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Discussion Starter · #1 ·
Hi everyone. My son is just about completing a frame off restoration on a 1978 TransAm. The car has an original factory 403 Olds engine which he sent out mid-west to have rebuilt. It has a Holley 650 vacuum secondary's carb. I've helped him some with the motor and we fine tuned it. It ran and sounded good last time I was at his house. He tells me last week he started the motor and it would run for 2 minutes or less, and then die out. Something definitely happened between my last visit and then. He's tried a few different things such as leaving the gas cap off, which he said isn't vented, changed out the fuel pump and tried a gravity feed into the carb. with something he rigged up. Said nothing helped. The tank, sending unit and lines are all new. The fuel pump produced fuel, but it wasn't coming out under a lot of pressure. The spark plugs were also slightly black. I thought it might be a vacuum leak problem and he checked all the hoses, which were on the correct ports and fine; not cracked. The carb. is new and he is having it checked out this week. Any idea what the problem might be?? Something we could look at?? Try?? He tells me it seems like it runs out of fuel. He does have a full tank. Many thanks, Carmine.
 

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When it dies, does he still have spark? I’m wondering if it’s faulty coil as engine gets warm.
shooting some starter fluid into carb while dead will tell you if it’s fuel related.
 

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He tells me last week he started the motor and it would run for 2 minutes or less, and then die out.
What does it take to restart it? Did he change the fuel filter?
 

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If you add a bit of fuel down carb does it start up? If it does then most likely the needle is stuck to the seat.
 

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Hmm, black plugs, gravity feed doesn't help. Two minutes is not long enough to point to heat breakdown of ignition module or a coil. Doesnt mean they aren't bad though.
Any chance it had a backfire recently?
 

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Black plugs could be running rich or not running long enough to burn the fuel, sound like a carby problem, would try poring some down the throat see if the engine runs longer
 

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Discussion Starter · #7 ·
Thanks guys. I just forwarded your questions to my son and as soon as I get the answers, I will post them, Carmine.
 

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Discussion Starter · #8 ·
OK. Here's what he told me.
New MSD Blaster 2 coil and he will check spark after engine dies.
Engine runs for 20-30 seconds tops, then dies out.
He can keep it going for a few more seconds with starting fluid.
After dying out, he can get it to start, but not always, needing to pump the gas. Best to wait about 10 minutes or so, for it to cool down some, then he restarts it, going through the same thing.
The carb. is a new Holley 80555c with electric choke and vacuum secondary's.
There is a filter between the tank and fuel pump, which is always full.
And, that's all I know. Thanks guys, Carmine.
 

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Ethanol in gas will break down rubber hoses. Had a chain saw that would act just as you’re stating. Start, run 10-15 seconds and stop. Went to repair shop and told mechanic symptoms. Right off, he said bad fuel line - do you use ethanol fuel? Engine starts and as it runs the suction of the carburetor collapses fuel line not letting fuel get to carburetor. Let it sit, fuel line expands and fuel is now able to flow properly. Starts right up and stops again after 10-15 seconds - repeating the scenario.

Fuzz

MAGA
 

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If its ignition related the float bowls will stay full when it dies. As far as I know all the newer Hollys have clear plugs in side of the float bowls so that you can see the fuel level A vacuum leak or somewhat rich condition won't kill it it will just miss or idle rough. If its flooding he should be able to see fuel dribbling out of the boosters or vent and the fuel will be over the top of the sight plugs. Once you rule out the fuel system you can go on to the ignition. I assume its HEI? Everyone loves them but I hate the darn things. Every one I have ever owned left me walking at one time or another with either a module or pickup coil failure. I have to get a service manual to figure out which.
 

