Hello,
I've been a long time guest reader of this site but my day has finally come and i need some help. I have a 1993 K1500 with a stock 5.7 6-month old GM long block. Every day when i first start the truck it fires right up and starts to idle erratically for about a minute and runs fine after. I can let the truck sit all day after driving it and fire it up again and it runs great. I was a certified John Deere Ag mechanic for 6 years so i like to think i know my way around a multimeter and torue wrench but i'm in no way a seasoned auto mechanic.
The problem started a few weeks after i installed the long block. For the install i rebuilt the TBI and replaced the fuel pump and all engine sensors. For replacement parts i used ACDelco when available but i have a few things like the IAC and TPS that are some off brand from Orileys but test out ok. Yes the EGR valve is a new ACDelco part.
The first thing that comes to mind when i see a problem like this is to check the CTS, EGR, IAC, and fuel pressure. Everything checks out fine and its pulling the correct amount of vacuum. I uploaded this video https://youtu.be/i2XjhGxxDHo of me starting the truck today for the first time. Some days it will idle for about 10 seconds before it starts to run rough until warm (closed/open loop?). I don't have anything to read live data so i think that's my next step. The truck has been at two different local shops but neither could find the problem. Any ideas would be greatly appreciated.
thanks
Mike
I've been a long time guest reader of this site but my day has finally come and i need some help. I have a 1993 K1500 with a stock 5.7 6-month old GM long block. Every day when i first start the truck it fires right up and starts to idle erratically for about a minute and runs fine after. I can let the truck sit all day after driving it and fire it up again and it runs great. I was a certified John Deere Ag mechanic for 6 years so i like to think i know my way around a multimeter and torue wrench but i'm in no way a seasoned auto mechanic.
The problem started a few weeks after i installed the long block. For the install i rebuilt the TBI and replaced the fuel pump and all engine sensors. For replacement parts i used ACDelco when available but i have a few things like the IAC and TPS that are some off brand from Orileys but test out ok. Yes the EGR valve is a new ACDelco part.
The first thing that comes to mind when i see a problem like this is to check the CTS, EGR, IAC, and fuel pressure. Everything checks out fine and its pulling the correct amount of vacuum. I uploaded this video https://youtu.be/i2XjhGxxDHo of me starting the truck today for the first time. Some days it will idle for about 10 seconds before it starts to run rough until warm (closed/open loop?). I don't have anything to read live data so i think that's my next step. The truck has been at two different local shops but neither could find the problem. Any ideas would be greatly appreciated.
thanks
Mike
