yup

you've done what you could. I think what bugs us the most is that it's so darn difficult to get to anything on these 4th gens that we become irritable just at the thought of going under the hood.

They are good looking cars but we paid a steep price in access

 

Here is their unbelievable reply to my review via Yahoo:

"todays.tech - 10/06/10
John F We will gladly perform a vacuum test in your presence so you may review the results. We also will explain the testing and results observed from our prior diagnostic tests. We will do this at no charge to you. We take pride in our business, and appreciate our customers. Robert Gulbrandsen Service Advisor Today's Technology Auto Repair"

Is this guy dense! What good would the test do me now.
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Here's my review in it's entirety to put the above retort by them in context:

First of all, I have recommended TT to literally dozens of people and have never received a single complaint from any of them.

Unfortunately, my first experience with them did not go so well. I have been a shade-tree mechanic for 30 years out of necessity. I am definitely not an expert in many areas but I have rebuilt motors, replaced tranny's etc. so I have wee bit of experience. I don't like working on cars any longer as I am in grad school working on a dbl master's and do not have much time or the desire to any longer quite frankly.

That said, I had a hesitation problem in my Camaro which I had troubleshot for a week or so and finally gave up. My "engine" light never came on so I could not pull a code with my OBD tester. There is a very expensive OBD tester ($4000+) which shops have and those will generate a great deal of diagnostic information that the cheap testers don't so I decided to give TT a try.

The day I dropped my car off I got a call from one of the owner's, Todd, who is a very nice guy btw, and he told me that they did a compression test, etc. and decided that the fuel injector in the #1 cylinder was bad. After a bit of haggling I got a $371 estimate down from $420.

The next day I was told that after tearing it down, taking off intake, etc. that his mechanic realized that the intake valve was not opening in the #1 cylinder and found out that the ramp (lobe) on the cam was worn. This is a major fix and the cost went up to $1200-$1400. I could not afford it regardless and told him to put it back together. If I was going to put that kind of money into this 15 year old engine I would just get a short block for $1100 and (grudgingly) do it myself.

My issue with TT was why they did not do a vacuum test before doing a compression test. A Vacuum test will show a valve train failure somewhere. When you have a engine miss and you suspect it is mechanical normally you test the vacuum with the engine running before you do a compression test. Finding a failed cam with a compression test is difficult and not practical in and of itself. If there is any of the lobe left on the cam at all it would not show up. Even if the valve only moved .05 the compression test is done at such a slow speed the cylinder would still have a chance to fill up. I expressed some of my concern to Todd when I went and picked up the car and his response was, "in a perfect world" they (Jason) may have been able to detect it earlier, I suppose. I really don't know what that means. I know that there was a complete misdiagnosis and a final bill of $221. I had to pay to put everything back together and take my 5 cylinder Camaro home.

I respect Todd (and still do) but I almost lost it while I was paying the bill when he told me, quote: "I didn't charge you for the valve cover labor/gaskets". "That would have cost significantly more". Really Todd? There were customers in the waiting area and I didn't want to be a dic% and explain what really happened. There is absolutely no doubt that a simple 5 minute vacuum test would have shown the bigger issue (not a simple fuel injector). The vacuum test would not have definitively diagnosed the cam but it would have been at least able to tell everyone that I had an internal engine problem VERY EARLY in the process. And, save me $150 for unnecessary gaskets and unnecessary labor replacing a supposedly faulty fuel injector that was not the issue.

I just want Todd and TT to admit their misdiagnosis and admit that Jason should have performed the 5 minute vacuum test and avoided an unnecessary tear down. Also, a refund check for $146 ($221-$75 diagnostic fee) would be nice. ALL fair requests.

Peace


Direct Link:
http://local.yahoo.com/details?id=36...w-11#rvw-11-bm

 

1995 3.4. I also used the 15,000 Mobil 1. Intuition told me this was counter-intuitive but I didn't listen. How the hell does one lobe on the #1 cylinder go flat and the others are fine?

