I'm trying to figure out this 95 Blazer I bought. It sat for 5 years and the gas tank was bone dry when I got it. I put a couple gallons in and it started right up. I drove it to the gas station and put in 3/4 of a tank, and drove it about 30 miles that day with no issues.
The next day I took it for a drive and noticed that it was extremely spongy with no power, so I drove it back home so as not to get stranded. The next day (yesterday) it would not start at all. Today it fired right up again but it was exhibiting the same spongy symptom and the service engine soon light was on. I hooked up my OBDII scan tool and it's acting like it is linking up alright, but when it reads it retrieves no codes. I checked my service manual for the procedure to check codes on an OBDI system and I do not have the proper pins in my connector so I'm fairly certain that it is an OBDII compliant system. Is it even possible to have a service engine light on with no stored codes? Could the scan tool be the issue here?
I was curious if the 3/4 of a tank of gas I put in could have stirred up deposits in the tank that clogged my fuel filter, causing the driveability issues. Any Ideas?

 

you could have a spark plug wire arching.

 

If the CEL is on, there are stored codes. There are actually three different ECM configurations for this year. Sounds like yours isn't fully OBD2 nor fully OBD1, but the mongrel OBD1.5 setup. You need a scan tool that is capable of reading your system.

 

Would that cause a Service Engine light with no codes to retrieve?

 

Is there a definitive way of checking to see which system my truck is equipped with? If it is the OBD 1.5 setup, can you point me in the direction of the proper scan tool? Glad I borrowed this one from a buddy instead of buying one right away (even though I should probably have one for the garage anyway)!

 

Search around. Both questions have been asked and answered.

 

I pulled this quote from another thread. This is the setup I have. Connector under dash, to the left of the steering column. The PCM under the hood, mounted to the coolant reservoir. This vehicle was in a front end collision before I bought it, so no sticker with OBD2 proclamation. The scan tool is an Innovia 3100. The occupied slots in my diagnostic connector are : 2,4,5,9,13, and 16. This should positively identify my vehicle as fully OBD2 compliant, correct?

 

you could disconnect the battery and reset the computer and see if the light comes on again and then try the OBD2 reader. an arching plug wire could explain the surging.

 

Tried the negative battery cable reset and the light comes on again. I still cannot retrieve codes. I even read the scan tool instructions!

 

maybe try another scanner?