suburban gas eater

[redneckbilly]

my friend has suburban 92, with 350 v8 on it. great car, but he is gas eater. sometimes it shows code 4, problem. this should be knock sensor right?
could that be problem with gas?

[ChevyTech]

Well, there isn’t a code 4 that is stored by the ECM so you should check the code again.


Here are some web sites with the basics on retrieving codes without a scan tool or code reader.

Poor drawing of ALDL but ok instruction + codes
http://www.cfm-tech.com/gm_tbi_trouble_codes.htm

OBDI terminal identification
http://robertpowersmotorsports.frees.../ALDL_plug.jpg

OBDI illustration and instructions
http://www.troublecodes.net/GM/

1985 – 1990 trouble codes instructions
http://www.iroczone.com/specs/TroubleCodes.htm

PS – I usually don’t post over here so send me a PM if I lose track of this thread.

[redneckbilly]

it was my mistake in writing...code is 43

[ChevyTech]

A code 43 can cause it to consume more fuel, because if affects spark timing.

Code 43 can be the hardest code to find the cause of. My first suggestion is to pay attention to when the code gets set. When diagnosing it, it is very helpful to know if the code 43 is being set during the self test, or does it get set driving down the road on acceleration when the system is seeing a ping or something rattling on the engine.


CODE 43
Each time the Vehicle is started and certain criteria is met (coolant temp, MAP reading, engine RPM), a self test of the knock senor circuit is run. The ECM adds spark advance while anticipating a knock signal. If no knock signal is detected during the test a code 43 will be set. Some GM manuals state that two consecutive tests must fail for a code to set. (All GM electronic spark timing systems are not the same. Some systems use a separate module between the knock sensor and computer)

Anything that prevents the knock/ping or prevents the system from detecting it will cause a code 43 to be set. A bad knock sensor, ECM failure, wiring, Timing way retarded or a very rich mixture can cause the code.

What many manuals will not tell you is that a code 43 can be set by something loose rattling on or in the engine. Lifters, cam, rod, crank and piston noises all have the potential for causing false knock signals to be produced.

The Knock sensor contains a piezoelectric crystal which causes a voltage to be produced. Loose components on or in the engine can cause the knock sensor to create a voltage and the system may interpret this as pinging. The system retards the timing because it determines it is pinging.

Loose torque converter bolts can cause a false knock signal to be detected.

Clear the 43 trouble code from the ECM memory. Make sure the key is OFF and removing the ECM fuses for tens seconds should clear the code. You could disconnect the battery to clear the code.
Drive the vehicle and try to determine when it sets.

[redneckbilly]

once more






THANK YOU

[ChevyTech]

No doubt, that is the biggest thank you I have gotten here.

You’re welcome. A thank you is always appreciated.

[redneckbilly]

heheeee

well, you help us a lot.....so thak you is normal. and you should know that when you are from croatia this kind of answer deserves big thank you. because we don't have any mechanics for those engines here....

today we'll erase code and check all and then i'll come back to you

[redneckbilly]

hy
i'm back. we erase code and what we learned is that when you give full throtle from start and just moment before it will change gear chek light goes on. after a while it goes off again. then we used injection cleaner in can to try to clean system and what i found is one conector which i don't know where to conect and one vacum outlet on injector body with S mark on. it didn't have cap on it so i try to seal with dead end hose...

you can see conector on pics...and this is that outlet i closed. was that good to do? i realy don't know...

and what is with conetor?

thanks in advance for answer. and God bless from croatia. here is thusday 8:55 pm and if i can be honest is so good to have sombady you can ask...

[ChevyTech]

I am wondering if someone took the EGR solenoid off that vehicle.
That would answer all three questions.
No EGR operation could cause pinging which will set the code.
That could be the connector to the EGR solenoid
The vacuum port that is unused could be the one for the EGR system.

In 1992 many vehicles still had the knock module external from the ECM, and trucks had it mounted on a bracket next to the TBI and the passenger side rocker (valve) cover. The wire connector is in the area that the knock sensor module would be, but that module should have 4 wires to it if I remember correctly.

