1.3 petrol - what sensor is this? - Rattle
My 1.3 Fiesta has been over revving when the clutch is depressed so I have decided to have a good look under the engine bay, I have noticed this sensor was unplugged (marked A) and since plugging in the car seems to run smoother and the over revving is not as obvious. However I can't work out what this sensor is or how its connected to anything that will cause the over revving.


i167.photobucket.com/albums/u141/amazingtrade/engi...g

Edited by Pugugly {P} on 19/10/2007 at 21:48

1.3 petrol - what sensor is this? - bell boy
A= map senser,car will run like a dog if this dont work
B=iat senser,it tests how cold the air is so that the fuel can be modified if its a cold morning
C- the lambda, often been blamed for blue tongue disease by the chattering classes but totally unfounded heresay

do i win a prize?
1.3 petrol - what sensor is this? - Screwloose
Rattle

Can we have a better picture of "A" please. There's a very obvious MAF sensor in the inlet pipe off the filter box and [AFAIK] they don't have both MAP and MAF on the same vehicle.

It could be an EVAP valve or an exhaust gas pressure sensor; but it's hard to see it clearly.

Edited by Screwloose on 19/10/2007 at 22:26

1.3 petrol - what sensor is this? - Rattle
i167.photobucket.com/albums/u141/amazingtrade/SENS...g

It is odd as I just cannot see what it is connected to, but A was unplugged. Also another thing above looks unplugged but cannot find anything to go connect to it. The other connector is going into the heater control valve I think which I have just replaced.
1.3 petrol - what sensor is this? - Rattle
Thanks :D

You have cleared it up, the car wasbasicaly over revving and running very jerkily it is a lot smoother now, it had just been serviced and when this did not cure the jerking I decided to try and fix it myself and spotted the disconnected sensor.

Now then a puzzle, you have to take this off on purpose the connector is very strong, so why would somebody do that?
1.3 petrol - what sensor is this? - Rattle
Sorry for the confusion, I replied to post number 2 before I saw number 3 apply so the better pic is actually posted above.
1.3 petrol - what sensor is this? - Screwloose
Rattle

It's an EVAP [canister-purge] valve. It sucks petrol fumes from the tank under ECU control.

It was probably disconnected to try and blag an MOT emissions pass.
1.3 petrol - what sensor is this? - Rattle
So this would have no effect on the running :( I did also tighten up other sensors and also wiggeled the wires a bit in the process so maybe this had some tempory effect. Why would this connected cuase to fail the emission test and should I be very worried about this?

The car was 3 days from the MOT when I bought it, so maybe they knew somthing and told the seller to sell it quick? Having said that in the 2000 miles driven in it since my ownership I haven't noticed any machanical problems apart from the over revving issue.
1.3 petrol - what sensor is this? - Screwloose

They may have [wrongly] thought that it was letting petrol fumes into the manifold and richening the mixture.
1.3 petrol - what sensor is this? - Rattle
Thanks. It makes sense, all garages seem to do is disconnect things at random and hope it hides the problem :P:

Just done some research on this which suggests in can cause irratic idle problems in some circusmtances though this was on the Scorpio website so not sure about the Endura engine.

1.3 petrol - what sensor is this? - Screwloose
Rattle

Be careful about believing things that are written on internet forums.......
1.3 petrol - what sensor is this? - Rattle
This was a proper site but indeed. I am going to investigate the TPS as this is probably the most likely cause, just seen the another thread and my car does have the curise control stock throttle sympton even though the cable is not jamming.

The TPS would have all these symptons. I am hoping cleaning the connectors will solve it but I doubt I will be so lucky.
1.3 petrol - what sensor is this? - bell boy
well im confused now? as i saw this as a map senser and have swapped these about in the past 2 years to get an emmissions pass mainly on mk 4 fiestas + one ka
the weird thing is the failing? on the mot----- i swapped it for another fiesta/ka one in stock and this passed the emmissions no problem
i have my own co mot testing machine
it has a pipe in and out so this does now make sense but didnt realise it was the purge valve
still cant work out why one car passes, one fails ,with the same component though
1.3 petrol - what sensor is this? - Rattle
Have you seen the new picture? If you look at that you can see there is no actual pipe going into it. Its just close to it.

I am also very confused, but garages get even more confused and charge you for a new engine in the process so I need to fix this myself.

