Blueprint LS Engine No Start - FIXED!!!

[lewma]

Hello All

Does anyone know if an LS engine, purchased through BluePrint already has VATS deleted in the ECU programming ? I'm having a hard time getting any life out of this LS, even swapped out the entire engine harness. Still no spark

Any help would be greatly appreciated!
mark

[sread]

I think Blueprint would be the best person(s) to answer that , but if you are sure there is no spark then the problem is most likely either a basic wiring fault (no power from the ignition switch in "crank" or maybe no input to the ecu) or a crank sensor or cam sensor issue. Should be fairly easy to verify with a basic diagnostic scanner. Did the engine package come with any install/troubleshooting documentation?

[lewma]

Its frustrating. I contacted Jose at Blueprint last week but unfortunately got the usual no response. I've ruled out the harness as i'm using a second one now. Next thing is to go test out all the sensors. I have power to the coils during cranking so that's not the issue.

I'll keep plugging away...

[sread]

If you are positive that you have power while cranking to the coils, then check the crank sensor. An LS will run with out a signal from the cam sensor but may have extended crank times. Also be sure the grounds for each bank of coil packs are grounded to each head.

[Its Bruce]

It would be an incredible oversight to not disable VATS.

Are you using BP's GM harness (ref. link (https://www.chevrolet.com/content/dam/chevrolet/na/us/english/index/performance/resources/installation-guides/crate-engines/01-images/ls-engine-controller-kits-all-naturally-aspirated-non-e-rod-except-lc9.pdf))? If so, what are you using for your ignition switch input?

[lewma]

Confirmed with Jose from BP that VATS and all other security features are disabled.

Using the harness provided with the engine, then also used a second harness with the same part number to rule those out. Confident this is not a harness issue.

I'm using a digital guard dawg setup and confirmed that the ignition feed is 12v and remains hot during crank.


mark.

[lewma]

If you are positive that you have power while cranking to the coils, then check the crank sensor. An LS will run with out a signal from the cam sensor but may have extended crank times. Also be sure the grounds for each bank of coil packs are grounded to each head.

Yep, confirmed power remains during cranking. OBD2 port confirms RPMS are seen during cranking.

The harness only has 3 ground eyelets and they came already attached to the heads.

[sread]

Verify you have ground continuity between the engine and the ecu - as well as the correct pin(s) being grounded for the ecu. If that checks out, remove the Guard dog and see what happens...actually, that is probably the first thing I would do.

[lewma]

Verify you have ground continuity between the engine and the ecu - as well as the correct pin(s) being grounded for the ecu. If that checks out, remove the Guard dog and see what happens...actually, that is probably the first thing I would do.

Yep, tested grounds between the engine and the ECU. It all checks out. ECU is alive. it spins up the fuel pump, clicks the throttle body and throws zero codes via the OBD2 port.

The guard dawg is only there to provide a 12v feed to the ignition wire. Not sure that would impact this ??

[FFinisher]

Lets not get lost in the complication of the Vats, and the computer and the guard dawg.

You need 4 things:

Fuel
Spark
Compression
Air.

First is -Do you have spark? If you have power at the coils you only have half what you need. You will have power all the time. YOU need a pulsed ground when cranking. Pull a plug set it against the block and see if it sparks when you crank. If it does, you have spark. If not fix that.

Second, do you have fuel? You need about 58 PSI to the fuel rail.( if using an intank pump you wouldn't be the first to have a fuel pump connector wired backwards). if using an external pump, is the pump installed in the right direction? (you wouldn't be the first to install one backward either;) Do you have that? If not fix that. Once that's fixed do you have power and a pulsed ground to the injectors? if not You need to find out why. (best way to test this is with a NODE light-available at most parts stores.

No pulse to spark and fuel sounds like crank sensor to me. I am not sure this has been established,but...... These are usually behind the starter. make sure its plugged in.

Check these and let us know.;)

With a brand new engine you must have compression and intake air. Never assume, but lets assume this for now.

[lewma]

Lets not get lost in the complication of the Vats, and the computer and the guard dawg.

You need 4 things:

Fuel
Spark
Compression
Air.

First is -Do you have spark? If you have power at the coils you only have half what you need. You will have power all the time. YOU need a pulsed ground when cranking. Pull a plug set it against the block and see if it sparks when you crank. If it does, you have spark. If not fix that.

Second, do you have fuel? You need about 58 PSI to the fuel rail.( if using an intank pump you wouldn't be the first to have a fuel pump connector wired backwards). if using an external pump, is the pump installed in the right direction? (you wouldn't be the first to install one backward either;) Do you have that? If not fix that. Once that's fixed do you have power and a pulsed ground to the injectors? if not You need to find out why. (best way to test this is with a NODE light-available at most parts stores.

No pulse to spark and fuel sounds like crank sensor to me. I am not sure this has been established,but...... These are usually behind the starter. make sure its plugged in.

Check these and let us know.;)

With a brand new engine you must have compression and intake air. Never assume, but lets assume this for now.

There is no spark. I'm using a spark plug tester and i never see any spark coming from it. That's the root of the problem. Why no spark.

Fuel is good at the rails.

I'm assuming that the crank sensor is good as I'm getting RPMS as the engine is cranking.

