Trying to start my LS for the first time.

[Factory Guy]

Ok, So I have my LS LQ4 (all GEN 3) ready to fire up. Vats are deleted, computer was reflashed by Brendan on LT1Swap.com. Wire harness, made by his buddy Andy, everything, near as I can tell is plugged in. Cranked it over yesterday as shown in the photo. It never even attempted to fire.

Most everything on this LQ4 is stock. It did get a cam swap to a SS2, new lifters and PAC1218 springs. 317 Heads were re done. Compression ratio is stock. (nothing was milled off the heads)

ENGINE is not in the truck yet. The engine cranked over very slowly but never attempted to fire. Cam sensor is plugged in, crank sensor is plugged in. Drive By Wire pedal is connected and it opens the throttle body.

I just check for spark plug fire. Pulled # 1 plug. it had fire when cranking.

Pulled all the spark plugs and cranked it over, it cranks really quick with no spark plugs and I had almost 40 PSI of oil pressure.



60psi on the gauge for fuel pressure. However, it did have some gas leaking out between the intake gasket on #1 fuel injector and the head? (It has a new gasket there?)

Is a minimum rotating speed required to start the engine? I pull the battery out of my daily driver to start this.


Want to make sure everything is working correctly, before installing this into my Squarebody.

Suggestions?

[hewittca]

What are you using for a fuse/relay panel, and more specifically, how do you have the "key on" pink wires powered? I don't have any further insight but I am in to see the solution because I will be starting up my LS for the first time soon as well.

[mongocanfly]

Dang...I thought I was the only one with a no crank issue... yours sounds just like what mine is doing..
It should hit but it wont run without the maf, unless your running speed density
Did you check for injector clogging?

[ls1nova71]

It will need a good strong battery, so start there. Definitely check to make sure the injectors are working. Clogged injectors from sitting happens all the time and are a cause of a lot of no start conditions on many first time swap starts. Also, as Greg said, hook up the MAF. When starting them on the floor, I usually just duct tape the MAF directly to the throttle body, it's not optimal, but it works.

[Factory Guy]

Originally Posted by hewittca

What are you using for a fuse/relay panel, and more specifically, how do you have the "key on" pink wires powered? I don't have any further insight but I am in to see the solution because I will be starting up my LS for the first time soon as well.

Andy made up a separate fuse/relay block panel that greatly simplifies the Factory fuses. It has relays built into it for the fuel pump, the Fan relays and etc.

"Keyed on" is marked and tied direct to my 12volts for stating this on the stand.

[Factory Guy]

Originally Posted by mongocanfly

Dang...I thought I was the only one with a no crank issue... yours sounds just like what mine is doing..
It should hit but it wont run without the maf, unless your running speed density
Did you check for injector clogging?

Thanks everybody for your input.

Agreed I thought it would at least try to fire?

All 8 injectors were professionally cleaned out by a well known injector guy, prior to starting this the other day. He has also offered to redo them if I find anything wrong with them. Fuel lines were purged and cleaned as well before I re-inserted the injectors.

Regarding the MAF it is my understanding that without a MAF it will run but not stay running. Am I correct? Anyway, I will try the MAF in front of the throttle body.

[Accelo]

Be careful, when the motor starts on an engine stand the resulting instantaneous torque can easily spin the engine on the stand or tip it over. You will need to have it supported to the floor, like outriggers of some kind.
Typically with out the MAF the motor will start or attempt to anyway. When you add throttle is where it will drop on it's face and die.
The biggest mistake, starting LS motor, has been pointed out. Check the power when cranking. Individuals hook power up and it checks fine. They they find out while cranking the power drops out.
Cheers

[mongocanfly]

Without the maf it should momentarily crank and then die

[ls1nova71]

Make sure you didn't miss a ground. The one behind the power steering pump is easy to miss and will cause a no start if not hooked up.

[Factory Guy]

It must need a connection on the MAF, cause it just started with the MAF and ran for about 2 mins until it ran out of gas.

I am hooking the ground up to the bottom of the motor mount.

Still seems to crank very slow however. As if I bumped the compression.

[Factory Guy]

Originally Posted by Accelo

Be careful, when the motor starts on an engine stand the resulting instantaneous torque can easily spin the engine on the stand or tip it over. You will need to have it supported to the floor, like outriggers of some kind.
Typically with out the MAF the motor will start or attempt to anyway. When you add throttle is where it will drop on it's face and die.
The biggest mistake, starting LS motor, has been pointed out. Check the power when cranking. Individuals hook power up and it checks fine. They they find out while cranking the power drops out.
Cheers

Yes I agree. But this isn't a Cheap HF engine stand. This is an extra wide Professional Engine stand that is probably 6 feet wide. It ran great idled good and made no unusual sounds. JUST DAMN LOUD.

I doubt I will run it any more now. I can started getting it installed in the truck since I know it runs and there are no issues, that was my whole point of this. Since I had never heard it run before.

[Accelo]

Darn happy for you. Always stressful.
So, what was the issue?

Be sure to check for oil leaks. I still have one I have not been able to identify.
I may have to pull the transmission and start the motor to find it as I have tried everything including a bore-scope.

[Factory Guy]

Originally Posted by Accelo

Darn happy for you. Always stressful.
So, what was the issue?

Be sure to check for oil leaks. I still have one I have not been able to identify.
I may have to pull the transmission and start the motor to find it as I have tried everything including a bore-scope.

Thank you, I guess the issue was, not having the MAF plugged in. I charged the battery, then it barely cranked over now and fired right up!

My oil leaks were present prior to starting and therefore I fixed them about 6 weeks ago. You can read all about it here:

http://67-72chevytrucks.com/vboard/s...=791250&page=7

[mongocanfly]

That great news..!!!!!

[rdc72]

The slow start is more than likely a ground wire, once it is in the truck and all grounds are verified it should spin over quicker, if not its another rabbit hole to go down!

[Accelo]

I checked out the "oil leak" link you posted. Yes, it isn't your HF style motor stand. I understand your comment as I have the same one. New they sold for about a $1000 years ago. I couldn't afford one so I built it. Has the same tapered feet, in two directions your has. Even replicated the chain rotational stop. One could put a Cummings on it without issue. NICE
Cheers

[Factory Guy]

Originally Posted by rdc72

The slow start is more than likely a ground wire, once it is in the truck and all grounds are verified it should spin over quicker, if not its another rabbit hole to go down!

Kind of what I was thinking!

[Factory Guy]

Originally Posted by Accelo

I checked out the "oil leak" link you posted. Yes, it isn't your HF style motor stand. I understand your comment as I have the same one. New they sold for about a $1000 years ago. I couldn't afford one so I built it. Has the same tapered feet, in two directions your has. Even replicated the chain rotational stop. One could put a Cummings on it without issue. NICE
Cheers

The people who where selling these years ago, used, didn't want anything for them. I think I paid $25 for it. Although when I started this LS swap I had to modified the engine mounts as there was no way to bolt it up and fire up the engine.

[Factory Guy]

Originally Posted by hewittca

What are you using for a fuse/relay panel, and more specifically, how do you have the "key on" pink wires powered? I don't have any further insight but I am in to see the solution because I will be starting up my LS for the first time soon as well.

The guy who did my harness supplied the fuseblock/relay panel as shown.