mercmark

Hi Guys,
Firstly can I say great forum, it’s already been super helpful. Hoping for some help to sort the problem. My car's a totally bog standard 1992 Saff 4x4 (yep I know not many left in standard form) It’s the N5C Catalyst engine, with the green cam cover, and at this moment I wish it wasn't. It's a one owner car before me, covered 130K miles, but has a full and virtually unbroken mainly Ford service history. Most of the miles are motorway miles and a recent compression test shows virtually no engine wear, so assuming all's well mechanically anyway.
I took the car for it’s MOT Test last week and the tester insisted being registered in September 1992, the car had to have the more stringent Cat test, on which it failed on CO emmissions. As the IACV (Idle valve) had been playing up, we tried the test again with the valve disconnected, and it passed the fast running test, but then failed the idle test.
Have sinced replaced the idle valve, fitted a new TPS (throttle position sensor, and set it to 0.20v at idle, set base idle to 900rpm, replaced both ACT and ECT sensors and cleaned out the throttle body. Took it back for retest yesterday and it was no better, although it seems to be idling slightly better, failed the fast running test, I think the figure was 1.45 when it should have been around 0.30. (If it fails this test the computer won't let the idle test be performed)
I’ve also noticed that there’s a slight misfire at idle, which fades out at around 1500 rpm, which is obviously not helping the case, and when I removed the ACT sensor it was wet and reaked of petrol. I've also tried adjusting the idle mixture screw on the ECU and it's not making enough difference.
When I got the car home yesterday evening I removed the throttle body, and I’m going to set the TPS to nearer 0v at idle, as I’ve read this is the correct setting for the 4x4. I’ve also removed and cleaned the injectors, inspected the phase sensor, dist cap etc and all looks well there.
After having trawled loads of threads on here I'm now thinking either MAP or Lambda sensor is/are the culprits. However I'm leaning towards a dodgy MAP as I've read Lamda isn't active at idle (correct me if I'm wrong!) Despite all the above, the car runs absolutely fine and boosts as is should.
Finally just one final thing, and not related, when I replaced the ECT (Coolant sensor) I broke the temperature sensor for the gauge (what a b*****d place to get to!), so have replaced that too, however since fitting the new one the temperature gauge reads higher, but there's no marked changes to the behaviour of the enine (fans cuts in as they should, no boiling, no over pressuring, heater works as it did etc, etc) The sender I fitted was listed in the Intermotor catalogue as being suitable for the Cossie, as well as quite a few other Sierras etc but I'm not 100% convinced as I would have thought a Turbo'd engine would runs hotter than a normally aspirated engine????

Any help/suggestions would be greatly appreciated!

Mark.

stevecossy

Hi mate arent cossies fun. 1st i think the lambda does work on idle to give you the closed loop, (im sure ill be corrected if wrong) as this tells the ecu the amount of unburnt fuel then its maybe faulty.
Also double check ya phase sensor and that its timed bang on in line with the mark on the dissy body, remember tdc on bot pulley is the lug and not the mark.
Sure someone else will add something ive missed.
Good luck. Steve

Twellsie

iTrader: (1)

cant really help on the map sensor/lambda sensor issue, but when i changed my temp sensor, it went from being about a 3rd of the way up the gauge to about halfway up the gauge, i believe this is normal as the resistance changes over time

iansoutham

Chances are that the lambda sensor had simply died with age.

However, now you have started messing with things, I would recommend getting it to a local (or trusted) tuner and getting it all reset back to correct settings as you could end up spending a lot of time and money chasing symptoms that simply will not be there if set correctly.

They can check the lambda readings @ the same time.

If that does not cure it, I would look towards the ECT sensor.

mercmark

Hi guys, thanks for the very quick and helpful replies.

Just to give a bit more info the Lambda sensor isn't the original one and has been replaced at some stage by a non-genuine part and connectod to the loom by bullet connectors. I've removed it and given it a good clean as it was black with soot. The ECT was the first thing I changed but hasn't made any difference.

With ref to the temp gauge after fitting the new sender it now runs with the needle at 3/4 whereas before it used to run bang on 1/2. That said it always stays in the "NORM" range though.

