07 Honda Fit L13A engine. CVT transmission operation

Hello everyone.

Symptoms: Sometimes engine stalls at D or R shift, (A/C On), idle and operation temp.
Sometimes engine drop to around 500 rpm and CVT disengage at D or R shift, (A/C On) and idle.

My first shoot: Two separate issues. the engine is stalling because lack of power at idle

Stage 1. I took this vehicle for a spin with a scanner connected to it and noticed a little lack of vacuum and slightly fuel delivery issue. I injected air into chambers and i found leaks in cyl #1,2 & 4 intake valves. I rectified valve seats and also cleaned injectors and replaced injector filters. Result: Now engine is not stalling and it feels a little powerfull at idle.

But at D or R (A/C On) foot on brake pedal and idle, engine still drops to about 650 rpm and CVT is still disengaging (a little shake because of disengaging and then it engages again and so on).

Is this PCM comanding CVT to disengage because of RPM are droping?

Is some of the clutches sliding?

Is the CVT chain sliding?

Thanks in advance.

Hello guys, new inputs.

I've found the basic description operation for this CVT (i mean is not giving me any signal waveform or pwm solenoid vs rpm data).

Power transmission sequence (D shift): input shaft -FORWARD CLUTCH - drive pulley - chain - driven pulley - start clutch.

(R shift): input shaft - REVERSE CLUTCH - drive pulley - chain - driven pulley - start clutch.

The "shake" thing is happening ONLY when A/C is On and A/C clutch is been applied.

Before engine adjustments (described in my first post), the engine stalled under A/C load.

MAP goes from 27Kpa to 50Kpa when i turn A/C On.

I also did Start clutch relearn procedure (A/C Off as requested).

It seems like PCM is applying to much pressure to Start clutch (which is accting as torque converter). But is only doing it wrong when A/C On.

How can i adjust pressure under A/C load?

Any idea is apreciated. Thanks.

Hello everyone. New input of the day.

Another road test (i don't want to take this CVT off without any direction).

1. Climbing test about 5% grade hill (no throttle pedal, no brake pedal, D or R shift, A/C off). The car is able to climb (slowly but climbs).

2. In the middle of climbing I turn A/C On, it shakes like described in my earlier posts. Which makes me think is not to much pressure in clutches/brake like said before, but something slipping (because i'm not breaking wheels like before, but let them move freely).

3. Then I tested now pressing brake pedal on the floor, A/C On, D or R shift and a little of throttle and it didn't shake anymore (which makes me think PCM is now giving more pressure to clutches/brake, which avoids slipping).

Is it time to tear this CVT down?

Does your trans have a fluid pressure port for measuring line pressure? I am not familiar with cvt trans. But seams like line pressure might be low.

The other posibility is ac clutch bearing is going bad is there any noise coming from it?

Scratch that reread info in prior posts this could not be it.

Hi Hardtopdr2, Thanks

You're right. Both posibilities are there.

A/C clutch/compressor: Is not making any noise but when you turn the A/C On, Map goes from (27kpa to 50kpa) about 4psi change. I have the idea A/C drain up to 25%.

Pressure ports: Yes it has. The manual suggest a stall test and says pressure only for that condition (far from idle pressure I need). Anyway I can play a little bit with those ports and try to diagnose something.

I also played with solenoid PWM, but it told me nothing because I don't have signal references.

Regards.

Ok you may want to check the ac pressures of the high and low side. If high side is really high like 400 psi or more a txv valve/orifice tube could be the issue. A stuck txv/plugged orifice tube would cause a heavy load on compressor making it hard to turn and potentially stalling car out. Though the pcm and or bcm should request higher rpm when underload of a/c being on. That would be the only other thing on the ac side of things to cause this issue otherwise it would be cvt trans issue/torque converter problem. If you can look at the trans input speed sensor reading and compare that to engine rpm when driving do the rpms match or is there a slip percentage being shown (tcc slip).

One thing that would not hurt to do would be to ohm the pressure control solinoid, tcc solinoid and shift solinoids if equipped. That info you should see in mitchell or if you have a snapon scanner it will list the acceptable ohm readings in guided component testing tab.

