Frustrated. Any ideas?
 

More problems. 535 IA II WP HP Heads. We got the engine rebuilt and in the car. It cranked but would not run. Get a nice vroom and it cuts off. Adjusted the timing but still wouldn't run.Thought it may be the carb,A 1050 I rebuilt. Changed to a 1250 rebuilt by a reputable local company,no difference. Checked compression on all cylinders,they were good. Traced all the wiring down didn't find anything. Put an HEI in it and bypassed the electronics, no change. Cam was degreed. It doesn't backfire or anything. It sounds like it's going to run but it loses rpm and shuts down. Any ideas?

Fuel pressure, volume? Sounds like it cuts off when bowls run dry. Did you check the pump, pick up and lines?

Also check the wiring to see if you are getting consistent voltage to the ignition.

After engine shuts off is there fuel in the carb? As its dying if you pump the throttle does anything happen?

sounds like dizzy is 180 out. how about that?

Sounds like you are losing power when you let off of the key in the start position. Possibly a bad coil ?

That was what I would guess... Or maybe rf noise from somewhere knocking out the ignition right after first fire...

vacuum leak.

Good fuel pressure, doesn't run long enough for the bowls to run dry. I tried another coil but nothing changed. then tried bypassing the coil and other electronics with the HEI(powered from battery),no key it's a frame car but still should have constant power the way we did the HEI. If we pump the carb it will run a little longer,but still dies. It would backfire if 180 out wouldn't it? It sounds good for the short time it runs.

does it sound retarded ?

sound advanced?

old fuel?
water in fuel?

HYD lifters needing pumped?

I feel retarded with all the trouble I've had with this engine. Fuel system cleaned,new fuel,solid lifters. Hard to tell but maybe retarded.

Has it ran long enough to set timing?

Advance the distributor a couple degrees and see what it does.

What's the valves lashed at?
Possibly too tight?

When it starts, try running it at a fast idle or more?

Gasoline I take it?

Probably something small, really.

:confused:

Gasoline. Hasn't run long enough to set timing,but we did the usual TDC number one then move in small increments till it cranks. I think the lash was .024

Check your voltage on your battery low voltage will not give enough spark to your ignition or msd. Sometimes bad cells on battery and not enough voltage to run your ignition on your msd box

Sorry I forgot. We did that too, and got a new battery.

Sure it's not 180 out?

That would be my guess...

At this point I'm not 100 percent sure of anything, but won't it pop and backfire if it's 180 out?

BEFORE you second- guess the cam timing chain installation,

set the card idle screw to a high idle. THEN TRY a 2-person effort to keep it running with pedal effort, and even starting fluid shots, and quick dizzy twist to attain "running".

Basically anything it takes to achieve warm-up, with constant monitoring of OIL PRESSURE, and thermal gauge(s).

Guessing: rehone or more causing rings to need re-seated?

No...it can act much like it is now.

you are probably loosing ignition, if it fires and when you get off the starter button it dies, if i read your post right.

X3 may not backfire if it is not running long enough.

Okay. It will be Thursday when I can work on it again. Thanks for the replies I'll let you know.

Not to insult your intelligence, but did you verify you are on the compression stroke by pulling the valve covers when installing the dist.?

You wouldn't be insulting my intelligence,just my engine knowledge. I know how to do what you're talking about, but no I haven't done it. The way it runs made me think it couldnt be that. In the past when I've had one 180 out it let me know as soon as it fired. This one has no miss or backfire. Though 10 or 15 seconds is the longest it has run. It just kind of peters out.

Go back to the basics. Timing - ignition and cam, fuel, compression, air. Test these 1 at a time until you find the issue.

1st take the #1 plug out, rotate the engine by hand, put your finger by the hole, when it puffs,pushes your finger out, stop and see where the rotor is pointing.
It should be pointing at the #1 post on the cap.

Go from there.

:)

it wouldnt run 10-15 seconds if the timing were 180 out. I think either your timing is retarded too much, serious vacuum leak. Even though you have tried 2 carbs, I would borrow a KNOWN good carb off of a running vehicle and try it.

I had a very similar issue with the first Pontiac motor I assembled. I did not notice that the aftermarket valley pan I used wasn't letting the intake set correctly against the heads. I had a vac leak at the intake to head on all 4 runners on the driver side. I ordered a thicker intake gasket and problem was solved.

you can also run the timing light when you are turning it over and see where its at and if its firing all the time too

When you have someone start the engine, put your hand over the primary side of the carb so you hand acts like a choke shutting off most of the air to the engine. If it keeps running then you have a vacuum leak. Plug all the vacuum ports of the engine and the carb and try it again. If you have to leave your hand on top of the carb to keep it running then you have either vacuum leak at the intake gaskets, an intake valve too tight or a leak at the carb.

John, that's the way I've always done it. And it's been reset that way at least 4 times. But I'm going to pull the valve cover Thursday to make sure. I have 2 dominators, both are rebuilt but neither is proven. I'm going to order an adapter and use a known 850 I have. Then if not fixed I'll start trying to track vacuum leaks.

if it's ran for 15 seconds, you're not 180 out. however, if you want to check, pull the pass side valve cover and put #6 into overlap. at this point the balancer should be close to zero, and #1 at tdc compression. check your dist to see where it's pointed.
I think it's fuel related, it shouldn't run for 15 seconds with a poor electrical connection.
what is your fuel pressure while it's running?

this sounds like a simple problem that you'll give yourself a face palm over once you find it.

check voltage to fuel pump when you have it running for a few seconds, or drizzle fuel into carb to determine if it electrical or fuel issue. If it stays running when fuel(or starting fluid) is being introduced, you can quit looking at electrical issues.

