My first post here and thanks for letting me join..
I bought a 95 blazer and so far it feels like a error.. I have been searching the forum for 3 days before this post and have found alot of useful information.. I have a few concerns with this rig maybe you can shed some light on.. first the 4 wheel drive didn't work, I found the cable unhooked and the diaphragm destroyed and full of atf, kinda weird...

of course atf is bypassing the seal and filling the transfer not a big deal, but annoying...

It ran rough but ran ok otherwise until i spent $500 on new tires, I decided to take it on the freeway for a 60 mile trip... It did pretty good for the first 30 we turned around an started heading back and it started running real bad surging at free way speeds... got home put it on the hoist cat looked like a cigarette lighter... temps were 400+ into the cat and over 900 out.. so i let it cool... went out and did a back pressure test was under 1 at idle and didn't bounce over 2 at 2500..

Did a fuel pressure test cycle key psi was 61 dropped exactly 5lbs in 10 minutes.. Since it was right on the edge, I pulled the valve out of the top of the intake and looked in with a flashlight fuel pressure side was washed, but not a puddle of fuel... was some oil in there though and 3 ports in the intake were perfectly clean....

Sorry this is getting so long trying to not miss info...


So with the top of the intake off I cleaned the inside off the lower intake blew it out with air and did another pressure test, pulled the poppets out set them on top off the intake to see it they seeped but didn't.

But what was weird was as i was blowing out the intake to dry it, as the air passed by the end of the regulator it was siphoning fuel out of it.. (there is like a weep hole in the end of )... Gonna order a new regulator today its is a 50 dollar try....

Tune up done, fuel filter, air filter, previous owner replaced egr, upstream o2 sensor...

this is a w code 4.3 4x4 auto trans.... Someone has already been in the intake cause there are wrong bolts holding it together with nuts as washers lol..

If there is anything else i should look at it would be greatly appreciated any direction or guidance would be great.... if i missed any info i'll edit later with the request...

This is my first chevy Not loving it so far LOL

Oh forgot I scanned it when i first got it had 2 codes Rich bank 1 and egr malfunction.. cleared codes and they didn't return in 300 city miles...

 

Your cat is definitely clogged, 400 in and 900 out is BEYOND hot, and i can guarantee thats why the engine was running bad, or at least a major contributor to it. the shop said my cat was 40% clogged when my cat temp was 260 in and 300 out. and you said yours is 900 out? Yeah get it changed lol. go with a Magnaflow high flow cat. thats what i did and i love it.

 

hmmm back pressure is within specs.. was thinking that it was just rich, or was hoping anyways after a 30 mile drive @ 75mph

 

*Moving to 2nd Gen Tech* - Please read the description of the forum sections and choose the one that most appropriately aligns with the topic you intend to post. Thanks!

 

Sorry sir... Think i'm on the right track of thinking?

 

Hmm.. if it was rich then the cat would be the same temp all the way across. or atleast that makes sense to me, but the fact that the pressure is within spec kinda throws me off. When the shop tested mine they just took the temp of the front and the back and since there was a difference they told me it was clogged somewhere along the way, they didnt look at pressure. and your temp difference is insane. also if it is was a fuel mixture issue i would think the rest of the exhaust piping would be excessively hot, and if its just the cat thats glowing red then that would lead me to believe theres blockage in the cat.

Other people on here have had identical symptoms and glowing red cat, and when they replaced the cat problems were solved. If you do some research you can find cats pretty cheap and most shops will put them on for about 50$ if you cant do it yourself.

You can also do some more searching on here for cat problems and you will see that alot of people have had the same issues (me included)

hope this helps!

 

Sorry, I had a lot of other administrative things to do and couldn't respond directly to your post at that time. I just had to move it and get back to it later (now). LOL

The temperature difference in the catalytic converter sounds excessive, but that could be caused by the rich condition in the engine. A clogged cat would typically have a higher temperature at the point of the restriction than it does further down stream of the restriction. And your low back pressure reading doesn't show sufficiently high pressure readings to suggest that the cat is restricted. With a rich condition, not all of the fuel is being burnt in the combustion process and the excess is then being burnt in the catalytic converter. So it makes sense that there is a rich code and that the outlet of the catalytic converter is considerably hotter than the inlet.

The present code would suggest that you are getting too much fuel into the engine and could take awhile to work the various parameters back up to alarm levels in the control module. Also, to explain a bit about the code, the control module has no way of discerning bank 1 from bank 2 due to it only having one downstream O2 sensor for measuring air/fuel ratio. So by stating Bank 1, it really could be either bank or both (typically it is really bank 2 that sees the rich condition from a leaking regulator).

Do you have a means of observing the long & short term fuel trims or any other engine parameters? These may not be available depending on the setup of your trucks control module. There were three different control modules used in '95.

The regulator siphoning out fuel is troubling and the fact that the pressure drops so rapidly is even more so. I would start with the regulator and go from there. Retest the pressure drop. If it still is not maintaining above 55psi 10 minutes after the pumps shuts off, then you may have to take a look at the fuel pump in the tank.

 

^^ He who is highly Intelligent has arrived.. and he who is not intelligent (me) didnt read the rest of your post to see that a O2 sensor was throwing a rich code.. well then you are most likely right lol

Sorry for the misinformation

 

installed new regulator now it won't hold 55psi for 30 seconds!!! crap before it held 56.. any way to tell if its the componet its self ?

 

Is it seated properly in the spider housing? Did you remove the housing to install the regulator? If so, you may have opened up a leak in the lines inside the intake plenum. This is very common as these lines do not like to be moved once installed and in service for more than a few months.