Graceland

Took the taxi for an MOT this morning and as expected, everything was perfect

Except for the emisions check

Spec is:

MSD Closed Loop
Siemens 55Lb injectors
Wasted Spark
ALS + LC
Fuel pump fully rewired along with every other live feed (14.1 volts nominal voltage)

At normal operating temperature, with either with the lambder sensor plugged in or unplugged the CO wouldn't fall below 4% and the Lambda reading on the machine was either high or low regardless of rpm.

Unplug the labda sensor and it remains the same.

Then the cooling fans kick in and lambda goes to a perfect 1 (give or take 0.01) and the CO drops to around 1%

As soon as the fans turn off the CO raises to 4% and lambda goes out of tolerance.

The first thing I did was to try and reset the CO pot by turning it 5 turns anticlockwise and then 2.5 turns clockwise - this made no difference with the radiator fans off but as soon as they came on and the alternator was under load I was able to gain some small adjustment, but nothing compared to what is expected.

I have a sneaky suspicion that it is either the fuel pressure is too high (no way of checking untill it goes to MSD for a setup and it is a posibility since fiting an 044 fuel pump during the rebuild), the coolant temp sensor is out of tolerance, the TPS is faulty or the lambda sensor is buggered (even though this is a brand new universal narrow band item)


Since Stu is on holiday, as is James, I thought about picking your brains on here to see if anyone has had similar issues.

tabetha

Just bridge the fan sensor wires so permanently on!!
tabetha

florent78

iTrader: (1)

I have too siemens 55 close loop

and I have too some problem with CO and my car is really too rich
"kill pugs" after only 30 miles

will send back my eprom to msd next week

"happy" to see I'm not alone to have those problems

Graceland

I wouldn't say it's a problem for me - it's just something I want some ideas throwing about to the cause - I've narrowed it down to one of 4 things above and was merely looking to see if anyone else had the same thoughts as me

Tabetha - don't be a dildo

Chip

iTrader: (3)

Sounds like a CTS issue.

The lambda side of things is all working pefectly once active, so its definately not the lambda sensor IMHO, cant see it being the TPS as that value isnt changing, its just the closed loop isnt being activated in the first place as it requires a CTS reading of higher than a mapped amount to do so, and I reckon that the CTS is faulty.


Take it over to stu to connect up to read the sensors and I bet its a sensor fault.

Graceland

I thought CTS initially Chipper, but with the new fuel pump I thought the pressure may well be high too

Looks like the RP-Labs kit is next on my shopping list too

I'll chuck another CTS in for the time being and re-check the emissions levels untill I get time to nip over to Stu's

Chip

iTrader: (3)

Fuel pressure isnt effecting the lamda side of things or it wouldnt be going to lambda one once the closed loop is active.

Fuel pressure might effect you when flat out obviously, but shoudlnt effect you in closed loop, and demonstrably isnt doing so in your case in fact.

Graceland

Silly question though, why would it drop into closed loop mode when the fans kickin or the engine is electrically loaded (headlights, heated screens etc etc) if the CTS is faulty?

Chip

iTrader: (3)

That sounds more like an earthing issue, didnt realise it happened with electrical loading, figured the fans were simply cutting in at the same point as the CTS was finally telling the ECU it was hot enough.

Graceland

Hmmm, I'll check and double check then, but I remade all the earthing straps for the engine/chassis using some rather chunky cable

I'll also recheck the ECU earth tomorrow, but I remade that too as it looked a bit scruffy

Graceland

Righty, I have just been doing some checking of various sensors and the general state of the wiring loom and have the following results - Do any of them look suspicious, as to me they all seem within tollerance, with the exception of the MAP sensor which shows a slightly lower voltage than expected (possibly due to the reference figure I have being for a standard item whereas I have a 3-bar item)

All voltages and resistances are with the engine OFF but the ignition ON.


MAIN POWER CHECK: 13.06v between ecu pins 19 and 20.

REFERENCE CHECK: 5.3v between pins 11 and 30.

MAP SENSOR CHECK: 1.63v between pins 11 and 15.

THROTTLE CLOSED: 0.1v between pins 11 and 17.

THROTTLE FULLY OPEN: 5.13v between pins 11 and 17.

CRANK SENSOR: 700 Ohm between pins 3 and 4

PHASE SENSOR: 833 Ohm between pins 5 and 23

INJECTOR: 2.8 ohm between pins 18 to 20

INJECTOR: 2.9 ohm between from pins 35 to 20

INJECTOR: 2.8 ohm between from pins 33 to 20

INJECTOR: 2.8 ohm between from pins 32 to 20

COOLANT TEMP: 2800 ohm between pins 29 and 11 - engine still warm (engine last run 4 hours previous)

CHARGE TEMP: 2200 ohm between pins 31 and 11 for 800 (engine last run 4 hours previous)

Thanasis

iTrader: (3)

adjust the TPS with closed throttle 0,18-0,19, open must be 4,87 approx,also check the throttle with a filler must be 0.5..let us know after that.....

PeterRST

iTrader: (1)

The "fan" phenomenon sounds like it could have to do with the ISCV. I'm not an expert, though. (far form it actually )

Paul_RS

iTrader: (4)

The fans are a seperate loom from the ISCV though? The ISCV shares the same feed as your TPS and amal valve...

Check the resistance between the battery -ve and engine head too, see if your earths are working correctly

Chip

iTrader: (3)

You are correct on the reasoning, they have the same voltage span but a greater MAP span, so each volt now represents more absolute pressure, therefore idle pressure is now a lower voltage, that is exactly as it should be.

Graceland

Paul - 2 brand new earths were put to the engine (one to the block and one to the head and then to the chassis and then direct from the same mounting point to the battery) so all earths are good. Also the fan loom is one of my own items and thus seperate from the car loom.

I think I cracked it earlier by setting up the TPS correctly as when I then unpluged the lambda sensor and adjusted the global mod screw on the ECU, the engine tone changed significantly when the screw was adjusted (adjusted being reset to a base point by 5 turns anticlockwise and 2.5 turns clockwise)


Cheers Chipper - that confirms another train of thought I had

Graceland

Just a little update to close this thread.

After resetting the TPS closed voltage to 0.27v and fitting a brand new ACT sensor and ECT sensor and a genuine Ford (Cosworth spec) lambda sensor, I took the old shed back to my mates garage to check the emissions on his Snapon Emisions testing machine.

Results are after a little twiddle with the CO pot that Lambda is now at 1 and CO is now at 0.9% - this is MUCH better than the 4-8% CO previously noted

So to sum up - a set of sensors from MSD at Ł65 + delivery (ACT, ECT, Crank and Phase) is worth it's weight in gold - especially if you don't know the condition of the sensors on your engine at the moment!

Glenn_

iTrader: (1)

Ive heard a few people say if you change the sensors for new ones the car runs miles better.

Chip

iTrader: (3)

Only if there is a fault with one or more of the existing ones.

More often than not on these 20 year old boat anchors though that is the case of course!

KSA-Cossie

iTrader: (4)

Changing all the sensors was one of the first things i did after changing the cambelt and tensioner.