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Hello everyone,
This has been ongoing for about a year and one that I have wasted a ton of money and time trying to diagnose. Hopefully someone out there can point me in the right direction. I will give as much detail as I can to help you. Here it goes…
Model Year: 2012
Make/Brand: Toyota
Complete Model: Tacoma – Base Model – Access Cab
Engine/Transmission/4WD/2WD: 2.7L 4-Cylinder/5 Speed Manual/Part-Time 4WD
Country (market) the car was sold in: British Columbia, Canada
Total Kilometers: ~ 60000 (One year left on lease and power-train warranty)
Driving Habits: Roughly 75% stop-and-go city and 25% highway. I have been the only driver since I got it in June 2012.Symptoms:
Visual
– No check engine light but two stored codes found by shop: P0353 & P0354. However, they have not returned since the shop cleared them back in October last year.
– Poor fuel economy: Used to get 20 mpg city and 23 highway. Has gone down to 18-19 for both city and highway.Feel
– When driving in the correct gear to keep the rpm above 2000, I have to push on the gas more just to maintain speed (~30-40%) on flat terrain. Worse on hills.
– If I attempt to accelerate, I have to push the gas pretty far, which causes a humming and vibration in the steering wheel and seat.
– Intermittent low idle on cold start (1000 instead of 1500 rpm). There were a couple of times when the engine would chug at really low rpm before raising and getting smoother.
– Symptoms more pronounced when truck has been driven for a while and the engine has warmed up.
– If the truck is in motion and I take my foot off the gas,I hear a thump and feel it at the bottom of my seat. The front end tilts forward very slightly. This is followed by a noticeable humming and vibration in the seat and steering wheel. The lower the gear, the more pronounced this is. The backfire usually accompanies this.
– If I press the gas after this happens, the thump occur again before accelerating.
– Idle feels rougher when I turn the A/C or heat on.Sound
– Backfiring that intermittently occurs on cold start and when decelerating in 1st and 2nd gear. Usually I am going too fast in the other gears to hear much.
– Backfiring sounds like an empty coke can being dropped under the truck. When sitting in the driver’s seat, it seems like the sound is coming from under the cab.Smell
– After going up a long mountain highway for about 30 minutes at 3000 rpm and pull over, there is a noticeable burning odor. No signs of burning parts.Warranty Work:
– New clutch at 25000 km due to master/slave cylinder failure and defective LUK clutch kit which is a known pattern failure.
– Front passenger seat weight sensor replaced.Actions Taken:
– Have been to several shops and Toyota dealerships who tell me the same thing: Everything feels and looks normal.
– Power balance test: Passed – engine shook after disconnecting every coil pack.
– New iridium spark plugs with no gap adjustment.
– Routine oil, oil filter, and air filter changes every 6 months.
– New front rotors/pads, and resurfaced rear drums.
– Inspected suspension components and wheel bearings with mechanic and found nothing.What am I thinking about doing next?
– Replacing PCV valve and hose
– Replacing u-joints
– New tires, balancing, and alignment
– Changing transmission, transfer case, and forward/rear differential fluids. I was thinking about checking the differential gears, but there is no way to access them.
– Compression test
– Replacing cylinder 3 and 4 coil packsYes this is a REALLY long list and I am really grateful if you even read this far. However, I really hate throwing parts at problems. I feel that I am in between a rock and a hard place and running out of options. Toyota denies that anything is wrong, and the problems keep creeping up. Is there anything else not listed that I should check or replace? Should I skip anything on my list above?
Thank you in advance!
