Prius (2004-09) :: Knocking With Medium-high Load On The Engine
Sep 27, 2011
I have an 06 with 105000 miles. Since about 95000, I've been starting to get what sounds like a fuel knock with medium-high load on the engine. Thought it was carbon at first, but a few applications of Techron didn't clear it. Higher octane does seem to solve it.
Do the knock sensors go bad on a Prius? What's the proper way to diagnose the knock sensor on a Prius? (can't exactly bang on the block with a wrench at idle and listen for fuel adjustments on a car that doesn't idle).
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I have been getting some knocking the under most any loads . I do not have any codes. I tried premium gas and that did not make any difference. If this is not fixed what issues can this cause? What should I look for do get this fixed?
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I've noticed, maybe a handful of times in the 5k miles I've owned the car, that the engine will rattle excessively for maybe 30 seconds or so on a drive. This only happens during high load/low speeds and I think after the engine has been off for at least about 10-15 minutes. It doesn't happen on start up, only after the car is warm, but hasn't been using the engine for a bit. I'm thinking this is fuel enrichment (really rough running) because the cat has cooled.
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My father in law has a 2011 Prius -3 - with 135,000 miles on it. He has an interesting issue. The front windshield wipers work on low and medium. When he tries to put them on high, the wipers barely moves. When I drop the stalk back at med or low and it works as if nothing is wrong. I have checked the 30amp fuse and it looks fine. I do not hear any grinding or noise when the wipers are working. I think it could be the motor. However before I go out and purchase the motor, I wanted to make sure there was anything else I could be missing... The dealer wanted 340 for parts and install.. .I know I can do the job myself as I have worked on their other Prius - 2005 with 240,000 miles and counting.
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I got the APR ECU Tune in June along with VW Racing air intake. Car runs great except... the engine is knocking under full load. The guy who did the install heard it right away but I just thought he was trying to up sell me. He suggested new spark plugs.
Well it's two (three?) months later and I've come to accept that I can't drive it in the 91 program anymore (I paid extra for the ability to switch programs - lucky!!). I was switching back and forth between 91 and stock and I can hear the difference.
Are spark plugs the likely fix, and how do I choose the right ones for my Mark VI Golf R? "one step cooler"??
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1996 gmc jimmy knocking at medium RPM no knocking at idle or high RPM it sounds like it may be coming from the transmission
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I am the original owner of a 2006 Prius with 265k miles. I use Mobil 5-30 synthetic oil and I drive a steep hill every day and the engine knocks in the summer afternoons when I use cheap 87 Octane gasoline from Safeway or Costco. If I use better 87 octane gasoline (Chevron, Shell) generally there is less knocking. Also during the winter months no knocking even with cheap gasoline.
During summer I can sometimes make the knocking go away by accelerating or decelerating. The knocking is intermittent and generally occurs only during the steepest parts of the commute. The engine might knock for 30 seconds to 60 seconds before its goes away as I try to change the engine RPM.
Unfortunately I am burning some oil at a rate of approximately half a quart every 5k miles. Generally I watch the oil level, but there have been cases where the oil level has fallen below the lowest mark on the dip stick so I suspect I have some carbon build up.
I've read posts where others have used additives like gumout regane and I've read posts that say not to use additives.
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I drive a 2012 SE V6 with 1600 km in it. Literally brand new car, two days ago I noticed a faint knock when driving normally over medium sized bumps in the road. Sound seems like it is coming from the front drivers side. It's not my first time around the block and wonder if it's suspension related or steering related. It's going to the dealer tomorrow...
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I am trying to get this car of mine into tip top shape (2000 Pontiac Grand Am SE). Ive been experiencing this problem where the rpms will jump while the engine is under a high load. If i apply more throttle, the problem goes away.(as shown in the video)
In the youtube video below, I am going up a 5% grade. This will happen at slower speeds, but i will need a significantly steeper grade of around 25-30% ...
[URL] ....
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it was warmer the day than it usually was so it dosnt make the noise as bad however there is usually a lot of clatter/knock from the engine when cold. does it at idle and while accelerating. it gets less once the engine warms up but has been doing it for a while. car has 93k miles and synthetic oil is used. there is also a metal rattle sound almost like a heat shield that is loose. idk if that is part of the engine issue or not. but it only happens in winter or when temps fall below 60 degrees. kinda hard to hear on the vid but its there.
