'97 350 Vortec wont start, need help.

[AyWoSch Motors]

I know its not a squarebody, but its still a chevy, and you guys are super helpful, and I'm at a loss.
Right now I'm working on my 1997, 3500 Chevy work truck, that has its stock 350 Vortec.
It blew an intake gasket while I was towing a snow plow. Went full steam train mode, and went all milkshake on me.
...anyway, it was snowy and nasty, so I parked it didnt touch it again until a couple weeks ago. Tore it all apart, cleaned everything, put all brand new gaskets, changed the oil a couple times, put it all back together. Just today, I put the last part on that I needed, and tried to start it.
Nada, nothing, zip.
Itll crank happily, it builds about 40 pounds of oil pressure just cranking it. I gave it about 5 gallons of gas and perged the fuel line. I pulled a spark plug, has a nice healthy spark. I put my analyzer on it, no trouble codes pop up.
I gave it a little squirt of gas down the throat, nothing. Gave it a spray of starter fluid, nothing. It just wont go, dont know why.

Any suggestions?

 

[Bextreme04]

Did you run a compression test? It sounds like you cracked a cylinder head or blew a headgasket. Both are very common on Vortec 350's.

If you are getting spark and it wont start with fuel or starter fluid poured down the TB, you likely have no compression in one or more cylinders.

 

[AyWoSch Motors]

Did you run a compression test? It sounds like you cracked a cylinder head or blew a headgasket. Both are very common on Vortec 350's.

If you are getting spark and it wont start with fuel or starter fluid poured down the TB, you likely have no compression in one or more cylinders.

No, didnt run a compression test. I find it hard to believe that it has no compression, truck ran beautifully all the way up until I parked it.
And it was so obvious that it was the intake gasket that blew out, the whole bottom of it was laying in the valley.

My dad said that maybe it's just really far out of time. When I put it back together, I had it at TDC on number 1, and faced the rotor at number one, so it should be close enough to get it to pop over.

 

[Bextreme04]

No, didnt run a compression test. I find it hard to believe that it has no compression, truck ran beautifully all the way up until I parked it.
And it was so obvious that it was the intake gasket that blew out, the whole bottom of it was laying in the valley.

My dad said that maybe it's just really far out of time. When I put it back together, I had it at TDC on number 1, and faced the rotor at number one, so it should be close enough to get it to pop over.

Sooooo.... you pulled the vortec distributor and didn't set it back in using the correct procedure? This isn't a normal SBC.. it is computer controlled using a 4x reluctor on the crank and a 1x cam sensor inside the distributor. If you are more than ~8 degrees off(I think) the computer will have a panic attack and wont let the motor fire up at all.

Here is the proper way to install the distributor to get it to at least START. http://www.gmtruckcentral.com/articles/distributor.html

Once started, you will need a scan tool that can see CMP retard offset in order to adjust the distributor to as close to zero degrees as possible. If it is not within 2 degrees, plus or minus, the engine wont run right and might throw codes.

 

[Bextreme04]

Also, just because you found what you think is the smoking gun, doesn't mean that is the only issue. If it wont run or had a major mechanical issue with the motor, step 1 is to run a compression test to assess the health of the motor. If you have low or no compression on one or more cylinders, the time to find that out is when you are pulling it apart for repairs... not after you have it all back together and it wont run.

When my truck just started running bad and then stopped being able to start, I chased around a bunch of what I thought were smoking guns to no avail... until I ran a compression test and found 0 compression on one cylinder. Turns out I had a valve spring break into 3 pieces. It fast and easy enough to do that I recommend it be one of the first things someone does on a motor with running issues.

 

[AyWoSch Motors]

Sooooo.... you pulled the vortec distributor and didn't set it back in using the correct procedure? This isn't a normal SBC.. it is computer controlled using a 4x reluctor on the crank and a 1x cam sensor inside the distributor. If you are more than ~8 degrees off(I think) the computer will have a panic attack and wont let the motor fire up at all.

Here is the proper way to install the distributor to get it to at least START. http://www.gmtruckcentral.com/articles/distributor.html

Once started, you will need a scan tool that can see CMP retard offset in order to adjust the distributor to as close to zero degrees as possible. If it is not within 2 degrees, plus or minus, the engine wont run right and might throw codes.

