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Hey Guys,
I'm Korvicus and I own a beautiful 2007 Saturn Ion 2.4l quad coupe that I rebuilt. Unfortunately I have a problem with it that I am not able to fix. I am quite good at mechanics, well equipped and I work on on ecotec for several years now.Here's the situation: when the car is cold, it runs perfectly. As soon as the engine reaches operating temperature, The car has difficulty reaching 4000k rpm. And its getting worse, waaay worse. As soon as the car exceeds 4500 rpm, it runs wonderfully and pull very very good. I have a bunch of codes. P0016-17-171. (I think Theys are all related too the same problem). The problem did arrive very gradualy over a couples of weeks.
Given the following codes, I decided to check the timing chain right away. It was loose. So I made the change. And decided to change Both Camsensor and the crank sensor. It didn't change anything, so here are the quick steps I went through given the codes and In the meantime, I had sent my computer to zZP to have it tuned. So I had a week or two to do some testing .I did a smoke test Everything was perfect..I then checked the injectors and the fuel pressure, one injector was cracked so I decided to replace all four. I changed the gas filter I found it a little dirty. Since I put in a long tube hearers, I had already replaced the oxygen sensors, On my computer the oxygen sensors are outputting good voltage data. I then checked the MAF sensor and decided to clean it. I looked at the data on the computer and everything is working perfectly. I thought it was the catalytic converter, so I took it off and put in a blank straight pipe. So there you go... I'm a little hopeless. I bought this car this winter while driving by to do Autocross and a few competitions here and there. I'm not expecting miracles here, but if it's already happened to someone, you never know.
Idle RPM at startup and when warm?
Compression test results wet and dry?
Coolant level dropping?
When does the engine go into closed loop control? Does it coincide with when the performance issues begin?
If you sent off the PCM, you have no PCM in the vehicle right now unless you have a spare.
Not sure if passlock will let it crank enough to do the compression test, and I don't know if the PCM needs to be there to complete other circuits to allow the starter to spin. But you can try.
If you based your parameters you sent to zzp on the parameters of a poorly running warm engine, I suspect you will have problems.
A compression test is the only thing that I have not done yet because I don't have the tools. Need to buy them. And the other reason why I didnt think it was the issue is that (I may be wrong) the compression should be better as the engine warm up. More heat better the compression right?
About 2-3 minutes of driving and the car cant push past 4000rpm, if downshift it Will accelerate perfectly to 7000rpm.
Fyi I had the computer send to zzp couples months ago. I ran some of the test that I described earlier with the ECU in place of course.
No oil nor water cooling consumption.
Thanks for the reply !
Nice looking Ion! But that engine is problematic, to say the least. I think you may be the victim of a slipped camshaft reluctor ring, probably on the exhaust cam. GM has a service bulletin on it at PIP4548F. There are a few YouTube videos where this was diagnosed as the problem. Solution is to replace the affected camshaft.
I would bet that your Ion has the same engine as my 07 Cobalt. My Cobalt cam sensor reads off the intake cam and is cast into the cam. No reluctor ring to slip on a cast cam. Do you have a 2.2 L61 or a 2.4 LE5? The L61 is what I have and it does not have variable cam timing. The LE5 is a 2.4 with variable valve timing. If you have the 2.4 you may have variable valve timing problems like a sticking cam phaser.
The service bulletin I linked above shows how to check the reluctor rings without removing the camshafts. You have to remove the valve cover, then check the drivers end of the cams where the reluctor rings are located. (They are the triggers for the cam position sensors.)
So, I worked on the car this morning. I'm trying to read the instructions. I don't fully understand because I don't know the valve numbers. The document you sent me talks about valve number 1 (for intake reference) and valve number 4 (for exhaust referance) so I'm stock here. But when I look it up on the internet, I am told to put cylinder 1 all the way up to check the timing and watch the intake reluctor. Should be at the exact flush with the Rocker gasket cover. I'm not sure about the instructions you left me as Gm doesn't give any reference on valve number correspondence.I will try to find the information on the internet.
For Now, You can look at my pictures, the timing is still perfect and cylinder 1 is perfectly on top.
Merci beaucoup!
Low Power when hot and at low RPM only
