Agreed on most points. If I was going swap cams why would I swap a used. A decent new one is only a few hundred bucks. If I had to pull the motor anyway I'd clean the heads up and put in a rebuilt short block. I've seen a few videos on pulling it out the top with lots o' wiggle and jiggle. Every option looks like more work than I can handle right now. Unless u know if pulling the cam out the front without removing the engine is possible, every option seems daunting.

 

I've never done a cam swap in a 4th gen but I'd think it could be done without dropping the motor out by removing the radiator.
My point on a used cam was simply a really low budget approach to getting it to run on six to sell it or trade it in somewhere,
I figure you might be ables to source a used cam for next to nothing and slip in it so it fires on six to off it.

 

Ok. Had a chat with a mechanic today, who just bought some property next mine, and who revealed some interesting info about my Camaro. He said, unless the shop actually measured certain parts of it (with a micrometer I assume), you can't know for sure. I think he was assuming a very slightly worn lobe not seating valve 100%. He also said something about all of the injectors won't function correctly if one fails. Sounds like he's saying they're piggybacked. Could he have been talking about the ECU and the rail sensor or control valve sensing a messed up injector? I was kind of in a hurry so I may have missed some stuff but it sounds like I may not have a 100% cam issue but an injector issue. I know if you can actually see abnormal valve lash, or an irregular wear pattern on the lifters it's pretty definitive with a borescope. The strange thing was I could actually still drive it. I drove it home from the shop way back then. I know, I know, I could have done more damage which is why I did finally park it.

Background: 15 years ago my 125,000 mile 3.4L Camaro was screwing up. Took it to a shop, they said it would cost <$300 to fix. A few days later they said they misdiagnosed the problem and it was going to need a new cam ($1500). They said after looking in the engine with a scope (through the oil filter hole?), the intake cam lobe for cylinder 1 was worn. Well..parked it, started it periodically for several years, stopped starting it. Now, 6 or so years later (last month), I decided to care again. Below are most of the things I've done in the past few weeks to simply get it started.

⦁ I put a new 15 gallon tank with 4 gallons fresh gas in it, new battery, new TRQ pump, new filter, relay tests good (resistance & power) - I also used a different relay from my other running '94 just in case.
⦁ 1st new TRQ pump had 40+ lbs. pressure to rail at 3 second start-up then back to 40+ while cranking. However, after 6 or 7 seconds of cranking, pressure drops to 0 and stays there unless you repeat above process.
⦁ I just put in 2nd new TRQ pump (today) from amazon and pressure also at 40+ lbs. but at least this one stays at 40+ the whole time while cranking. However, pressure still drops immediately when you stop cranking.
⦁ I live in a very humid area so interior fuse block/fuses was pretty corroded. New (1st) pump wouldn't even purge after install until pump 10amp fuse connection was cleaned. I had to scrub every individual connection and stuck electro grease in each slot just in case. I've been using tons of those little dehumidifier containers from dollar tree for the last 5 years to absorb most of the humidity.
⦁ Schrader valve does have a leak but its not gushing. Looked at first like it was leaking around base but I think its got to be leaking through needle and its just creeping up and over external threads onto the base.
⦁ "Canister Purge Valve" near fuel rail was completely clogged with what looked like hard-packed charcoal granules. Easily cleaned though. That may mess with the idle later but it should not be relevant right now I assume.

So, my next step is to pull fuel rail off and just replace all 6 injectors since they're so cheap. Thoughts?

 

Just a few thoughts:
You can check the lobe of a Cam with a dial indicator. In fact, that is the best way to check it. The only way to Mic a Cam is with the Cam out of the engine. With the valve cover off you put the dial indicator right over top of the push rod and turn the motor over. Exhaust and intake will have different travel but all the exhaust or all the intake should be about the same to each other.

