Rough starting idle

[delta_p]

might could double check the TBI gasket or some of the others that might get a little softer and pliable when the temp reaches 60 - 68 degrees and things move a bit. sounds like some tbi work occurred recently.

 

[c1500deathtrap]

First i know its not -40 in Florida. Your coolant temp sensor is bad. Not the one in the head, the one in the manifold on the front coolant crossover, near the thermostat. Their failure mode is infinite (or sky high) resistance which reads as -40 degrees ( the max low value in the program). test it with an ohm meter just to be sure, there are 2 pins just read resistance across them. Also on a lot of live data type programs this sensor shows up as intake air temp, which may be the confusion. It is there to add fuel because in a wet flow setup when the manifold is cold the fuel will wet to the manifold surface, so you need more fuel to compensate. So if the motor thinks it is -40, it pours on the fuel
.

You must be registered for see images attach

 

[c1500deathtrap]

Also a side note you do not need a scan tool to discern when you transfer from closed to open loop. Jumper the obd1 connecter like you are reading codes, then start the truck. the MIL will flash quickly indicating open loop operation, then as the ECM transfers to closed loop the flashing will slow down.

 

[magimerlin]

First i know its not -40 in Florida. Your coolant temp sensor is bad. Not the one in the head, the one in the manifold on the front coolant crossover, near the thermostat. Their failure mode is infinite (or sky high) resistance which reads as -40 degrees ( the max low value in the program). test it with an ohm meter just to be sure, there are 2 pins just read resistance across them. Also on a lot of live data type programs this sensor shows up as intake air temp, which may be the confusion. It is there to add fuel because in a wet flow setup when the manifold is cold the fuel will wet to the manifold surface, so you need more fuel to compensate. So if the motor thinks it is -40, it pours on the fuel
.

You must be registered for see images attach

I really need to go and change my location..[emoji2957][emoji2957].. I'm actually in Raymond, NH now. Where it still isn't-40, we where at -7 actual temp today..lol. I understand and know bout that sensor and what it does...but didnt know bout some diag computers data stream reading the coolant temp as the iat tem. Interesting, never would have thought that was a posibility.. I have replaced that sensor twice now. I'll ohm it out to make sure and check my wiring to just in case... thank you for the info.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[magimerlin]

Also a side note you do not need a scan tool to discern when you transfer from closed to open loop. Jumper the obd1 connecter like you are reading codes, then start the truck. the MIL will flash quickly indicating open loop operation, then as the ECM transfers to closed loop the flashing will slow down.

I know bout reading the codes that way but didnt know bout that open and closed loop check... I guess you can teach an old dog new tricks..lol... thank you.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[magimerlin]

May have found an issue... I turn the key on to prime the fuel pump and noticed, accidentally by the way..lol, that the passenger side injector dribbles like a faucet....lol..

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[magimerlin]

A video I took of it..

xc_hide_links_from_guests_guests_error_hide_media

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[Knuckle Dragger]

The official name for that is no bueno

 

[c1500deathtrap]

Whats wrong? More fuel more better right?