Ok first of all i have a 1993 chevy s10 blazer with a 4.3 L CPI engine code w.

I put a new fuel pressure regulater on it about 4 months ago and it has been running fine until now. I got rear ended a week ago and ever since then it has had a bad smell of gas or raw gas coming from the exhaust so i did a fuel pressure test on it. I hooked my guage up to the shrader valve near the back of the intake and turned the key on. The guage went to 60 psi then quickly back down to zero but when i started the blazer it stayed at around 56 psi the whole 5 or 10 min it was running. ALso, when i drive it on the highway for more than 5 min the check engine light comes on. I did the paperclip trick and it came up with a 45 engine code which means Oxygen sensor voltage was over 0.750 volts for 2 minutes in closed loop operation with a throttle angle between 0.6 and 1.9 volts.
If anyone knows what the problem could be or any suggestions that would be great

 

so does anybody know, could it be my injectors, or possibly a fuel pump although i hear the fuel pump come on and everything. anything would be helpful

thanks

 

Have to say that this part sure sounds like a bad fuel pressure regulator.

 

thats what it sounds like to me too but could anything be causing the fuel pressure regulator to be goin bad cause like i said i just changed it not too long ago

 

if your FPR is dumping too much gas you will hydro lock your engine and it wont run, plus it will end up in your oil. Now if you are dumping the right amount of gas/air mixture into each chamber and the plug isn't firing. Verify you are getting spark to all plugs.

Although it sounds more like the return fuel line is leaking close to the tank. The Fuel Injectedsystem pumps more fuel to teh engine then the engine can use, the excess is returned to the gas tank, this also cools the fuel, and hte cool fuel cools the fuel pump. Verify you dont have a fuel line leak. There are three fuel lines and the third line returns gas vapors, check it as well. Thsi may in fact be your leak, no fuel so you wont see it, however it will smell like gas, and since your tank is under the back of the truck you could think it is coming from your exhuast.

 

yeah ive had somebody tell me that might be the problem already havent really checked it out too much yet, but what would be the easiest way to check that? Would i have to drop the tank? Also, i know there has to bea little gas coming out of my exhaust cause everytime i start it white smoke comes out of it and it sprays a blackish residue out of it onto my driveway

 

White smoke, if it is really white smoke is condensation, water somewhere in the exhaust system. It could really be blue smoke, yet so faint that it looks white and is easiely confused with white smoke, however the blue smoke would be oil seeping past your valves guides. The smoke should go away shortly after start up, burnt off. If it keeps bunring blue smoke then you need service work, valve job. It is normal for the valve guides to leak on older engines. I had an enigne blow the blue smoke at start up and never had any trouble with the engine. I bought the truck with 60,000 and retired it at 286,000 miles. It blow blue smoke for over 200,000 miles.

As for the black stuff, that is carbon in your exhaust system, and the water vapor is drawing it out and onto the ground. Again no big deal and normal for a older truck. And no doubt the black stuff is fro=m your oil seeping past the valve guides. Oil doesnt burn clean like gas and it leaves a black residue, which in your case is moved through the exhaust system with condensation. By the way, the job of the cat is to convert harmfull stuff into water vapor, hence the water dripping from your exhaust after the engine has warmed up, plus if your getting oil into the exhaust it will burn in the cat, nad the carbon will get carried away via the water vapor.


As for the fuel line, the easiest way, trop the tank. This may not be very easy though. PB Blast the hell out of those bolts. You will need plenty of extensions and a cheater bar/pipe. If you twist the bolt in half no big deal. Replace it with new hardware. There are 4 olts holding the old style gas tanks in place. There will be a ton of debris on top of the gas tank. Where face protection when you tip it, you will end up with a face full of crap. Use WD-40 on the rubber lines. It softens them up so you can pull htem off. When you get it down and check for damage your local autoparts store will have everything you need to fix it. You will need fuel line hose, not rubber vacuum hose. Hardlines are easy to bend and should come with the right fittings.. GM uses standard fittings, Ford doesn't. Post up if you got more questions. I highly recommend you start the tank removal on a weekend, or when you have time. In a '93 this could be an all weekend affair. If you get lucky it will take 15 minutes, but dont count on it.

 

yeah i looked at it a little closer and it does appear to be blue smoke so im guessin its the valve guides, but my boss has a bunch of old 4.3 parts that i might just buy from him such as heads and a full gasket kit so i might just do that and while i have everything apart look into the intake and make sure my injectors, fpr, fuel lines, ect arent damaged

 

I just took the spark plugs out of my blazer and the plugs on the drivers side are almost black. But the ones on the passenger side are fine. After taking all the plugs out and cleaning them and putting them back in i started it anda little black smoke would come out of my exhaust the second i hit the gas but once i was on the gas for 5 seconds it would go away,