James
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Replies
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I would say you are correct with doing a compression test. See what happens, may be an internal problem. Also check the fuel pressure… Visually inspect the fuel line for kinks or damage. Another thing that comes to mind is a restricted exhaust. I would recommend visually inspecting the entire exhaust system for something unusual. The low mileage seems like it would not be a clogged exhaust, but would still look for physical damage. A vacuum test (Eric has a video on this) can check to see if there is a restriction internally. Lastly, it may be a transmission issue…
Good luck
-Karl
[quote=”ToyotaKarl” post=162492]I would say you are correct with doing a compression test. See what happens, may be an internal problem. Also check the fuel pressure… Visually inspect the fuel line for kinks or damage. Another thing that comes to mind is a restricted exhaust. I would recommend visually inspecting the entire exhaust system for something unusual. The low mileage seems like it would not be a clogged exhaust, but would still look for physical damage. A vacuum test (Eric has a video on this) can check to see if there is a restriction internally. Lastly, it may be a transmission issue…
Good luck
-Karl[/quote]
Hey Karl,
Thank you so much for the feedback! The only thing on your list that I can’t handle is checking the fuel pressure. I understand there is a meter out there for this, but have no idea where to hook it up on my particular engine.
Exhaust
I have already inspected the exhaust. A while ago I hooked up a shopvac to the tailpipe, sealed it, and turned the vacuum to reverse-flow to pressurize the exhaust system. After taking a spray bottle of soapy water to the exhaust, I found bubbles forming at the spring loaded flange that connects the manifold to the exhaust pipe. When I took the truck to an exhaust shop to get their opinion, the tech wasn’t able to feel the leak. I didn’t feel anything either. The engine was hot at this time. It’s possible the metal expanded and sealed the leak. No other physical damage is present.Fuel System
Part of the reason why I have such low mileage on this truck is because when I went on deployments, I would leave the truck parked for long periods of time (1-4 months). However, I usually put in a bottle of fuel stabilizer, topped off the tank, and drove it before leaving town. When I first started driving the truck, I would usually fill the tank when it got to 1/8 full or when the light came on. I learned later on that this is bad for the fuel pump. So I always fill up at 1/4 tank now.Drive-train
In addition to the frequent stop-and-go driving I do, my city has TONS of speed bumps. When I first started driving, I also made several panic stops. Since I didn’t have anything in the bed of the truck, panic stops resulted in wheel hop every time.Ignition
When I replaced the spark plugs, the old ones didn’t look too bad. The electrodes had a light brown burn mark that seemed normal.[quote=”ToyotaKarl” post=162492]I would say you are correct with doing a compression test. See what happens, may be an internal problem. Also check the fuel pressure… Visually inspect the fuel line for kinks or damage. Another thing that comes to mind is a restricted exhaust. I would recommend visually inspecting the entire exhaust system for something unusual. The low mileage seems like it would not be a clogged exhaust, but would still look for physical damage. A vacuum test (Eric has a video on this) can check to see if there is a restriction internally. Lastly, it may be a transmission issue…
Good luck
-Karl[/quote]
Okay so I performed a compression test today. I removed all the spark plugs and disconnected both fuel injectors before starting. Here are my results:
Front
1 – 180
2 – 100
3 – 160
4 – 150
BackI repeated the test on cylinder 2 again and got the same result. After adding a teaspoon of oil to the cylinder and trying again, the compression raised to 110. After another attempt, the compression stayed at 110. So here are two questions I have:
1) Would this be an indication of bad rings or bad valves? As far as I can tell, the oil level hasn’t changed and there hasn’t been any blue smoke coming out of the exhaust.
2) If this has been going on for a year, why hasn’t the bloody computer stored any codes or triggered the check engine light?
[quote=”Crockett85″ post=162551][quote=”ToyotaKarl” post=162492]I would say you are correct with doing a compression test. See what happens, may be an internal problem. Also check the fuel pressure… Visually inspect the fuel line for kinks or damage. Another thing that comes to mind is a restricted exhaust. I would recommend visually inspecting the entire exhaust system for something unusual. The low mileage seems like it would not be a clogged exhaust, but would still look for physical damage. A vacuum test (Eric has a video on this) can check to see if there is a restriction internally. Lastly, it may be a transmission issue…
Good luck
-Karl[/quote]
Okay so I performed a compression test today. I removed all the spark plugs and disconnected both fuel injectors before starting. Here are my results:
Front
1 – 180
2 – 100
3 – 160
4 – 150
BackI repeated the test on cylinder 2 again and got the same result. After adding a teaspoon of oil to the cylinder and trying again, the compression raised to 110. After another attempt, the compression stayed at 110. So here are two questions I have:
1) Would this be an indication of bad rings or bad valves? As far as I can tell, the oil level hasn’t changed and there hasn’t been any blue smoke coming out of the exhaust.
