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#1 |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Trying to start my LS for the first time.
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?
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#2 |
Registered User
Join Date: Jun 2014
Location: Mocksville, NC
Posts: 1,747
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Re: Trying to start my LS for the first time.
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.
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Builds: Green Gus the 68 C10 ; Sullii the 72 1500 - Instagram: @dr.hewitt - C10 Concept/Development Photos: Master Thread |
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#3 |
Post Whore
![]() ![]() Join Date: May 2015
Location: Alabama
Posts: 14,635
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Re: Trying to start my LS for the first time.
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?
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver Last edited by mongocanfly; 03-16-2023 at 03:29 PM. |
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#4 |
Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Trying to start my LS for the first time.
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.
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My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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#5 | |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Quote:
"Keyed on" is marked and tied direct to my 12volts for stating this on the stand.
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http://67-72chevytrucks.com/vboard/s...d.php?t=791250 Last edited by Factory Guy; 03-17-2023 at 12:31 PM. |
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#6 | |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Quote:
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.
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http://67-72chevytrucks.com/vboard/s...d.php?t=791250 Last edited by Factory Guy; 03-17-2023 at 12:33 PM. |
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#7 |
Senior Member
![]() Join Date: Mar 2015
Location: washington
Posts: 2,236
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Re: Trying to start my LS for the first time.
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 Last edited by Accelo; 03-17-2023 at 12:33 PM. |
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#8 |
Post Whore
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Location: Alabama
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Re: Trying to start my LS for the first time.
Without the maf it should momentarily crank and then die
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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#9 |
Registered User
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,119
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Re: Trying to start my LS for the first time.
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.
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My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html |
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#10 |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
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.
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#11 | |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Quote:
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.
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#12 |
Senior Member
![]() Join Date: Mar 2015
Location: washington
Posts: 2,236
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Re: Trying to start my LS for the first time.
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. |
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#13 | |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Quote:
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
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http://67-72chevytrucks.com/vboard/s...d.php?t=791250 Last edited by Factory Guy; 03-19-2023 at 07:02 PM. |
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#14 |
Post Whore
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Location: Alabama
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Re: Trying to start my LS for the first time.
That great news..!!!!!
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Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver |
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#15 |
Registered User
Join Date: Apr 2018
Location: Waynesville, MO
Posts: 46
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Re: Trying to start my LS for the first time.
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!
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#16 |
Senior Member
![]() Join Date: Mar 2015
Location: washington
Posts: 2,236
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Re: Trying to start my LS for the first time.
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
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#17 |
Senior Member
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Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Kind of what I was thinking!
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#18 | |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
Quote:
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#19 |
Senior Member
![]() Join Date: Jun 2019
Location: Midway USA Kentucky
Posts: 562
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Re: Trying to start my LS for the first time.
The guy who did my harness supplied the fuseblock/relay panel as shown.
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