Converter lock-up on/off cycle

[razer1000]

I recently got the transmission rebuilt on my 94 camry v6. 4 speed ECT auto. After figuring out my loose steering caused by failure of the shop to retorque my steering box mounting bolts, I now have another issue:

Sometimes my transmission works perfectly and sometimes the converter will lock up and then unlock and lock up again, cycling through on and off. This is all while throttle is constant and load is constant (ie flat road constant speed) It seems like the problem either happens constantly or not at all during a drive (ie I’ll drive to the store and have it cycle on/off, then after I start it up again, it may work perfectly on the way home)
I’d swear it shifts too harshly when it’s acting up as well. When it is locking up fine, perfect shifts.

Before trans. work, the torque converter never locked up, and always had a flashing O/D w/code for shift solenoid. After rebuild, no flashing O/D, no codes for solenoid.
I don’t want to drive it like this because it can’t be good for the transmission which just drained my wallet. When searching online for this symptom, the most commonly found cause was the TPS. I just scanned my ECU and came up with o2s & lean mixture codes so i cleared the codes, started it up, killed it, and rescanned, nothing. I imagine the lean is only after it fully warms up. Nonetheless, no TPS specific codes. Is this an issue with the engine or electronics, or should I take it back to the transmission place and complain? Thanks

Topic

[Bill]

I would return to the trans shop and ask, not complain.

[razer1000]

[quote=”wysetech” post=83472]I would return to the trans shop and ask, not complain.[/quote]
of course, “complain” does carry quite a negative connotation. Good point. And i’ll do that and post the results. My only concern is that it won’t misbehave when i drop it off (as per usual lol)

[college man]

Could you post the codes that were given? It could
be a performance issue.

[razer1000]

[quote=”college man” post=83483]Could you post the codes that were given? It could
be a performance issue.[/quote]
Will do, and on that note, here’s comparison of various issues before and after trans rebuild:
Before:idle high (1200 avg warm) and usually surging up/down about 100-150rpm every ~5secs,
After: idle varies between normal(7-800) and 1100-1200 warm, but is consistent, no surging. Each time i drive it, the idle seems to change.(initially what made me think of a possible correlation between the issues) However, when idling at normal RPMs, it seems rough. I’ll run fuel system cleaner when I get home too (which I normally do at least once a month) plugs have 40k on them and rated to change at 60k
Thanks

[razer1000]

Sorry about the (extreme) delay in response. I’ve been busy with school which makes DIY diagnosis difficult Since I have to drive it almost daily. I haven’t had any significant lock-up/unlock cycling since my last post a few thousand miles ago, but it did act like it was going to start doing it again once then quit.
Most recent, still idling rough (usually seems to be a cyclical rough idle, RPMs stay (as per the dash-tach) constant, but I feel a vibration every few seconds like clockwork. The only code is one which has remained ever since I go the car over 50k miles ago; p0135 o2s heater circuit malfunction. I’ve never had any reason to be worried about it since it didn’t manifest any noticeable symptoms. Recently though(last 2 tanks), i’ve been getting CRAPPY gas mileage. Usually avg 25, last tanks were 21, then 18 which is concerning to say the least. I haven’t seen or smelled any leaks so I assume it must be running really rich. It started when the cold weather/ “polar vortex” hit.
I know that cold weather and winter-blend gas will hurt gas mileage…but 7mpg/28%? It’s warmed up on the last tank and i’m fairly certain the mileage is still bad judging by typical tripmeter/fuel-level milestones.
Recent tests/maintenance
-ECT=in spec
-MAF=in spec
-TPS=in spec (from what I could tell, it’s difficult to do with only a DVOM and 2 hands lol)
-IAC=in spec electronically
-Cleaned throttle body and shot some around IAC
-New air filter (~100miles)
-New fuel filter (~4000miles)
-Found that spark plugs (45k miles) have a slight grey deposit on them, nothing too heavy. Electrode still good
There’s no easy way for me to do a fuel pressure test at my apt(no garage at school 🙁 ) and the car has no test port, or I would do that too. Is it something I should consider having done to eliminate as a potential cause? (Keeping in mind i’m a poor college kid)
The o2s throwing the code is the pita one on the firewall. testing it would require me to get under the car somehow, but i’ll try that soon too and post results. Thanks everyone for all of the help. It is so very much appreciated!