Mark.

paul thornton

As far as i know no saff cossies need to have the cat test done for mot. the test goes off the build date of the car not the registration date and because the last saff rolled off the production line before september 92 it makes them exempt from the test. mines a 93 k green top with a magnex exhaust and no cats on it and ive never had a problem . hope this helps

KSA-Cossie

iTrader: (4)

Rubbish,mine gets cat tested (1/1/93) but pisses it anyway with cat removed thanks to MSD closed loop.

mercmark

That's what I originally thought, and tried my best to persuade the MOT tester. I'm in the trade and they MOT quite a few of my classic Mercs, but it didn't carry any weight, he said there's absolutely no way he could peform the non-cat test as the car is down on the data base as needing this test (by 3 weeks ) even though it was probably manufactured before that date, and was pre-reg by The Ford Motor Company at the time they couldn't sell Cossies due to astronical insurance premiums. I might have another word with the MOT bloke as it would comfortably pass the earlier test.

Failing that, I think it's a new Lambda, as it seems the closed loop system isn't working.

Mark

paul thornton

ive had a look on one of the vosa mot sites and there seems to be a lot of confusion with cars of that era (up to 94) sounds like if you take it for mot with no cat on they dont do a cat test weather its supposed to have one or not. proberbly why ive always got away with it.

mercmark

Hi Paul,
You got me thinking now. I've just decoded my VIN number and it turns out the car was made in June 1992, so I wonder if there's any mileage pursuing the non-cat test avenue???

This is the info the decoder gave:

Manufacturer Identifier: WF0
Body type: 4 Door Saloon
Line: Ford Germany (Own Assembly)
Assembly Plant: Genk (Belgium)
Model: Mondeo/Cougar/Sierra/Cortina/Taunus
Year: 1992 (some codes are used for more than one year)
Month: June


Mark.

paul thornton

i will try and find out a bit more tommorow ive got a few friends who are mot testers , but i;m sure when you put the car details into the mot computer it gives the information you need as regards emmisions testing just cant quite remmember.

mercmark

Cheers for that Paul

Just looking back through the history and it seems it had the Cat test in the early part of it's life, as the emmission sheets are stapled to the MOT's. The later certificates 2000 on, don't have the emmission sheets with them.

If it's any help, here's the results of the emmissions at (fast idle) that failed last week's test:

CO: 1.94% Vol
HC: 122ppm
CO2: 13.60%
O2: 0.28% Vol
Lambda: 0.954
OIL Temp: 22 Deg C

What I find strange is when the IACV was unplugged, it passed the fast idle test (CO came right down) but then failed the natural idle test, however at that point in time the base idle was too low, so wonder if it would have passed with the base idle set higher?

Mark.

mercmark

Hi Guys,
I "think" I may have found the root of my problem. To cut a long story short I disconnected the vacuum pipe to the fuel pressure regulator, plugged the end and the idle immediately smoothed right out, and the periodic misfire has gone! Idling beautifully, rock steady at 850rpm and nice steady exhaust note!

So then I sucked on the end of the vacuum pipe to the regulator and could taste neat fuel.

What I think is happening is that the regulator diapram has a small hole opening up in it as vacuum increases, which is allowing unmetered fuel into the inlet manifold. Also the vacuum on the diapram is not uniform and the fuel pressure is wavering slightly because of it, and there's also the complication of fuel entering the inlet manifold. Obviously as this fuel is unmetered it's pushing up the emmissions, which the closed loop system can't adjust to.

It's the original regulator, so I'd say after 15 years and 130K miles, it's goosed.

I'm going to fit a new regulator as soon as I can get one, so will report on the results.

Fingers crossed!
Mark.

AndyPen

iTrader: (24)

Good news if that is it mate - well spotted!

ON THE TEMP GAUGE SIDE THEY ALL FADE AWAY WITH AGE... oops sorry about the caps lock! So the new one is probably accurate as mentioned. Just done the same with my 2wd saff and got similar results.

stevecossy

Nice 1 mate hope that sorts it out for ya.