2) If this has been going on for a year, why hasn’t the bloody computer stored any codes or triggered the check engine light?[/quote]
You can perform a leak down test to see where if something isn’t sealing right but the computer can’t tell if it doesn’t have good compression in one cylinder. I mean it is noticably lower than the other cylinders which is a problem, but it is over 100 so even if the engine could see low compression that probably wouldn’t trigger it.
Sent from my iPhone using Tapatalk
[quote=”ArtTheConfusedGuy” post=162563][quote=”Crockett85″ post=162551][quote=”ToyotaKarl” post=162492]I would say you are correct with doing a compression test. See what happens, may be an internal problem. Also check the fuel pressure… Visually inspect the fuel line for kinks or damage. Another thing that comes to mind is a restricted exhaust. I would recommend visually inspecting the entire exhaust system for something unusual. The low mileage seems like it would not be a clogged exhaust, but would still look for physical damage. A vacuum test (Eric has a video on this) can check to see if there is a restriction internally. Lastly, it may be a transmission issue…
Good luck
-Karl[/quote]
Okay so I performed a compression test today. I removed all the spark plugs and disconnected both fuel injectors before starting. Here are my results:
Front
1 – 180
2 – 100
3 – 160
4 – 150
BackI repeated the test on cylinder 2 again and got the same result. After adding a teaspoon of oil to the cylinder and trying again, the compression raised to 110. After another attempt, the compression stayed at 110. So here are two questions I have:
1) Would this be an indication of bad rings or bad valves? As far as I can tell, the oil level hasn’t changed and there hasn’t been any blue smoke coming out of the exhaust.
2) If this has been going on for a year, why hasn’t the bloody computer stored any codes or triggered the check engine light?[/quote]
You can perform a leak down test to see where if something isn’t sealing right but the computer can’t tell if it doesn’t have good compression in one cylinder. I mean it is noticably lower than the other cylinders which is a problem, but it is over 100 so even if the engine could see low compression that probably wouldn’t trigger it.
Sent from my iPhone using Tapatalk[/quote]
I was just watching Eric’s video on doing a leakdown test. At this point, my gut is telling me that it’s a exhaust valve issue. Here is my reasoning:
– Loss of compression is only in one cylinder and there is no white smoke coming from exhaust – So that would eliminate the head gasket.
– Little change in compression after wet test, no blue smoke from exhaust, and no visible change in oil level – That eliminates the piston rings.I still want to do a leakdown test to verify my theory. Is my reasoning sound though?
Yes, do a leakdown test on number two and listen for escaping air at the tailpipe and the intake. For your purpose, if you don’t have a leakdown guage set, but have compressed air, you can use a fitting to apply compressed air at the spark plug hole. You are not so concerned about having a guage reading. Your goal is to hear where the air is escaping from.
Hope this helps.
Good job finding the compression problem. Time to get it documented by Toyota before warranty runs out..
[quote=”cj1″ post=162581]Good job finding the compression problem. Time to get it documented by Toyota before warranty runs out..[/quote]
Thanks man! That is exactly what I plan to do. It’s a shame that this truck has had so many problems. On a positive note, its probably a good thing I got this truck. I have gained so much experience and knowledge about diagnostics and interpreting symptoms. That being said, I hope this doesn’t happen again in the future lmao
After I get a leakdown test done on Tuesday, I will come back and post the results and what the dealership says.