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Discussion Starter · #11 ·
If its ignition related the float bowls will stay full when it dies. As far as I know all the newer Hollys have clear plugs in side of the float bowls so that you can see the fuel level A vacuum leak or somewhat rich condition won't kill it it will just miss or idle rough. If its flooding he should be able to see fuel dribbling out of the boosters or vent and the fuel will be over the top of the sight plugs. Once you rule out the fuel system you can go on to the ignition. I assume its HEI? Everyone loves them but I hate the darn things. Every one I have ever owned left me walking at one time or another with either a module or pickup coil failure. I have to get a service manual to figure out which.
Fuzz, he does have a factory rubber line which is new. I'm assuming it's between the fuel line and fuel pump. It's been exposed to gas for less then a year.

I don't know about his distributor, but will find out. I also advised him of what else you mentioned and he will check it out.
Thanks for your help, Carmine.
 

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Ask him to remove the air cleaner, is the electric choke closed or open if closed it may be preventing the engine from running.
 

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Discussion Starter · #13 ·
Not much more new to report. The car still runs like crap. The distributor is a MSD. The choke partially opens when trying to start, but hard to tell thereafter because the motor only runs for 10-15 seconds or so.
He had his new Holley 750 carb. looked at and they found nothing wrong with it. He also called Holley who told him that when the line to the carb. is unhooked, turning the engine over, gas should spurt out the line under some decent pressure. He says that doesn't happen. It pulsates out but not under pressure. This is with both new fuel pumps. This motor is fully rebuilt with no road mileage on it whatsoever. Collectively, maybe an hour running time. I'm wondering if that lobe on the camshaft or whatever it's called, that the fuel pump arm works from, is bad?? I don't know how with such little running time, Carmine.
 

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Get a clickety clacky pump hook it to the fuel inlet and put the suction in a gas can wire it to a battery and see if it runs. I think a Olds uses a eccentric that bolts to the cam like a Ford not a lobe on the cam like a Chevy. Maybe the bolt came loose or something.
 

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Discussion Starter · #15 ·
My poor son, he can't seem to get a break. Now he tells me he has previously been turning the engine over a lot, and two days ago while doing so, he heard a grinding noise underneath. Took a look and saw some teeth on the flywheel, were in bad shape. The top squareness was gone. The teeth on the starter were also sad looking. Apparently the starter should have been shimmed, but wasn't. So, he ordered a new flywheel and starter. Will have to deal with this before going further with the engine. Just thinking some, I don't recall ever having to shim a starter or even knowing how to do it. Guess I've been lucky. Have changed a few, Carmine.
 

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If the starter bolts into the bell housing as with original trifives (except TurboGlides, idk?), no shimming is needed or even possible.
If the starter bolts are vertical and into the block, then you must use the special knurled shaft starter bolts, and shim the starter properly.
The way I used to set up the shims is to remove the starter solenoid and bolt the starter in place with the old set of shims (if available) or none to start with, pull the solenoid core to engage the bendix drive teeth into the flywheel teeth, and check for clearance. I would then install the minimum set of shims such that the two sets of teeth would not bind against each other as the bendix drive was engaged and disengaged manually.
You can often hear improperly shimmed GM engines whine or howl momentarily when they start up and kick out the starter bendix gear. This makes a very distinct and unique sound. It's like fingernails screeching on a chalk board to me.
Also, if there was originally a support holding up the far end of the starter, don't leave it off! Starters don't like the other end hanging loose, especially when they're bolted up vertically.
You can get by with worn flywheel teeth if they're not too bad...
Just make sure the starter's bendix drive teeth are in good shape, and the drive's one-way clutch is behaving smoothly, as designed.
 

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And GM starters are easy to rebuild. New brushes, bendix drive or even bushings and solenoids aren't hard to replace. (Ford starter brushes are h*ll to replace,)
If the armature and housing is in good shape, I much prefer to keep and fix up a good GM starter than take a risk on a rebuilt.
Perhaps we were using a bottom of the barrel rebuilder decades ago where I worked, but we saw more than a few rebuilt units that drew way too much current under light to normal loads. One Nissan starter I worked on was missing one of the four brushes, so it was running on half the current (somehow it still managed to work reliably).
 
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