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Just did the first start up on a built motor. Built by Gord bush in Toronto.
It will start instantly and run perfectly for 4 seconds then die. It will respond to throttle initially but no matter what level of throttle it will still die after 4 seconds. I've adjusted fuel pressure from 30psi to 60psi, still dies. No engine lights, fuel pressure holds after startup. I have oil pressure.
It's as if something is telling it to turn off. Any idea on what could be causing this? I'm stumped.
Thanks,
Channing
Last edited by channing2294; 06-03-2024 at 09:26 AM.
Was the flywheel installed correctly?
OEM crank sensor used?
What's af/r showing when start / giving throttle.
What is throttle %?
Does throttle % change with scan gauge when depressed?
It's being tuned with UPREV. Talked with tuner (Tony at Dynamotorsports), he knows the build and said it should run no problem with current ( stock block tune). Will be bringing it in for tune once cooling system is bled.
As far as I can tell flywheel installed correctly, no timing issues, it runs perfectly and then shuts off after 4 seconds. OEM Crank sensor installed and no code for Crank sensor. Car doesn't run long enough for a/f guage to get reading. But again, runs perfectly the initial 4 seconds so a/f isn't the issue I don't think. Throttle is working fine, will respond to throttle no problem but power is cut after 4 seconds and then dies. No level of throttle will keep the car running after 4 second, just dies. Its like something is telling it to turn off.
Originally Posted by iideadeyeii
What is it being tuned with?
Was the flywheel installed correctly?
OEM crank sensor used?
What's af/r showing when start / giving throttle.
What is throttle %?
Does throttle % change with scan gauge when depressed?
Last edited by channing2294; 06-03-2024 at 12:24 PM.
Battery has been trickled and has full charge. Starts strongly.
Dont see the blower disconnected changing anything, theres no boost at idle.
Car runs and shuts off same period of time, every time. Doesn't sputter, just runs for 4 seconds, and turns off. It's like something is killing power electronically. No engine lights either which is the real kicker.
Originally Posted by OldManZ350
put a Full Charge on the Battery.
take off the COG BELT, to see if that helps. It's earyer to work out problem with the Blower disconnected.
Battery has been trickled and has full charge. Starts strongly.
Dont see the blower disconnected changing anything, theres no boost at idle.
Car runs and shuts off same period of time, every time. Doesn't sputter, just runs for 4 seconds, and turns off. It's like something is killing power electronically. No engine lights either which is the real kicker.
I would heed OMZ advice and remove the belt … Likely one of the smartest VQ and/or SC VQ owners the platform has seen (take a deep dive on his threads and see what he’s accomplished).
Have you dont anything to your fuel system? Did you put a new pump in it? Did you put a return fuel system on it? Do you have the ability to monitor your fuel pressure?
I would heed OMZ advice and remove the belt … Likely one of the smartest VQ and/or SC VQ owners the platform has seen (take a deep dive on his threads and see what he’s accomplished).
Have you dont anything to your fuel system? Did you put a new pump in it? Did you put a return fuel system on it? Do you have the ability to monitor your fuel pressure?
I know his history, I just don't see the correlation. Will try anyway to eliminate variables.
Same fuel return system used on stock block, fuel pressure maintains on startup, no drop. Only change is a walbro 350 now on the new built block instead of a 255 walbro used before.
Check out this link and have a look/listen, I'm raising the rpms above 2k in the video.
https://youtu.be/sV5Onxr6ejU?si=Mp-1h_hIdVnadrC7
QUOTE=bealljk;11126877]I would heed OMZ advice and remove the belt … Likely one of the smartest VQ and/or SC VQ owners the platform has seen (take a deep dive on his threads and see what he’s accomplished).
Have you dont anything to your fuel system? Did you put a new pump in it? Did you put a return fuel system on it? Do you have the ability to monitor your fuel pressure?[/QUOTE]
Last edited by channing2294; 06-06-2024 at 01:33 AM.
I Watched the Video, sounds like a Fuel Issue IMO.......
Sounds like it has enough fuel to start and run for just a few seconds, then runs out.
check you entire fuel system. you just installed a fuel pump, recheck install & rubber oring sleeve for cracks.
I'ts possible to maintain some FP at Idle, but not have enough enough fuel.
recheck All ECU Setting..........
Hope this Help.......
I told you things to do, to help you diagnose the problem.
IIt just makes it easier for you, even if you don't understand. Not having Extra Load on the Motor from the blower at Startup & Idle just help to figure out problems........
Ah, I wondered that. I'll recheck the fuel pump install and get back to you. May even install the old 255 if it persists.
Thanks for the direction, I'll check in later
Cheers
QUOTE=OldManZ350;11126923]I Watched the Video, sounds like a Fuel Issue IMO.......
Sounds like it has enough fuel to start and run for just a few seconds, then runs out.
check you entire fuel system. you just installed a fuel pump, recheck install & rubber oring sleeve for cracks.
I'ts possible to maintain some FP at Idle, but not have enough enough fuel.
recheck All ECU Setting..........
Hope this Help.......
I told you things to do, to help you diagnose the problem.
IIt just makes it easier for you, even if you don't understand. Not having Extra Load on the Motor from the blower at Startup & Idle just help to figure out problems........
Yea it seems like the fuel just gets cut right off all of a sudden. I been wrenching for years now but im definitely not a tuner but wouldnt the car kind of sputter before shutting off completely? Its enough to start up but for it to shut off just like that its kinda strange. Maybe an ingnition issue here?
I agree, there would still be tonnes of fuel in the rail, and fuel pressure isn't dropping. Something is cutting power, but what and why lol. Is this some sort of fail safe? But why no code?
Im still not 100% convinced its mechanical. But the only reason I think it may be, is because the computer isn't picking it up. There would be SOME sort of code, telling me hey, there's an issue.
So ill atleast start with the fuel pump and start the elimination process.
Originally Posted by bre240z
Yea it seems like the fuel just gets cut right off all of a sudden. I been wrenching for years now but im definitely not a tuner but wouldnt the car kind of sputter before shutting off completely? Its enough to start up but for it to shut off just like that its kinda strange. Maybe an ingnition issue here?
Same fuel return system used on stock block, fuel pressure maintains on startup, no drop. Only change is a walbro 350 now on the new built block instead of a 255 walbro used before.
so are you monitoring fuel pressure when you go key on? When you activate the starter? When the car is running for 4seconds? And when it dies?
Seems pretty simply:
If you have 52’ish psi of pressure from key on to when the car dies than fueling is not your issue.
If you do not have 52’ish psi of pressure from key on to when the car dies than you know fuel is your issue
so are you monitoring fuel pressure when you go key on? When you activate the starter? When the car is running for 4seconds? And when it dies?
Seems pretty simply and straight forward if you ask me:
If you have 52’ish psi of pressure from key on to when the car dies than fueling is not your issue.
If you do not have 52’ish psi of pressure from key on to when the car dies than you know fuel is your issue
2/3rds of my no-start issues over the years I’ve owned a VQ have been fueling…
Spoke to my tuner. He asked if maf was installed backwards. And it was. The maf can only go into the charge pipe one way but I had the CHARGE PIPE backwards, not the MAF.
06-03-2024, 09:23 AM
New Built Engine Start-up issue
