Ok here it goes, 92 Chevy s10 Blazer CPI Vortec motor. CEL would come on intermittently and it would bog down. Shut the truck off, restart and it would be fine. Now the CEL is on all the time and the truck is still "bogging" down. It runs but not like it should. If I sit and idle it will overheat and quickly. It only wants to overheat when the CEL is on. Had a computer put on it today and it can't communicate with the truck. (?) I have replaced TPS, Fuel pump, fuel filter, fuel/ac relay, ignition module, oil pressure sensor, coil, distributor, spider injector and gas cap. Had a complete tune up in February, so I am at a complete loss on this. ANY ideas are GREATLY appreciated. When the light is off she runs like a champ....HELP!!!

 

Well, first thing to fix is the non-communicating. For this, the first check is your fusebox. The fuse for the cig lighter is the same as the comm port for the computer. If this fuse is blown, replace it. If its still blowing, check for a dime in the bottom of the lighter shorting it out.

You can also read codes with the "paperclip" method... Look this up online.

The problem you have with the CEL is going to be ignition related, not fuel related.

Fix that fuse or short, and give us the codes it throwing off.

You may also wish to service the EGR valve. If its sticking open it will cause bogging and stalling out of the engine. Just take it off the truck, and soak it in some diesel overnight then go at it with your old toothbrush and clean all the crud out of it and put her back on. Make sure you clean out the hole in the intake while you have it off. Make sure the pintle on the EGR valve itself moves nice once cleaned.

 

I changed the EGR valve yesterday and it still throwing a code. I was able to finally get a code off it. 43 which is the ESC, in my research I am not able to determine where the hell it is located on the truck. Would the ESC cause the issue that I am having? Thanks for the reply and advise.

 

Yup, the ESC is the electronic spark control. Its the thing that does the electronic spark advance. If you are not getting advance on the spark, you will get sluggish response and over heating condition.

You will find it inside your distributor when you pull the cap off. Then take the rotor off, and now you can see it. Its the thing that all the wires plug into. Unplug them, undo the screws, and you will find a bunch of junk slime under it - or rust...

You can have this part tested at autozone... Or you can just buy a new one. The cheap one is about 40 bucks, and the quality one is about 60. Get the good one and some dilectric grease. Coat that new parts bottom up really good and put it back in. Done.

You might also be having a probelm with th knock sensor. Located under the distributor on the pass side (?) I think. Hard to get to, and the distributor has to b taken out.

Start by testing the ESC or ICM or whatever you want to call it.

 

^^^what he said. As for the part,buy a ac delco. they are a bit higher,but has a much lower fail rate. Ive had a few bad ones test good. so thats a gamble too.

You also have a small connector,and 1 single wire (tan with a black strip) under the dash,passenger side way up around your foot area behind the carpet. Pull the carpet back and you'll find it. you disconnect this to adjust timing. If its broken apart or unplugged this can your issue too.

 

Had another mechanic adjust the timing, this fixed the bogging down problem. Still have the CEL and it just doesn't run right. Dropped it off this morning to have a complete diagnostic ran on it. GOD HELP ME lol IF the mechanic gets it figured out I will be sure to let ya know. Thank you everyone for your input and advice.

 

Welp all who tried to help, my computer was fried. At least at this point almost all the important parts are new No more CEL Thanks again everyone for you advice and guidance.

 

It matters more that the system was flushed completely when changing different types of antifreeze than what type you use. On the highway the fan isnt needed but radiator hoses that dont collapse at high speed are needed. You said the shop ran the Blazer for half hour and it didnt overheat, but on the highway it does. Colapsed lower hose, or partially plugged radiator or trash in front of the AC condensor.