Your 3.4 has a roller Cam shaft. Lobe failing by itself is very rare. If a roller lifter fails on turns in the motor than that will wear off the lobe. This is not normally a quiet process. Roller cams reduce friction and can last longer than the older Cams but when they fail there is a LOT of noise and they do not fail a little. Imagine a harden wheel on a hard lobe with the wheel not turning and the lone turning. If you took off the valve cover and looked at the rockers and they all appeared to be working and there was no noise, chances are there is no issue. With old cam someone could crank down the rocker and hide a worn Cam lob. Normally just someone that thought the valve needed adjustment.

A bad lobe on a cam will not affect the valve seat seal. A worn lobe means the valve will not open as much as it should, It is the job of the valve spring to close the valve and cause the seal. There is nothing in a valve train that can hold a valve open unless a human cranked the rocker arm down too far. This would also mean there is no way to fix a valve not sealing by changing anything in valve train. Now after saying all that if there was some sort of major failure in the valve train and things were breaking a part then any loose metal could do all kinds of other damage. Again this would not be quiet.

Valve issue causing an injector issue? Your can is NOT direct injected. This means the injectors are in the intake. A bad "backfire" into the intake could hurt them, but it would take either one huge backfire or a lot of little ones. I have seen cars with bad timing chains spit fire 10 feet in the air and not had an issue with the injectors once the timing chain was fixed. If your car was direct injected then a rich or lean condition could affect the injectors. That sounds like info from a newer mechanic.

 

Ok, wow, thanks for all that info. I remember that the engine just ran like crap. There was definitely no crunchy metal sounds, just felt like it was missing really bad-very sluggish acceleration and loss of power. Believing it was only running on 5 cylinders was not a stretch. Ftr, I got the Camaro at 53,000 miles in 2001-02 for $3000 from an extremely responsible old friend who religiously changed the oil from the day he picked it up at the dealer in 1995. His dad was a career GMAC accountant and got him a huge discount stacked on a new Chevy deal going on at the same time. He made me promise to continue using synthetic which is absolutely the only thing that has ever been in this engine.

I don't know why I said anything about the valve not seating. I know the valve springs function. I was confused I guess. It was late and I'd been reading, writing, watching dozens of videos, & copying/pasting all kinds of stuff lately. Even if a bald lobe was responsible for a valve seating or not, it would be stuck shut, not stuck open. I remember I assumed when the 2nd diagnosis of a bad cam from the shop back then meant that that cylinder simply wasn't getting gas. I even felt fortunate that it wasn't the exhaust valve stuck shut. Also, I don't know why I said: "I think he (my neighbor) was assuming a very slightly worn lobe not seating valve 100%". I assumed (again) the measurements he was talking about were of the lobe. He was probably talking about using the measurements from a "dial indicator" you mentioned. As I said, I was kind of in a hurry while talking to him. I do know these injectors are not direct injection. It's kind of obvious since they're planted in the plenum. Btw, I always thought that an injector tip subjected to that much repeated combustion in direct injection would be problematic, even if they were composed of titanium.

Finally, Re: the injector's "piggybacked" ECM-controlled pulse or sensor function: Would a failing injector or three trigger the ECM/sensor to shut down or whatever?

 

You called it Gorn. I cleaned the fuel rail and put a new regulator & injectors on it. It wouldn't start (yet) but you could tell it wanted to. The generic fuel pressure tester was showing 30-35psi at prime but never went above 30. It held at 30 for a few minutes but slowly bled down over the next hour or so. I thought maybe the check valve in the pump might be bad. I then put some new plugs and fresh oil in it. After a spritz of starter fluid, it fired up with some pedal feathering. The engine sounds wonderful, especially after sitting since 2009. Unfortunately, I can't get it to idle. All vacuum hoses look good. Zero fuel leakage from rail to pump. It doesn't cut out at all as long as I keep the pedal down a bit. I'm thinking MAP, IAC, or maybe the pump still. I haven't checked the pressure again since getting it started so I'll do that first manana. Ftr, I did an "EGR Delete" to access the plugs more easily-built my own block plates- no leaks.