[sread]

Verify that you have the correct crank sensor for that engine, i.e. 24x vs 58x. It wouldn't hurt to try a new one anyways. ..and I still say take the guard dog out of the equation while troubleshooting. If all that checks out it sounds like a bad ecu.

[JimLev]

Do you have the pink wire in the GM harness connected?
If not, it won’t start.

[lewma]

Do you have the pink wire in the GM harness connected?
If not, it won’t start.

yep, pink wire is connected. The harness is very simple really. 3 grounds to the back of the heads, main power to the fuse box then ignition power to the pink wire. The harness came connected to the engine from BluePrint.

Still trying to get some life out of this thing....

[Kbl7td]

100 to 1 it’s a bad sensor somewhere. Do you pull plugs after turning over? Are they wet?

[lewma]

100 to 1 it’s a bad sensor somewhere. Do you pull plugs after turning over? Are they wet?

Thanks for the suggestion however this is a BluePrint provided engine that has been dyno'd so I have to assume ( perhaps incorrectly ? ) that the sensors are working.

This weekend I'm going to take a closer look at how the engine is grounded. Perhaps add a ground from engine to battery directly, engine to ECU, engine to my other car, engine to my house ground, engine to neighbors ground too just incase :)

[cgundermann]

That’s a bummer - good luck over the weekend.

Chrid

[lewma]

Added a ground from the engine block directly to the battery - no spark
Moved the ground to drivers side head - no spark
Added a ground to the ECU - no spark
Removed the guard dawg from the setup - no spark

If anyone has any other ideas, i'm all ears.

mark

[lewma]

Blueprint's advice was to rest a spark plug on the head to verify spark. Did this and no spark. Also noticed that the plug was dry so injectors are not pulsing either ?
I opened the schrader valve on the fuel rail and have confirmed fuel in the rails.

So now no spark, no injectors either.

[sread]

sounds like time time to try another crank sensor and/or ecu

[lewma]

Success!!!!

Problem was caused by a ground pin in the cam sensor pigtail. The Gen4 LS3 engines use a cam sensor at the front of the engine along with a mounted pigtail. Turns out the ground pin in the pigtail connector was not fully seated and was not correctly grounding the sensor. Ripped it all apart, fixed the pin and boom! Started right up!

Glad this is finally solved. Of course I looked everywhere else apart from that pigtail. 4+ straight weekends of tearing my hair out.

Onto the next challenge.... leaking hydraulic throwout bearing :(

mark

[Its Bruce]

Good update, thanks for the closure. Now back to waiting for my BP 427LS delivery...

[Jim Frahm]

Success!!!!

Problem was caused by a ground pin in the cam sensor pigtail. The Gen4 LS3 engines use a cam sensor at the front of the engine along with a mounted pigtail. Turns out the ground pin in the pigtail connector was not fully seated and was not correctly grounding the sensor. Ripped it all apart, fixed the pin and boom! Started right up!

Glad this is finally solved. Of course I looked everywhere else apart from that pigtail. 4+ straight weekends of tearing my hair out.

Onto the next challenge.... leaking hydraulic throwout bearing :(

mark

Mark,

I'm having the same problem, crank but no start. I've already checked the harness at the cam and crank sensor. Everything looks good. I'm about to replace both sensors and hope that fixes the issue.

Thanks for letting us know what fixed your problem.

Jim

[lewma]

Jim

I took out the cam sensor, hooked it up to the harness and turned the ignition on. Back probe the center ground pin then try one of the other pins to read a voltage. Take a wrench and wave it infront of the cam sensor. You should see a fluctuating voltage from one of the remaining 2 pins.

For the crank sensor, are you seeing an rpm reading anywhere when cranking ?

mark

[Jim Frahm]

I took both sensors out and checked the grounds and 12 volt supply, both were good. My engine was built by a local shop and they used old sensors. I decided to replace both and they try starting it again. My RPM gauge isn’t hooked up at the moment so I didn’t check that while cranking. However, my FiTech has a hand held controller that will show RPMs but I didn’t think to check that while cranking the engine. Oh well, both sensors were less than $50 so I might as well install new and then give it another try. I’ll post a follow up once I figure it out.

Thanks again,
Jim

[lewma]

Do you have good fuel pressure at the rails? Mine is 58psi. Does the throttle body click and the fuel pump spin up when you turn the ignition? Finally are you sure your 12v ignition feed remains hot while cranking?

[Jim Frahm]

Do you have good fuel pressure at the rails? Mine is 58psi. Does the throttle body click and the fuel pump spin up when you turn the ignition? Finally are you sure your 12v ignition feed remains hot while cranking?


Yes, I checked all of those items first. I have good fuel pressure and power during ignition on and cranking. Like you, my injectors aren’t opening either as the plugs were dry when I pulled them out to check for spark. I also checked for grounds and power at each sensor during ignition on and cranking and they also checked out okay.

[lewma]

Yes, I checked all of those items first. I have good fuel pressure and power during ignition on and cranking. Like you, my injectors aren’t opening either as the plugs were dry when I pulled them out to check for spark. I also checked for grounds and power at each sensor during ignition on and cranking and they also checked out okay.

Do you have an OBD2 port scanner ? Can you see if the ECU is throwing codes ?

I'd also verify that you can see RPMs while cranking. Mine was showing around 170RPM during crank before starting