Performance Problems

[benzino]

OP i'm not hijacking your thread... what i am asking is related to a previous post by trey05
... don't be silly anyway, who cares? I dont think you're that lazy to read a couple of extra posts...

[rkarl89203]

OK, folks, thanks for the help, apparently someone else owns this thread now.

sheesh....

not silly here

If anyone has any answers to this odd performance problem, please PM me or send your ideas to rkarl89203@aol.com...

[Trey05Woo]

RK your freaking out for no reason homie. lol there is nothing unusual about your situation, infact its quite common as egr system faults will normally set p0300 and 303 codes along with the respective egr code.

The reason being due to the design of the system, and the location of the egr valve. Cylinders 3 and 4 are the first to receive the exhaust gas and at a higher quantity than 1 and 2, therefore a faulty egr will affect the performance of these two cylinders more so than the latter two. Ive had instances where a car shows code p0303 and the problem was the egr itself. No matter how perfect an engine might look, its not. All cylinders perform, flow, and produce differently than one another. Thats the real world for you. Even a race engine will have cylinders which produce more power, flow better, less etc. Its what the aftermarket gurus try to accomplish: perfect and balanced engine operation, but it doesnt exist.

Anyways back to your problem I need to step out around mid day or so, Ill take advantage and stop by the house and do all the preliminary EGR tests on my woo, take pictures and post them for you here, because I know tech babble can get confusing... Im guessing you do not have a scan tool which displays engine data and allows you to test EGR so I will perform all the electrical tests with a test light and DMM.

Benzino Ill test TPS too and provide pics...

[rkarl89203]

Thanks for the info....

Benzino, my apologies, just getting VERY frustrated by this problem....

Apologies to all....

Looking forward to your help, Trey, thanks!

[Trey05Woo]

Ok well as promised I checked the entire EGR circuit on my Woo which is running 1000% on point, and took lots-o-pics! Basically what I did was check for ground, check the reference voltage from the PCM, checked for a short in both the ref circuits, and valve position circuits, and finally removed the valve and physically checked the operation of the valve's pintle, and how it seats in it's bore...

The EGR valve is a two component part. It is the physical valve and internally houses the egr position sensor. The valve is electronic or linear, and is completely operated by the PCM based on inputs from the TPS, and MAP sensors. The PCM operates a toilet plunger like pintle by moving it up and down. This allows more or less or no exhaust gas into the intake manifold via feed tubes connected to the intake manifold.

STEP ONE THE CONNECTOR AND DESCRIPTION:
this is basically the connector with the access butt removed. In order from left to right
PINK: egr high circuit (full open)
LIGHT BLUE: PCM 5.0v reference signal
BROWN: egr position sensor signal
ORANGE/BLK: valve/sensor ground
GRAY: egr low circuit (full closed)

first thing check the ground with a test light to Batt + should illuminate like so:


all is well so far checking for a short to ground in the reference signal circuit with the test light still connected to Batt + SHOULD NOT ILLUMINATE probe the rear of the lt/blue wire:


checking the egr position circuit for a short to ground. Test light to Batt+ again NO ILLUMINATION probe the rear of the brown wire:

The test light should not come on AT ALL. probing the light blue wire with a test light directly to batt + will cause everything PCM operated to come on (fans, purge valve will click, fuel pump will run, relays will click) this is absolutely normal, and means the ref circuit is working correctly.

STEP 4 CHECKING THE 5.0V REFERENCE SIGNAL WITH DMM: basically I killed two birds with one stone, double checked ground, and checked the voltage by probing with a DMM blk lead to orange/blk (ground) and red lead to lt blue (ref signal) should read 5.0v or near 5.0v like so:


continued......

[Trey05Woo]

Ok so now you determined that all the circuits are functioning correctly. One finaly step before moving on to the actualy physical valve, is checking the full on command. By jumpering the 5.0v ref signal (light blue) to the egr position signal (brown) using the DMM black test lead to batt ground, positive to the rear of ref signal (light blue) should read 5.0v or a little bit above like so:

(pic is loading will be up soon)..



Now you have completely eliminated any possible electrical problem with the system the only other component left is the position sensor which is located inside the egr and cannot be cleaned or repaired. Valve must be replaced. One final check valve pintle operation:

STEP 7 EGR VALVE CHECK:

remove the two 12mm bolts and carefully pry off the egr valve. You will notice two orfices. One is the intake feed, the other is the bypass:

You want to make sure the pintle(small hole) is completey closed sealing the entrance. it should not be half way, or all the way in. Should be just like pic

STEP 8 CHECKING THE PINTLE MOVEMENT :
Taking a thin screwdriver you want to probe the pintle. It should SMOOTHLY move in and out, and should not be hard, or get stuck. It should release and return to full closed position immediately and all by itself once you remove the screw driver. Should also have a SPRINGY feeling to it


If the pintle is hard or stuck you can clean this part of the valve by spraying it with cleaner first to loosen carbon buildup, then pushing the pintle in and spraying more carb or throttle cleaner. Using a wire brush you can clean the pintle head, and the orfice opening to insure it seats and seals properly. Once you achieve a smooth operation, you can reinstall the valve and see if this eliminates the problem. If you continue to get the 0405 code, the EGR Position Sensor is faulty, and the ERG VALVE MUST BE REPLACED ALONG WITH A NEW MOUNTING GASKET...

