Can a CPS output be dependent on temperature?
- Thread starter toml
- Start date
possible. i have seen it happen though when the system held pressure over night w/o issue and the car did have a bhg. you might consider starting a new thread as this one is kinda gummed up about CPS info. check your oil cap for milkshake.
for the origional posters, check your tps. it is temp sensative and when mine went out it would act like what you are describing. it didnt throw a CEL and it was fine after a certain point.
also dr.j i can vouch for ya on the code 52 and the car will run fine. heck mine even made 300rwhp with a code 52 (didnt realize i had it until after when i checked codes! d'oh)
for the origional posters, check your tps. it is temp sensative and when mine went out it would act like what you are describing. it didnt throw a CEL and it was fine after a certain point.
also dr.j i can vouch for ya on the code 52 and the car will run fine. heck mine even made 300rwhp with a code 52 (didnt realize i had it until after when i checked codes! d'oh)
Well, my car is now having a misfire problem! 
I thought this would be the best thread to ask in...
So my problem is a lot like toml's, but my car misfires when warm, when the engine is cold, it runs perfectly, like nothing is wrong, very smooth, no misfiring.
However, once the car has warmed up, it will start misfiring randomly at idle, and up to 2k RPMs, after that it seems to smooth out. It also has a hard time with hot starts...it will start okay, but it will stumble and misfire quite a bit. I have to hold the RPMs above 1k for the car to recover and run somewhat smoothly (still misfires pretty badly).
I have changed out/checked the following:
•Igniter swapped out. *no change*
•Spark Plugs changed *no change*
•Tried two sets of plug wires *no change*
•Replaced wiring to coil packs *no change*
•Replaced ISCV *no change*
•Tested EGR valve as per TSRM, and it seems to be working perfectly.
I am getting pretty frustrated, and the only thing I haven't tried replacing are the coil packs.
Any ideas/thoughts?
I thought this would be the best thread to ask in...
So my problem is a lot like toml's, but my car misfires when warm, when the engine is cold, it runs perfectly, like nothing is wrong, very smooth, no misfiring.
However, once the car has warmed up, it will start misfiring randomly at idle, and up to 2k RPMs, after that it seems to smooth out. It also has a hard time with hot starts...it will start okay, but it will stumble and misfire quite a bit. I have to hold the RPMs above 1k for the car to recover and run somewhat smoothly (still misfires pretty badly).
I have changed out/checked the following:
•Igniter swapped out. *no change*
•Spark Plugs changed *no change*
•Tried two sets of plug wires *no change*
•Replaced wiring to coil packs *no change*
•Replaced ISCV *no change*
•Tested EGR valve as per TSRM, and it seems to be working perfectly.
I am getting pretty frustrated, and the only thing I haven't tried replacing are the coil packs.
Any ideas/thoughts?
Possible intake leak making it run lean.
I would do the usual checks for the ECU. Gives us the Vf voltage, and make sure that the O2 sensor is cross counting.
http://www.mkiiitech.com/forums/viewtopic.php?t=593
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119
I would do the usual checks for the ECU. Gives us the Vf voltage, and make sure that the O2 sensor is cross counting.
http://www.mkiiitech.com/forums/viewtopic.php?t=593
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&Page=119
jdub: I am using Denso spark plugs gapped at .026, and MSD 8.5mm wires. I heard them all snap into place when I installed them.
3p: I've never done that test before...If I'm understanding those links correctly, do i have to jumper the diagnostic terminals (Te1 and E1), and with those jumpered, measure the voltage between Vf1 and E1?
edit: I forgot to mention that I have a Bosch 3-wire universal o2 sensor. (screw-in type)
3p: I've never done that test before...If I'm understanding those links correctly, do i have to jumper the diagnostic terminals (Te1 and E1), and with those jumpered, measure the voltage between Vf1 and E1?
edit: I forgot to mention that I have a Bosch 3-wire universal o2 sensor. (screw-in type)
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Johnathan, you can use Vf one of three ways depending on T and E being jumpered and the IDL contact in the TPS being opened or closed:
1) T and E jumpered @ idle: Vf shows whether codes are present or not. 5 volts means no codes are present, 0 volts means codes are present.
2) T and E jumpered, off idle at a steady rpm: Vf shows emulated O2 sensor (signal after ECU processing). At 2500 rpm cross counts should be at least 8 in 10 seconds with an average voltage of near 2.5 volts.
2) T and E not jumpered, either idle or off idle: Vf shows long term fuel trim.
1) T and E jumpered @ idle: Vf shows whether codes are present or not. 5 volts means no codes are present, 0 volts means codes are present.
2) T and E jumpered, off idle at a steady rpm: Vf shows emulated O2 sensor (signal after ECU processing). At 2500 rpm cross counts should be at least 8 in 10 seconds with an average voltage of near 2.5 volts.
2) T and E not jumpered, either idle or off idle: Vf shows long term fuel trim.
Okay, I have my laptop out by my car and just did this:
1)No codes.
2) With T and E jumpered, @ idle it says 4.9V, and as soon as i touch the throttle at all, it goes straight to 0.00, then once I let it return to idle, it goes back to 4.9.
3)T and E not jumpered, it goes between 2.2 and 3.5V.
1)No codes.
2) With T and E jumpered, @ idle it says 4.9V, and as soon as i touch the throttle at all, it goes straight to 0.00, then once I let it return to idle, it goes back to 4.9.
