Topic

Still having emission issues! C.o high above 2000rpm,drop below 2000 leval drops,thinking that map sensor is playing up.Car is a 1998 mpi with sensor in the ecu,going to recheck this week with p,scan to check the readings at differant r.p.m's.My question is if the map readings are out,has anybody bypassed the sensor in the e.c.u & added an external one,ie from a v.v.c?

Oh, for Heaven's sake! If you cannot work out why your car's emissions are faulty, what makes you think that you have the skills to modify the engine's hardware to try and cheat an ECU that you don't understand? We are all friendly and courteous here and I know I sound harsh but take a step back and have a reality check. What you are proposing won't fix the problem. Fitting an ECU from something else is many, many times harder than fixing the problem properly and if you can't, take it to somebody who can. It is invariably the cheapest and easiest way. Many of us on here have a lifetime of tinkering with cars, some at a very advanced level indeed. None of those people would modify their way out of a faulty engine problem on an engine that works perfectly well if it is correctly diagnosed. There are a large number of expensive guesses that might be responsible for your problem and you can burn a lot of money and time going nowhere. There is no shame in running out of knowledge. I recently spent several weeks debugging a problem on mine and I'm pretty good. I strongly advise you to find a good professional diagnostician, au fait with the K series engine who will identify the problem correctly.

So maybe i did not explain my idea fully,if my map readings are out of range i was thinking that could i use a map sensor from a v.v.c engine & adapt the wiring to the new map sensor.I at no point thought that i could cheat the e.c.u.I know that you can get used e.c.u's or repaired units but i am trying to save money due to a certain mr Khan extending the ulez zone to our area so the mgf will have to go.So thank you for your comments,but i thought these forums were a sounding board for people with problems that some others may have had or come across.

Try reading how others have solved the problem, then. A clue. You cannot do this from a basis of bodging it to save money which is really what you want to do

Why not just fit the correct map sensor? It would be cheaper in the long run than buggerising about with one that doesn’t suit, find it won’t work properly and end up fitting the correct one anyway

I would suggest that you go back to the basics on emissions.
That is 02 sensor and the catalytic converter.

Your reading for 02 sensor voltage does not look right. Do you have a graph of the voltage available? It should look like this.

Is it the original cat or has it been replaced? If so, was it replaced with a cheap one? Cheap cats are notorious for failing after a short period. (They usually manage to pass one MOT but fail the next due to minimal amount of reactive metals.)