GM 3400 crank no start except with ether after head gasket job

[Adam Singer]

Hey y’all I’m really struggling I would appreciate any help.

I replaced the head gasket and intake manifold gaskets on my 3400 motor. Chevy Venture van.

The van has extended cranks before starting and and often will not start unless I give it a shot of ether. Once running it seems fine although a slightly rough idle. During extended cranks I have confirmed to have spark.
-New coil packs, one was bad.
-New fuel pressure regulator, the old one was leaking.
-Fuel pump pressure is about 48 PSI with engine on and running.
– New spark plugs and wires.
-I rechecked the injectors, all around 13 ohms and spray when given power. Not the best mist more of a stream but ok.
– Thoroughly cleaned throttle body and replaced IAC valve.
– Throttle sensor tests good.
– Cleaned MAF sensor
– Crank sensor output appears good.
– Replaced fuel filter and gas cap

Any direction at this point would be appreciated, I just want the van to start consistently.

• This topic was modified 2 years, 12 months ago by Adam Singer.

Topic

[Adam Singer]

Things I’m suspecting:

-Poor ground/weak spark of some sort?
-I didn’t check the actual voltage to the fuel pump at the pump but all connections were looking good. No corrosion at all. I’m not sure what spec the fuel pump pressure should be.
-I did not check cam sensor signal

What else?

• This reply was modified 2 years, 12 months ago by Adam Singer.

[Richard Kirshy]

My suggestion(s) would be:
Go back and check that all connectors are clean, tight and fully seated and in their proper locations
Next check that all vacuum line are properly attached in their correct locations.
Then start looking for any possible vacuum leaks starting at the intake snorkel forward to all vacuum hoses.

[Adam Singer]

Thanks.

I built a smoke tester and found no leaks except around the air box itself.

I also manually grounded the block to no avail.

The van pretty consistently will start on the second crank but idles rough. If I rush it, it won’t start and needs fluid.

[Richard Kirshy]

Check for any codes.
It would be useful to hook up to a scan tool and look at live data.

[Author]

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