3)T and E not jumpered, it goes between 2.2 and 3.5V.
No cross counting. The system is either in open loop (or driven full lean) or the O2 sensor has failed. Hold the engine at 2500 with T and E jumpered and try again.
Just did that. Stays at 0.00 the whole time, and as soon as I let off the throttle, it goes straight to 4.9.
Bosch oxygen sensor is less than a month old, btw.
Still no codes.
Bosch oxygen sensor is less than a month old, btw.
Still no codes.
Well, the sytsem is stuck lean then. Doesn't make sense though. Without E and T jumpered Vf shows things to be OK but with them jumpered there's no cross counting. That's highly unlikely. Set you meter to millivolts and measure the OX terminal. See if it's jumping around.
Measure OX1 or OX2? Do you mean connect the negative probe to E and positive to OX1?
Do this with TE and E jumpered?
Do this with TE and E jumpered?
Ok, I'm not sure if i did it right, but I set my meter to 200m, un-jumpered TE and E, and connected the negative probe to E, and the positive to OX1 (there is no OX2 terminal), and it just stays at 29.9-30.1 mV...at idle or at 2500, it doesn't really change.
It's going to jump around a lot at 2500 so checking it at idle is better when using OX. 200 mv is a bit low for the meter setting because the raw sensor signal should cross count between about 100 mv and 800 mv. That's why using Vf is better, because the ECU bumps it up to swing between 0 and 5 volts.
What kind of meter are you using?
Here is what I suggest,
If you use the Vf1 signal (T jumpered), you say it reads rich at idle (5V), then pulling off the brake booster hose should make it go lean (0V).
If you use the OX signal, it should be reading 800mV (rich) at idle, and go to 200mV (lean) when you pull the booster hose off.
Give it a try. Replacing the O2 sensor before you know its bad is just a shot in the dark, and a potential waste of money.
Here is what I suggest,
If you use the Vf1 signal (T jumpered), you say it reads rich at idle (5V), then pulling off the brake booster hose should make it go lean (0V).
If you use the OX signal, it should be reading 800mV (rich) at idle, and go to 200mV (lean) when you pull the booster hose off.
Give it a try. Replacing the O2 sensor before you know its bad is just a shot in the dark, and a potential waste of money.
I tried a new o2 sensor (free exchange) and the problem is exactly the same.
3p, I will try what you suggested tomorrow.
3p, I will try what you suggested tomorrow.
Err, someone's not paying attention. Don't forget the TPS in all this. Vf with T grounded and IDL closed reflects code status, not O2 emulation. The 5 volts at idle with T grounded is saying there are no codes set in memory. It has nothing to do with being rich. You need to be off idle to see O2 emulation on Vf with T grounded. Read my previous post about Vf usage carefully.
Stop screwing around with that stupid little E terminal in the diag block and just reference everything to battery negative. It's electrically the same point. You can do this even when checking codes.
If your sensor is truly hard over you'll be getting an O2 code soon. After a couple of key cycles or two trips down the road. That said I suspect your O2 sensor is working fine. I smell cockpit error here. And even though it's possible I doubt the misfire is related to all this. A simply way to verify it would be to unplug the O2 sensor and let the TCCS default to slightly rich.
Stop screwing around with that stupid little E terminal in the diag block and just reference everything to battery negative. It's electrically the same point. You can do this even when checking codes.
If your sensor is truly hard over you'll be getting an O2 code soon. After a couple of key cycles or two trips down the road. That said I suspect your O2 sensor is working fine. I smell cockpit error here. And even though it's possible I doubt the misfire is related to all this. A simply way to verify it would be to unplug the O2 sensor and let the TCCS default to slightly rich.
I unplugged the o2 sensor, but the TCCS did not throw a code. :icon_conf
Also, I HAVE been testing for crosscounting off idle, btw.
I will be taking the car to diftmotion (bigaaron) tomorrow...so I'll post up what he finds.
Also, I HAVE been testing for crosscounting off idle, btw.
I will be taking the car to diftmotion (bigaaron) tomorrow...so I'll post up what he finds.
I was referring to your acceptance of 3p's suggestion. He's confused. Since I've never seen him wrong about anything before he's entitled once in a while. We all are. That said you should answer the man's question about your meter. He's trying to help you, as am I. (God only knows why ).
As I said in the last post you shouldn't get O2 codes right away because they use two-trip logic. The fault has to occur for a certain period of time twice with a key cycle in between. Your previous measurement Vf (if accurate) of 0 volts off idle with T grounded indicates a system hard over on the lean side so pulling the booster hose would only make it leaner. If the engine was really in lean misfire disconnecting the sensor would make it default to rich and the misfire should disappear.
That it doesn't, along with the normal Vf you reported when T isn't grounded, implies not only that the sensor is working but the misfire isn't mixture related. Hard to tell from here though. I dunno about you but I'm going to sleep on it
).As I said in the last post you shouldn't get O2 codes right away because they use two-trip logic. The fault has to occur for a certain period of time twice with a key cycle in between. Your previous measurement Vf (if accurate) of 0 volts off idle with T grounded indicates a system hard over on the lean side so pulling the booster hose would only make it leaner. If the engine was really in lean misfire disconnecting the sensor would make it default to rich and the misfire should disappear.
That it doesn't, along with the normal Vf you reported when T isn't grounded, implies not only that the sensor is working but the misfire isn't mixture related. Hard to tell from here though. I dunno about you but I'm going to sleep on it