right iv got a fueling problem on my 3dr cosworth wot its doing is when the car is nise and warm i can set the fueling on the ECU with the help of my stack AFR gauge and set it to about 14.7 / 14.4 and the fuel reg is running at 3bar and 3.5bar with the pipe of . so then i go for a drive and bring it onto boost and bang it back fires like a dog and the AFR gauge is in the RED very very lean i pull up and the AFR setules in the mid 12,s i then pull off and it gose very lean till im just hovering the gas . pull up and the fueling is in the RED again very lean .iv just done a test on the wires running the FPS and the MAP and the wires are all good the car is on its second fuel reg which is holding pressure good as i have a gauge which i can see wot the fuel pressure .
SO WOT DO YOU THINK IT COULD BE THEN

 

MAP sensor faulty?

 

iv been thinking this for a long time now as it the only thing on the car that has never been changed . we are going to put my mates MAP on the car this week and see wot that dose any more help from any one would be good

 

Wiring to the fuel pump needs replacing ?

Steve

 

we did test that xmas when the car had the same problem and it was ok . we will re test it and it all so has a new pump on it a 044

 

Map sensor is the most likely cause here.

 

Is it still on the original wireing thou?! If it is its still worth replacing it, both my last 2 cossie's were loosing voltage due to the wiring.

Probably nothing to do with that but still a worth while thing to do!!

 

I've got an exact problem like yours mate,i've changed the 3Bar Map sensor,FPR is fine as is fuel press. undre load,pump voltage is 13+volt.
I'm thinking that my PLX r-500 wideband isn't all that accurate,i've got 8 injectors but the dam car is always lean??.
I'm waiting for my MSD wasted spark kit to see if i can rid myself of a dangerous missfire aswell...

 

Check the TPS operation too...

Most chips add additional fuel based on throttle position and if it isnt working properly it can lean off the map.
(Usually 80% or more open)


Overfuelling, missfires and leaded fuel will reduce the life of a wideband sensor drastically.
Get the sensor calibrated (Most sensors have an open air quick calibration facility)

 

Right bit of a update we have been working on the car all night and this is wot we have done.

put a new map sensor ............it did make the car run better and the AFR was better
but still not right

new TPS
but still not right

new fuel reg
still not right

new plugs with a gap of 0.6mm
still no good

and for the last thing on the list the pump wire which we did Xmass and it was ok then
well when the car is on tick over we have 11.8v and still 11.8 when driving
so we ran some wire in the car but it was only 1mm but it did lift the volts to 12.6 the car still ran shit we then put the volt metre on the wire coming from the battery and that was showing 13.8 so we are down on the volt at the pump now . so we are going to have to rewire it this weekend and get a new map sensor of MATT LEWIS

Now do i have to spend Ł40/Ł50 on a pump wire kit or dose some one have the info on wot to do and sizes of wire to do this job

 

all you need to do is take a 12v feed direct off the battery with a decent gauge wire (cant tell you the size off the top of my head) with an in line fuse of (cant remember that rating either lol) and take it to the back of the car, where in the spare wheel well there is a red/black wire which is your ignition feed. You need to connect this to a new relay of about 20A rating i think and then make an earth to complete the circuit. Pretty simple really, but by the time youve sourced the relay, crimps, wire, heatshrink you might as well save some time and spend another 15-20 quid and buy one thats ready to fit with instructions. HTH

 

They all seam to be about Ł50 on EBAY

 

theres loads of threads on here about how to rewire the pump
wont cost much,
relay, a fuse and a handful of cable.

 

If you can get over 12.5 volts at the pump then it is my opinion you wont improve its output by running thicker wire to a signicant degree.

Have you checked the fuel pressure is correct for the boost at high rpm ?

 

Take it to an expert and save money in the long run

 

I think i will be on the phone to MARTIN this week some time i just dont wont to send the car in with prolems that might cost me more than getting the car all mapped and set up as thats going to cost a nuth in its own

 

We keep the wire in stock Ian, its not a difficult job.

 

I had a prob where car leaned out and back fired like a cunt when warm. We removed the filter and tank as the LAST option. Tank was fucked. Poured out brown petrol. Changed it and all was well!