 

A conventional camshaft is a cast iron stick that has the rough shape of journals and lobes on it. The cast iron stick has round journals and sort-of egg-shaped lobes machined into/onto it. At this point it's a pretty cast iron stick, but still soft and grey.
Then the "stick" is heat treated. This can be by flames or electric coils but, regardless of the method, the heat treatment makes the outer layer or "skin" of the casting hard. Hard enough to take the extreme pressure of lifters pressing against it with valve spring force (almost 200 pounds when the valve is fully open). Only the lobes and journals (the wearing surfaces) are hardened. The rest of the cam is still soft grey iron.
You can imagine that the hardened material thickness will vary with exposure time to the heat and the actual temp of the flame/coil. If one lobe happens to get shortchanged for any reason (dirty torch tip, failing electric heating coil, etc.) then that lobe will be softer than the others and it will wear quicker.
Also, oil pressure varies at different places in the engine. If the worn lobe is near the end of the oiling circuit, the lower pressure there is a factor.
And... In many engine designs the cam lobes are lubed primarily by oil thrown from the spinning crankshaft. (This is why you should NEVER let a freshly rebuilt engine idle upon initial startup -- the cam lobes aren't getting enough splash lube.) If the engine has tight clearance on a connecting rod big end or a main bearing, less oil will be thrown from that area onto the camshaft.
So there are a bunch of very good reasons why one cam lobe can wear faster than others on the same cam.

 

I have noticed as long as I can remember the oil pressure gauge fluctuate greatly depending on rpm's. I know some fluctuation is normal but what exactly is the range for 3.4? Do I need higher performance cams necessarily like Crane or whatever on the premise that they will have been built with more diligence towards quality. All manufacturer's still make mistakes of course but you'd think for the extra cost you'd get that extra assurance also.

 

I know what a vacuum reading shows for leaky valve(s), cylinder, etc. but what is the reading in my case where the intake valve was always closed because of flat spot on cam?

 

A leaking intake valve with show a dramatic Vacuum change. A non-work valve will show but the needle will only move 3-5 inchs on a V6.

Here is the way it should go.

Car comes in with a miss. You hook the car up to an engine anylizer/Scope. The scope would show a low spark fire in Cylinder one. (More pressure in a cylinder the more current it takes to fire the plug). I would then hook up a Vacuum gage. You would see a jumping needle. The jumping needle would tell us the motor is not sucking air evenly. At that point you are pretty sure it is a mechanical engine issue. If it was an electrical issue ( ie a shorted plug or a lack of fuel) the vacuum needle would have a very small fluctuation. I would then pull the plug and do a compression test wet and dry on that cylinder. If the compression decent wet and dry I would assume a bent pushrod unless the customer told me the car had a history of “tapping”. Pulling the valve cover at that point would give the whole story.
Back in the early 80s we use to do 3-6 cams a month in the 305’s

 

Is the tapping usually always indicative of the lifter/cam failing?

 

Yes 95% of the time tapping is a lifter. The other 5% is is a Cam wearing out, a rocker arm coming loose or a bent push rod. This assumes it worked right at one time. If you put a new motor together and it taps it is a lot longer list of what can be wrong.

 

Yeah, that's what I figured. What are the chances that the Camaro wouldn't generate some sort of a code before cam went flat, BTW? I can smell the cat working overtime now trying to handle the extra rich mix. Why hasn't my O2 coded yet? And why wouldn't the MAP have registered the change in pressure a month ago and flagged the ecu also? I know a 3-5" disparity is hard to detect and I know early detection would have just prolonged the inevitable but at least I could have read the code(s) with my lappy and avoided $220+ in unnecessary diagnostics. $220 would have have helped pay for my new block. My oil pressure is starting to go south now also. Hovering around 40 after warm. 20 at idle.



Still waitin' for my check Rob G... Do the right thing Todd.