Could it run with just 30 psi? Will a simple ohm/voltage test for sensors be good enough? Could the ECM need tweaking with new injectors?

I know now for sure the original problem was an injector or two. The motor hasn't sounded this good since I got it with 53,000 miles on it. The #1 cylinder intake valve's cam lobe was supposedly the one that flattened out. It wasn't. All the cylinders are firing just fine. I can't effing believe this entire time it was a relatively simple fix.

OEM injectors & regulator.

 

If the injectors are at stock flow they should not need any program tweaking. It when you start messing with higher flow injectors you need to change the mapping. I have seen guys use adjustable fuel pressure regulators to tweak their fuel pressure at the track but that was before everyone had a laptop to fix it right.

No, 30 PSI is not enough to run your engine. You will need to sort that out. The amount of fuel that enters the cylinder has a very small band of error. The reduction of fuel that enters the motor cannot vary 30%. The system is designed to allow the fuel pressure to run within its spec. but once it drops even 2 PSI below its allowed variation you can get a check engine light. 3-4 PSI the car would run poorly I would expect it not to start at 10 PSI below. In fact I would not want it to start at that fuel mixture if you could drive it you would probably melt the piston. Idle would probably not hurt it but it would lean back fire and the cylinder temps would be twice normal.

You may have to do some more diagnosing on the pump and maybe clean out the tank. There is a sock at the bottom of the pump that work like a filter and if the car has been sitting that could be partially plugged. Because of the sitting you should do a voltage drop test to see if you are losing any voltage or a ground. It may be more simple to just run two large wires right from the battery and see if the pressure get better. I would not run the car that way but,,,, If everything is clean and you have good voltage you probably just need a pump. Its pretty common failure on these cars. The pump is a pain to get at you may want to search out "Hatch method" on this sight. This shows you how to cut a small hatch to access the pump. Turns it into a 1/2 hour job. In my opinion the hole is not large enough to effect the strength of the unibody and the lid you use can be thicker than the metal you remove. if you are worried about it. The last pump I put in I bought a cheap one for my V6. I ended up replacing the pump 3 times in 6 weeks. Sure glad I did the hatch. I can't even imagine how pissed I would have been if I had to remove the exhust the rear and the tank 3 times.

Do not use a shop vac to suck out the gas tank. The gas fumes and 120v motors do not play well together. Do the research. Don't take offence to the that statement. I always assume other people will find this post and I do not want to be the reason some 16 year old burns his family's house down.

 

did you blow out the fuel lines and change fuel filter? judging by the shape of things it looks like you got rust and bad gas all through the system. just hope the injector screens are not plugged already.

 

It's been a minute since my original post a few weeks back. When I decided to tackle the Camaro a couple months ago, I knew, after lots o' experience with my two f-body's, dremeling two pump access panels, 5 fuel pumps, etc. that the 15 yr old gas in the tank had disintegrated the pump. It was ugly. Since there was no chance I was gonna ever drop the tank, I spent a week 1/2 on tank alone. I started with 13 gallons of vinegar (big fan now) soaking for a week. Then, I built my electrolysis rig which took a while. I only had a 10 amp charger and tank baffles to contend with (linear process). Then I pressure washed it for an hour and after soaking as much moisture out with lint-free cloths, I used my heat gun to eliminate and residual. Also, lots of air compressor and shop vac. Needless to say, it was basically brand new. Then I put in the first new pump and a new filter of course. When I isolated intake line to the pump with Chevys' built in jump wire to bypass relay it held steady at 70psi. That's how I knew the problem was rail/injector/regulator related. It would help if my $40 amazon special pressure gauge was calibrated.

 

The intake line from the tank to the rail was cleaned and a fresh filter. I'm putting on another new filter tomorrow. I didn't blow out the return line.