Corolla verso too rich fuel and pinging

[aerodss]

Hi everybody before anything, a big thank you for all the users who contribute to auto problem resolution, this is my first post because I try to evacuate my questions using mainly the search button, but right now I need a guide to fix my car's problem.

I have a Corolla Verso 2005 D-CAT 2.2 with ~~180 000 kms on the clock

Since last month the car started having very bad economy and small hesitation under load after warming up. When cold no problems, after 15~20 min of driving you start feeling the problem very subtle. This is the list of the symptoms:

• Runs fine when cold

• With engine warmed, hesitation under load and pinging (knocking) around 2000 RPM

• If driving under 2000 RPM you don't notice too easily

• Coolant is being expelled during driving by the overfill hose in the reservoir cap

• EGR valve has a wet look carbon film instead the usual dry black mate coke

• no trouble codes but I had a P0400 yesterday after taking off and back on the EGR valve unit to test the impedance

• Suspected vacuum leak at manifold (low pressure, see below)

I downloaded the Toyota service manual to have all the parameters to correctly check every sensor involved but I have a question regarding the Air/Fuel mixture sensor, the manual says to measure 2 pairs:

B+  -----------  HT                  1.8 to 3.4 Ohms  (I think this is the heater line), and

AF-  ------------  HT                           10 KOhms or higher 

I checked the impedance

B+  -----------  HT                  3.2 Ohms  (apparently OK)

AF-  ------------  HT                           no connectivity (is this ok or not? because it is infinite resistance > 10 KOhms) 

What do you think is this sensor theoretically good?

Test I have done :

	Reference value	My values
Cleaned EGR and checked impedance Pin 1(+B) with pin 5 (EGRS)	6.5 to 7.5 Ohms	7.6
Pin 3 (VC) with pin 2 (E2)	3.5 to 6.5 Ohms	3.15

With scanner I checked these values:

	Reference value (idling)	My values
Calculated Load	10% - 25%	22.7%
MAP (idling) kPa	85 -93	74
MAP @ 2500 rpm kPa	105 – 120	87
MAP @ 3000 rpm kPa	120-140	101
MAF (idling)	2.8-5.2 gm/s	4.7
MAF @ 2500 rpm	27.5-32.5 gm/s	30.7
Coolant temp	80 – 95°C	95°C
Fuel pressure (idling)	37-43 MPa	39MPa
EGR (idling)	0-60%	50%

 

[aerodss]

Can anyone tell me in what part of the system could be a leak between the cooling (antifreeze) and intake manifold ? I think that would explain the low pressure in the intake manifold and the excess pressure in the cooling system

Thanks

[alan333]

Check for cylinder head gasket failure.  If you have exhaust gas in the coolant it'll throw water out the header tank pipe.

[aerodss]

Thanks Alan, I will make the chemical CO2 test today to confirm if it's the gasket or something else.

I'll post back results later

[aerodss]

Well I made a chemical test for detecting CO2 and yes, it is venting CO2 thru the radiator overfill hose.

I have one question regarding this:

The primary suspect is a blown gasket but, could the EGR cooler be the problem? I'm not familiar with this cooling circuit but according to the service manual it is located  under the turbo right near the firewall, could the symptoms be the same?

thanks

[The Cheerful Tree Rat]

I have no useful comments re: the problems you had, but can I ask where you got your copy of the Service Manual from? I'm feeling slightly nervous about not having a manual to hold my hand while I attack my car...