One more question…should i get all the cylinders tested or should i just focus on number 2?
The dealer can quickly do current ramping compression test to spot the cylinder/cylinders that have weak compression. This will give them a basis to do further leak down test to determine where compression is being lost.
The 100 psi you measured should easily show up on the current ramp test.
The 150/160psi seems low. I would think that all should be close to 180 since engine has low mileage.By comparison my 2007 2.7, 95% stop/go 50,000 miles, reads within 5% of 180psi across all cylinders.
Hope you can get a warranty fix. Sometimes the dealer doesn’t like to look to deeply into warranty issues.
Need to hold their feet to the fire.[quote=”cj1″ post=162585]The dealer can quickly do current ramping compression test to spot the cylinder/cylinders that have weak compression. This will give them a basis to do further leak down test to determine where compression is being lost.
The 100 psi you measured should easily show up on the current ramp test.
The 150/160psi seems low. I would think that all should be close to 180 since engine has low mileage.By comparison my 2007 2.7, 95% stop/go 50,000 miles, reads within 5% of 180psi across all cylinders.
Hope you can get a warranty fix. Sometimes the dealer doesn’t like to look to deeply into warranty issues.
Need to hold their feet to the fire.[/quote]I have some serious bad blood with my dealer and doubt they will help me. The last time I went in for this, I told them exactly what was going on. When they called me later in the day and told me they couldn’t find anything, I went over and asked politely to speak to the service manager. After sitting in the waiting room for 20 minutes, the operations manager came out instead and said I should go for a test drive with the shop foreman. The foreman claimed that everything was normal. I barely managed to keep my cool but my patience was wearing thin.
When we got back to the dealer and spoke to the operations manager again, I insisted that something was wrong and that they need to look deeper than computer codes. He refused to help me and his response was “i’m sorry but we can’t do anything for you” in a calm but i don’t give a damn about you way. I ended up leaving the truck at the dealer and walking away. I was so furious that I was close to doing something rash. I came back the next day after cooling off, paid the $100 bill, and left. This was when I decided to do most of the maintenance myself.
That is why I feel like I am in between a rock and a hard place. I can’t afford to hire lawyers and go to small claims court. I feel like I have no recourse at all other than documenting the issues and covering my ass.
[quote=”Crockett85″ post=162475]Hello everyone,
This has been ongoing for about a year and one that I have wasted a ton of money and time trying to diagnose. Hopefully someone out there can point me in the right direction. I will give as much detail as I can to help you. Here it goes…
Model Year: 2012
Make/Brand: Toyota
Complete Model: Tacoma – Base Model – Access Cab
Engine/Transmission/4WD/2WD: 2.7L 4-Cylinder/5 Speed Manual/Part-Time 4WD
Country (market) the car was sold in: British Columbia, Canada
Total Kilometers: ~ 60000 (One year left on lease and power-train warranty)
Driving Habits: Roughly 75% stop-and-go city and 25% highway. I have been the only driver since I got it in June 2012.Symptoms:
Visual
– No check engine light but two stored codes found by shop: P0353 & P0354. However, they have not returned since the shop cleared them back in October last year.
– Poor fuel economy: Used to get 20 mpg city and 23 highway. Has gone down to 18-19 for both city and highway.Feel
– When driving in the correct gear to keep the rpm above 2000, I have to push on the gas more just to maintain speed (~30-40%) on flat terrain. Worse on hills.
– If I attempt to accelerate, I have to push the gas pretty far, which causes a humming and vibration in the steering wheel and seat.
– Intermittent low idle on cold start (1000 instead of 1500 rpm). There were a couple of times when the engine would chug at really low rpm before raising and getting smoother.
– Symptoms more pronounced when truck has been driven for a while and the engine has warmed up.
– If the truck is in motion and I take my foot off the gas,I hear a thump and feel it at the bottom of my seat. The front end tilts forward very slightly. This is followed by a noticeable humming and vibration in the seat and steering wheel. The lower the gear, the more pronounced this is. The backfire usually accompanies this.
