No start help after swap; 2008 5.3 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jonboy · 06-30-2015, 07:02 PM

Checking to see if some of the gurus here may have any help for me. I swapped a 2008 5.3 (non flex fuel) into a '77 C10. Used an aftermarket stand alone harness with a "tuned" PCM. I am having a no start issue. Fuel is 55 at the rail during prime, moves from 55 to 65 during cranking (assuming that means the injectors are firing?). New Delco plugs; have a bit of a burn spot on them, but not complete. Compression on all cylinders, anywhere from 160 to 170. I pulled the injectors and let them soak in a container of Seafoam thinking they might have been clogged. I am getting spark on #1, and there is signal at the injector plug verified by a noid light. I do have power on the switched power wire during key on and crank, constant power is good.

What could I be missing? It doesn't even act like it wants to try and start.

solidaxel · 06-30-2015, 07:15 PM

Watching !!

aknovaman · 06-30-2015, 10:53 PM

Will it try to start with a bunch of starting fluid? If so you may just have a bunch of air in the fuel rails that need purged.

Your tuner may have also not properly deleted the vats. On the newer ecu, he needs to do a write entire and not just write calibration the first time. If you are adjusting the tune the rafter, you can just write the calibration.

Angryman117 · 07-01-2015, 11:26 AM

Sounds like VATS is still enabled. Also with everything powered up does the throttle operate correctly?

**truckdude239** · 07-01-2015, 09:07 PM

Try groundi g the case of the computer it self mine wouldnt starr and i ground the computer case and it started right up

Jonboy · 07-01-2015, 11:31 PM

Will the VATS let it start then die, or will it not start at all?
Posted via Mobile Device

BR3W CITY · 07-02-2015, 03:06 AM

Both honestly. Sometimes VATS won't let it run at all, other times is will allow up to 7 seconds. Usually the first time after a battery reset VATS will allow the longer run, once it fails it will usually only allow it to sputter then die without really ever "catching".

faribran · 07-02-2015, 07:54 AM

Did you turn engine over with the fuel rail and injectors pulled, to see if they are spraying?

solidaxel · 07-02-2015, 09:23 AM

Quote:

Originally Posted by truckdude239

Try groundi g the case of the computer it self mine wouldnt starr and i ground the computer case and it started right up

That may be true for a stock computer but my VATS has been turned off and it is sitting on the floor on top of carpet and no ground from the case to the chassie/engine and the engine does what it is ment to do.

I am glad I did not read this before I tried to start the engine as I would have placed a ground from the case top the engine.

Thanks for bringing that info up I will add it to my trouble shooting log

BR3W CITY · 07-02-2015, 12:40 PM

Quote:

Originally Posted by solidaxel

That may be true for a stock computer but my VATS has been turned off and it is sitting on the floor on top of carpet and no ground from the case to the chassie/engine and the engine does what it is ment to do.

The ECM is internally grounded through the wiring harness. You only ever need to ground the case if the internal grounding circuit died. (It happens more than you'd think actually). The direct-grounding of the case is just the easiest way to check for it.

Jonboy · 07-03-2015, 10:11 AM

I have not had a chance to check throttle actuator yet. I usually only to get to work on it at night, after the kids go to bed. I was going to pull the rails to check injector pattern this weekend. Since the noid light lit up, it led me to believe they were firing.

Jonboy · 07-08-2015, 05:57 PM

Throttle actuator is working. I can hear it moving, and verified it via scantool. I did an injector balance test, and fuel pressure only dropped on one cylinder (#7). I was able to get a set of injectors from a buddy, and swapped them in. It fired, but runs really rough. The newer set of injectors sat for a while as well; it may just need to run some fuel through them to try and unstick them. The truck has no exhaust on it, so I will mess with it more this weekend. The only time I really get to work on it is after my kids go to bed.

**Hart_Rod** · 07-11-2015, 08:43 PM

I would put my exhaust on before I messed with it any more....

06-30-2015, 07:15 PM	#2
solidaxel Registered User Join Date: Dec 2002 Location: Cactus Patch So. Az Posts: 4,749	Re: No start help after swap; 2008 5.3 Watching !! __________________ 53 TuTone Extended Cab 350 4-Spd 3:08 (SOLD) 53 Chevy Moldy pearl green ZZ-4 4L60E 9" 3:25 55 GMC 1st Black Mll (ZZ4) ZZ6 TKO 600 5 sp 3:73 62 Solidaxle Corvette Roman Red (327 340hp 4spd 3:36) C4 & C5 suspension tube chassis LS 3 4L70E 65 Corvette Coupe 327 350hp 4spd 4:11 78 Black Silverado SWB (350/350) 5.3 & 4L60E 3:42 2000 S-Type 3.0 (wife cruiser) 2003 GMC SCSB 5.3 4L60E 3:42

