on the money. (The reason that I said to keep it simple is so you weren't ripping your hair out trying to think of some esoteric explanation.) So, when you were 40 + 0 + ? (Rear Fuel Trim) =Total Fuel Trim. In theory, the STFT at that point could've been -15 or -20% but the LTFT would still be 40%. Changes things a bit, no? The reason I bring it up is because of this…