tempature change causes flat spot
- Thread starter martyward
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
- Joined
- Aug 3, 2010
- Posts
- 29,203
- Reaction score
- 24,310
- Location
- Usually not in Ohio
- First Name
- Andy
- Truck Year
- '77, '78, '79, '84, '88
- Truck Model
- K5 thru K30
- Engine Size
- 350-454
When the engine temp changes or the outside temp changes?
If it's engine temp, does the flat spot occur when the motor gets hot?
If it's engine temp, does the flat spot occur when the motor gets hot?
chengny
Full Access Member
- Joined
- Feb 22, 2012
- Posts
- 4,086
- Reaction score
- 1,010
- Location
- NH
- First Name
- Jerry
- Truck Year
- 1986
- Truck Model
- K3500
- Engine Size
- 350/5.7
How about the MAT (manifold air temperature) sensor?
Only used in 305/4.3 applications and it's output signal to the ECM is directly dependent on ambient air temp.
Thing is - if it's malfunctioning, a 23/25 code will be set. But, you didn't mention any MIL or DTC 's.
Anyways, I'd check the sensor's resistance as a function of temperature using the charts below.
Location:
Low error - DTC 23:
High error - DTC 25:
Only used in 305/4.3 applications and it's output signal to the ECM is directly dependent on ambient air temp.
Thing is - if it's malfunctioning, a 23/25 code will be set. But, you didn't mention any MIL or DTC 's.
Anyways, I'd check the sensor's resistance as a function of temperature using the charts below.
Location:
You must be registered for see images attach
Low error - DTC 23:
You must be registered for see images attach
You must be registered for see images attach
High error - DTC 25:
You must be registered for see images attach
You must be registered for see images attach
