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Lack of acceleration

Tiny
WILKINSONT22
  • MEMBER
  • 2009 SATURN OUTLOOK
  • 3.6L
  • 6 CYL
  • AUTOMATIC
  • 150,000 MILES
When I drive at normal speed it's fine. When I go uphill or step on the pedal it lacks acceleration and loses speed. I can feel the car is dropping into overdrive when I push the pedal or hold the pedal going uphill. When I step on the pedal I feel it dropping twice (i'm guessing its overdrive for the overdrive). No check engine light. I don't think it's fuel pump or filter. I'm thinking VVT or transmission solenoid. Something that doesn't trip the check engine light. Any help is appreciated.
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Friday, May 1st, 2020 AT 9:31 AM

15 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
You could be right that it is one of these two options but those are highly monitored and more then likely you would have a check engine light on if the VVT or solenoids were causing low power. We should start with just checking for codes and make sure there are none even though the engine light is not on.

If there are no codes, I would actually suspect a fuel pressure issue because it sounds like you are just losing engine power and as you are, you are stepping on the accelerator and then the transmissions is downshifting like it should. As you give more accelerator, the trans should down shift to give a lower gear, higher RPM, which is more power. It is doing all this except for the more power portion.

I would start with fuel pressure when this is happening assuming there are no codes.

Here is a guide on pulling codes. If you just want to stop by a parts store, they can pull them free of charge as well.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If there are no codes, the let's check pressure when this happens. You can just hook up the gauge and tape it to the windshield and drive it to see what it is when this is happening.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/symptoms-of-low-engine-power

Let me know and we can go from there. Thanks
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Saturday, May 2nd, 2020 AT 9:13 AM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
10, 25, 45, 55, and 60psi took five times of priming to get to 60psi.
44-50 at idle.
44-46 under load ( holding brake pedal and giving gas).
I also attached a video of me driving up a freeway on ramp. You can hear it shift and the psi goes from 44 to 62psi. I let off and then pushed the pedal to the floor and the psi goes from 42 to 72psi. Thank you for your help.
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Sunday, May 3rd, 2020 AT 1:47 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
Also I didn't find any codes.
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Sunday, May 3rd, 2020 AT 2:19 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
Little background on car. The cam actuator sprocket screws backed out causing the sprocket to lock up and snapped the chain and intake actuator. I replaced the chains, tensioners, intake and exhaust actuators, and cam shaft. Also replaced 2 coil plugs. The car sat for 3 years before I got it and fixed it. The car starts and sounds new. Good compression. 149,000 miles. There was shavings in oil from the actuator screws backing out. I cleaned it all out and put 10w30 oil in. Just found out it was the wrong oil and so I changed it and put the correct 5w30 in.
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Sunday, May 3rd, 2020 AT 2:38 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
So I suspect you have a pressure issue. Not only during key on, you should have 56-62 PSI at first key on. Lack of priming is enough but then running pressure should stay pretty constant around 55 PSI and then it increases as you accelerate harder. With it bouncing like that and then being low around 40 just isn't correct.

So you either have an issue with the pump or a restricted fuel system. The filter on this vehicle appears to be part of the fuel pump module so it is not something that you can try changing.

Based on this info, I would change the pump and retest the vehicle. If you want more proof, I attached more testing of the pump. Let me know if you have more questions. Thanks
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Monday, May 4th, 2020 AT 6:14 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
I was driving it on the freeway going up hill. I was going 65 mph. I started to lose speed and I gave it gas. On the first downshift I was getting 3,500 rpm's and was losing speed. It downshifted to the second downshift and the rpm was 4,500. Do you still think it's a fuel pressure problem? Just trying to give you as much information to help me. Thanks again for the help.
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Monday, May 4th, 2020 AT 6:31 PM
Tiny
KASEKENNY
  • MECHANIC
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If the transmission was at fault on this I would suspect codes that would relate to this. Same thing with the throttle sensor. It just appears everything is working but you have no power. This could be something else but with this info, I would chase down fuel pressure.

Just to clarify though, did all these issues happen after you did the work to the chains? Or do you not know how it drove prior to that?
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Tuesday, May 5th, 2020 AT 5:39 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
I don't know anything prior. I read the Chilton and it said the fuel pressure should be 44psi. When I step on it or it downshift going uphill it sounds like the engine is revving up and it gets to a point where it sounds like its hitting a rev limiter. Like the rpm is cutting in and out real fast, Lol. I wish it would throw a code to make this a lot easier.
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Tuesday, May 5th, 2020 AT 5:58 PM
Tiny
KASEKENNY
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So that is a bit odd. You actually are hitting a rev limiter but that normally only comes on when there is no load on the engine and its basically just protecting the engine from over revving. So that actually does not point to a fuel issue. The fact that the RPM's are jumping up like that acts like it is shifting to neutral. Is this the only time you get the lack of power, when accelerating hard up a hill? Will it pull the same hill if you don't accelerate as hard?
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Wednesday, May 6th, 2020 AT 5:57 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
No, I will lose speed. It will then downshift and I will lose speed but not as fast. It will downshift again and it will hold its speed but it sounds like I'm about to blow up the engine.
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Wednesday, May 6th, 2020 AT 6:03 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
How steep is the hill? It sounds like it is under powered but this is a mid-sized SUV with a 6 cylinder.

Has this just started? Meaning did it not do this before but now it is not keeping up on the same hills you normally drive?
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Wednesday, May 6th, 2020 AT 6:44 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
I don't know how it was before. When I got it from auction it had the broken timing chain. The hills have about a 5% grade but it does it on small hills and big hills. If I'm going at a low speed like 35 mph I don't notice it. It when I'm on the freeway going up hill. I have tried to stay in the pedal to hopefully trip the check engine light but I don't have any luck.
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Wednesday, May 6th, 2020 AT 7:22 PM
Tiny
KASEKENNY
  • MECHANIC
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With that being the case, it is possible that this is related to the timing but with not much more to go on, we would need to start taking it apart to check timing and hope to find something. However, if it were timing I would expect a check engine light as you are looking for. Unfortunately we just don't have a lot to go on with this one.

If we are going to do anything I would say we need to make sure timing is correct but again if this is not happening at slower speeds then I doubt it is timing. The engine doesn't care how fast the vehicle is going. It operates the engine based on RPM so if it were the engine timing then it would have lack of power at that same RPM no matter the speed.
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Thursday, May 7th, 2020 AT 6:40 PM
Tiny
WILKINSONT22
  • MEMBER
  • 24 POSTS
So I found the problem and fixed it. This vehicle has 3 catalytic converters. 2 of them has o2 sensors but the back one doesn't. The back one was plugged from the front catalytic converter going bad. This is why I had loss of power with no codes. Thank you for your help.
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Thursday, June 11th, 2020 AT 10:14 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Very interesting. Thanks for the info. Clearly that one slipped past me as I wasn't thinking of a plugged exhaust with everything else that we were seeing. However, a plugged exhaust is a major cause of lack of acceleration so just goes to show I need to stick to all the basics first.

Glad you got it resolved and thanks for using 2CarPros.
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Friday, June 12th, 2020 AT 6:55 PM

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