[razer1000]

2/17/14 Update:
Tested o2s and not only did the rear sensor’s heater have no continuity, but it was physically damaged as well. Needless to say I started by replacing that with an OEM denso sensor, still seems to run the same and appears to be getting crappy mileage still. I continued testing sensors as per haynes and FSM.
-A/C idle-up checks out.
-The condition of a few of the injector and coil harnesses is hurting, but nothing new in the 50k i’ve had the car without any misfires or stalls because of a loose harness.
-Cam position sensor was soaked in oil, I disconnected the harness and oil was sitting puddled inside the cup of the sensor’s connector. I took it out wiped it off and checked the gasket which appeared to be ok, don’t know how the oil got there but now the harness is crumbling apart.
The sensor resistance checks out, but when running, I can disconnect the sensor and it doesn’t affect the idle one bit. Is this something to look further into?

Here’s something else I’ve noticed though:
First off, my a/c has never fully functioned, I get no voltage to the signal wire to trip the a/c relay so to turn on my a/c, I install the relay (which i taped closed-circuit) and press the a/c button inside the car to get the engine to idle up (which still works from the switch, just not the relay). Recently when I turned my a/c on for the first time since the car’s been acting up, the rpms were much more drastically affected by the a/c system than usual. When I activated compressor (installed taped relay) the rpms dropped down to like 600, then I hit the switch to turn a/c idle up on and it jumped up to like 1300-1400rpm (higher than the already high idle when fully warmed up)
-Idk if I’ve mentioned this previously, but once the car warms up if I kill it and immediately restart it it starts at around 1300 then slowly drops to almost dead-on rpm-wise (about 800), but after about 10secs something changes and the idle goes up to around 1100-1200. The engine sounds like it does when you turn the a/c on (increased load and idle compensation) but if I hit the a/c switch, it will jump up even higher.
This is begining to keep me up at night.:dry:
I really appreciate all of the help I get here. Thanks for any/everything

Questions:
What could be causing this much MPG loss without throwing a code?
Am I missing something to test?
The coolant seems a little low, could this cause the erratic idle and or bad mileage?
Is there a way to find out if the car is successfully entering and staying in closed loop once warmed up?

[EricTheCarGuy]

Couple of things. The first is did you do the install? You said you had it rebuilt, but did not state who did the r&r. That said, if a shop did all the work, you should not mess with it any longer and take it back to those that did the work. If you attempt to repair the problem and then try and take it back to the shop that did the work, they’re likely not to help you. If you have an issue with a shops work, take it back ASAP and do not attempt any repairs on your own.

Next. How do you know it’s not going into lock up? I know you say you have drivability issues, but what proof do you have that the torque converter is not working as it should?

It sounds like you have many other issues that existed before and after the transmission work. To me these don’t seem related. The idle issue for one is probably due to an unrelated problem.

All this said, I will suggest you read through these articles before you respond as they cover many of the things to check in your situation. If you had a shop do the transmission job, I would suggest taking it back to them and explaining the issues that you’re having to see if they can help you. In the mean time, please read these articles as they do directly address some of the issues you’re having.

http://www.ericthecarguy.com/faq/solving-transmission-problems

http://www.ericthecarguy.com/faq/solving-automotive-performance-issues

http://www.ericthecarguy.com/faq/solving-automotive-idle-problems

http://www.ericthecarguy.com/faq/finding-and-fixing-the-causes-of-poor-mpg

Good luck and keep us posted.

[Author]

Replies