Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[8364]

Thanks for letting me in

Beware of wall of text.

This is about a 2000 Omega 2.2, Y22XE as far as I know. Earlier this year the car failed the yearly inspection due to emissions, high CO if I recall correctly. They also said they thought it was running a bit rough/irregular, which I had not experienced myself at that time.

I was advised to replace the spark plugs, which I did. Made no difference at all. Then after a little research (on here I think) I replaced the front O2 sensor. Then I went to the inspection again the value ended up right at the maximum allowed limit, which was good enough to pass but I still felt that it should be better than that.

Some time after that I started seeing the orange light with a car and spanner. I had a mechanic connect his diagnostic tool and he said that my EGR-valve is bad and I should clean it. But that valve is nearly new, replaced 2 years ago, so I did not alter it at that time.


So here's what I then discovered:
When starting from cold, the rpms stays on like 1100 for a while and then start decreasing (kind of how it used to be). But instead of just decrease, smooth out and stabilise, the idle just gets increasingly more erratic/rough until it abruptly goes up slightly, stabilises and the light goes on. In that state, I can drive normally but something feels wrong, like it is sluggish, jerky, low on power or something.

I have also noticed it hesitates to start some times. Like it takes a few more turns to get it running, and when it does start the light goes on immediately an stays until I shut it off.

If I restart the engine while up to temp, it usually does not come on and everything feels pretty normal. But if I shut it off, wait 5-10 minutes, I can get it to do one of the above again.

But if I start the engine from cold and I start driving immediately the light very rarely goes on (if ever).

Had a second and third opinion from larger auto repair shops, they also insisted that something is wrong with the EGR. I then replaced it with a brand new one, but the problem is still there. Also everything is exactly the same if I leave the EGR unplugged...


List of the things I have done since the failed inspection mentioned above:

• Replaced spark plugs
• Replaced coil pack
• Cleaned throttle body, hoses and the black metal pipe
• Replaced front oxygen sensor/lambda
• Replaced cam position sensor
• Replaced the EGR valve
• Tried to clean the airflow sensor (there wasn't much to clean)
• Inspected the pipe to the pressure regulator (could not see anything wrong)
• Replaced air filter
• also the valve cover gasket was replaced by a mechanic earlier this year

All replacement parts were brand new.

I cleaned the plug wells before fitting new plugs and the new coil pack.

The code that the mechanics were seeing is P1405 which points to EGR, but I'm doubting this as nothing changes when it is disconnected.

One of the mechanics also saw these codes below, but I'm not sure if it is relevant or if that is because I have been messing with these parts (lambda, cam sensor, maf etc):
P0170, P0136, P0130, P0340

Any ideas? Any more tests I can do myself?

ChatGPT thinks it could be a failing throttle body or MAF. Are any of that likely?

What about the crank position sensor?

[Doctor Gollum]

What make of sensors did you use?

Any sign of a head gasket failure?

[Osmo]

I had same kind problems with one engine some years ago. It was mass airflow meter sensor.
It looks clean, but doesn't work properly. I changed it and everything was ok.

[8364]

What make of sensors did you use?

Any sign of a head gasket failure?

See below.

I'm not really experienced enough to properly diagnose head gasket failure. I'll see if someone can have a look.

I had same kind problems with one engine some years ago. It was mass airflow meter sensor.
It looks clean, but doesn't work properly. I changed it and everything was ok.

I replaced the airflow sensor, with a new PIERBURG 7.07759.74.0. It may have made the engine run a bit smoother (not sure if placebo or not), but the thing with the light going on and all that is still present.

I then had a mechanic fit a new crankshaft position/pulse sensor, VALEO 254117. I don't think it made any difference at all.

As for the other parts:
Coil pack: HÜCO 133880
Cam shaft sensor: VALEO 253845
O2/lambda: generic Biltema part
EGR: MAGNETI MARELLI 571822112053

[Doctor Gollum]

When you removed/cleaned/replaced the throttle body did you do any of the following:

In no particular order...

1. Replace the gasket between the TB and inlet manifold?
2. Replace the associated vacuum and breather hoses?
3. Clean through the breathers from the sump to the throttle body?
4. Clean ALL the orifices in the throttle body, including the 1mm one and not just the main breather one?

If the answer to any of these is no, start there

[8364]

When you removed/cleaned/replaced the throttle body did you do any of the following:

In no particular order...

1. Replace the gasket between the TB and inlet manifold?
2. Replace the associated vacuum and breather hoses?
3. Clean through the breathers from the sump to the throttle body?
4. Clean ALL the orifices in the throttle body, including the 1mm one and not just the main breather one?

If the answer to any of these is no, start there

1. The gasket was replaced.
2. Only one hose has been replaced, a few years ago, the rest seems fine.
3. If that is the black pipe with a 90-degreee hose on top, then yes it was cleaned last year.
4. I cleaned the throttle body and all the associated hoses quite carefully two times last year, and replaced the gasket the second time. I never noticed any difference however.

