Hello!
I have a blazer 4x4 4.3l 1991 that gives me some trouble..
She starts and runs for a few seconds and then she dies..
I´ve checked the injection system and it pumps fuel just fine.. no problem..
I changed spark plugs and wires, checked the firing order and ignition timing, I also cleand the disturburator and all electrical contacts..
I got the car for a mounth ago and before that she stod in a barn for four years..
Can anyone please help??

 

Drain the bad gas out if you havent already. Pop off the egr valve and clean it,as well as the IAc.

 

There is about 20l of new gas in the tank.. when we first ran her she started perfect and idle just fine just over 1000 rpm on cold start and droped to about 750 rpm when she got warm but as soon as I pusched the gas and she got to about 1500 rpm she missed and only fired occatunally and as soon as I let her idle she ran fine on idle.. at that point I lifted the cable from the ignition coil to the disturburator and saw a lot of white corotion.. I cleand it and tried to start and lost all idle.. only start whit full gas.. and runs porly as i described above.. Then I changed all cables, sparkplugs and checked the fuel injection.. but still the same.. I cleaned the rotor and disturburatorcap and still she ran like above.. I looked att the disturburator( I did not take it out) saw a lot of corotion from the copper pieces and a bit of rust.. I cleaned it as good as i could and put it back but no change in running.. I try the EGR valve as you sad and se if it makes a change and also I´m going to check so the engine realy has number one in top one more time to be sure.. what is Iac that you told me to check?
Thank you very much for your help..

 

make sure the gap on the plugs is right
and change the fuel filter if u haven't done it
and idea if the iac is original and check the metal flap and see if theres and carbon build up u might just need to clean it out so that might be the intake issue and check your vacuum lines

 

You have not mentioned fuel pressure, so I suppose you have not checked the fuel pressure, that could be the problem.

Also, you have not mentioned fuel filter, setting four years I would imagine there has been much condensation. I suggest it would be a very good idea to change it.

From what you said about the distributor, a new one would be in order if it was mine, plus a rotor button. In fact my 92 S10 4.3 that I bought new when it had about 60,000 on it, it was not running very good. When I checked the distributor and rotor button, it looked like the one you described, I replace both along with the plug wires, and spark plugs, and at 160,000 plus it still runs great. Oh, I did put that stuff on all connections, I forget what its called, maybe someone else will give the stuff a name.

 

do a good tune up make sure you put ac delco parts . these trucks are picky and they run way better with delco in them . GL if the tune up dosn't work i say start checking your fuel pressure

you could also do some research with the 2 links on the bottom of my signature who knows you might find your answer there !

 

Now I have checked the EGR, the IAC, the fuelpump and filter.. I´ve also changed the rotor and the disturburator cap, new cabels and sparkplugs..
also checked the fuelpressure.. I´ve dubbled check the engine timing and firing order(1 6 5 4 3 2) and also checked that the rotor hit number one when it´s in top... and still no life..
I noticed that from the ignition coil the spark looks strong but att the spark plug it looks weak..
Please help anyone..
I´m out of ideas..
Or soon a real fine blazer gonna meet the angels..

Best regards..

 

have u check the codes see if they say. i had similar prob. with my 2.8L they use the same tbi system on mine it was the map sensor came unplug might try connection on it my friends 4.3l was mounted on the passager side top of valve cover

 

Does the check engine light come on?

If youre seeing weak spark, perhaps the pickup coil on the distributor is malfunctioning. It tells the coil when to fire based on the rotor position.