I am a computer engineer so I understand ECU stuff quite well, its th pysical act of machanics I am not too good on (e.g tappets I would not touch).
1.3 petrol - what sensor is this? - bell boy
your letter A is on a map senser to me it is on a v shaped holder that is back to front on a ka,there are 2 pipes goes to it one to the inlet manifold,the other i never followed,the pipes (rubber) stick on the plastic connecters and the plastic bit breaks if you dont work carefully :-(
1.3 petrol - what sensor is this? - Screwloose
bb

Fear not; these things can confuse a lot of people. If it's got two pipes it's an EVAP or an exhaust gas pressure sensor to detect a blocked cat. [They're as rare as hen's teeth, but do show up from time to time.]

One pipe to the inlet manifold and it's a MAP. MAPs don't need a rubber mount, because they don't buzz.

There are both MAF and MAP controlled versions of the Endura. The Ka usually has a MAP system - but some Festers do too.

The give-away here is the MAF; they don't [ever?] fit both.
1.3 petrol - what sensor is this? - Number_Cruncher
>>they don't [ever?] fit both.

I've never seen both fitted; why would you?

All a MAP or an AFM does is estimate engine load. Fitting both would be like fitting 2 different types of coolant temp sensor - pretty pointless IMO.

Number_Cruncher
1.3 petrol - what sensor is this? - Chrashcool
Hey up SL

So you're saying that two pipes = EVAP, do they ever combine the EVAP with a MAP? Just asking cos on my car Fiesta 1999 zetec 1.25 I can't seem to find either the MAP or MAF if that is the EVAP.

I think that it is because the pipes are traceable to the inlet manifold and also back through the bulkhead. Though this would leave the car with no other way to measure air temp or flow.

I'm a little confused. Also these EVAP valves seem to be impossible to source and cos the earth. Any ideas?

Cheers

Glenn
1.3 petrol - what sensor is this? - Screwloose
Glenn

All of them have an EVAP.

A 1.25 [completely different engine and control system] usually has a combined MAP and inlet air temp sensor hidden away on the plastic inlet manifold.
1.3 petrol - what sensor is this? - Number_Cruncher
your letter A is on a map senser


Not it! **

It's a purge valve. The two wires are used to energise the solenoid in there. One pipe to the manifold, the second to the carbon canister.

A MAP sensor would more likely have 3 wires, power, earth, and signal; it would also just have one vac pipe to it, from the manifold. Why would you want to connect a MAP sensor to anything else.

Number_Cruncher


** Oops sorry - after reading the "overbearing backroomers" thread, perhaps I should have said - Humbly begging your forgiveness, craving your indulgence, fearing any potential offense, and fully respecting your knowledge and experience, I meekly would beg to differ ever so slightly....
1.3 petrol - what sensor is this? - Rattle
So in real terms this EVAP valve does nothing other than make the people in Brussels happy?

Edited by Dynamic Dave on 20/10/2007 at 00:59

1.3 petrol - what sensor is this? - bell boy
i would just like to add no animals were harmed while i disconnected my maps-- oops sorry purge valves-- and any spiders i find behind the heater valves in future i will leave in peace thanks guys ive learned something tonight

did i tell you freddy the spider got killed last saturday night when a car coming the other way on a narrow road took my drivers mirror clean off :-( probably this should be under discussion but ive been so downbeat all week about it and darent even call the nissan dealer about a costing on a replacement
1.3 petrol - what sensor is this? - Screwloose
NC

I've a feeling that that "overbearing" thread may have been partly aimed at me too; my somewhat forthright style has been described "elsewhere" as being "as subtle as a Panzer division."
1.3 petrol - what sensor is this? - bell boy
i thought it was about me SL as i tend to have forthright views
1.3 petrol - what sensor is this? - Screwloose
bb

We've earned them!
1.3 petrol - what sensor is this? - Number_Cruncher
So in real terms this EVAP valve does nothing other than make the people in Brussels happy?


In one sense, yes, it's quite possible to design and set up an engine to run without one, although the evaporated emissions would be lost straight to atmosphere, so it probably wouldn't pass euro regs.

In the sense of could you simply do away with it on your engine, then, I'm afraid the answer is no. Even ignoring the iritation of the dahboard warning light, when the purge valve opens, the injectors inject a little less fuel, because the ECU expects the engine will be breathing some nice fuel perfumed air. If the engine either sucks nothing in, or sucks in fresh air, then there has to be a correction made by the ECU - not ideal.

-----------

SL, BB,

Without your contributions, [whatever their tone or style ;-)], the Technical Forum would certainly wither and die - there's simply no-one else posting with enough relevant experience. [I managed to escape the trade 15 years ago, so you can see how modern my knowledge is!]. There has been a couple of people from the trade who appear and post for a while, but for various reasons, they felt unable to be challenged on their opinion (notably! robcars). If an opinion is good, then there must be some reason or evidence to back it up - simply saying that I'm telling you this is true and you should believe without question isn't quite enough!