As I didn't really know what to do I just replaced the whole throttle body and gasket (again), with brand new parts. After that everything just went way worse. Now it is somewhat hard to start, and the orange light goes on right from the start. Then it has audible erratic idle and jittery/stuttering RPMs when driving. Sometimes the throttle just stops responding completely. This can't possibly be related to throttle body now? Fuel issue?

(yes, I waited nearly a minute before first start)

What is the small round part that is connected to the throttle body by a very thin pipe? is that something that needs attention?

(not my photo)

[8364]

Ok here we go again. I replaced the fuel pump (new, Delphi branded) and its associated hose and clamps.
After that the car ran exceptionally good with zero issues for a few days, then suddenly all of the previous issues came back.

Just out of interest, I tried starting it without the EGR connected and that made no real difference. Except that the spanner indicator light actually did not light up immediately.
I connected it back and disconnected the MAF instead and started again. It barely ran at all, with RPMs irregularly fluctuating up and down with no throttle pedal response (and some people say it runs better without MAF?!).

I really don't think the new MAF would be non-working but would a Tech2 or similar unit show if any sensor is sending invalid/incorrect signals? Any other ideas?

[TheBoy]

MAF on a V6 should read about 12kg/hr with A/C off, and 13-14kg/hr with A/C on.  2.0/2.2 will probably be around 1-2kg/ht less.

OBDII code readers aren't often successful on a 2.2, so you will need something a little more GM specific or upmarket.  If a given code reader reports in g/s, just use maths to convert to kh/hr

[chrisr]

I had a similar problem on my 2002 2.2. It was solved with a new throttle body.

[8364]

I went back to the original (?) throttle body again and the car ran somewhat ok for about a week and then the previous issues slowly came back. I would then assume that the throttle bodies weren't the problem.

I then figured I could try replacing the "new" cam sensor with a used genuine siemens one (supposed to be working), which I did, with no real difference in the end.

Perhaps I should replace the crank sensor with a genuine one,
but where would I get one? No matter where I look I can only find these made by third party companies like Valeo, Delphi etc.

(starting to think that maybe these sensors were never a problem to begin with, perhaps it was just the fuel pump until I randomly started replacing parts)

[8364]

I finally got the opportunity to use some diagnostic equipment with the ability to show live data,

These codes were shown at one point, however many of them seem to come and go randomly, varying from time to time.

P1405 - (2) Exhaust Gas Recirculation (EGR) Valve Feedback Voltage Low - Present
P1120 - (2) Accelerator Pedal Position Sensor 1 Low Input - Present
P1550 - (1) Electronic Throttle Control Reduced Power - Present
P0130 - (4) O2 Sensor 1 Open Circuit - Present
P0120 - ( Throttle Position Sensor 1-2 Correlation - Present
P0340 - (4) Camshaft Position Sensor Circuit No Signal - Present
P1120 - ( Accelerator Pedal Position Sensor 1-2 Correlation - Not present
P0220 - ( Throttle Position Sensor 1-2 Correlation - Not present
P0170 - (1) Rich Exhaust - Not present

When the P1405 is "not present" I can activate the EGR manually just fine, but when it is "present" its completely dead and showing 0,0v.

Is there any specific voltages the Accelerator Pedal Position Sensor should be within? These values also seem to vary wildly between every occasion.
At the last occasion they were starting at 0,33 / 0,47 to 1,18 / 1,8 at full throttle. But I have seen it as high as 3,5 earlier.
The pedal sensor itself is new (NOS), I just replaced it to be sure it wasn't acting up.

MAF reads about 13-14 kg/h after about 10-15 minute idle. AC off.

The first O2 sensor is showing as being constantly at ~350mV. Not sure if that is the actual value or the ECU making up for a lack of a signal?
The second O2 sensor is varying between 550 to 700 mV.

O2 sensor loop is always at "open".

The fuel consumption is way too high but I suppose that is a side effect.

I experience pretty much the same throttle symptoms as described here:
https://www.omegaowners.com/forum/index.php?topic=123621.0

I also now have a delayed start pretty often, which tends to make the spanner indicator light up right from the start.

As several sensors seem to report incorrect or out of spec values, could this point to a bad ground somewhere? I have checked and measured the three grounding points I know of and found nothing. Where is the real sensor ground, is it the ECU ground?

Any other ideas?

[omega2018]

What mileage is this car? What did the plugs look like? Being a Desmond I'm thinking maybe the engine is simply knackered...

[TheBoy]

Given the number of faults, and that they keep changing from Present to Not Present, start by checking out the engine earthing straps.

Excessive cranking is a symptom of that P0340, which is often the cam sensor itself, fairly common on the 2.2.  It seems fussy on sensor brand as well.

The first O2 sensors not changing implies a fault with the sensor and/or wiring (inc engine straps), but second O2 should be fairly static if the cat isn't shagged.  Check they are wiring correctly.  The fact the first O2 isn't working properly (according to ECU), it'll never go closed loop.  Rich running will destroy the cat.