Mombu the Chevrolet Forum sponsored links

Go Back   Mombu the Chevrolet Forum > Chevrolet > EGR issues on my 95 blazer 4.3
User Name
Password
REGISTER NOW! Mark Forums Read

sponsored links


Reply
 
1 22nd February 11:39
doitlaynstyle
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


Ok so to make a long story short this is what I have done so far:

2 new O2 sensors (front and rear)

1 new IAC valve (Idle Air Control)

plugs, wires, Cap, Rotor

New EGR and gasket. While changing to new one found a piece of an
ALTOIDS lid blocking both ports behind the gasket

While replacing the egr Sprayed Carb cleaner down both ports

So after replacing the EGR the light came back on and I called the
dealership again and they read the codes AGAIN. The scanner reported
"Insufficeint EGR flow" which is better than the EGR stuck closed
Message I got before. I took the egr back off and ran the truck. It
rev'ed up to about 3500 rpm and held so I sprayed more cleaner while
running into the intake (Top?) side of the port. I put it all back
together and reset again and the light came back on.

I have read many posts and it would seem that my next logical step
would be to pull the plenum off and clean the ports themselves because
you cannot tell if the inner portion is clogged. I have not found any
other info on this and any other Ideas would be helpful. I am going to
do the seafoam down the vacuum hose trick right before I tear it apart
again. any and all comments on this would be greatly appreciated. I am
so frustrated with that light that if I cannot get this to work out I
am going into the dash to pull the light and I am going to fire it out
the end of my 12 ga. HAHA
  Reply With Quote


  sponsored links


2 22nd February 11:39
doitlaynstyle
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


And just to be clear I would love to see a description or even
pictures of someone cleaning their plenum so I can see where the ports
are and I know what I am looking for when I get in there.
  Reply With Quote
3 22nd February 11:39
doitlaynstyle
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


OK. I did the seafoam into the brake booster vacuum line. Drove it
around for a while and the GODD*MN SES light came on again, It was
idling really rough and was starting to smooth out a bit towards the
end of the test drive. I pulled the EGR valve again after getting home
and I can tell that it is actuating because it had carbon buildup
around the intake side of the valve. Also I had to shake some carbon
chunks out of it. While I had the EGR out I fired up the truck and it
rev'ed up to 3500 rpm again and I did notice that it sounded like it
had a really bad exhaust leak. I have an extendable magnet and I
placed it over the exhaust port and the exhaust sound went away. I
placed the magnet over the intake port and the truck went back down to
idle. So I can say with confidence that the ports are not clogged and
that I think the EGR is functioning properly.

I also did some electrical tests on the plug with the ignition on. The
results are as follows looking at the female end of the plug with the
locking tab up. Left to right
pin one registered about 50 ohms
pin two registered at almost 0 ohms
pin three registered at about 200 ohms
pin four registered about 5v
pin five registered almost 12v

Please help me out here. I cannot figure this out. I don't know why
the ses light code is registering as "insufficent egr flow"
  Reply With Quote
4 22nd February 11:39
garrett fulton
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


OK. I did the seafoam into the brake booster vacuum line. Drove it
around for a while and the GODD*MN SES light came on again, It was
idling really rough and was starting to smooth out a bit towards the
end of the test drive. I pulled the EGR valve again after getting home
and I can tell that it is actuating because it had carbon buildup
around the intake side of the valve. Also I had to shake some carbon
chunks out of it. While I had the EGR out I fired up the truck and it
rev'ed up to 3500 rpm again and I did notice that it sounded like it
had a really bad exhaust leak. I have an extendable magnet and I
placed it over the exhaust port and the exhaust sound went away. I
placed the magnet over the intake port and the truck went back down to
idle. So I can say with confidence that the ports are not clogged and
that I think the EGR is functioning properly.

I also did some electrical tests on the plug with the ignition on. The
results are as follows looking at the female end of the plug with the
locking tab up. Left to right
pin one registered about 50 ohms
pin two registered at almost 0 ohms
pin three registered at about 200 ohms
pin four registered about 5v
pin five registered almost 12v

Please help me out here. I cannot figure this out. I don't know why
the ses light code is registering as "insufficent egr flow"

This may be no help at all, since it was on quite a different engine. Had
the same problem on a '92 Olds Cutlass with the
3.4 DOHC V6. Code for insufficient EGR flow. It had a staged EGR valve, 3
separate EGR metering poppet valves each of different diameters, and 3
solenoids in the EGR valve assy. I went to the dealer to get some advice,
and the mech. there told me he was familiar with the problem on that
particular engine. He said that the passage in the plenum between the
valves and the egr port that fed the intake manifold would become plugged
and they were next to impossible to clean. The passage had many turns in
it. He said they normally replaced the manifold, but this was an expensive
part on this engine. He said that a couple times he had fixed it by taking
a section of speedometer cable and fraying one end as it came out of the
housing, and chuck the other end in a drill and feed the frayed end down
into the EGR passage to clean the carbon out. With the manifold off, of
course. This worked for me. It's all I can think of in your case, as it
seems you've changed all parts that could have caused it, and even though
the passage appears to be flowing, maybe it's not flowing enough. Hope this
helps.

