xr7

82 Z28 5.1L auto, indy 500 package (crossfire injection, fuel injected)
I had just replaced the radiator and tranny fluid cooler lines (I stripped the bolt when reinstalling) in my 82 z28. A day later I drove it about 30 miles throughout the day. I went to the mall was inside for about 45 minutes, came out and drove halfway across the parking lot, when the car started revving "funny" a bit higher and more erratic. It stalled, I started it, got it into a parking space and it stalled again.
When I tried to restart it it wouldn't. It cranks OK, and every once in a while it almost sounds like it fires. I even hear a tiny bit of rumbling in the exhaust.
So far I've replaced the ignition pickup (under the distributor cap), rotor (thinking it might be related to an earlier issue where the rotor managed to get destroyed), cap, coil. I've verified all the plugs and wires are seated.
I noticed a high pitched "chattering" sound that seemed to come from the front of the engine while cranking.
I am going to verify the distributor is rotating right now (duh, didn't think of it when I had it all apart before....)
I am also going to see if I can get a spark by holding a wire close to ground at dusk. (I don't have a spark tester).
I don't believe the injectors are firing because I should be able to see them, but I do smell gas when cranking. ( I can't remember if I should be able to see gas when cranking, but I KNOW I should be able to when idling)
I used starter fluid into the intake which had no effect on cranking.
I suspect a broken timing chain. Are the injectors tied into the timing chain somehow?
Thanks for any help in advance!!!!!!!!!

Quick_Trans_Am

iTrader: (2)

that chattering sound almost locks it in for me... I would definitely check your timing chain out. How many miles you have on the motor? I had a similar experience over the summer, the timing chain tensioner just broke out of the blue, which didn't break the chain, but it DID end up wrapping pieces of it around the crank gear, causing the whole thing to lock up. I replaced the gears, chain and tensioner, and it ran great.

RB83L69

Yep, sound like a timing set. It's probably not the chain as such, usually the thing that actually breaks, is the phenolic teeth strip off of the chinesium center of the cam gear, leaving nothing but little chinesium gums.... but you have to replace the whole set, so it really doesn't matter esactly which piece was the one that failed.

Bummer dude. That costs like $20, plus a gasket set at about $12 or so, and it may have worn a hole in your timing cover which will set you back another $15 or so for a chrome one, and you might as well change the oil cause now it's full of all that stuff. And worst of all, you have to rent a balancer puller and a gear puller, and they charge {gasp} nothing for those at Auto Zone and places like that.

But it's a tow bill and an evening of work, probably 3 hours or so, not a whole lot of fun.

xr7

Here is more info about my problem.
The rotor IS turning.
Injectors ARE firing (with the key in the on position I connected the battery, and saw fuel spit into the intake.) That seems to rule out the fuel part of the equation.
I tested the ignition pickup coil, and it was not grounded and it measured about 750 ohms between the terminal (within spec)
The primary terminals of the coil (between bat and tach terminals) is an almost dead short as it should be. between secondary and ground shows a high amount (not infinite, ~15kohms) and between tach and ground shows infinite.
I believe the only other part here could be the ignition module. Could a slipped or broken toothed timing set prevent spark from happening? Even with the rotor turning?

ZZ28ZZ

If the dist is turning and there's power to the batt connection at the dist, there should be a sparks coming out the plug wires.
Disconnect the tach wire if installed, just to be sure something in that circuit isn't causing a problem.

You can pull a wire off a plug and connect it to an extra spark-plug and lay it on the intake (so it's touching metal) to check for spark.

You should see a bright blue spark. Not a wimpy little white one. Shouldn't have any problem seeing it, even in the day time. You can hear it too.

How many miles on the eng?
Seems like my timing chain went out around 70K miles.

If you're able to get it started, check the timing. If it has suddenly shifted a lot, the chain probably jumped a tooth. (Don't forget to disconnect the little wire near the blower motor to ck timing)

A compression check might tell you something too.

The ign module is definately a strong possibility. They USUALLY work for a little bit when eng is cold, then just plain act wierd after they get hot. If you replace it, be sure to apply the heat sink compound (some like to use dielectric grease) on the back of the module so it will conduct the heat away. A new one won't last long w/o it.

