95 4.3 problems

[old Rusty C10]

truck is a 95 S 10 blazer with a 4.3 Vortec motor automatic. My son in law bought this with like 133K on it. It may have sat for a while prior to him buying it from one of the dealers that sells cars dontated to chairty.
Upon buying the truck we had to do some work to make it road worthy but for the price we paid for the truck, it wasnt too much.. I put a set of tires, upper control arm bushings, lower ball joints , wheel allignment, a trans fluid flush and a oil/filter change.

The truck had been overheating but we did notice that the coolant was low and it did leak some.. there is a hole in the radiator that has stopped itself up and the coolant is brown in color ( someone said that it appears someone mixed dex cool and green coolant i dont know)
The truck runs and drives ok but when we took it for the NY Emmisions test it ran at 2.50 HC which is the hydrocarbons and the NOx was off by .3
the limits were 1.6 on the HC i forget the limit for the NOx

He goes home and changes the spark plugs which were prolly from the shape of them the ones that came brand new with the truck, and he changes the ignition wires . He used Delco plugs as per the auto parts store and the mid grade wires from pep boys
We bring it back for inspection and it reads 1.80 HC
The mechainc i have been using for such things has gotten himself into kind of a pickle in the economy and he is losing alot of business.. and this mechanic tells me to leave the truck and he will run a diagnostic test in the AM.
Next day he tells me that the truck will never pass inspection and he cant do anything take the truck home.. He doesnt tell me what is wrong with it except its throwing oil... I figure hes full of it cause forst off he didnt charge me for the diagnostic and second HC means raw fuel not burning oil, and secondly when the plugs were pulled the diode was missing and there was just a little brown and grey ,like typical wear and the after junk left on the plugs by gasoline additives. They did not smell of gas and had no oil residue on them
Also since he has owned the truck he has put about 1000 miles on it including a trip to my upstate house and back.. since the hole in the radiator has plugged itself up it has not lost any coolant and it does not overheat. There is no coolant smell out the exhaust and its not lost any oil nor has the oil gotten that funky water in oil coffee with milk color

there is no dash lights on and we are kinda at a loss... I was thinking perhaps that because the old plugs were so old and because the truck sat a while ( i heard that this lot had tax problems and the vehicles sat about a year)the gas may have deteriorated some and the cat may be partially screwed up..
Can anyone give me any ideas? Meanwhile tomorrow im going to see if i can get the son in law here to have the radiator and all flushed and maybe plug the hole or something...
Money is a tad short here and also we need to get this truck past inspection as the state time is up and he can start getting tickets..

[truckdude239]

might be time for a set of cats

[xflyboy]

Originally Posted by truckdude239

might be time for a set of cats

is it hard to start after sitting for a long time (overnight)?

if so could be pressure regulator good news is they are not that expensive...
the bad news is it's inside the manifold on the the injection spider.

[protrash64]

Originally Posted by truckdude239

might be time for a set of cats

I agree with this as a strong possibility. I had an old Blazer(75) that I got harrassed by the tailpipe cops every time I went in to have it run. Finally went in to get a new exhaust and it had one empty cat. Had it replaced and never had trouble passing the test again. Worth finding out if its good.

[Damien]

HCs are hydrocarbons. They are in the gas and oil, so either will raise your HC counts. The engine is probably due for a tune up, which you have a good start on. You should check your O2 sensor. They do wear out and burning oil is one of the main causes of O2 sensor failure. If the O2 sensor is responding slowly, the AF ratio will be rich and raise your HCs. The O2 sensor can be degraded and not set any DTCs. If you have access to a scan tool you can look at the cross counts. There should be 8-11 cross counts per second for a good sensor. Bad O2 sensors are the most common cause of emissions test failure.

[old Rusty C10]

I appreciate the input... Today im going to see if i can get him into another shop i know and see if they can run his another diagnostic and i will mention the 02 sensors and see if i can have him tweak it enough that it will pass emmissions...otherwise ill got for an aftermarket cat and see if that helps it any any other advice is appreciated

[old Rusty C10]

here is todays doings.... the coolant was real bad so i told him cause he uses the truck to go to PA sometimes that i would pay to have the radiator and block flushed and boiled out.. they also replaced a tank that cracked ( Lousy plastic junk) anyway after this the truck ran even lousier and almost refused to idle and stalled a couple of times.
My buddy was around and he started playing with sensors and there is one ontop of the intake that appears to be an AIC and when he unplugged that it ran alot better.. the truck also runs junky when uit gets wet... so the CEL is on now and we are going to run codes and see if we can clean out the IAC and see what that gets us

[Damien]

Is this the CPI engine with the all aluminium intake or the newer style vortec with the plastic upper intake.

[old Rusty C10]

i wont see my SIL for a couple of days but i believe it is a metal intake with a small plastic cover on it that says vortec

[lvschevytrucks]

if this is what it looks like this its the alumimun one

[Damien]

That is the CPI.
The IAC on those can get dirty and stick. clean it out. Make sure all of your sensors are pluged in. I won't hurt to take the EGR valve off and clean that out too. Sometimes a piece of carbon will get stuck in the pintle and hold it open.

[Dooley]

Make sure you have the correct spark plugs. Most I've known, with that engine, always end up with the wrong plug. CR43TSM is correct.