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HHR doesn't rev past 4000 rpm and won't go over 40mph
Problems/Service/RepairsIf you have a problem with your HHR, want a tip on repairing or performing a particular service to you HHR here is the place to post!
The I/M readiness explains why there are no codes. The testing is being inhibited by something. The O2 test runs immediately and constantly
By definition a historic code is one that previously caused a CEL. It would not be there if it had not lit the CEL
P0171 is from running without the downpipe connected.
The P0420 test will not run when the engine is in open loop. It is in open loop if the O2 sensor test has not run. P0420 test involves both O2 sensors by comparing their outputs.
Here is a link to an explanation of the types of codes: https://www.autoserviceworld.com/car...ermanent-dtcs/
The author seems to think technicians know something about the digital systems. This is against my experience, I have heard of too many technicians replacing crankshaft sensors because of a P0017/P0017 which mean the sensors are working and the timing chain needs looking at. For some reason they all think coils of wire encased in epoxy fail more frequently than the things they monitor..
With no codes showing there is no way I can help from this far away. Everything that could cause the behavior should cause some code. Maybe the throttle body is broken or the accelerator pedal sensor is bad, those should throw at least one code. Maybe the transmission park/neutral switch is telling the computer it is in neutral, there is a RPM limiter in neutral. Maybe the transmission is not shifting out of first. P0700 literally means "there is something wrong with the transmission".
The transmission does shift out of first and actually shifts all through third gear, but everything just kind of bogs down at 40 mph so I don't know if it's getting into lockup or not.
Like you, without some sort of code I am not even sure where to go from here. I did remove the gas pedal assembly and inspected it and clean the contacts, did not visually see anything wrong there. The butterfly in the throttle body is very responsive to the gas pedal, so without some sort of a test for that I would assume it's acting as it should.
Should I just get in the car and drive around at 40 miles an hour until something comes up? That was kind of my next thoughts to see if it will trigger any kind of a CEL light.
I can get the live data using O'Reilly's code scanner, would that help anybody? I'm not experienced in that area so I'm not sure what I would even would be looking at.
So I got everything back together and I got in and drove it and for about the first three or four miles everything was great, I was doing 50 miles an hour and didn't seem to have a problem and then all the sudden I lost all power and could barely get it going 40 and about three blocks from home I could barely get it to go 20 mph. The CEL did light up, it's showing logged p0171, pending codes of 0171 and 0300, And of course the historic code of PO420.
Here is the info I can get with the vehicle running right now.
A fuel pressure test might show something. Symptoms sort of sound like not enough fuel pressure to the injectors.
Here is the procedure, the tool specified is just a pressure gauge you can borrow. The pump on runs for a few seconds without the engine running so jump the relay unless you have a scantool. I think the reason they say do not start engine is a liability thing, a reckless D.A. might spray gas on something hot. I have just hooked up and started the engine with a rag wrapped around the Schrader valve and the release valve. The part about decreasing is pump off to test the check valve
KOEO fuel pump goes to 60 psi And after 1 minute it is still holding at 58 psi. Did an engine running test and it's holding it 60 psi.
I did try to start the vehicle with it in gear as suggested, and that's not the problem.
Any other thoughts, tests, ideas? I very much appreciate everyones help so far and all the suggestions,. I'm hoping I can get this figured out because my wife wants her car back that the son had to borrow to get home and to work.
One other thought, the engine looks and acts like it has a small miss when it's at idle. But I'm not getting any codes regarding that.
08-04-2023, 02:23 PM
