According to ALLDATA this engine does not have a balance shaft. The picture shows a cam gear, crank gear, tensioner, and water pump.
There is another possiblity, they installed the timing belt wrong and damaged one or more valves. A compression check would verify this. One cylinder with low compression would cause the engine to idle rough but when the rpm’s are higher you don’t notice it.
Exactly Willey…this is what we were saying with that one tooth off theory… And the damage that can and will result… I haven’t worked on the Honda 5cyl engine yet I do know that its in the car the old fashioned way…in line front to back…and that’s nice. With no bal shafts man they have it EZ…No? The Cam/s should have been checked, rechecked…double checked…and then check it again… ALL while you still have it apart and before you button it up. This is why you are supposed to crank the engine over BY HAND…several revolutions. Also to ensure that the T-belt tensioner chokes up on the slack in the T-belt…ALL of these items are done right after you finish the job and BEFORE BEFORE BEFORE you button it up…that way you don’t run into this.
I have to be honest…when I do some complex T-belts…the Hand Cranking is a GODSEND… I have caught meself many X…it usually occurs like this… You get the belt on every pulley etc…then when you Hand crank and the tensioner does its job…sometimes miraculously…One of the cams has found its way to being one tooth off…surprises me each time it has happened…but AGAIN…the hand cranking…HELL its even in the INSTRUCTIONS…can you believe that? LOL…
I’m certainly not going to accuse the mechanic of any wrongdoing but in many cases an engine that idles smooth before a timing belt job and idles rough afterwards usually means that someone has made an error during the T-belt job. Off a tooth or two, vacuum line loose or vacuum fitting broken, and in a worst case such as Willey mentions; damaged a valve, or more than one.
It would not be unheard of for someone to lay the blame off on something else (motor mounts say) and use that revenue to cover any prior mistake while laying the BS on a bit thick.
The above is purely hypthetical at this point.
Side question: If the customer thinks the tech should re-check the timing (i.e., dig in there and almost re-do the job), but the tech says that that is not the problem, how should the finances work for this high-cost re-check? If the customer is right ,and the timing had been mis-set, surely the customer owes the tech nothing. But what if the timing was correct all along – should the customer have to pay for the work? (That seems fair to me, but I’ve never worked as an automobile tech.)
The mechanic shouldn’t even TRY to charge the OP…because if the OP is correct the mechanic just put the guy in a situation that is a MAJOR Health risk to his engine…and if he caused it…he knows he needs to remedy… Now that’s how I work (I’d be worried if I was the tech for sure, but this simply DOES NOT happen to me…Hand cranking the engine weeds this out Perfectly…that’s the entire point to it)…Who knows what the Pirates out there will try to pull.
To simply re-check the T-belt job on the Cam/s only is not an extensive job…at all. Most vehicles have a separate plastic cover that is outside the actual Valve cover…You Simply put the engine at TDC on the #1…and then remove the Plastic Cam cover “door” and take a looksie… You can do it in under an hour EZ…Oft times a few minutes really.
Many engines do not have any obstructions up top and near or around that upper Cam sprocket cover…so not much to it really… It gets ugly when…if he looks at the cam sprocket and they are dead on…and now he needs to check the Balance shaft/s (if so equipped)…now to do that is akin to tearing the engine down prior to doing the entire T-belt job. The balance shafts are usually located down low…and require a lot of part removal simply to see them…
I am betting a cam is off a tooth and can be easily found… Now how do you remedy the one tooth off? SOME engines allow you to reach the lock bolt on the T-belt tensioner thru a plastic cover…some DONT (Honda’s DO)…and if you can do that you may get lucky and be able to “slip” the belt into the correct position.
Blackbird
It’s a 30 second job with a vacuum gauge to know if the cam timing is off or not.
Honda Blackbird, OK4450,
Thanks for the info. I’ll reserve my question for if ever a high-cost case does come up.
WELL… I’m back!! just wanted to bring you up to date on the ongoing saga of the vibrating 97 Acura TL…
EVERYTHING you all suggested has been checked and rechecked! One motor mount and a valve has been replaced…no difference! By the way my mechanic ( he’s listed in CAR TALKs BEST MECHANICS IN YOUR AREA) has NOT billed me for any of this work, since it didn’t solve the problem. He even took it to Acura with ALL the paperwork and receipts from the parts he used and paid for the diagnosis. They had it for 4 days. Their receipt says “runs as designed”. When I talked to them, the service manager suggested, due to the age if the car, it was time for…MOTOR MOUNTS!!! Then he said “after market parts were used” and I produced receipts for “original equipment by Honda”. I also reminded him that Acura replaced the valve. The vibration is now erratic and only occurs when the engine revs above 1000 rps. When you stand touching the front drivers side fender, you can feel the vibration, but when you place your hand on the engine at the same, you don’t feel any vibration in the engine at all. So…where is this coming from??? Transmission Mounts??? Just thought I would fill you in and wait for more input!! Anyone up to the challenge? We’re running out of ideas…and I don’t like my Acura anymore.
I don’t see how changing the timing belt could cause you to need new motor mounts. Presumably you needed motor mounts before, but they are still good enough you didn’t notice before the timing belt change. If so, it seems to me – while they indeed may need replacing – they should remain good enough for now such that the engine idles at least as good as before and with no greater vibration than before. Motor mounts seems a red herring.
There’s many possiblities of what can cause vibration, but here’s what I’m thinking to be the most likely given the car’s recent work.
If it isn’t #1, then
The engine idle speed may simply need adjustment to spec. If the idle speed is set too low, vibration can be a symptom. It is fairly easy sometimes to bump the idle adjustment screw and cause the idle speed to drop or increase when doing work on a car. I’ve done this on my Toyota. Have your mechanic check your warm and cold idle rpm.
Some vaccuum hose or wire or something else was taken off as part of the repair and not put back on or two vacuum lines were switched. Usually there is a diagram of the vaccuum hose placement on the underside of the hood on most cars. Check what you have compared to the under-hood diagram to make sure everything is hooked up correctly.
Best of luck .
thanks for the info…had my Acura tl to the Acura dealer yesterday. They took it apart (again). ckecked EVERYTHING again and said everything points back to the motor mounts. Said the ones installed were bad OR after mkt. My mechanic is going back to his vendor and still has not billed me for any work ( neither did ACURA). The car does not vibrate as bad, but now it’s erratic and sometimes doesn’t at all…will keep you posted!