Ok So I have a 2002 Camaro Z28

I recently did a head/cam on it...

I have caddy lifters, TSP hardened pushrods(7.400"), TSP torquer v3 cam(231/234), Yella Terra rocker arms, 5.3 stage 2.5 heads. with beefy valve springs.. LS6 ported oil pump. double roller timing chain..

all bolt ons. LT, ORY, Magnaflow catback, Lid, CAI, K&N, smooth bellows, home ported T/B, powerbond 25% underdrive pulley, ALuminum FW, LS7 clutch, Moser 12 bolt 3.73s, PST aluminum driveshaft. Full suspension..

made 432rwhp and 412 rwtq...

all was great..

car was tuned and drove about 80 miles, no problem....

when I got hime I had a little valvetrain rattling... I am unsure what it was , but was thinking it may be a loose rocker arm..

OK here is where the issues start...

I was driving it that day to the mechanic for them to diagnose the problem.

As I was driving, my car died and didnt re-start. It would just try and crank over, but wouldnt fire or would fire 1 or 2 cylinders and not run..

I was a block away from the shop so I had em come and spray carb cleaner and the car fired up... but soon died.. plus there was no noise , that the fuel pump usually makes..when I turned the ignition on.

So I towed it to another mechanic shop, since he can get the fuel pump for way cheaper and had him work on it...

Ok , so he tested the fuel pump and it had 0 fuel pressure...

He installed the new one and it had full pressure.

But the car still wouldnt crank over.

he pulled up a DTC PO336, which means the crankshaft position sensor cant tell TDC.. he tol dme my computer is bad and needs to re-learn.. I called my tuner and he said its total BS. But maybe he fried the computer. because my mechanic did mention a few fuses needed to be replaced.

So he called a GM tech and supposedly they re learned the computer, but it still wouldnt fire up...


he changed the crankshaft position sensor, because it had a bad connection / or was broken. and said it had only 5 ohms, after he changed it it had 26 ohms( I believe)

but still the car wouldnt start.. all I hear is the starter trying to crank it over.

So I took my computer to my tuner and they checked it, everything seemed fine and my tune was not erased from the computer.

meanwhile my mechanic thinks iI have a broken timing chain, which I sincerely doubt, since how did it break or come loose when the car wasnt running?

Anyhow, my tuner put my computer in another car, and the other car fired up. Meanining my computer is fine..

So what seems to be the problem here? Its not the fuel pump anymore, its not the computer, my spark plugs are new and they were running just fine before my fuel pump went out...

sorry for the long post, but I really need some advice/suggestions here.

Thanks

 

Sorry, maybe this thread is better suited in the General maintenece section?

 

The only things I can think of but it wouldn't explain the code. Is the cam sensor. You also didn't say if you checked if it had spark but I assume you did and it does.

 

I have no idea but i'm interested, let us know what you find out!!!!

 

do you think cam sensor? there isnt a code for it though... and Im only asking because I broke th eplastic retainers for the cam sensor when I pulled off the flat panel that mounts above the camshaft, under where the intake manifold sits.. But the sensors were unharmed and we used rtv sealant to seal the plastic boot above the cam sensors, so it wouldnt move..

 

If you broke part of it, there's a fair chance that it isn't seated properly. I would replace it before you go off looking for more complicated problems.

IMO. (I'm not really all that knowledgable, but a broken cam sensor is not something I'd want.)

 

This would be the first thing I would look at.

 

For any one trying to help, here is a little history on this guys build: read it all the way through
https://ls1tech.com/forums/generation-iii-internal-engine/829322-so-finalllllyyy-im-doing-my-head-cam-swap.html

As you'll see in the above thread, it seems as if this guy was in over his head doing this kind of work in the first place. Definatly not meant to be an insult towards the OP, but you seem to be in too much of a hurry or something. We tried to warn you to go slow and make sure everything is correct.

As was posted above, the cam sensor would be the first place to start, since you broke the tabs that hold the thing in there. It very well could have worked its way back enough to make a bad connection.

Also, it kind of seems to me that your mechanic is just throwing parts at it till something works. Seems weird that your fuel pump died at the same time as all this other stuff. The fact that he jumped right to your computer being bad....then finding out its fine should make you at least just watch him closely.

 

yeah I would look into the cam positioning sensor.... sounds like a reasonable lead..

 

So tomorrow Im gonna do the following...

put my ECU back in, see if it fires up.. then if not, change the cam sensor, under the intake manifold.., if still no.. then Im gonna tow it to my tuner and see what he can do..

 

was that your black SS at the shop on friday?

edit:

NVM because that car had an exhaust through the rear, had black z06s and was an SS, not Z28..

 

Good luck man, Let us know how it goes.

As your checking the cam sensor and all that, double check everything along the way. You may find a little something here or there. Just keep an eye open. Hopefully its something easy

 

My mechanic and I both are going to check the cam sensor tomorrow.

However! I was wrong when I first wrote, that I broke a cam sensor. No, it was the knock sensors, plastic that I broke. Not the cam sensor. So sorry for the misinformation...

the 2 knock sensors that are above the camshaft... I broke 1 or 2 of the plastic pieces..

 

This may be far fetched, but with those heads/cam/pushrods, and lifters is the PTV clearance ok? Lifter preload also. You said you heard some valvetrain noise. Bent valves would for sure cause a no start condition. Ive had buddies with simialar no start issues, and it was due to the valvetrain not being set up correctly with their setups.

If you have verified fuel, spark, air, and you computer fired another car up then you may need to start looking at mechanical stuff. I would do the crank sensor first though because that will usually always cause a no start

 

well the PTV should be okay, texas speed assured me so.

Even if it wast, It was driven about 120 miles with no tune and then 80 miles after it was tuned and during the tuning was taken to 7000rpms multiple times. So if the valves were bent, It would have been known also since the power I made wouldnt have been the same power if the valves were bent..

I just dropped in my hydraulic rller lifters after soaking them for 24hours.. please explain more ot me on the lifter preload...

the crank sensor seems to be fine now, now we will check the cam sensor. but yes, I am now looking into mechanical parts if everything electrical is now working, plus spark and fuel is present..

 

If you had the lifters soaking in oil you should be ok preload wise. I have known some to just throw the lifters in and tighten down the rockers with no oil in them. Thats when you get preload problems

 

im wondering if u have an adjustable timing chain. i had a VERY similar issue with my car, heard a bit of valvetrain noise and then car wouldnt start. For the longest time my mechanic thought it was a tuning issue, but eventually i decided i needed to go in and take **** apart. it turns out the bolts on the timing chain werent tight enough and after driving a hundred miles or so, very close to the miles you drove, the cam started to advance and retard itself. therefore causing valves to hit pistons and the car wouldnt start.

 

I bought the Double roller timing chain. I dont think its adjustable.. Its a rollmaster double roller. I got it with the head/cam package from texas speed.

 

Ok my mechanic says:

fuel pressure ok

fuel ok

all inputs okay

He says that there are 2 problems

there isnt spark present... and the engine cannot determine what cylinder is at TDC.

he says thats the 2 problems..

 

That points to crank sensor and cam sensor, and associated wiring for these.