Chevy 350 starts rough, check engine light

[bud991649]

Hi All! I ahve a 1992 GMC K2500 with TBI 350. Sometimes when I start the truck it starts real rough and idles hi/low ( like it's trying to die) for about 10-20 seconds. Then the check engine light comes on and it seems to run OK. The injectors are definitly spraying fuel. After a few starts it usually stops. Any ideas?

 

[tunedportk5]

If you pull the code for that check engine light it probably will tell you the problem

 

[bud991649]

I'm sure, but unfortunatly I don't have a reader, was hoping someone might have an idea with the symptoms.

 

[dheavychevy38]

not sure if it will work on that year but on my 89 k5 you can use a paper clip in the a@b terminal and count the light flashing and that will be your code

 

[K5MONSTERCHEV]

Jump the to terminals in the upper right. IAC, EGR?

 

[tunedportk5]

you do the papaer clip thing and turn the key on and the check engine light will start blinking codes it should start with a 12 three times and then what ever set your light off that code will flash there might be a few each code will blink three times then the next and then it will start over at 12 again

 

[bud991649]

Thanks for that info everyone, that sure is usefull. I an getting booth a code 33 and code 59. Anyone know what these codes are for?

 

[tunedportk5]

well 33 is for MAP sensor- leaking or restricted vacuum hoses;poor elecrical connection' open or short in circuit; defective MAP sensor; defective ECM. but the 59 it don't show is that one right

 

[bud991649]

That is definitly what it is reading, it blinks once, then short pause, then blinks twice.. does this 3x. Then blinks 3 times, short pause, the blinks 3 times again. 3x for that also, then 5 blinks, short pause, and 9 blinks, 3x. Th code 33 could be for a cloged PCV valve? I noticed some oil around the TB.

 

[tunedportk5]

you could do a google search for 59

 

[bud991649]

thanks... code 59 is: Transmission code - TTS low temperature (sensor or signal wire open). The engine trouble must be the MAP sensor, I will try to track that down, thanks for all your help.

 

[dyeager535]

If there is someone here that is nice, perhaps they will scan or post the service manual troubleshooting flow chart for your error codes. Will save you some money in parts, thats for sure.

The service manual is a very valuable tool if you can swing buying one.