It would help if you could take another picture of the passenger side of the engine from a little farther back so we can see the EGR valve, TBI unit, and that connector all in one photo.

[redneckbilly]

i'll try to take pic today and poste it

[72lb4x4]

It might help if the OP mentioned the MPG or liters per KM to get an idea of where they are. A baseline is good to have.

A Suburban doesn't get great mileage to begin with, so is there actually a problem?

[redneckbilly]

trust me it's way to much....

this is little more than 40 liters per 100 km

i belive in my mathematics it's 6,5 MPG

[redneckbilly]

i'm on my work and just thinking to go through e bay maybe something blink in my had..and what i found is this. it could be the answer...

but we'll look again and picture everything...but what i can remeber tis there is some kind of bracket there along with valve cover somwhere near that conector....hmmmm il post pics of that

this is egr solenoid....gm 89-95

[ChevyTech]

The part with the vacuum hose connected to it is the EGR solenoid.

The Flat part on the back with 5 terminals is the knock sensor module (spark control module). Usually the connector that plugs on to the knock sensor module only has 4 wires in it on a 1992 TBI truck, so one terminal is unused.

[redneckbilly]

now i belive we are on right trail...

i'm going in my shop now, and i hope my friend will come later to investigate all this and take some pics

ChevyTech you are great man, you helped us a lot.

i'll post as soon as i'll be near the car.

[ChevyTech]

To keep a step ahead of you on what may be one of your next questions.

One nipple on the EGR solenoid should not have a vacuum line connected to it, because it is a vent. The earlier trucks had a sponge like filter on the vent nipple. It is fairly common to see the filter missing on older vehicles.

On the EGR solenoid, as the solenoid is de-energized (vacuum supply cut to EGR), vacuum would be trapped in the EGR if it were not for the vent passage, to let air in. As the EGR diaphragm moves, when the EGR valve is closing, air is drawn in through the vent.

Dirt can get in the solenoid and damage it if the filter is gone.

[redneckbilly]

now we did't photo session...

you could se bracket i am talking about....

[redneckbilly]

we'll take notice on that thanks.

[ChevyTech]

Your engine has no EGR valve on it.
Look at my photo and then look at your manifold and see in there is a plate bolted over where the EGR valve is in my photo.
The EGR valve is the round thing, with a vacuum line to it, just to the left of the IAC in the photo.

Notice: This photo is of a 1993 that has the spark control module inside the computer/PCM, so there is only an EGR solenoid on the mounting bracket that is like the one in your earlier photo.

Look at the emission sticker on the fan shroud and see if it says federal emissions or European emissions or ??

[redneckbilly]

sorry i'm not able to see that right now it's 22pm now but i have pic from that angle.....

can you see something from it?

man call me dumb, but i'm so glad mine K5 doesn't have injection...and so much wires lol....

[ChevyTech]

I am thinking that it is a possibility that that vehicle has an emissions system unlike the vehicles in the United States.

When you get time to, it would help if you get some codes off the truck for me.
These codes are referred to as RPO codes.
The RPO codes are on a sticker that is inside the glove box.
I want you to tell me all the codes on the sticker that starts with an “N” that has two letters and then a number.
It would look like this “NM1”

NM1 would stand for Emissions system, Switzerland, Sweden

Also let me know if no holes are drilled in the manifold for an EGR valve.

It only 3:12 pm her now!

[redneckbilly]

i don't belive it is in european standard at all. this was US ambassy vehicle here...so...

what's weather like in minnesota? did snow fell?

[ChevyTech]

I have worked on some US government cars that were NOT like regular production vehicles. That truck could be built to specifications much different then standard production vehicles, and the RPO code for the emissions system may show that to be the case.

The weather here in Minnesota is ok. The temp now is (34 F) which is just above freezing, around (1 C). We have no snow on the ground now, but the smaller lakes and ponds are frozen.

[redneckbilly]

it's seam s we have same climate...but i hope it will snow this year...

so i'll get back with codes

[redneckbilly]

and here are the codes:

NA4
NA5
NM8

or you can see it in picture...