transmission Problem?

[5seryan]

I got this weird problem with shifting and i dont know what the problem is.Basically tho the car will not shift out of 1st gear until i release the gas and then press it again. I ran the diagnostic test and got nothing says its OK. I have no idea as to what it could be. Wes thinks it might the TPS sensor but is not sure any help will be appreciated. here are some links to videos so you know what I'm talking about.

http://q45.spilky.com/Q/Q45%20018.avian ... %20019.avi

Make sure you got the volume up so you can hear the engine.
Modified by 5seryan at 8:23 PM 9/6/2005

[elwesso]

Some extra [helpful] information that I obtained while speaking with him

- Problem seems to have gotten progressively worse - Has been doing this for a while- transmission has been rebuilt with approx 12k on it right now- performed self diagnosis and no faults

Also, in the videos, if im correct, he is holding the pedal down all the way.. with that being said, if its stopping at liek 5000RPM, my guess is maybe the computer has already retarded the timing, and is giving the signal to shift, but theres inadequate pressure to shift... I dont know, im just thinking out loud...

Either way, its either something electronic or its new transmission time...

[rsiwicki]

hey....whats the TCS light doing on there on the dash board? Somebody turned off their TCS stuff

no idea what the problem is but hope it is not too $$$$

btw...I forgot what a stock Q45 sounds like......very nice sound it does have even when stock.

[5seryan]

bump.. wes this might need to be moved.

[elwesso]

Not a problem!

[DominickJ30]

Did you check the pressures in the transmission while you were driving?

That would be the first thing you should do.

From all this it sounds like the throttle valve is sticking causing the delayed and Im guessing HARD shift.

Check pressures and consult the FSM.

[5seryan]

I ran diagnostics and everything came back ok..and no i did not check the pressures in the trans while i was driving. And yes very delayed and pretty hard.

[3Q Jay]

what does it do if you don't mash it? do the revs just sloooowly float up without a shift?can you go over 5500? what if you hold it in '1'?

my 1st guess is low line pressure, did they flush out your cooler when the replacement went in? might be a simple as a clog--the re4r03a is known for clutch shedding plugging things up. 2nd guess a bad tp sensor voltage, telling the trans you are on it when you are not. the thing is the 5500 rev limit would not be consistent with #2....

[elwesso]

EIther way, when he brings his Q I'll figure out whats going on with it

[elwesso]

Alright... I told Sean ehre that Id bump his post, so I DIDNT FORGET! HA!!!!

Heres my take on the situation... This definitely feels electrically related... When your say, at less than 1/2 throttle, the transmission shifts fine... Fairly smooth and right on key/schedule... however, when you start getting into the throttle, it wont rev past 4000, its like the computer is retarding the timing too soon or something like that..... If you let off the throttle, it will eventually shift.... its like, the transmission knows its not time to shift, but something is keeping the RPMs from going past 4000-5000, and the car is really slow too.....

I checked the fluid, and it didnt look pretty..... He will address that ASAP ( )

So the first thing that came to my mind was the TPS... We swapped on a known good one, no difference... Swapped in a known good ECU, no good... We didnt swap in a TCU, maybe we should have done that...

Ive never heard about anything like this..... Its truely weird, and it doesnt feel like the transmission is at fault.

[3Q Jay]

Wes, i know you know how to backprobe the tcu: see if it [tcu] is commanding the transmission shift solenoid to engage 2nd [sorry, forgot if that was a, or b]. tcu may be telling it to shift [could also explain ecu backoff], but maybe signal is not getting to transmission, or shift solenoid/valve is hosed. but let me not get too far ahead: is the tcu telling it to shift?

hey, buddy...help me out with how to post .pdf excerpts within a thread.

[DAEDALUS]

Take a snapshot of the .pdf and post a .jpg.

Backprobing the tcu is as much work as backprobing the ecu.

[elwesso]

Take a snapshot of the .pdf and post a .jpg.

Backprobing the tcu is as much work as backprobing the ecu.

yeah just go into the PDF, you can select an area, copy it, and put it into paint and save it as a JPG (not BMP, bitmaps are the DEVIL!! )

Anywho... I agree with you Jay and I see where your going with this, but why would the transmission shift fine under a small load but not under a larger load.? If that were the case than its gotta be in the TCU thats the problem (seems strange as those *never* actually fail)

SOmething is definitely backing off engine timing...