Number_Cruncher
1.3 petrol - what sensor is this? - Rattle
Thanks.. I am borrowing an OBC II scanner tomorrow so hopefully that will tell me about what is going on.


The wiring loom appears to be the modified one not the original one which had rust problems and the idle control valve appears to be new, so it is looking more like a TPS problem.
1.3 petrol - what sensor is this? - jc2
The purge valve that purges the EVAP canister is only opened when the engine is running "closed-loop"-ie.the calibration is being controlled by the HEGO sensor(lambda).It thus can make no difference to the emissions from the car-the EVAP canister absorbs the emissions from the fuel tank whilst the car is not running.
1.3 petrol - what sensor is this? - Number_Cruncher
>>It thus can make no difference to the emissions...

I think there's a certain amount of truth in that, but I also think that there's a little bit more to it.

If the lambda sensor really could sort out all fuelling changes and errors, then there would be little need for coolant temp sensors, air flow meters, throttle position sensors et al.

Even when running closed loop, the ECU will take it's input from all sensors, and arrive at a basic injector pulse time.

Owing to the time delayed nature of the system - the lag between fuel injection and measuring the corresponding pulse of exhaust gas (which is, of course longest at low engine speeds) the driveability would be very poor if the lambda sensor were in total charge of the fuelling.

So, by taking into account the extra waft of fuel rich air that you get when you open the purge valve, you can;

a) avoid the temporary enrichment that you know will happen when the valve opens
b) avoid the temporary weakening (and possible flat-spot) when the valve closes

So, I would say that closed loop running is effectively using the open loop fuel mappings to get somewhere near the operating point, and then only using the lambda sensor to correct small errors.

Number_Cruncher
1.3 petrol - what sensor is this? - Screwloose
NC

You are too kind; there are many others whose input is invaluable - Doc and 659 to name but two.

The question that I still can't find an answer to is: where are the youngsters?

The generation that was born with a ZX80 in their hands; they should have driven grizzled old codgers like myself off to the old folks home years ago.

Instead; the few of us, that are still functioning, are being dragged deeper and deeper into the nightmares that the dealerships techs just can't comprehend - let alone be trained to address.

It cannot be a lack of computer literacy that is the missing ingredient; there seems to be a lack of mental resilience, or discipline, necessary to confront difficult problems.

Is this a comparatively recent educational issue? As you can imagine; it's been some years since I - just stopped attending - school.

Anyone know for sure why youngsters can't be trained to diagnose?
1.3 petrol - what sensor is this? - Rattle
This is what I don't get. I am not a machanic at all but I am a computer engineer so sensors, voltages, ampage and fiddely connectors don't scare me. Ask me to change the plugs and I will find it hard, ask me to measure the resistance of a TPS and its a doddle.

I think part of the problem is some peoples brain works one way, machanical but this does not seem to extend to diagnoses and ECU issues.

I sacked my last garage when they just said the reason the Escort was burining fuel is the ECU was faulty and they will get a new one from the scrap yard when actually all along it was a stuck valve.

I also don't get how garages can charge customers for parts used in the diagnoses process (e.g not needed).

Also I would like to add that ECU and engine management is covered in detail in colleges but I am guessingf most the students don't take much notice of it.

This is why I am fixing this problem myself. It seems tobe anything electronical I fix anything machanical I leave to my machanic.
1.3 petrol - what sensor is this? - spikeyhead {p}
It's because anyone capable of solving a complex problem is now sitting behind a desk designing things, helping a computer network to continue to run or somesuch similar work.

Most people that are capable of solving such problems are attracted to decent salaries, long term employment prospects without being face to face with several different customers each day and plenty of other reasons for avoiding the motor trade. They're also growing up with cars in the family that are too complex for their dads to fix, though I didn't learn much about car maintenance until I got to university when plenty of time and a lack of money meant I had no choice.

In also hard work, and on a selfish level I'm glad that the youth of today are taking the easy route. There's very very few that are choosing to work in RF and microwave electronics, which is generally reckoned to be the most difficult to work in. As the old ones retire there's no new coming through, so the laws of supply and demand mean I can charge more and more for my services. On a less selfish level I think that it doesn't bode well for the future, either for finding someone to fix my cars that actually knows what they;re doing or for enough people to be working to pay my state pension. Fortunately I've not included a state pension in my retirement plans.
--
I read often, only post occasionally
1.3 petrol - what sensor is this? - TurboD
Do many people now regard cars as disposable?
I have bodged cars for 40 years, but now have pretty well given up. My 2lMondy -2yrs old- seems happy enough with the dealers - spelt properly again, if I have to edit anymore I'll just delete the whole post as it's so much easier £200 visist each year.
If it last 7 years its pretty well worthles and by then a much better motor will be along so it'll be a banger.
I really think the mending brigade are departing and that includes garages- just replace the car. meanwhile it is nice to have informed opinon on faults

Edited by Dynamic Dave on 20/10/2007 at 22:14

1.3 petrol - what sensor is this? - Number_Cruncher
>>Anyone know for sure why youngsters can't be trained to diagnose?