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I have an 2001 Ford Escape V6 3.0, about 130,000 miles. When the engine gets under high load and low RPM, before downshifting, it will shudder (misfire?). Local shop couldn't reproduce it, but they thought it might have to do with slightly cracked vaccume hose, which they gouged me to replace. No improvement. Next they wanted $700 to replace Valve Cover Gaskets. I decided to become a mechanic and learn how to do that one myself. Sure enough, there was a little oil dripping onto one plug. I replaced the gaskets and all 6 spark plugs successfully. Still didn't fix the problem though.
Symptoms will occur reliably when driving at 45-50 MPH with the transmission in overdrive (1500 RPM), and I begin a slight incline. The vehicle will kind of chug forward (feels like sporatic misfires) in overdrive, getting down to 1200 RPM before deciding to downshift. Generally, I can just give a little more gas to force downshift and avoid the nasty-feeling misfires. Some days, however, it is much worse, and will misfire at idle, and make me feel like I have to treat the gas as an on/off switch to keep the engine from dying. (It has never actually died.)
During a really bad day, I got a flashing check engine light. I did not check codes in time - they've all cleared.
I now have an ODB2 reader logging real-time data. All I can do is prove the conditions that cause the symptom: high engine load at low RPM is the recipe. Nothing seems to show a cause... I may just not know what I'm looking at :-/ . I haven't monitored long enough to record a 'bad' day.
I've read about ignition coil issues on this engine, and weather might explain why this is worse some times than others. However, I wouldn't expect that to be load dependant.
Most of the time it feels like the transmission just isn't shifting when it's supposed to, but on the bad days it seems more than transmission related. When stopped at a light in Drive, this can still occur.
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I have a '07 Sonata GLS with the 2.4-liter Theta engine and the 4-speed automatic. It has 52k miles on it and has always been serviced regularly. It's been a pretty decent car but is starting to feel a little tired, most notably the worn/bouncy suspension.
Anyway, the other day I was driving down the highway and gave it a little gas to pass a slower car. Doing 60 MPH it downshifted to 3rd (~2000 to ~3300 RPM) and I thought I heard a noise in the engine bay, but I wasn't sure. I ended up needing more power so put it to the floor and as it kicked down to 2nd at ~5000 RPM the rattly noise got a lot more pronounced. Driving around normally I don't hear it but any time I put it to the floor (merging/passing) I will hear the rattle. I can also hear it if I lock it in 2nd gear and give it full throttle up a hill at low speed, like you might do with a stick shift.
It seems like it only does it under load because if I rev it to ~4000 RPM in park in the driveway, there's no noise, even at full throttle. I know the V6s had tensioner issues but I haven't heard much about the 2.4s. I'm not super concerned as it is still under warranty but what might be wrong with it as this is my first Hyundai vehicle, especially in case the dealer can't replicate it.
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94 blazer ac fan will work on low and med but not high replaced resistor under hood but still no high speed fan?...........
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Had my first drive with the windows down for a long time and noticed a new medium to high pitched whine, stays relative to engine speed. Not the turbo, its much louder than that, i searched about the water pump issues and no one seemed to mention any associated noise, just coolant on the driveway. Waterpump? Alternator?
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Driving home the other day I noticed some vibrations up front. Reminded me of out of balance wheels. Then the check engine light started blinking. Then it was on steady, then blink, then steady... Took it easy the rest of the way home. Code reader said P0138 Oxygen sensor circuit high voltage bank 1 sensor 2, and P0304 Cylinder 4 misfire detected. At home is where I saw the engine shaking and extra noise from it (visions of piston rod slapping around in there). Removed plugs (original? tough to get out!), compression tested all 4 cylinders (130 to 140), new spark plugs (had they been in there for 196K miles?). Start engine and same, shake shake with some extra noises that weren't there before (car just sitting in driveway).
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For the techs in here, I have a data logger (AutoTap) and the symptoms are low idle and sometimes it runs rough idling and driving. It had me thinking the fuel pump was going out. That is not the case. I did get into part swapping mode so I have new plugs and coils and new VCTs all in the last 24 hours. The engine has 85K miles on it (rebuilt ford long block), truck had 150K. I'm not sure what parts were replaced when the longblock was replaced but I'm guessing the 02's are original.
