Ok well I know how to work on cars if some one tells me what needs to be done. I just got a 85 4x4 v6
auto. it runs ok but it diesels when I turn it off, and when I drive it the check engine light comes on and off
randomly that's about all. Any help would be awesome ohhh and the back window and tail gate rattle and it
is so freaking annoying how do I fix that? Thank you [sm=gobble.gif]

 

Maybe a tune up or maybe O2sensor? light will go off when u fix the deiseling problem.Back window, just loud music fixes that lol...Good Luck!

 

It could be caused by timing or a fast idle.
Is it idling to fast?
Does it rattle when you go uphill?

The computer will compensate timing to a point. There is a timing set connector just below the glovebox. I believe it is a tan wire. If you disconnect that you can use a timing light to set the timing.

It could be that the rear door latch strikers are out of adjustment ( for the rattle)

 

I'm not too sure how computer controlled the '85 is... I do know it isn't quite carb'd and it definitely isn't fuel injection. I believe it is called feed-back carburation (IIRC)... All I know is I had a heck of a time getting my old '85 S10 2.8L to run right and I finally gave up and bought a refurbished carb for it.

Now I didn't have any dieseling problems like you are experiencing, but... More often than not, dieseling is caused by a buildup of carbon in the cylinders or from timing being off. You can verify timing with a timing light, but make sure that any vacuum or electronic advance is disconnected. Carbon can be taken care of with a seafoam treatment (run a search we've discussed it a lot lately). It probably wouldn't be a bad idea to go through and do a complete tune up as stated above. Plugs, wires, cap, & rotor should do you some good. I don't think you have any O2 sensors though.

And on the rattle, yeah, check your strikers in the back. You should be able to move them in to tighten up the seal. If you adjust the tailgate, the window will be adjusted to a certain extent as well.

Good luck and let us know if you need anything else!

 

Thank you guys I think I have a good start another thing I'm gonna look at is the cat I think it may be clogged and increasing engine heat. can any one tell me witch diagnostics system will work with my truck I found the diagnostics plug but I cant seem to find a diagnostics device for a 85 blazer they all start at 87

Thank you

 

I'm not really sure if there is a diagnostic system on that old of a vehicle... I don't think much of anything is computer controlled.

For your cat, one way to check is to open up the exhaust somewhere before the cat and see how it performs.

A universal cat isn't going to set you back much if you did need it. You'll just need to measure your pipes and the length of your stock cat. Cut the stock one off and weld in the replacement.