KSA-Cossie

iTrader: (4)

Nice one fella.

pa_sjo

You can always tell the tester the engine is from a 1991 car and hence should be tested for pre-cat emissions

mercmark

Hi Guys,
Took it for retest and it’s failed again on CO emmissions, reading this time was 1.69% so it’s come down a bit from 1.94%. However it needs to be 0.30% or less.
MOT tester insisted point blank the car needed a CAT test, and wouldn’t be swayed, which is annoying as it would sail an normal BET (Basic Emissions Test)

So far this is what I’ve replaced:

TPS
ECT
ACT
Lambda
IACV (Idle Valve)
Fuel Pressure Regulator

I’ve also re-gaped the plugs to 1mm and phase sensor to 0.2mm and cleaned the crank sensor. I’ve also cured a couple of air leaks on the inlet side.

I’ve also tested all the wires to the ECU for continuity, and cleaned all the engine earth points, and added a couple more earth straps direct to the battery.

It’s idling so much beter now, but at the top end seems to hesitate on boost (maybe due to Spark plug gap, possibly??)

I’m fast falling out with this car now (and the MOT station). All I can think now is the MAP sensor, unless anyone else has any other ideas. The MOT tester seems to think the Cats are not at fault as the reading’s so far out.

Any help would be much appreciated!!

Mark.

Stu @ M Developments

iTrader: (12)

Have you actually tried turning the Co down during the test? It may be the calibration screw just needs a tweak.

Also, ENSURE the engine is fully hot before you do the test. FULLY hot, and for that, the THERMOSTAT must be fitted and working properly.

mercmark

Hi Stu,
Yes tried all that, screwed the CO potentiometer screw in as far as I could get away with before the test, although am I right in thinking that the screw only alters the CO content by a relatively small amount anyway? I need to reduce the CO by 1.2%'ish

Car was fully warmed up at MOT, gave it a good thrashing before I took it in, and the emmissions test was done immediately.

Mark.

Stu @ M Developments

iTrader: (12)

In is RICH on a L8 mate.

AlexD

iTrader: (3)

I used to turn it down a bit and disconnect the idle control valve on my saph... to get it thru .

.

mercmark

sorry Stu, I meant out, honest Would it make that much difference to the CO content, I thought it was just a trim of +/- 0.25% and does it alter the CO accross the whole map, or just at idle?


failing that do you think disconnecting the Idle valve would work?

mercmark

......just checked the MAP sensor, and the voltage at idle from the signal wire was 1.1v, which I believe should be nearer 0.2-0.6v which would explain the over fuelling I suppose. On revving the engine the reading was all over.

I'm not holding my breath but it's looking likely this could be the cause.

mercmark

as I don't like to be stuck on 13 posts (unlucky for some) I'll just add Input voltage was 5V as it should be, and signal voltage with ignition switched on was the precribed 2.25v. Earth fine too.

mercmark

Hi guys, Just a follow up on my post, I know it’s been a few weeks, but the car actually drove me to distraction, so I parked it up and left it, especially as I had other things to do.

Anyway, I found a bit of motivation and decided to carry on with it this week, and this is where I'm up to. The car is a 1992 bog standard Saff Cossie 4x4, green cam cover N5 Cat by the way, and so far here’s what I’ve replaced:

ECT Sensor
ACT Sensor
TPS (set to 0.0v at rest)
Idle Valve (second hand but works fine)
Lambda Sensor
Phase sensor (gapped correctly)
Distributor cap
Rotor Arm
Spark Plugs (Genuine Ford and gaped to 0.9mm)
CPS (gapped correctly at 0.6mm)
Fuel pressure regulator
MAP sensor (2 Bar as car is bog standard)

...in short just about everything!

Took the car down to the MOT station this afternoon, so I could use their gas analyser (car nice and hot after a good caining) and this is the results I’m getting:

If the CO (circa 0.30-0.50) is ok at idle, then on fast idle, it fails the Lambda test, giving a reading of 1.080 – 1.100, sometimes more, so then if you use the CO pot on the ECU to richen the mixture, to get a Lambda reading of around 1.000, and a CO content of about 0.1 – 0.2 – all is fine then it passes the fast idle test, however when you let the revs drop for the natural idle test, the CO doesn’t drop far enough, stopping around 1.28% (should be 0.50 or less)
......so, adjust the throttle pot at idle so the CO falls to 0.4-0.5 ish, and that’s fine, but then it’s too weak on the fast idle test, failing the Lamda test.