Some of the pics got cut off, need to resize them, but cant do that here at the office. Need to wait till I get home. Also one is pending. But you get the idea.

[Trey05Woo]

ok Benzino here you go TPS CHECK:


STEP ONE THE CONNECTOR DISCRIPTION AND SENSOR:

The tps has a three wire circular type connector they are
BLUE: sensor signal
LIGHT BLUE: 5.0v pcm reference signal (same for all sensors get it?)
BLACK: SENSOR GROUND

STEP TWO CHECKING 5.0V REF SIGNAL:
I didn't bother to test light check the ground, I obviously have ground when I connect a DMM blk test lead to blk wire, red lead to light blue and read 5.0v or near like so:


STEP 3 CHECKING SENSOR SIGNAL:

take the blk test lead to battery to chassis ground (easier to access) and connect the red lead to the blue (darker wire) and read the voltage:


Should read at or near above. All cars are different, but anything less than 3v suspect a problem.

[Trey05Woo]

Sorry for the cut off, had to attend a cust and somebody jumped on the computer and I guess clicked submit...

Anyways one thing I failed to mention is Im using a auto ranging dmm so the readings are x.x volts. If your using a manual range, set it to .o mv readings to get a more accurate reading.

Anything under .3 mv is too low, and anything over.5 is to high at closed throttle.. The reading should be FIXED not fluctuate at all with the tb valve not moving. I didnt take a picture of this because I ran out of hands lol but basically you want to crack open the tb slowly and operate it from closed, to 25%, to wot, pausing and holding at certain points all while monitoring the readings. Should be smooth constant, and hold when you hold the valve at any position. You also want to check this with the engine cold, operating temp, and also want to tap the sensor with a screwdriver or 1/4 extention.

The reason being the sensor might work cold, but fail hot, or work fine but fail when exposed to vibration...

[benzino]

Thanks heaps for that!Excellent write up and pictures
If i ever live in the states... and in Dade county... with a daewoo... I'll bring it to you
hahaha

and RKarl, chillax... it's all good bro
this is a daewoo forum not a honduh forum

[rkarl89203]

hey no prob benzino, just frustrated by this weird prob


Thanx for all the help, trey...I know what I'll be doing the next coupla daze!

[rkarl89203]

found two hoses that were bad, replaced both...

No Change. Maybe even MORE of the Cylinder 3 misfire code than before.

Gonna check the wires and plugs I replaced a month ago and if that doesnt change anything will do the EGR thing AND the TPS, in that order....

sheesh

[rkarl89203]

So, checked all plugs and wires.....

Reseated plugs, reseated wires....

Performance has increased, but STILL an occasional 303 error and flashing CEL for that code. Found a strong gas smell in two cylinders( on the plugs) closest to the passenger side of the car.

Since the overall performance is better, I am going to dump a ton on injector cleaner in this to make sure a clogged injector isn't the problem.

Next, EGR inspection, then TPS......

[Trey05Woo]

Well like I stated an EGR fault will affect the performance of those two cylinders more so than 1 and 2. As I also stated exhaust gas IS NOT COMBUSTIBLE! Therefore, EGR is strangling those cylinders. The cylinder cannot properly burn the mixture without oxygen what happens to compressed oxygen when its introduced to carbon? It bonds to it forming carbon monoxide. Gasoline needs three components to combust: spark, compression, and oxygen.

Sooooooo if you have high levels of carbon stealing oxygen in a cylinder, it makes sense fuel would not combust no? This would explain the rich condition, and even if the problem is elsewhere, you problem is too much fuel not lack of. So injectors/fuel system is not it.

Fix egr man, THEN worry about anything else. U cannot properly diagnos a misfire if the egr system is malfunctioning.

Lastly DO NOT dump any type of cleaner in the system. These do not work, and can cause more harm than good. Google fuel injection cleaners and see for yourself. If you suspect your injectors clean them with a toothbrush and carb or tb cleaner. The fuel rail on these cars remove in an instant. There is no possible way a fuel injector could become "clogged" gasoline itself is a cleaner so unless your fuel system was contaminated (due to outside tampering) this is impossible. What happens is carbon builds on the tips and plug the nozzels, this causes a drip rather than spray or in exteme cases a leak if the nozzle stays open. Cleaning them with a toothbrush corrects this.

[Trey05Woo]

Oh btw the reason the engine performance worsened when you corrected the vaccum leaks was because you removed an oxygen source. A vaccum leak is an unmonitored induction of air. Since exhaust gas is choking the engine, a vaccum leak introduces oxygen and helps performance a bit. Once you correct this, the engine only relies on the air entering via the air box and idle circuit...

More theory EGR is your problem...

[rkarl89203]

OK, trey...will check it out!

Thanks!