Data that looks odd to me in the Autotap real time data logging is this:
- STFT Bank 2, goes from 10-15% and climbs till its over 300% and then the truck goes into Open Loop due to an error (per the Autotap) but it never says what error and the CEL never lights. Idle goes up when its in open loop and then after a minute or two it will drop back into closed loop.
- Fuel pressure never drops below 37
- Idle will drop to 250rpm
- Engine load at idle is 25%?! With AC on and idling (at 550rpm) engine load is 42%? Seems high no?
Nothing else other than the STFT Bank 2 and the high engine load seems out of miss. No misfires, codes, etc. What else should I look at?
Other background/patient history:
- Alternator #3 was installed 2 weeks, It replaced alternator #2 that went in 4 months ago to replace the original alternator (144K miles). Both died and caused low voltage/battery dying symptoms and verified by volt meter.
- FPDM was replaced proactively 8 months ago just because I don't want it to break down when I'm towing my race car.
- I have not tried cleaning MAF, EGR?, IAC, nor have I replaced O2s. The only thing that leads me to believe MAF might need cleaning is the load?
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If we have the air on a medium or high setting (A/C or just vent air) and coming out of the middle vents (at your face in other words), then turn the car off with the fan speed on that medium to high setting, then turn the car on later, the air comes out of the defroster (windshield) instead, even though the middle (face) setting is selected.
I have to turn the air fan speed right down to the lowest setting, then the air switches to the vents (face), and I can then turn the fan speed back up again. Its like it has a weak flap or something in the dash that diverts the air around. Car is an 03 6.0l limited with the "climate control" (the buttons and digital display).
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I have the Bridgestone Turanza EL400 radials on my car and now at 8000 miles I have started hearing a noise that is hard to describe. It sounds like a singing, or medium to high pitched whine (no, it's not the transmission sound others have reported). It occurs anytime I'm above 20 MPH. I can put the car in neutral at 55 and coast and it's still there, so it's not the engine (which is idling while I'm coasting). I can't detect any noise from the engine at all at idle or at speed. I took a dealership technician on a ride and he thinks it sounds like tire noise. I have heard some complaints on one of the tire sites about this brand being noisy after a few thousand miles.
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Recently, our 2009 Sonata jumps to relatively high and not normal RPM when start cold (and I don't mean winter-cold; I mean first start in the morning). It jumps to around 2500 rpm for 3-4 seconds before it goes down to the normal 1200-1300 or so for a cold start.
Also, not sure if this is the normal Sonata engine sound, but when we push the accelerator it sounds like the engine is knocking, almost like a whistle of fuel flowing.
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I am having overheating problems at high speed/high rpm/under load. The only codes ive gotten are EGR dpfe (0401). Truck is 99 f250 with the 6.8 new egr valve, dpfe, new coolant, new thermo, new sensor under manifold. I blew 90 lbs air pressure thru the egr lines, big and small, they were clear.
So whats left? I never hear my fan clutch......should I? I've had other trucks and the fan roared when first started for a few seconds, and then again when you were hot...they really roared.
Is it possible for the egr port where it goes into the throttle body to be plugged? guess I should've checked that when I had the egr off. Would an aux. fan be a waste of time?
This is pulling a 3500 lb camper trailer up moderate hills.
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2002 Ford Escape. My car was sitting for a week in cold weather. I started it yesterday with no problem, but only waited for a minute or two before driving. I was driving at city speeds, and heard a knock. I was accelerating up a hill and it hesitated/ jerked once or twice. The check engine light came on, and now it knocks every few seconds when I am stopped at a light. It also doesn't seem to catch the highest gear (5?) when it shifts, making a constant knocking sound and vibrating. Letting go of the gas or accelerating so it shifts back down makes the noise go away. In other gears it seems fine, with an occasional jump... It is an Automatic V6. I am taking the car in Monday, but I would like to know possible causes.
This morning I let my car warm up for 40 minutes (15 minutes in park and 25 idling at the bus stop). The problem was no better. By knock I meant it feels like someone bumped the engine. My foot vibrates on the brake for a second. And when it changes into the highest gear, it shudders ( until I release or further press the gas pedal. The revs don't change while it is shuddering or knocking.
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