1st start-up on swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

novafrog · 03-20-2018, 10:59 PM

will start then die, will not idol for longer than 10-15 sec. but if I rev it up, say 2500-3000 rpm's runs like a top, motor just setting in truck, no 02 or maf sensors hook up,2000 5.3 thanks for any help

Ghost's68 · 03-21-2018, 08:37 AM

VATS removed in the computer?

novafrog · 03-21-2018, 09:05 AM

Quote:

Originally Posted by Ghost's68

VATS removed in the computer?

lt1 wiring did the harness said they did

BR3W CITY · 03-21-2018, 09:38 AM

Vacuum leak? Fuel Pressure?
What codes is it throwing? give us something to work with.

davepl · 03-21-2018, 10:27 AM

Does it run better without the MAF connected? If so, that'd indicate that your measured and actual air amounts are different. That could be air leaks or MAF placement if so.

racecougar · 03-21-2018, 01:56 PM

Why are you attempting to run it without the MAF and O2 sensors installed and connected?

novafrog · 03-21-2018, 06:02 PM

Quote:

Originally Posted by BR3W CITY

Vacuum leak? Fuel Pressure?
What codes is it throwing? give us something to work with.

no codes,fuel pressure 58-60 lbs

novafrog · 03-21-2018, 06:09 PM

Quote:

Originally Posted by davepl

Does it run better without the MAF connected? If so, that'd indicate that your measured and actual air amounts are different. That could be air leaks or MAF placement if so.

maf was on a long tube took it off and put it up to tb and tape it up good,still start and die but give it a little fuel and let off it would idol everytime I would start it I would have give a little fuel hen let off before it will idol

novafrog · 03-21-2018, 06:17 PM

Quote:

Originally Posted by racecougar

Why are you attempting to run it without the MAF and O2 sensors installed and connected?

motor is just sitting in truck,with core support and grill off wanting to make sure everything is ok before I put it back together, exhaust don't have 02 sensors in yet

racecougar · 03-21-2018, 08:48 PM

I have a very hard time believing there are no DTC's with the MAF and O2's disconnected. I'd recommend finishing the installation before attempting to run the engine any further. Without the MAF and O2's, the EEC has no reference to calculate load and determine appropriate fueling.

03-20-2018, 10:59 PM	#1
novafrog Registered User Join Date: Apr 2009 Location: dunlow wv Posts: 435	1st start-up on swap will start then die, will not idol for longer than 10-15 sec. but if I rev it up, say 2500-3000 rpm's runs like a top, motor just setting in truck, no 02 or maf sensors hook up,2000 5.3 thanks for any help __________________ 72,2wd short bed cheyenne,350,350trans,air,tilt,tach,posi 373 gears 70 nova 5.3,350 trans 80 z28 350,350,trans,bought new 03 cat. 06 gmc swb ext cab

03-21-2018, 08:37 AM	#2
Ghost's68 Registered User Join Date: Jun 2016 Location: American Canyon, CA Posts: 253	Re: 1st start-up on swap VATS removed in the computer?

03-21-2018, 09:38 AM	#4
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: 1st start-up on swap Vacuum leak? Fuel Pressure? What codes is it throwing? give us something to work with. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

03-21-2018, 10:27 AM	#5
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: 1st start-up on swap Does it run better without the MAF connected? If so, that'd indicate that your measured and actual air amounts are different. That could be air leaks or MAF placement if so. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

03-21-2018, 01:56 PM	#6
racecougar Registered User Join Date: Jan 2013 Location: Imperial, MO Posts: 999	Re: 1st start-up on swap Why are you attempting to run it without the MAF and O2 sensors installed and connected? __________________ Rod @ AzzKicker Cars 1965 C10 SWB - Build Thread

03-21-2018, 08:48 PM	#10
racecougar Registered User Join Date: Jan 2013 Location: Imperial, MO Posts: 999	Re: 1st start-up on swap I have a very hard time believing there are no DTC's with the MAF and O2's disconnected. I'd recommend finishing the installation before attempting to run the engine any further. Without the MAF and O2's, the EEC has no reference to calculate load and determine appropriate fueling. __________________ Rod @ AzzKicker Cars 1965 C10 SWB - Build Thread



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