This is what it sounds like to me too.

GT.

like no juice in the run position of the ignition swi...

Yep; It almost sounds like when you let off the key it looses spark.

GT.

Did you change the firing order on your cam? (4-7 swap) Do the plug wires match the firing order. I know that sounds stupid but sometimes we can overlook the simplist things.

It sounds more like this to me as well.

If you're still using a key switch it could be just a bad switch.
I'd run a new wire to the ignition box/dist and try again.

I hope its something simple.

If the car has the lock cyl in the column, w/ the ign. swi. on the column.......... Have you fooled w/ the column lately??? The electrical part of the switch could be out of adjustment, a hair, and do this, I HATE working on those... I pull the drivers seat out so I can get to the switch easier, only way to work on it....:attention

[QUOTE=Half-Inch Stud;4816348]BEFORE you second- guess the cam timing chain installation,

set the card idle screw to a high idle. THEN TRY a 2-person effort to keep it running with pedal effort, and even starting fluid shots, and quick dizzy twist to attain "running".

Basically anything it takes to achieve warm-up, with constant monitoring of OIL PRESSURE, and thermal gauge(s).

Guessing: rehone or more causing rings to need re-seated?[/QUOTE]

If it's not a power/spark loss in the key run position.... Guessing: rehone or more causing rings to need re-seated? No compression = no run

The latest. Tried a proven carb, turned distributor 180(backfire),checked for vacuum leaks(none),checked compression 160-165 every cylinder, changed ignition system. No change. It fires and makes you think it will run then starts popping back through the carb.I think weve rulled out everything outside the engine. Maybe a valve or lifter sticking? Cam ground wrong?

Do you have a 4-7 swap cam? If so, it will run poorly and sputter like that. My buddy was running with a very high idle like this a even made two passes before he remembered the cam had the swap in it. Changed the plugs wires around and voila.

Ls1 firing order.

And your positive you are puting the wires accordingly?

And your positive it is LS1 order?

Sure there are no vacumn leaks on the bottom of the intake runners? If ok, then i`d go back and check the cam ICL.

Pull the valve covers and follow the intake lobe.

Calvin Hill
Hill Performance
708-250-7420

Yes, sure of the firing order. Sure of no vacuum leak. We decided to pull it apart. The lifters can be moved by hand, but they do catch a little. I don't think it's enough to stick,but maybe. Redzone lifters with bronze sleeves. Rockers and push rods look Good. Haven't taken the heads apart yet. So don't know about the valves. Will check those and the cam next week.

Sorry Calvin posted before I saw your post. We did just that.

Since we are guessing here, this has to be a basic issue. When you installed the timing chain, did you line up the dots on the gears or line up the key ways? Did you degree the cam when you installed it? Perhaps you are a tooth off.

Three things needed to make it run IF the rest of the engine has been assembled correctly. Fuel, spark and air. Too much air or fuel, engine won't run. Same if there is too little of either. Like some others, I suspect a vacuum leak. maybe a port open on the manifold or carb. Perhaps an ill fitting gasket or manifold. A spray of carb cleaner around the manifold edges will reveal a vacuum leak. Did you have a lot of port work done? Maybe there is a break in one or more of the ports, say from a valve cover bolt hole or where a different intake gasket might be called for.

Spark; Got to have something to light the fuel. Have you pulled the coil wire out of the distributor cap and help it near a ground while cranking? Spark should be strong and blue. You should be able to spark across a 1/4 inch gap with no difficulty. How about the rotor? Is it old? Perhaps it has a hole in it or the rotor is damaged in some way. You could pull a plug wire from a spark plug and see if there is a strong spark there. Check ground straps from block to frame. Redundant ground straps are worth their weight to be sure that the electricity has a good return path. Is there a rev limiter installed? Wrong RPM chip, bad chip or perhaps missing the chip.

Since you say it sounds good once it runs, I don't think it's a compression issue. Looks like you confirmed that with the numbers you posted.

If all the above checks out, it might be valves are set too tight. Hydraulic or mechanical, there needs to be some lash or at least no more than zero lash with a hydraulic cam.

Try some fresh gas if the fuel has any sort of bad odor or strong discoloration. Leave a sight plug out of the bowl and just turn on the fuel pump for a minute. You should see fuel at the bottom of the threads or even spill out a small amount. If you can't see fuel, perhaps there is a delivery problem. Pull a fuel hose loose and see how quickly you can fill a cup with fuel. Should be fairly rapid. Clogged regulator or filter could cause a delivery problem. Pump should have a full 12 volts to it. Does the pump run smoothly?

Hope this helps. My first camshaft change I had a similar problem. Lined up the keyways instead of the dots on the cam gears. Fired right up once they were lined up correctly.

One last thing, if the car has a torque converter, be sure it is engaging the front pump of the transmission. It's possible that you have such a load on the crank shaft from a mis-installed converter that the engine cannot overcome the drag. I'd think the engine would crank slowly and quite noisily if the converter was incorrectly installed.

Is there and exhaust system? Perhaps something is restricting the exhaust. Had a car backed up against a small hill and the tailpipe was stuck in the dirt. Car wouldn't start until it was moved from the parking space and away from the dirt plugging the tail pipe.