06-30-2015, 10:53 PM	#3
aknovaman Registered User Join Date: Aug 2013 Location: Tecumseh Posts: 355	Re: No start help after swap; 2008 5.3 Will it try to start with a bunch of starting fluid? If so you may just have a bunch of air in the fuel rails that need purged. Your tuner may have also not properly deleted the vats. On the newer ecu, he needs to do a write entire and not just write calibration the first time. If you are adjusting the tune the rafter, you can just write the calibration. __________________ Current project 1959 Willys = GEZR TRUK Geezer is a Latin compound word made up of two roots. Gee meaning Urine Stain and Zer meaning your pants are open! FMCDH GBU and GBA http://www.youtube.com/user/aknovaman/videos

07-01-2015, 11:26 AM	#4
Angryman117 Registered User Join Date: Jul 2013 Location: VAFB, CA Posts: 227	Re: No start help after swap; 2008 5.3 Sounds like VATS is still enabled. Also with everything powered up does the throttle operate correctly? __________________ Angryman117's 47 Chevy Build 89 Silverado Z71 LS Swap (sold)

07-01-2015, 09:07 PM	#5
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: No start help after swap; 2008 5.3 Try groundi g the case of the computer it self mine wouldnt starr and i ground the computer case and it started right up __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

07-01-2015, 11:31 PM	#6
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: No start help after swap; 2008 5.3 Will the VATS let it start then die, or will it not start at all? Posted via Mobile Device

06-30-2015, 07:02 PM	#1
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	No start help after swap; 2008 5.3 Checking to see if some of the gurus here may have any help for me. I swapped a 2008 5.3 (non flex fuel) into a '77 C10. Used an aftermarket stand alone harness with a "tuned" PCM. I am having a no start issue. Fuel is 55 at the rail during prime, moves from 55 to 65 during cranking (assuming that means the injectors are firing?). New Delco plugs; have a bit of a burn spot on them, but not complete. Compression on all cylinders, anywhere from 160 to 170. I pulled the injectors and let them soak in a container of Seafoam thinking they might have been clogged. I am getting spark on #1, and there is signal at the injector plug verified by a noid light. I do have power on the switched power wire during key on and crank, constant power is good. What could I be missing? It doesn't even act like it wants to try and start. __________________ 1974 Jimmy- 5.3/4L80e/NP241

07-02-2015, 03:06 AM	#7
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: No start help after swap; 2008 5.3 Both honestly. Sometimes VATS won't let it run at all, other times is will allow up to 7 seconds. Usually the first time after a battery reset VATS will allow the longer run, once it fails it will usually only allow it to sputter then die without really ever "catching". __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-02-2015, 07:54 AM	#8
faribran Registered User Join Date: Jul 2005 Location: AL Posts: 1,828	Re: No start help after swap; 2008 5.3 Did you turn engine over with the fuel rail and injectors pulled, to see if they are spraying? __________________ "

07-03-2015, 10:11 AM	#11
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: No start help after swap; 2008 5.3 I have not had a chance to check throttle actuator yet. I usually only to get to work on it at night, after the kids go to bed. I was going to pull the rails to check injector pattern this weekend. Since the noid light lit up, it led me to believe they were firing. __________________ 1974 Jimmy- 5.3/4L80e/NP241

07-08-2015, 05:57 PM	#12
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: No start help after swap; 2008 5.3 Throttle actuator is working. I can hear it moving, and verified it via scantool. I did an injector balance test, and fuel pressure only dropped on one cylinder (#7). I was able to get a set of injectors from a buddy, and swapped them in. It fired, but runs really rough. The newer set of injectors sat for a while as well; it may just need to run some fuel through them to try and unstick them. The truck has no exhaust on it, so I will mess with it more this weekend. The only time I really get to work on it is after my kids go to bed. __________________ 1974 Jimmy- 5.3/4L80e/NP241

07-11-2015, 08:43 PM	#13
Hart_Rod ************* Join Date: Apr 2005 Location: Pensacola, FL Posts: 17,858	Re: No start help after swap; 2008 5.3 I would put my exhaust on before I messed with it any more.... __________________ Rob - https://www.instagram.com/hart_rod_c10 As Iron Sharpens Iron, So One Man Sharpens Another. Proverbs 27:17 FOR SALE: DBW pedal bracket - http://67-72chevytrucks.com/vboard/s...d.php?t=651123 FOR SALE: Hood Brackets http://67-72chevytrucks.com/vboard/s...d.php?t=679945 1987 Silverado SWB - 34.5K original miles http://67-72chevytrucks.com/vboard/s...d.php?t=801834 1969 SuperBurb - http://67-72chevytrucks.com/vboard/s...d.php?t=200387 1968 Farm truck - http://67-72chevytrucks.com/vboard/s...d.php?t=358692 1968 SWB - http://67-72chevytrucks.com/vboard/s...d.php?t=551258 1948 Chevy - http://67-72chevytrucks.com/vboard/s...=122164&page=3



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