I can't offer complete certainty and generality of my answer, but this what I've seen;

Just before I left, I had worked with an apprentice who was a remarkable person. He had the discipline and drive to be in the British Gymnastics team, and he brought similar levels of appllication and dedication to his work.

In the 15 years since I left, I have kept in touch with him. Over that period, when we've met, we have talked through all matter of automotive stuff. From working through the hydraulic circuits, testing and operation of autogearboxes to working out faster and better ways to test circuits beyond the manufacturer's instructions.

This extra-curricular work has happened because fundamentally we're both interested. The only pressure and encouragement that comes from the dealership is to improve efficiency and hit workshop sales targets. Activities like diagnosis, which take time and money are never going to provide an income stream to compete with routine servicing for a dealer workshop.

My friend now spends quite a bit of time travelling between the local dealers in the group doing their diagnosis for them. If he left, they would struggle - but there's no-one in management there who is pro-active enought to see this as a weaknes or to act upon it.

We've also talked about the general running of the garage, and the state of the trade locally. Staff turnover has been high, but in the 15 year period, only one person has had both the attitude and aptitude to do any meaningful diagnosis. This fellow left soon after finishing his apprenticeship!

Once Number_Nipper is out of nappies, will I be showing him how to change oil filters, or will I be showing him about physics, maths, electronics, and comuters? I know the answer!

Number_Cruncher
1.3 petrol - what sensor is this? - Rattle
Done the ECU test. I have a code which says HO2511 mixture to lean. There is quite a bit of carbon on the rear box so this would make sense. However no fault seem to indicate why its over revving :(.

Am I right in thinking that H02511 could be anything from a MAF to a faulty lambda?

What is odd is their is very little smoke from the exhaust certainly no visibile evidence of it burning fuel but the MPG does seem poor.
1.3 petrol - what sensor is this? - Screwloose
Rattle

What on earth did you read it with to get that "code" - it's nonsense.

H-O2-S-II is a Heated Oxygen sensor #2 [a post-cat sensor - which you probably haven't got...]

What is your engine code and year? It should be shown on the VIN plate as Mot. Type.

Edited by Screwloose on 21/10/2007 at 16:13

1.3 petrol - what sensor is this? - Rattle
It was a Genicon or (gericom or somthing) it was borrowed. It is quite an expensive tester not the ebay things.

It is a 1.3 Endura Engine (Dec 97 R) but made earlier. Can find out from the VIN if you need more. From my understanding of the engine management system from the Ka which i the same it does have two lamda sensors.

www.dervman.com/obdii.htm#oxygensensors

According to this it does have two senors, one of the manifold and one post cat.

Done about 5 miles in it since I reset the ECU and it the car seems have a lot more pulling power.
1.3 petrol - what sensor is this? - Screwloose

The post-cat sensors were only fitted from around '01-on.

At around that time; these are a nightmare to plug in. Ford were using all sorts of protocols, it's probably EEC IV DCL if it was built in '96; but could be EEC V if later.

Did this interface support live-data?
1.3 petrol - what sensor is this? - Rattle
So that reading could be inaccurate? Most the markings on the car indicate the car was built in late 96 early 97.

The car is running a lot better now since the ECU reset, there is a lot more low down power, but it still over revs to about 1500 rpm, annoying but its not the end of the world.

I am just going to see how it goes for the next week and then look at the TPS and road position sensor if it dosn't clear up/gets worse.

The seller basicaly has not been honest I am suspecting this problem has existed for a while. Funny how it ran perfectly during the test drive though.
1.3 petrol - what sensor is this? - jc2
Two sensors were only needed for EOBD which came in with St.III & IV emissions-certainly not 96-7.
1.3 petrol - what sensor is this? - jc2
EEC-IV modules had 60 pins and wires connected-EEC-V had 104.
1.3 petrol - what sensor is this? - jc2
Rattle-please quote us the last two letters of the VIN-the two before the five numbers-they're the build date code.
1.3 petrol - what sensor is this? - jc2
There are a number of errors in these pages-for example,he states fuel consumption test includes a cold start-it doesn't-the emission test does but the fuel test is driven to the same cycle but with a hot start.
1.3 petrol - what sensor is this? - Rattle
Sorry for the the late reply. Just checked the VIN and decoded it. Its was made in October 1996 (even though it was registered in Dec 97).