Post the list of the readings for us as well as the pressure readings for trans in park, neutral, od, d, 3,2 and 1. The info for tests pass fail will be listed in trans section of Mitchell DIY www.eautorepair.net

Is there an easy way to engage A/C clutch and don't load engine with that A/C power demand?

I am trying to find out if slipping is due to A/C power drain (compressor work) or is just that PCM is setting wrong settings for A/C condition.

Perhaps taking belt off of ac compressor and turning it by hand with power applied via a 10 amp fused wire to compressor clutch would be all i can think of but i would check high side pressure first with it all connected.

Hello everyone, new input (unexpected one).

I took the car to check A/C pressures (IDLE high side: 210psi - low side 35psi). (3000 RPM high side 250psi - low side 35psi). Everything ok.

I noticed that while they were cleaning the condenser (A/C radiator), they sprayed water and high pressure dropped rapidly from 200psi to 110psi.

So, i decided to ask for help to spray water to the condenser while I pressed brake pedal, turn A/C On, no throttle pedal, shift it to D or R and the car didn't shake anymore.

I ran to post my findings to you, so i have to repeat it many times.

Regards.

Ok pressures are good. With the water running on the condenser that is an expected result which is normal for ac pressure drop.

How much gunk came out of the condenser when they sprayed it?

Was it dirty or fairly clean run off?

Also how many miles are on car?

When was the last time the trans fluid and filter where changed or a flush done to system? If known .... i ask this because a trans fluid filter if its plugged up with gunk can cause a similiar issue with a regular trans.

Hi hardtopdr2,

Thanks again for your prompt response.

I have repeated the test three times with same results.

The clock says 93k km. I am going to ask about flush and filters.

The condenser was fairly clean.

With water running on the condenser, PCM has not to open IAC so wide. Is going from 27kpa to 42kpa (about 2.1psi). In earlier post i mentioned with no water is going from 27kpa to 50kpa (about 3.5psi actually).

Ok well this rules out the air conditioning system as a source of problem. The pressure control solinoid on the transmission will need to be tested (ohm testing solinoid and wires to pcm), (line pressure tested) getting readings when its commanded on and throughout the amp range in the bi-directional test function in scanner if yours has the capability. Also with pressure gauge installed write down pressures in park, reverse, drive, 3,2 and 1and compare those to what mitchell1 has

Hi everyone,

Still not able to check pressures (getting the fittings for my tool).

Meanwhile I checked pressure solenoids resistance (6.2 ohms as specs).

I also checked PWM output for every solenoid. This trans has only three for pressure control (one in charge of compressing the chain walls in drive pulley. A second in charge of compressing the chain walls in driven pulley and the last one in charge of the start clutch (torque converter). The rest of hydraulic pressures were stablished by factory inside valve body.

I scoped signals for drive and driven pulley solenoids and confirmed wheter A/C is On or not, pulse width and frequency are the same (seems it doesn't change pulleys pressurd for A/C operation).

Start clutch solenoid never change at all (seems it only changes with speed as expected).

Once I get pressure readings with my gauge, i'll let you know).

Ok guys, i 've found the root cause of the problem (not the solution yet).

"The start clucth is being forced to much at idle"

There are only two posibilities to this trans brake the engine:

1. Fordward clutch and reverse clutch acting at the same time: I removed forward clutch test port bolt, meawhile i shifted R and no pressure was in forward port. Ruled out this one (no brake between them).

2. Start clutch is putting to much power at wheels: I cheated PCM by simulating start clutch with a resistor in connector and leaving solenoid with no power. The engine never droped in rpm (everythin else pulleys, forward and reverse clutches working). The engine not even drop a few rpm.

Possible solutions?
*Oil flush (i doubt it)
*start clutch calibration
*New PCM

You can try a recalibration if scan tool lets it. If it doesn't work could mean that solinoid needs replaced or its plugged up with stuff. Can you command it on and off with scan tool ? If you can then command it off and on with scanner while turning on and off ac with it in drive brakes applied. Think you may have found the problem.

Thanks again for your replies.

My scanner is not able to do that, but there is a procedure described in manual (which I already did). The thing is that procedure calibrates start clutch with no load (which is working fine in deed).

I am going to play around that solenoid and its valve body spring control pressure valve.

Thanks for all your help.