what is a Code 538?

[Amyz93Ranger]

Hi, hopefully someone can help, I have done a search of the forums and nothing answered my question.

I have a 93 Ranger 4.0 auto. I have replaced plugs, wires, O2 sensors, Alternator, MAF, Air filter, PCV valve, had the injectors cleaned (not replaced), and still I am having a failed KOER test. When its idling, i can hear a 'tinging' sound from underneath (much like a loose heat shield which I removed cpl years ago). I have also noticed it occasionally 'hot starts'. I would drive 15 -20 minutes, park for 10-15 or so, and when i start up, the idle fluctuates and sometimes dies...

I really hope I have described this problem well enough to lead me in the right direction for an answer... of course any help would be GREATLY appreciated.

thanks again...
Amy

 

[Sasquatch_Ryda]

Did your scanner ask you to 'snap' the throttle? It should ask you this when you do a KOER, if you did not do this that is why you have the DTC 538.

 

[Amyz93Ranger]

yea, it said turn wheel 1/2 turn to the right hold for 4 secs, hit the brake and then slam the gas to the floor and release...

 

[Amyz93Ranger]

anyone? Its my daily driver... i dont need it to die on me...

 

[fireguy12117]

about your warm engine start issue, i read a while back on this site that the earlier model 4.0 engines have a design issue with the intake to fuel rail matting surface. something vaporizes out of the fuel (or the fuel itself) when the engine is off, but hot. this is a result of the fuel rail sitting almost directly on top of the lower intake. there is only the thin gasket separating the two and the heat transfers well enough to vaporized either the fuel itself or something in the fuel. when you go to start the truck your actually starving the engine for fuel and it causes that poor idle that clears up once you throttle it or drive for a minute or two. this was solved sometime around 95 or 96 with a 6 or 8mm plastic separator piece that isolated the fuel rail from the lower intake. some people have swapped this intake with success. i was going to do it but never had any luck at the junkyard getting my hands on those years engines. newer models, 98ish, have a different intake setup, some of the cooling passages changed (at least the one motor i pulled apart did) so you defiantly need the right year for the right parts.

as for the tinging sound...um...no dice. i dont think the two are related...take a long screw driver and put the handle against your head near your ear, and poke around with the tip touching various things. you'd be amazed at what you can hear. i diagnosed a friends tensioner pulley going bad using that method.