Trouble code

[CSchafer]

One of the things that intregued me about the first gen was the lack of electronic "goodies" and all the problems that go with. So the other night I was a little suprised to see the wait to start light start was flashing at me. Can't tell that any thing is wrong with the truck and the wait to start light still cycles when it is cold and does aid starting. Could any one tell me what that is about.

TIA Cade

 

[Paychk]

That can be an indication the pre-heat control module can't read the temp sensor in the intake manifold. Ether the sensor or the wiring that connects it to the module has gone bad.

 

[CSchafer]

Am I wrong In thinking that that light can only tell me about problems with that system so I don't have to look at any other systems to find the problem?

 

[KSommer]

no, that light will not tell you anything wrong with thetruck. never heard of one flashing, though.

with the lack of electronic goodies, alot of your diagnostics will be done by the seat of your pants, too.

kent

 

[Paychk]

Am I wrong In thinking that that light can only tell me about problems with that system so I don't have to look at any other systems to find the problem?

No you aren't wrong. I'll post some diagrams up for the electical system, that should help figure out what the problem is.

 

[Greenleaf]

Just for the "wreckord" and future reference... ... ... . Paychk didn't mention that lamp and some others are not the factory trouble codes. These lamps WILL alert you to a problem however the "trouble codes" are obtained by the flashing stop engine lamp... ... ..... or is it the service engine lamp(?) after cycling the ignition key switch.



Anyway, it's one of them. The brake code(s) are also easily obtained by grounding the controller and watching the lamp flash. The truck has to have to computer to spit out the (engine) codes. The 90 will not have the ECM/PCM (whatever) for it.

 

[Paychk]

Here are those diagrams:



BTW The temp sensor is listed as "thermistor" in the diagrams.



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[CSchafer]

thanks guys. Like I said the pre heat system is still working I just was making sure nothing else could be goin on. Thanks for the diagrams I'll look at it tomarrow for any thing obvious.

 

[Paychk]

From what I can tell for the 89 FSM the system will still work, just all the time, I think.