[Migz]

Hi thanks with the car not running the o2 sensor is reading 0.4V thanks

 

[Migz]

Hi thanks with the engine not running the o2 sensor is reading 0.4V

 

[LvR]

So the O2 sensor's heater element is still working and is getting fed 12V from the ECU - good.

You said you were going to do compression tests today - results?

Next question - engine idling - what is the MAP sensor reading as a value - you need around 30kPa

Since both O2s apparently agree with the running rich thing (last graph you posted) you now need to confirm you do not have any air/vacuum leaks present. I would say get a can of easy start, and with the engine idling, start going around the intake manifold and spray every joint, seal, hose, sensor involved on that plastic intake manifold ............ any change in engine speed or sound will indicate you found the culprit area

Same for the exhaust manifold up to the first O2 sensor - any bad joint/hole sprayed will indicate by change in idle speed or sound

 

[Migz]

Hi thanks for this information, the compression tester I had arrive today was to big to get down in the spark plugs holes so I have to wait until tomorrow now to do a compression test when hopefully the correct one arrives. I will also do as you suggested with checking for vacuum leaks. Thank you

 

[LvR]

View attachment 195172

Hi thanks for this information, the compression tester I had arrive today was to big to get down in the spark plugs holes so I have to wait until tomorrow now to do a compression test when hopefully the correct one arrives. I will also do as you suggested with checking for vacuum leaks. Thank you

If the scanner is reporting valid data, and the engine was idling and you not touching the throttle while capturing that screen, you already have your answer - ie - absence of vacuum .........................

Question is whether its because of a vacuum leak sucking in unmetered air, a mechanical problem like a a dud cylinder (rings/valves etc) or simply a gaga MAP sensor

That engine is, according to the MAP reading not sucking anything like it should (need around 400mBar or better to achieve reliable combustion)

 

[Migz]

Hi yes that was on idle. I will get a can tomorrow and spray all over and let you know.

 

[LvR]

If it was idling why so high? ......... should be around 750rpm no?

Is the throttle body properly bolted to the manifold and that seal ok?

 

[Migz]

The rpm on idle is very unstable since I've had this problem. it ranges between 600 and 1000 rpm needle is all over the place. Would a compression test show me if there is a fault on a cylinder ie rings or valves?

 

[LvR]

It could, but I am betting on a simple vacuum leak at this stage..................

 

[Migz]

I'm really hoping it is! Other wise it's looking like a big job!! As soon as I can in daylight tomorrow I will be checking for a vacuum leak all over I did notice I may have found a issue stright away it looks to me like a non return vavle is split! I assume its a non return valve?

 

[Migz]

This is not my engine I got the pic on ebay but thus is the valve!

 

[LvR]

I'm really hoping it is! Other wise it's looking like a big job!! As soon as I can in daylight tomorrow I will be checking for a vacuum leak all over I did notice I may have found a issue stright away it looks to me like a non return vavle is split! I assume its a non return valve?

That will cause miseries for sure - looks like its the brake booster valve?

 

[Migz]

Sorry when you say brake booster valve what does that mean / do ect?

 

[LvR]

Brake booster runs off vacuum ............. if you have a leak going to that, your brakes will also be affected. Valve on the booster suction line isolates keeps the suction side of the diaphragm primed even when the vacuum is used for other things on the engine

 

[Migz]

Hi quick update, fixed the vacuum leak and made no change thankfully amazon delivered my new compression tester and the bad news is cylinder 2 has 15 psi on compression and cylinders 1 and 3 has 180 psi. I dropped a a teaspoon of oil into the cylinder and repeated the test and it made no difference so I guessing its a vavle issue? Thanks

 

[LvR]

Hi quick update, fixed the vacuum leak and made no change thankfully amazon delivered my new compression tester and the bad news is cylinder 2 has 15 psi on compression and cylinders 1 and 3 has 180 psi. I dropped a a teaspoon of oil into the cylinder and repeated the test and it made no difference so I guessing its a vavle issue? Thanks

There you go then - the most unpleasant result but now you know.

Critical to do compression before any serious electronic faultfinding.

Could, unfortunately, be rings, valves, cam, followers, rockers etc etc etc .

I would suggest take off the cam cover and go from there - see what is obvious with the cover off .............

 

[wozz]

@Migz
bad result, I sympathise. I may be wrong but it seems very low for a valve seal issue (but good that you've found it) - just out of curiosity what mileage has the engine done?.
Was there a step change or did this happen over a period of time?
Any obvious noises apart from the usual 3 cylinder rattle?
(Disclaimer I really don't like 3 cyl engines, son had one in a C1 and the idle when working properly (which it was) was a constant source of irritation.)

 

[Migz]

@Migz
bad result, I sympathise. I may be wrong but it seems very low for a valve seal issue (but good that you've found it) - just out of curiosity what mileage has the engine done?.
Was there a step change or did this happen over a period of time?
Any obvious noises apart from the usual 3 cylinder rattle?
(Disclaimer I really don't like 3 cyl engines, son had one in a C1 and the idle when working properly (which it was) was a constant source of irritation.)

Hi the problem first arrose on a morning about 3 weeks ago when I woke up to harsh frost and snow. I drove it 50 miles and it was terrible all the way so turn around and tool it back home. Been looking at possible problems ever since the car has done 88k miles now and its never had a single issue prior to this. When the car was running fine I couldn't even hear the engine when I was in the car at all it was like it was not running it was that quiet. Now it's like a bloody moped!!!!

 

[Migz]

Quick update I've taken off the cam cover and all looks perfect under there so I will have to strip the head off completely and try see if there is noticeable damage on it... probably do this stright after Xmas now as I'm sure the missis won't want me doing it on the last shopping day before!!

 

[wozz]

Any fluid leaks or oil in the coolant?
I'm wondering if it's a head gasket.