superhatch69

ok im in need of some help, 89 ranger 2.3 fuel injected runs rich as all hell on first cold start up throws cel dont know how to check it. as soon as it reaches 180 cel goes off the truck runs awesome, i did notice whens its cold when i turn the key in the on position the fuel pump should prime normally, well when its cold the pump stays running for as long as i keep the key in the on position it will start just run rich as all hell,im not sure if its an injector or not, like i said once its warm absolutely no trouble starting no cel i already changed the coolant temp sensor

plazma

You made sure to replace the correct coolant temp sensor right? There are 2 of them if i'm not mistaken.

Where was it located and how many wires was it connected to?

Might check fuel pressure regulator but it's unlikely your problem.

superhatch69

i changed the coolant temp sensor it located under the intake manifold had to wires going to it , that didnt seem to help at all, when the key is turned to the on position normally the pump will prime and shut of what makes the pump shut off is it pressure or something else

Hurstmeister

Sounds like possibly an O2 issue but usually its the complete opposite. Runs ok on start up/open loop but soon as O2's give the temp signal for closed loop the engine turns pig rich because it goes in limp mode.

Not sure,.. and no idea how to test. But its common for many vehicles with 150k plus miles to still have their original O2's. People never change them. Something to possibly look into. Perhaps someone familiar with the problem.


Hurst

barry bledsoe

the ecu tells the pump to cut off after priming.bad ecu or sticking relay. the temp sensor for the ecu on my 88 merkur is in the middle of the lower intake by the injectors and the one for the gauge is in the lower intake where it curves facing the drivers fender, but I have seen them in different places. you really need to check the codes that would help a lot