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.

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"

"Doitlaynstyle"  wrote in message

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

Doitlaynstyle wrote:

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.

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.

Doitlaynstyle wrote:


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.

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?

Doitlaynstyle wrote:


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.

Well I started having another issue. The truck is getting hot really
fast and the radiator keeps running empty. I am noticing a lot of
extra steam from the exhaust in the morning. Diagnosis: Blown head
gasket. Probably from having to use ether to start the truck. So
tonight I tore the the engine down to the heads and I am too exhausted
to continue tonight. I will pull the heads this weekend.

I have a question. How would I know if the spider injector assembly
was bad? I got the upper half of the intake off and I was really
surprised at the buildup in there. There wasn't puddles of fuel but
the inner portion there was absolutely filthy. brown residue
everywhere. Is this a sign the the spider is leaking and I should
replace it while it is open? also the EGR port on the lower half was
super clean. I was really surprised at that as well. However the port
in the head was almost completely blocked off. It took some serious
screwdriver scraping and a shop vac running at the same time to clean
the port out.

In that link you gave me I saw a spider assembly on the page for 320.
Is that the one I need? It doesn't really look different but you say
its a new style?

Doitlaynstyle wrote:

Check them REALLY close. 4.3s are tough engines but those were the years
when they started playing with gasket formulations. You still have the
better intake design with better clamping but the materials were
starting to be crap.


YEP that's the common blockage location. Why I said you would need to
pull the intake to get to it.


The 95 ECM uses the old style driver but the guts have been updated.
 From the sounds of it either the spider/regulator or lines are leaking.
Common problem. I like to replace them all at once since you have to
pull it apart to get to them anyway.
It could also be the reason for the plugged ports and poor starting. You
shut the engine down and the fuel leaks out of the injection system and
floods the engine when you try to start it. The ether would light off
regardless and you get a bigger bang because of the extra fuel. The
extra rich mix while running goes into the exhaust stream and comes back
as carbon build-up. I would also check the cat. to see if it has been
fried while you have things open. Just look into the inlet side and see
if the guts are partly melted.

--
Steve W.

I was also wondering if the new assembly comes with a new regulator.

Doitlaynstyle wrote:

Last one I got came complete, just added the fuel line kit and good gaskets.

--
Steve W.

What a weekend. I tore it down to the block. Had water in cylinder 5.
Rebuilt it all the way back up including the new injecter assy, nut
kit, fuel pump relay, gaskets, oil change, the works. I had the upper
half of the plenum off and I "key on" tested the fuel pressure. No
leaks. It hit 50 psi and bled back down extremely slowly. I drove it
to work this morning and It still has the same starting issue and the
SES light came back on. From everything else I have read I am guessing
that the fuel pump is performing poorly. I think it is supposed to
"key on" between 60-66. Does anyone else have thoughts on this?

Doitlaynstyle wrote:

No leaks is a good thing. ;-)

Low fuel pressure is a bad thing. ;-(

55 is minimum pressure KOEO, Ideally you want 60 - 65 psi.

Don't go with a cheap pump. Lot's of folks try to cut the price down by
using a low end pump and then get to do this again when that pump fails.
The OEM pump is a Delphi FE0114 But that is only the pump, no seals or
clamps. If you get an AC Delco kit EP381 you get the pump, seals and
clamps. You will also need a new strainer since you pry the old one off
to change the pump. When you take it apart check the wiring REAL close.
When the pumps start to fail they usually draw more current as well,
this can cause the contacts to heat up and lose tension making it worse.

--
Steve W.

Just a recap on everything I have done. New plugs, wires, cap, rotor,
injector assy, fuel line kit, fuel pump relay, EGR, IACV, head
gaskets. SES Light code registers Insufficient EGR flow.

Doitlaynstyle wrote:

Didn't see it mentioned, but did you also change the fuel filter?
Also, the EGR valve will sometimes build up carbon on the actuator
shaft, causing the valve to stick. I had one that was sticking open and
had to disassemble to clean carbon from the shaft to get it to move freely.
Frank

Thanks Frank, I Just replaced the EGR It has less than 50 miles on it
since then and only 11 since the rebuild. I plan on Replacing the pump
with a NAPA Pump part number NFP P74074. It comes with gaskets and O-
rings. The factory replacement is rated at 61 PSI and the one I am
looking at is rated at 65 PSI. I am also going to replace the filter
because I dont know when that was last replaced. I do know how flow
and pressure work tho and if it was just the filter I would be getting
the correct pressure and not enough flow.  I will update if this fixes
the issue. I am also Thinking that I should replace the EGR control
solenoid part number CRB219225. If that isnt functioning right the EGR
may not be opening at the correct time or opening enough and may be
causing the insufficient EGR flow code that I am getting. What do you
think about that? I am thinking this because I know (because I cleaned
them all the way to the head) that the EGR ports are completely free
of blockage and I am Still getting this code. Also just as a
precaution I fired the engine right after the rebuild with the EGR
valve off So that any debris/ carbon left after the cleaning would be
blown out of the port.

Doitlaynstyle wrote:

If the fuel filter is clogged bad enough, then at key-on, the pressure
can't rise much above 50 psig before the pump times out (turns off). If
you do 3 or 4 key on tests back-to-back and pressure gradually rises a
little each test, it's a good indication that the filter is clogged. I
would just change it and be done with it.

I was thinking you had a pwm type (5-wire) EGR valve, but apparently
yours is a diaphragm type. Not sure if you have OBD-I or II. I think
with the old diag connector you can ground one of the terminals and test
the control solenoid--it should open and cause the engine to run rough
at idle. Steve W probably has better info on this.

Frank

I went to pick up the egr control and it def wasnt for my truck. It
was listed incorrectly on the NAPA page. I have the electronic EGR. I
did that test that you mentioned (Key on and off multiple times) and
all I am getting is 50 peak. It snaps from 0 to 50 also. No hesitation
which would indicate no restriction. I noticed that the truck has had
the same issue with the SES light since I bought it almost 2 yearas
ago. While I was doing the rebuild I noticed that someone else had
attempted the same repairs that I have completed. My guess is that
they installed the wrong fuel pump or they never got that far. I will
be putting the fuel pump and filter in tonight and I will report back
on the results tomorrow or the next day. I had to wait a couple of
days to run the fuel out of the tank so it isnt as heavy when I pull
it out lol.

Question: As you look at the engine there are two vacuum and
electronic solenoid type pieces of electronics just to the right of
the intake manifold. What are these? I would like to know just for
reference. I know what ALL of the other electronic and vacuum devices
are on the engine and what they do except for these two. they are
hooked in line to each other with a vacuum line and have plugs from
the wiring harness going to them.