Breathing problems on mk mondeo 1.8

[Olley]

i have a pipercross induction filter, with a home made cold air feed, and sometimes usually in second gear i get a flat spot at about 4000 to 4500 RPM. anyone have any ideas? gets annoying, especially when tryin to out do someone off the lights!!!

 

[turbonutter69]

Is the car up to date with services etc?
Did it do this before you installed the air filter?

 

[Olley]

before the filter it was worse, and was more noticeable in third as well as second, and as far as services go it is fine!!!

 

[obi_waynne]

Get the lambda sensor checked out in this rev range. You might have a dodgy MAF sensor. It would be interesting to see if it is cutting out because it is running lean/rich or that the timing is being retarted/advanced. There is usually a simple explanation but problems like this are pretty hard to track down.

 

[Olley]

cheers wayne, i think it may be something to do with increased air flow, and no increase in fuel pressure. ie fitting an induction kit and not doing anything with the fuellin. but i'm not all that clued up about that part of things, so any advice would be good. i've heard you can put a resistor in the MAF sensor that tricks it into upping the fuel pressure, is this true and does it work in practice?

 

[pgarner]

fitting the induction kit will have next to no big increase on the airflow to be honest mate your only looking at maybe 10g/s over the MAF.

fitting the resister to the MAF works as it tricks the engine into thinking theres more air than there really is. i your MAF has the air temp sensor inside it can also make trhe ECU think the air is colder than it really is. Both of these changes make the ECU inject more fuel. it wont increase the fuel pressure as the regulator willl return excess fuel to the tank over the set pressure (properly 2.5 - 3 bar)
although it works its not recommended as it causes the car to run rich. hence why the "tuning boxes" on ebay - nothing more than a resister that connects to the MAF sell for a couple of quid and a proper remap costs around £2-500 depending on where you go.


id agree with waynne changes are itll be the MAF or lamba sensor. get a diagnostic done on the car and see if it shows anything up before forking out for parts. also make sure you go for gen OEM parts as cheaper ones might not work as well

 

[Olley]

thanks PG! although i now think the problem may be from something else. as it only happens if i'm at full throttle, if i build the speed up slowly it's fine, i don't really know what a flat spot feels like i was only guessing, but i now think it may be the clutch slipping slightly and gripping higher up in the revs. i have no idea, but will still get a diagnostic to see if it brings anything up. cheers for the info and i will keep people updated... anyone have any advice on buying a nissan silvia S13? i'm thinking about upgrading....

 

[turbonutter69]

Make sure it's a genuine UK model and also try and find one with plenty of service history and you should be fine. You want to find one with Nissans SR20DET engines as they are indestructable.