Oooh.. did not know that. This is my first vortec. I've changed distributors in a bunch of old small blocks, with no problem, didnt know this one was fickle like that. Thank you.
I will check out that link later. That's probably the issue.
I do need to get a compression tester, don't have one, and they do come in handy. I'm gonna get one next time I go to town.

I guess I was naive to believe I could just throw a gasket on there and have it be fine. I really should have done a head gasket too while I was that far into the engine, but it seemed so obvious what it was, I was happy to just do the intake gasket and say good enough. I'm probaly going to regret that, but it might be just fine once I fix the timing, we'll see I guess.
Thanks for the help

 

[Bextreme04]

Oooh.. did not know that. This is my first vortec. I've changed distributors in a bunch of old small blocks, with no problem, didnt know this one was fickle like that. Thank you.
I will check out that link later. That's probably the issue.
I do need to get a compression tester, don't have one, and they do come in handy. I'm gonna get one next time I go to town.

I guess I was naive to believe I could just throw a gasket on there and have it be fine. I really should have done a head gasket too while I was that far into the engine, but it seemed so obvious what it was, I was happy to just do the intake gasket and say good enough. I'm probaly going to regret that, but it might be just fine once I fix the timing, we'll see I guess.
Thanks for the help

The best thing to do, even with old SBC, is to just put the engine at TDC before disassembly and then mark where the distributor is in relation to the intake and where the rotor is in relation to the distributor before you remove it. Then you only have to put it back to the exact spot it was when removed when you reassemble it.

 

[AyWoSch Motors]

The best thing to do, even with old SBC, is to just put the engine at TDC before disassembly and then mark where the distributor is in relation to the intake and where the rotor is in relation to the distributor before you remove it. Then you only have to put it back to the exact spot it was when removed when you reassemble it.

Ive done that on other engines, and I would've done that to this one, but I wasnt the one that took it out.
My dad decided he'd tear apart the whole engine after it blew up to find out what happened. Hes also the one that convinced me that I shouldn't bother with doing the head gasket, lol.
It's his truck, I'm just his mechanic that he doesnt have to pay.

 

[Bextreme04]

Ive done that on other engines, and I would've done that to this one, but I wasnt the one that took it out.
My dad decided he'd tear apart the whole engine after it blew up to find out what happened. Hes also the one that convinced me that I shouldn't bother with doing the head gasket, lol.
It's his truck, I'm just his mechanic that he doesnt have to pay.

Hahaha, I can relate to that. Good for you for helping the old man out

 

[AyWoSch Motors]

Hahaha, I can relate to that. Good for you for helping the old man out

Haha, thanks.

Since the day I started working on cars, he stopped. He just expects me to fix everything now. I fix the mower, the weed wacker, the tiller, the chainsaw, all his car, all the trucks, on top of all my stuff.
Hes like "this broke, fix it" and hands me the keys. I'm like ".... okay?"
I'm just used to it now, I think its funny.

 

[bucket]

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If you are accurate enough, that will get you close enough to where the ecm will be happy.

 

[AyWoSch Motors]

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If you are accurate enough, that will get you close enough to where the ecm will be happy.

Thanks, that's very helpful. I think with that and the link above, I can get it going.
I see now that its very sensitive.
I just threw it in there like I've done on all my old small blocks.

 

[Poppy 87]

Thanks, that's very helpful. I think with that and the link above, I can get it going.
I see now that its very sensitive.
I just threw it in there like I've done on all my old small blocks.

Late to the discussion, but if Dad took it apart, are you sure that you are tdc on the compression stroke? Ask me how I know that this can happen!!

 

[Ricko1966]

I'm not going to read all this,fell into this trap last weekend trying to help someone. Doesn't matter if you find it hard to believe it lost compression.You need to check it. I know why it could have lost compression, why,how and how to correct it.First verify if it does or does not have compression so we can move on.

Sorry, that sounds grouchy.

 

[AyWoSch Motors]

Late to the discussion, but if Dad took it apart, are you sure that you are tdc on the compression stroke? Ask me how I know that this can happen!!

Haha, yeah I'm sure about that. Made sure the line on the balancer and the timing mark were aligned, and I also put a pen down the spark plug hole and watched it stop going up.
And both the valves were closed (i.e. compression stroke)