I tried for well over an hour to find a happy medium between the two using both the CO pot, and idle air screw, but over stayed my welcome a little, and to be honest I would have been there all night!

I have to say when the CO content is right at idle it seems to run decidedly lumpy at the top end, probably because of the weak mixture which was almost as low as 0.00 at 3000rpm, which can never be good on a Turbo’d engine. It actually runs better with CO, and hence Lambda set correctly for the fast idle.

One thing I did notice when the CO was high at idle, the HC content went up too, indicating unburnt fuel....could this be down to incorrectly gapped plugs....the Ford ones that are in there are at 0.9mm. I also tried it with the Idle valve both connected and disconnected, but that made very little diference.

It’s a bit frustrating really, as I’ve gone from having a car that’s running too rich, to one that’s running way two weak.

I’m sure now, it’s nearly there, but there's something just not quite right. To make matters worse, while I was messing around at the garage and just to further lay the boot in, the ABS light came on, so that’s something else to sort now!

Please help Stu, Tabetha, anybody!

Mark.

KSA-Cossie

iTrader: (4)

You're not far from MSD to get it sorted once and for all pal.

Jimboxr4x4

Sounds very good advice to me. A good set up is well worth the money.

mercmark

...problem I have is the MOT and tax have expired, and I can't retax the car without the a valid MOT certificate, so I'm in a catch 22 situation. Driving the 120 miles roundtrip to Blackpool and back with no tax or MOT would be too risky, with my luck of late, I'd probably get caught by the the rozzers and end up getting the car seized as no tax or mot = invalid insurance.

If I could just get it through the MOT, I could get it to MSD and have it set up properly.

big mac

iTrader: (7)

if the vehicle was registered on or before 1st of august 1992 it does not have to have cat test get the tester to check the manual mate

mercmark

...just my luck I'm afraid, even though the car's build date was June 1992, it was registered September 1992...I've tried all sorts of avenues here, but the car is down in VOSA's computer system as requiring a Cat Test and according to the MOT guy that's it, no loop holes...it must achieve 0.5% CO (or less at Idle) and around 0.3% CO and lambda 1.000-1.030 at 3000rpm.

STUCOS

iTrader: (8)

Mates rs focus.with no cats and 280 bhp conversion ,just went threw an mot,youn need a new mot tester,there is ways mate

cheeRS stu

stevecossy

Where abouts in yorks are you ? anywhere near beverly?

mercmark

Hi Steve, no unfortunately, Beverley is nearly as far away as Blackpool! I'm on the West/North Yorks border near Skipton. I'm going to take another look at it today. I think the problem source is at Idle. I'm thinking a slight misfire is resulting in inefficient burning of the fuel. Further up the rev range everything seems to be working fine.
I'll start by re-gapping the plugs to 1mm, and just have another look at the phase sensor setting too.

Also got to sort the ABS now too, but think that's just down to dirty sensors - car was stood for a few weeks, so rust from brake discs has probably stuck to them.

IANS2RST

iTrader: (1)

what plugs are you using & where did you buy them from?

mercmark

They're the Ford 071's and I got them from Matt Lewis. I think they come out of the box gapped at 0.8mm, but as my Saff is standard, I've increased it to 1mm. It seems to have smoothed out the idle, just hope it's OK on boost!

big mac

iTrader: (7)

find another test station mate !!! sounds like the tester is being a bit tight to me it aint like its dangerous and it is very close

col93saphcos

iTrader: (2)

i had similar problem few mots back replaced lamnda sensor and passed,even mot boy was a bit amazed that thats what it was,he was gonna have me getting re-map from ford!!tit!just a thought tho
col93saphcos

Glenn_

iTrader: (1)

I would find another mot tester.My good friend is a tester and he does my cossie.Mine is running a bit rich and i told my mate last year that i could turn the co down for the test but my mate just passed it.I hope you get it sorted mate.

mercmark

Thanks guys...hear what your all saying, so it's going to another MOT station tomorrow. It's not like the car's going to pollute the earth, it only did 500 miles last year and besides, it's only slightly rich at idle!