Engine Or Transmission
 

Newbie here to the forum.
I have a 2010 HHR 2.2L with 141K miles that ran like new up until about a week ago. First thing I noticed was occasionally I would really have to get on the gas to get up to speed. Then it got worst. As of now to get up to and maintain 60-65mph I have to run it at 3.5K RPMs. To get it up there I have to hit 4K RPMs. No OD. Shifts through first and second ok but to hit 3rd and OD I have to floor it. Only when I floor it does it throw a misfire code and a code for the CAT /BANK1.

I am at lost for which it my be, engine performance or bad transmission so here's what I have done thus far. First, changed spark plugs, coil packs, injectors, air filter, MAF sensor, trottle position sensor changed along with throttle body and exhaust including cat and the gas presure was checked for 50-60 psi. Engine idles OK, but nothing indicating misfire or clogged intake valves.

As for the tranny, I checked the level and replaced the speed sensor on it. I am getting the same result. This problem exist hot or cold doesn't matter. No OD and seems to lack power when shifting between 2nd and 3rd. Hills kills and coasting only in 3 at 3-3.5K RPM. The few times that I floor it (out of frustration) the car dropped off as if I had thrown it into neutral and through misfire and cat codes. The misfire codes were on random cylinders and the cat code was P0420.

Hi chessplayer41, :welcomewagon: to the forums!!

Sorry to hear you're having these issues. Just to be clear, the only codes you've had are P0300 and P0420, is that correct?

You've thrown a lot of parts at this, in just a week or so. Have you inspected the wiring for the O2 sensors? Sometimes they get chafed or burned. Are you still using the original O2 sensors?

What about compression and leak down?

After you replaced the cat you are still getting P0420?

Misfire on what cylinder? What code numbers?

Has the trans fluid been changed, ever?

Have you hooked up a scanner capable of reading the transmission codes.

Have you popped the cam cover off to inspect the timing chain? Any slop indicates stretching.

You sure did throw a lot of unnecessary money at the problem. Just about everything you replaced has codes associated with their failure.

What is the state of the battery?

Description of codes tell us nothing, we need the number. What about stored codes? The P0420 will prevent some other test from running, as will some other stored codes.

Welcome to the site, a lot of questions to be answered, so I wait till you answer the above ^

Questions Answered
 

I have not tried checking for compression, that was on my next list along with changing the tranny fluid. After replacing the cat I still get the P0420 code and the misfire is random on each cylinder which caused me to replace all coil packs and spark plugs yet I am still getting it only after gunning the engine to the point of shut down. The scanner that was hooked indicated that 1-2, 2-3 noids in the tranny are working but the some sensor (speed shaft control sensor...?) reads 0 RPMs inside the tranny. Yet the speed sensor that appears to work because my tach and MPH dials work and the speed sensor only have two wires indicating that it's doing it's job as far as giving a proper read out. The two codes for both misfire and cat are the only ones stored. Normal driving does not throw codes, only when I attempt to get on the highway and up to speed. Also, I forgot to mention that it lacks power when shifting through 2-3.
I am also using the original O2 sensors. I have been told that if that engine can do 4000 RPMs then the engine is doing it's part.

Forgot to add, the scanner used to monitor the car was only good for car up to 2008 even though the guy informed me that it would still communicate with my car so I am not holding much stock in it's read out

1996 is when OBD2 started, however the "up to 2008" part is why you disregard the verbal part of the code, use only the NUMBER. The OBD2 code numbers are still the same.

If the "misfire is random" means P0300, you are misunderstanding the meaning of the code. It does not mean all of the cylinders are misfiring randomly. It means that there is a misfire happening at a random time, could be 1 cylinder is randomly misfiring, just not consistently.

If it was actually "misfire is random on each cylinder" you would also have P0301,P0302,P0303 and P0304.

The transmission has no internal computer; that is the TCM that is right behind the ECM in front of the fuse box. The TCM will show P07xx codes and maybe some Uxxxx or Cxxxx codes if there are sensor or electronic failures.

All sensors have OBD2 codes associated with failures. Sometimes the failure doesn't get to the warning threshold.

Look at the timing chain. Do a compression and leakdown. Check the fuel pressure. Take it to a trans shop for a diagnostic. I am taking a flying guess at a bad fuel pump assembly.

Don's comment on check the timing chain is my direction, a loose or broken front guide or a weak tensioner can cause this issue.

Don, great point and thanks!! No TCM codes and the fuel delivery system is optimal, check for fuel pressure at the injector rail and it's at the correct PSI. In the process of elimination I disconnected the data cable from the tranny and drove the car to see if the gears were changing due to pressure or computer control and the result was only first gear. This leads me back to engine and as you suggested, a compression check. This will be done first thing tomorrow along with timing chain/belt check. One thing for sure, after this I too will be an HHR expert. Quick question, does the speed sensors on the wheel also get factored into the speed control or is it just for the ABS?

No timing belt, just chain.
The hub sensors are just for the ABS and traction control purposes.

