TBI....really bad idle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**texassquarebodies** · 07-05-2012, 03:06 PM

Bought an 1987 burb the other day. 350tbi. It idles like it has a huge cam in it. Drives good down the road. Anyone have ideas where I might start looking for the problem?

Jonboy · 07-05-2012, 04:10 PM

I would start with the CTS. If you have a scan tool, you can look at the sensor readings to give you a little bit of an idea what it might be. A bad CTS will act like a stuck choke and make th evehicle run rich.

70inline6 · 07-05-2012, 06:22 PM

I agree with Johnboy, but you can also do a quick check to see if you have any burned wires (O2 sensor, temp sensors) and for split/loose vacuum lines. The computer won't know what to do if there are massive leaks or grounds where there shouldn't be.

**texassquarebodies** · 07-05-2012, 06:53 PM

Jonboy....whats a CTS?? I probably call it something else.

Jonboy · 07-05-2012, 07:11 PM

CTS is the coolant temp sensor. It should be located on the front half of the intake, and have 2 wires.

**texassquarebodies** · 07-05-2012, 07:32 PM

I know exactly where that is. You can't be using all those fancy words with me. I will probably just switch it out with a good one I have.

07-05-2012, 03:06 PM	#1
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	TBI....really bad idle Bought an 1987 burb the other day. 350tbi. It idles like it has a huge cam in it. Drives good down the road. Anyone have ideas where I might start looking for the problem? __________________ Tony Kee Texas Square Bodies

07-05-2012, 04:10 PM	#2
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: TBI....really bad idle I would start with the CTS. If you have a scan tool, you can look at the sensor readings to give you a little bit of an idea what it might be. A bad CTS will act like a stuck choke and make th evehicle run rich. __________________ 1974 Jimmy- 5.3/4L80e/NP241

07-05-2012, 06:22 PM	#3
70inline6 Registered User Join Date: Jan 2008 Location: Pell City, AL Posts: 255	Re: TBI....really bad idle I agree with Johnboy, but you can also do a quick check to see if you have any burned wires (O2 sensor, temp sensors) and for split/loose vacuum lines. The computer won't know what to do if there are massive leaks or grounds where there shouldn't be.

07-05-2012, 06:53 PM	#4
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	Re: TBI....really bad idle Jonboy....whats a CTS?? I probably call it something else. __________________ Tony Kee Texas Square Bodies

07-05-2012, 07:11 PM	#5
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	Re: TBI....really bad idle CTS is the coolant temp sensor. It should be located on the front half of the intake, and have 2 wires. __________________ 1974 Jimmy- 5.3/4L80e/NP241

07-05-2012, 07:32 PM	#6
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	Re: TBI....really bad idle I know exactly where that is. You can't be using all those fancy words with me. I will probably just switch it out with a good one I have. __________________ Tony Kee Texas Square Bodies



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