[5seryan]

BUMP! Somebody please help me get my car back.

[DAEDALUS]

We kind of need more to go on that just the symptoms. A fever can be caused by many ailments. Backprobe the controllers, take pressure measurements, etc. Have you already flushed the fluid? If it's a known problem, fix it first, then go from there.

[5seryan]

Tell me what to do and how to do it and i will.

[DAEDALUS]

Did you replace the fluid? Do that first. You have to make an assumption about whether the transmission is the problem or whether there's an engine problem (possibly compounded by a transmission problem). An educated guess would be nice. If you assume the transmission is the only problem, then focus attention on the inhibitor switch and the vehicle speed sensor (VSS). These are the only 2 things in the transmission that can affect the running of the engine. I.e., if these are both fine, then I don't see why the engine would be rev-limited, unless the transmission is just plain fighting the engine for some reason. Check the inhibitor switch first with a multimeter using the characteristics in the FSM. I don't see how it could be the inhibitor switch. If that checks out, and since you're in the area, check the VSS continuity while spinning the tires (also in the FSM). Note that slow spinning may not reveal problems that show up under load--ideally you'd want to splice a probe into the wire and measure frequency while driving, but that would take some rigging.If there's an engine problem, then there are several other suspects. It could be fuel related, MAF related, or TPS related, among other things. You could have more than one problem, but work on one at a time. Measure fuel pressure, MAF voltage and TPS voltage, and compare values to FSM.

[NISTECH]

If you can swap in a known good MAF and try again. I suspect your MAF is toast.

[5seryan]

The same thing happens when it not in gear. WOuld this rule out the transmission?

And unfortunately i dont have a known working MAF to try.TPS is fine, Wes and i tried a known working one and also compared mine to to specs in the FSM. so the TPS is not the problem.
Modified by 5seryan at 2:18 PM 9/13/2005

[DAEDALUS]

Do you not have access to a multimeter. Basic ones are a lot cheaper than a MAF.

[5seryan]

I was under the impression that the only way to check to see if the MAF was faulty was to take it out and tst with a known working one. And no I dont have a multimeter but i think i will go get one. But please correct me if im wrong in about MAF testing.

[5seryan]

Ok now things are really bad. I went to go to the store to pick up a multimeter and well i didnt get very far. i had to turn around less then a block from my house. Basically i felt like the engine was going to die. I barely made it home. Now i cant even drive the things because im to scared it will die on me.

[DAEDALUS]

The FSM contains 3 MAF voltage values--car off, idle and 2000 RPMs. I can also tell you that the voltage should rise to around 4-4.5V as you approach redline. Not too much difference between MAF systems of modern cars, except that some cars are going to higher voltages for better resolution.

[DAEDALUS]

Ok now things are really bad. I went to go to the store to pick up a multimeter and well i didnt get very far. i had to turn around less then a block from my house. Basically i felt like the engine was going to die. I barely made it home. Now i cant even drive the things because im to scared it will die on me.

Unplug the MAF and start it. If it doesn't run it probably isn't the MAF.

[5seryan]

I unplugged it and turned on the engine. it started up and when i hit the gas it redlined at 2k. dont know if that means anything.

[DAEDALUS]

Sounds like Nistech is right. Plug it back in and measure the voltage to confirm.

[5seryan]

i dont have a multimeter. i was goin to get one but i had to come back as my car was about to die on me. Ill see if my neighbor has one.

[DAEDALUS]

Confirm it to be certain, and start looking for a MAF in the meantime. Shame...one just went on ebay for around $40, with the ignitors and water pump too. Maybe could have divided the parts up across a few threads here.

[NISTECH]

Side note. I have probably done 50 or so Maf's in 2000-2001 maximas with this identical complaint. The symtoms are dead on. The maf voltage when tested is very judgemental and may be interpited as ok during the intial stages of failure. I suspect now though in your case they will come up low on the signal side during throttle application, since it has gotten so bad. We use consultII to moniter GPM to determine the failure early on. It usually wont exceed 70 or 80 GPM at full throttle while driving. Should be able to easily exceed 130. We also find during the occurance injector pulses make out at 7ms and O2's flat line at 0v along with the alpha on both banks hitting in excess of 130%

[DAEDALUS]

What causes the failures? Do you only mention Maxes becuase they are far worse than most Nissans? Units of measure seem off.