I have also driven on a quiet road where I have test it more. Basicaly it only over revs when the clutch is pressed in and only when the car is moving. It does it mainly from 1st to 2nd and also when you put the clutch down to slow down.

I have tested the TPS with my multimetre and it appears to work fine, I tested it with the throttle handle in the engine bay and the peddle and I get the same resistance changes which suggest the throttle cable is fine.

I have not tested the connection from the TPS to the ECU, not sure how to this and don't want to disconnect it to see if it behavs madly (like no TPS would cause) because it would show up an unwanted error code on the next ECU test I am doing next week.

Not done the rolling road test yet. Where is the road speed sensor located btw?
1.3 petrol - what sensor is this? - Screwloose

If it's revving with the clutch down, then the VSS is working.

What was the voltage on the middle pin of the TPS at idle?

With ignition off; split that big multiplug under the plastic cover and see if any water's got in.
1.3 petrol - what sensor is this? - Rattle
The fuse box or the airbox? Haven't measured any voltage. Am I measuring the middle pin on the cable that goes to the TPS? I assume I can put the negative connection on any body panal and do it that way? My hands are not that steady and don't want to short anything while measuring the cable.

1.3 petrol - what sensor is this? - Screwloose

The fuse box or the airbox?


The in-line multiplug next to the EVAP.
Am I measuring the middle
pin on the cable that goes to the TPS? I assume I can put the
negative connection on any body panal and do it that way?


Leave it connected and stick a pin in the back of the plug to access the terminal. Any good neg will do,

My hands are not
that steady and don't want to short anything while measuring the cable.


Don't worry too much, you're downstream of a resistance. [Try taking more water with it.]
1.3 petrol - what sensor is this? - Rattle
Thanks I assume you mean this big plastic inline connector here on the left.


i167.photobucket.com/albums/u141/amazingtrade/SENS...1


What does this do btw? Sorry for the all the questions I just like to know how it all works.

Will also check the voltage.

Edited by Dynamic Dave on 26/10/2007 at 14:49

1.3 petrol - what sensor is this? - Screwloose

It's an in-line wiring connector.

It connects the engine wiring - in an in-line sort of way.
1.3 petrol - what sensor is this? - Rattle
Thanks, I just tried it but can;t split the box off without putting a lot of force on, I fear that if the wiring is already dodgy I break this connection completly.

Its garage time I think. At least it should saved some money doing all this diagnostics as Iwill ask him to check the wiring befoe the snesors etc.

1.3 petrol - what sensor is this? - Screwloose

The cover is separate to the connector. It hinges along it's length.
1.3 petrol - what sensor is this? - bell boy
before you spend money on this car Rattle at a garage

you have checked the switch on the clutch pedal? is there and working? it works like a brake light switch
you have cleaned out the idle control valve?
1.3 petrol - what sensor is this? - jc2
October 1996 was TY.
1.3 petrol - what sensor is this? - Rattle
There dosn't appear to be a clutch switch, where abouts on the peddle would I find one?

Not cleaned the idle control valve yet but I was told if this was faulty I would have other symptons such as it stalling. The car works perfectly when idle and starts at 1100rpm and then slows down to about 800rpm like all of these engines do.

I could bemissing somthing though.

Could somthing cause the idle control valve to 'open' when the clutch is pressed?
1.3 petrol - what sensor is this? - Screwloose

In motion and at part throttle, the valve should be wide open. In motion and with throttle at idle; it should be about half open.

When the VSS pulse stops; it should drop the idle to the pre-programmed idle revs.

Most of these problems are caused by the ECU not realizing that the throttle is shut.

How well the ECU sees that centre pin voltage on the TPS is the crux of it - concentrate on that.
1.3 petrol - what sensor is this? - Asbesto

Sorry to hihack the thread - I was there for this EVAP valve related to some problems in my FORD Fiesta IV (i'm from Italy) - and I just saw this comment related to ZX80 computer, and I flipped up! :) As a Computer Museum curator, this really hit me :D

BTW I'm having problem with my Fiesta IV and I just discovered that the rubber tube connected to the valve box is cracked. This means that fresh air can be "sucked" and so this can be the problem of my car going crazy sometime, as if it's loosing one cylinder, and maybe for this high fuel usage I have now (12km/l for an Endura-E 1299cc)

ps this forum is very very nice! :D

greetings,
Gabriele

ps museum.freaknet.org about the computer museum I was talkin'bout
 

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