 

Iv tryed to send you a PM MARTIN but your PM box is full

 

Right im been working on the car again tonight . Iv put a brand new 3bar map on put a brand new rewire kit on the car . set the faze to .25 . Put the boost down to 15/16psi and its still poping and banging . iv only got one more thing i can swop out as ( Lambchop ) said do the filter which i will get a new one tomorrow the filter that is on the car has only done 4,000 miles but im will to try any thing as im pulling my hair out now as the car has had a fult like this from day one but it dose come and go but it has the fult 80% of the time .

we have changed

map sensor
tps sensor
fuel reg
chip
injectors
plugs set at .7mm and now at .6mm
ht leads
the car has wast spark now but the fult was there befor and its still here now
new crank pully
crank sensor set at .8mm
all wiring has been belled out and OK
new pump 044
new pump wire kit
phase has been tested OK and set at .25mm
fuel tank new when i built the car so 2 years old
fuel filter new when i built the car 4,000 miles

 

stupid question but when it backfires does it jolt the car really violently too?!

If yes have u checked the inlet for an air leak at all?! my last cossie had split on the inlet plenum gasket and that caused it to randomly jolt and backfire for no reason!!

Changed it and all was good....

 

YES the car had a 4x4 inlet on it and it had the problem and over xmass i put a swedish plenum on the car all new gasgets and still got the problem

 

Jesus man that's some list, no wonder your pulling your hair - hang in bud you'll find it

 

wot is the smallist size the supply fuil pipe can be as my car has 3/8 copper but brassed into the inside of the pipe i have moded air line fittings bore size at this time i dont no . but the car dose run ok some times

 

if i dont sort it soon it will be MARTIN,S problem but he has no hair to pull out so he will have to sort it

 

hi lads iv tuck the fuel filter of the car tonight i cut it open with a pipe cutter then put it in a glass jar with some clean fuel in it then gave it a shake and this was the result 4,000 miles thats all its done . im just trying to get a new one for the car then we can see if it will solve the problem or not

 

I asked if you checked this on Monday dude...lol damn im good

 

i do remember you saying it mate and i did say i had not but 4,000 miles you would not think it would be like this

 

Hopefully will be all good now mate, just get a genuine Ford filter and should be all good.

 

i do hope as its doing my head in now .....and were did this shit come from

 

i really hope this is the fault with your car fella. There is nothing worse than your car not working properly.

 

Not a clue mate, might be worth flushing the pipes through, getting the injectors cleaned and dropping the tank to make sure its all good in there also as what ever it is will be in the whole fuel system.

 

Iv had the injectors out and all the small filters in the end seam to be clean but we will see as when it gose to martin im going to get him to get them cleaned just to be on the safe side

 

is the car sorted yet? i have similar prob on my saff, might have to check my filter aswell

 

iv not got the new filter yet mate but i will put up wot ever it dose when the new one gose on

 

if the filters like that then the tank must be pumped as chopsky sais.....


new tank from dingbro is like 55quid, recently fitted a brand spanker to an XR4i


new filter is probably just going to clog up and do the same.

That could have been diagnosed in a RR session, Ł60 instead of buying that whole list of new parts! (if thats the prob)

Still, hopefully it'll be fixed this time mate

 

i will pull the tank down and have a look inside it to see if its ok thanks mate for the info

 

just a quick on iv got a check sheat that we have been using to try and find the fult with my 3dr cosworth and one thing that came to light tonight was this . PINS 24. AND 25. SHOULD HAVE 4.5 VOLTS . Well i have 1. volt on tick over and 3.5 volts at 5,000rpm dose any one no or think it could be my ECU at fult or are the readings ok . have a look on this sheat which was sent to me by RYAN Car Looms UK . LOOK at number ( 16 )

 

LOL, I wrote that


The voltage readings for item 16 can ONLY be measured with the engine stopped as mentioned in Item 9

Also, Item 16 it should read IGNITION and not INJECTION so thats a very old copy but I probably wrote it out quickly on an old thread.

 

with the engine stopped i have 0 volts