Also check the fuel injectors for a well defined cone-shaped spray pattern. If you have a fuel press gauge, the press should be 12.6 psi. if I remember correctly. If the pressure is only off a pound or 2, the eng will run like crap.

Oh, and something else, the cams installed in 82 Camaros (and maybe other years/models too) wear out prematurely. The defect was a inadaquate parkinization (chemical surface hardening) treatment. I pulled mine at around 100,000 miles and the lobes were almost completely gone! A friend of mine had the exact same problem with his cam. Watch the rocker arms while cranking to check for a lobeless cam.

Those phenolic teeth that RB was talking about have been known to plug up the oil pump inlet screen. If you discover the teeth are in fact are all gone, pull the pan if you can to clean out the debris.
If you can't pull the pan, for whatever reason, keep an eye on the oil press after you get it going.

One more thing, welcome to the board!

ZZ28ZZ

double post

xr7

I replaced everything that was under the rotor except the pickup coil and the main ignition coil. (module, condensor, wiring harnesses) I used the dielectric compound under the module, and now I am getting spark. Nice blue spark. The car has about 195000 miles.

Now when cranking it, it actually sounds like it is firing about 35% of the time, I hear some noise from the exhaust as well (almost like it is igniting in there)

There is a popping sound and a bit of fuel mist (when the sound happens) that is shooting back out of the throttle body. I have yet to check the timing set, I will do so this weekend.
Has anyone else seen this happen?

Is there a guide somewhere or can someone give me pointers to check out the timing chain?

RB83L69

Usually when the timing set fails, the chain remains intact, and the cam gear strips. Naked. Then, when you try to start the engine, as the chain sort of drags over the gums where the cam gear's teeth used to be, the gear will move, just nowhere near as fast as it's supposed to... it will turn a bit, then the chain will slip, then turn some more, then slip.... The effect that you see is that the motor will spin as if it has no compression for a time; then it will start to spit fuel mist out of the carb, maybe backfire a time or 2; then maybe sound almost like it's going to start; then make popping noises in the exhaust; then start sounding like it has no compression again. And of course, as the cam turns at part speed and happens to reach the various points of coincidence or lack of it with the crank, it will go through this cycle repeatedly.

If it's doing that, don't waste your time any further, just go buy a timing set and do it.

If you haven't disturbed the distributor timing, DON'T; it will just cause you more work when you fix the real problem. If you leave it alone, then when you get the cam back lined up with the crank, the distributor (which of course follows the cam) will be right where it belongs. Resist the temptation to twiddle it.

dans82bird

haha what's up rob... your going to have to change the timing set ... YAY! gonna have to drop the oil pan, pull off the harmonic balancer then the water pump then the timing cover; now you have access to the gears and chain fun fun fun... if you want you can use my balancer puller.

xr7

I have replaced the timing set in the car. Not too difficult but I did have to get a few tools (harmonic balancer puller and common gear puller. Autozone rocks! just a deposit of like 15 dollars that you get back for these tools!)
I got the double roller chain and it went in with no clearance problems. I got the timing marks lined up correctly. I had to give up before it was all together cuz of darkeness but all I have left to put on is the belts, the brackets and the fan shroud. Hoping to have a good day today once I get off work!
BTW the timing gear was OK, but the larger gear (not sure its name) was almost totally stripped of teeth in two spots... I easily see that this was causing the trouble.

dans82bird

the cam gear

RB83L69

Right... the cam gear. Half of the timing set. There is no "timing gear" as such, you have a crank gear (on the crank, believe it or not) and a cam gear.... I'll leave it to your imagination to figure out where that one is.

I guess you could see exactly how it's made; the chinesium center, and the phenolic teeth that strip off leaving nothing but little chinesium gums.

Glad that's all it was, it's real common, not expensive at all, and not even all that much of a hassle, but I know of more than one whole car that got crushed for that. Hope it cranks right up and drives off for you.... it should, if you didn't mess with the distributor timing. If you did, that's just that much more work you'll have to do.

dans82bird

that's just disturbing

xr7

Started on the second crank. Thanks for the help and clarification everyone...

IROCZTWENTYGR8

iTrader: (1)

Where'd you get that extra .1 of a liter?!

dans82bird

:sillylol:

xr7

It was hiding next to the zero on the keypad