– If I press the gas after this happens, the thump occur again before accelerating.
– Idle feels rougher when I turn the A/C or heat on.Sound
– Backfiring that intermittently occurs on cold start and when decelerating in 1st and 2nd gear. Usually I am going too fast in the other gears to hear much.
– Backfiring sounds like an empty coke can being dropped under the truck. When sitting in the driver’s seat, it seems like the sound is coming from under the cab.Smell
– After going up a long mountain highway for about 30 minutes at 3000 rpm and pull over, there is a noticeable burning odor. No signs of burning parts.Warranty Work:
– New clutch at 25000 km due to master/slave cylinder failure and defective LUK clutch kit which is a known pattern failure.
– Front passenger seat weight sensor replaced.Actions Taken:
– Have been to several shops and Toyota dealerships who tell me the same thing: Everything feels and looks normal.
– Power balance test: Passed – engine shook after disconnecting every coil pack.
– New iridium spark plugs with no gap adjustment.
– Routine oil, oil filter, and air filter changes every 6 months.
– New front rotors/pads, and resurfaced rear drums.
– Inspected suspension components and wheel bearings with mechanic and found nothing.What am I thinking about doing next?
– Replacing PCV valve and hose
– Replacing u-joints
– New tires, balancing, and alignment
– Changing transmission, transfer case, and forward/rear differential fluids. I was thinking about checking the differential gears, but there is no way to access them.
– Compression test
– Replacing cylinder 3 and 4 coil packsYes this is a REALLY long list and I am really grateful if you even read this far. However, I really hate throwing parts at problems. I feel that I am in between a rock and a hard place and running out of options. Toyota denies that anything is wrong, and the problems keep creeping up. Is there anything else not listed that I should check or replace? Should I skip anything on my list above?
Thank you in advance!
James[/quote]
You hit on everything except CLOGGED CATALYTIC CONVERTER, which sounds like it could be accounting for SOME of your issues, particularly backfire, and BURNING SMELL. your spark plugs would probably be burned up as well. You can usually even see hot gasses escaping when the car is turned off (wavy air.)Sent from my SM-N900V using Tapatalk
“I can’t afford to hire lawyers and go to small claims court”
In that case, escalate problem to Toyota area manager along with documentation and an independent shop analysis of the problem.
A professional third party diagnoses may help to move this along.Let us know your progress and good luck.
Hey everyone,
Just an update for you all. I made a mistake on that compression test. When I called a local shop to schedule a leakdown test and told the mechanic about my compression test results, he asked me if the engine was warm when I did the test. The engine was cold….ooooppppps lmao
So after driving around and getting the engine to operating temperature, I did another compression test. Here are the numbers:
Front
- Dry: 175# ; Wet: 190#
- Dry: 182# ; Wet: 195#
- Dry: 182# ; Wet: 190#
- Dry: 180# ; Wet: 195#
Back
After finding a manual for my engine, it said that normal compression pressure is 178# with no more than 10% difference between cylinders and a minimum pressure of 128#. I guess my engine is fine after all. Yayyyy!!!
Yesterday, I also changed the driveline fluids, greased the u-joints, and put some dielectric grease on the spark plugs and coil packs, The truck was due for this maintenance anyway, so I figured that I would hit them all at the same time. When I drained the driveline fluids, I checked both front/rear differentials, x-case, and transmission fluids with a magnet to see if there was anything. There was a small amount of sludge and a couple of metal shavings, but nothing that would make me raise an eyebrow.
After doing all of this, I went out for a long drive. The drive seemed to be smoother at first. However, the vibration started to come back when I did heavy acceleration or engine braking in gear.
So this leaves the u-joints, pcv valve/hose, catalytic converters, and tires.
Try contacting Toyota directly. Dealers can be well, like you found out. The only issue now maybe that you have done work to it yourself. You have to even get a warranty approved oil change up here or its void.
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