The "E" in 4T45-E, the designation of the trans, stands for "Electronic". It is controlled by computer.

Wheel speed sensors only connect to ABS/TC.

The output shaft speed sensor on the trans provides the data to the BCM for vehicle speed.

Are you checking the fuel pressure at only idle? I am thinking maybe a clogged filter screen starving the injectors at high speed.

After a P0420 there should be a freeze frame in the computer, it may not tell much, but it might.

Thanks Oldblue. I'm learning this car for sure.
Ok, here's an update as of this morning 6/18/17. I did both compression check and a leak down. All cylinders held compression just fine and I detected no leak down. So my next step is change tranny screen. I have notice when I drop into LOW, and then into I (not sure what that stands for) there seems to be power but once I go back into the DRIVE option the car becomes sluggish and on OD.

From the owners manual:

I(Intermediate): This position is also used for normal driving. However, it reduces vehicle speed without using the brakes for slight downgrades where the vehicle would otherwise accelerate due to steepness of grade. If constant upshifting or downshifting occurs while driving up steep hills, this position can be used to prevent repetitive types of shifts. You might choose I(Intermediate) instead of D(Drive) when driving on hilly, winding roads and when towing a trailer, so that there is less shifting between gears.
PERFORMANCE SHIFTING: If the vehicle has this feature, it can detect a change in driving patterns while in the Intermediate position. If you make an aggressive driving maneuver, the vehicle's transmission automatically shifts to the lowest possible gear to maximize vehicle performance. The vehicle will automatically return to normal operation when you return to normal driving patterns.

So I changed the trans filter and fluid...having same issue. Not a lot of power yet I have noticed something that I was only able to do on an empty highway. Even though It take up to 3.5K RPMs for the gears to change I have noticed that if I can get the car up to 65 or 70 and I ease up off the gas paddle the OD will kick in but there is no power to maintain speed. So it seems I'm back at look at the engine that also appears to be running optimal.
Is it normal to have a strong smell of exhaust coming from the back of the engine even though the exhaust pipe is connected?

Sounds to me like a cracked or damaged flex pipe from the back of the engine to the cat, that will create the smell of exhaust and create all kinds of performance problems.

Check your TCM connections, look for bent pins, loose pins, corrosion and such.
Also check the ground connection at the front of the transmission just down to the right of the oil filter cap.

Check the flex pipe,

https://www.chevyhhr.net/gallery/fil.../7/b_35144.jpg

It might look like this when you get it apart


https://cdn.carcomplaints.com/compla...abd56764er.jpg

First mention of odor, yes a good point! Especially with a noise.

Would also explain the P0420.

Well, I have taken it to a regular mechanic with no affiliation and talked to another ex Chevy mechanic and both are perplexed as to what this car is doing. No one can say for sure if it's the engine or the tranny. We did confirm that there is a leak at the flex pipe as OldBlue mentioned. If that's the culprit then I'm not understanding how exhaust could cause this issue regardless of the car being hot or cold. SO...looks like I will have to do what I have been dreading all along, take it in to the dealership and see how much they are going to hit me for just to tell me what's wrong with it... :( Until then I'm still up for suggestions.

I've experienced this in my HHR, as have many here.

Well it's less then eight years old, if it's under 80,000 miles the flexpipe is part of the emissions warranty

I don't see why a dealership needs to be involved

Why do you need someone else to tell you what's wrong? A broken flexpipe can cause all kinds of problems. It allows metered air to escape, it allows unmetered air to enter. This confuses the computer, causing the engine to fluctuate between rich and lean conditions.

Why not fix the part that is endangering your life and hope a bunch of internet bozos are right?

:jester:

Bozo

http://a57.foxnews.com/images.foxnew...65697.jpg?ve=1

Or Krusty

https://static.independent.co.uk/s3f...y-simpsons.jpg

Full circle...Started out with the exhaust and ended with the exhaust. A few small crack along the inside of the flex pipe was causing all this mess. Sealed the hole and now I'm back on the high way...just like that. All that money and in the end all I needed was about $2 worth of Muffler Weld paste place on the inside around the edges. Thanks to you all for the great advice. Looks like a have a new favorite forum...as long as I have my HHR.

FYI. That weld paste won't last. It's a flex pipe and thus flexes under torque from the engine. Weld paste doesn't flex.
Plan on replacing the flex pipe in the near future.

You're gonna need at least one of these

https://i.ebayimg.com/thumbs/images/...C8W/s-l225.jpg

But get it welded in!

Here's a how to

https://www.chevyhhr.net/forums/how-...ex-pipe-31536/

Yes the paste is only a temp fix so that I am able to go and get a new exhaust and CAT for $350. It still feels good going from a max of maybe 60 at full throttle to 75 coasting. Amazing how much a small exhaust leak can effect the performance.

OK, we have proven we are right once, why not accept the second idea and save yourself $250?

Because , just because! Some shops will only install their parts they procure and sell.