Garrett Fulton
  Reply With Quote
5 22nd February 11:39
steve w.
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


Ports inside the intake are plugged on the end that feeds the EGR gasses
back into the system.
The best repair is to pull the intake, clean the ports from both ends
and clean up everything. Install the newer gaskets for the intake and
button it back up. Usually if you're seeing the low flow code top
cylinder cleaning isn't going to do much, the cleaner has to soak in and
blow the carbon through the system. Also since this is a 95 you may want
to look into a Kleen Screen gasket for the EGR, that will stop the
chunks of carbon that come free from blocking the EGR open.

Since the intake gaskets like to fail on the 4.3 over time this isn't a
bad time to do it all. If you're handy with tools the entire job can be
done in about 4 hours, OR if you're the average DIYer it will kill a day
or so.

--
Steve W.
  Reply With Quote
6 22nd February 12:33
doitlaynstyle
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


I def am thinking of going that route. I fired her up this morning
after letting her sit all night with the BAT cable off and drove to
work and the light stayed off. As I mentioned the exhaust gasses that
were coming out were incredibly high flowing. I think that maybe I
just caught a couple chunks durring clean out and that might have been
the cause. If the light comes on again I am going to remove the EGR
again and force feed some seafoam into the ports and let it soak
overnight and see if that will blow out anymore chunks. I really dont
want to pull the manifold. I noticed that the manifold is in two
sections. Can you clean the ports by removing only the upper half or
do you have to pull both? I also noticed on the radiator shroud that
the spark gap is supposed to be 45 and when I changed the plugs it
looked the the plugs were pre-gapped to around 31-35 and I didnt think
twice about installing them cuz that is pretty much a typical gap.
This may be a portion of my lack of power while accelerating.
  Reply With Quote
7 22nd February 12:33
steve w.
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


The upper half just uncovers the injector and the intake air valving.
The ports are in the lower half.

Close gap could cause some power loss but the 4.3 usually pulls pretty good.

--
Steve W.
  Reply With Quote
8 22nd February 12:33
doitlaynstyle
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


Well I checked the spark gap and it was spot on. While doing that I
did a compression test and got 120. I guess I am going to have to tear
the intake off and clean it out but I have one more question. The
truck will not cold start anymore with out ether. Anything below
50deg. and the Damn thing just cranks and will not fire up. I pull the
brake booster hose and shoot a small shot of ether into it and it
fires right up. What could be causing that? Is there some sensor that
might be causing the engine to flood? That is what it is acting like,
Right when you first crank it over it might fire just for a split
second but then it just cranks and cranks, A small shot of starting
fluid and It fires right up. As long as I keep it in my garage it
fires up just fine in the morning but if I leave it outside it wont
fire. Maybe like you said Steve the intake gasket has gone bad and I
am getting too much of a vacuum loss untill the engine warms up and it
re-seals.

Any other Ideas would be greatly appreceated. I am just stumped here
and I will take all the advise I can get. Also what am I going to need
for cleaning the ports on the intake? replacement intake gasket? Do I
have to split the two sections? Is there a second gasket there?
  Reply With Quote
9 22nd February 12:33
steve w.
External User
 
Posts: 1
Default EGR issues on my 95 blazer 4.3


Check the fuel pump relay. Sounds like it is bad and not turning the
pump on for the initial start up.
When the ether causes the engine to fire you get enough oil pressure to
turn on the fuel pump and it starts.
Common for the relay to go bad. You can also check your fuel pressure
low pressure will cause a power loss easily. You want 58 or more with
the KOEO and over 55 with the engine idling.


You get a complete intake gasket set and it will have all the gaskets
you need. You will need to split the intake simply to check the injector
for problems (if it is leaking which is a common problem) you can get
the new style unit that will bolt right in for less than the cost of
rebuilding the current spider injector.
http://www.lindertech.com/reconinj.htm

--
Steve W.
  Reply With Quote
Reply


Thread Tools
Display Modes




Copyright 2006 SmartyDevil.com - Dies Mies Jeschet Boenedoesef Douvema Enitemaus -
666