Rob Day

iTrader: (78)

Hello, as some of you are aware im having issues with the car following a recent power upgrade. The car was showing misfire codes during mapping, the mapper informed me that this is due to the added torque which seem about right. If memory serve me right no Misfire was noticed on the map .

Anyway I took the car to Scoobyteknix for a replacement "Neutral Postition Switch" which was done. The car then seemed ok although i did get a few P codes for misfires stright after so i returned. The car then settled down and no faults for 3 days.

I then went to RS Tuning for the Group buy Rolling road session where the car seemed relatively ok although after putting out a miserable 293bhp on the 1st run the car jumped into limp mode. The P codes returned for misfires again . The 2nd and 3rd run were useless as the car went into limp mode although i wasnt driving on the RR obviously. The car was drove off the RR and parked up for a few hours whilst i observed the other RR sessions. When i got in the car to go home although the engine check light was on it drove ok (certainly not in limp mode). The car hasnt been in limp during me driving to my knowledge.

The car currently keeps flashing up with misfire codes occasionaly although i have never felt its missed a heart beat.

Can anyone suggest what i should do next? I have posted on here for yet another replacement NPS although Scoobyteknix are adamanet that the one they put in is fine. Im lost what to do other then meeting up with Andrew Carr to take the car out with it plugged up to see what is going on.

Ive recently bought some ported headers that i intend on fitting soon, so once these are fitted i was going for a re-map. I didint want to see Andrew before fitting to resolve my issues and then fit the headers and then re-map again £££

Any thoughts would be great and I apologies in advance for the length of my Post, if you managed to read it without falling asleep.

Engine newly built 7 months ago.
New Walbro fitted 2 months ago
Refurb Pink Injectors 2 months ago
New Full 3" decat Exhaust 2 months ago
New STI Turbo up pipe 2 moths ago
New VF30 2 months ago
Green Cotton Filter 2 months ago
Mapped 2 Months ago
STI TMIC 2 Weeks ago

Ported headers not yet fitted.

Kind thanks
Rob

jd5217

Check the fuel pump, had this on mine a few years ago and turned out to be the fuel pump failing.

Rob Day

iTrader: (78)

Ah right i best divulged a little more ^^ edited my original post.

Cheers
Rob

jd5217

Still double check the fuel pump, could be the relay failing.

With mine it kept on flashing up missfires on both banks but reset itself very quickly, there was no logic to it.

Rob Day

iTrader: (78)

Hmm I will mention it to Andrew, I suppose he can watch the pump/injector performance via the laptop?. My Misfires are not patterned although it appears to be P0301 mainly, but it can be anything from one to all four cylinders!

jd5217

Yep, exactly what mine was doing.

Seemed almost random which cylinder was misfiring.

Rob Day

iTrader: (78)

Interesting .

How did you come accross narrowing it down to the pump, and how did you resolve it?

Thanks
Rob

jd5217

We stood listening to the car scrathing our heads and heard the fuel pump whining like mad, louder than normal. Changed it and all good.

Turbotits

iTrader: (2)

Ive also had a walbro fail. Car was no and again low on power and pump became noisy when had been running for a fair while leading to a drop in fuel pressure

Rob Day

iTrader: (78)

Thanks guys, but i find it hard to believe that the Walbro i bought off Mark at lateral 2 months ago is now faulty . Surely a pump that has only covered 1000miles isnt on its way out already?

Rob

Turbotits

iTrader: (2)

I agree. but it is worth checking the install> there only has to be a slight leak/pin hole in the small pipe that connects the pump to the outlet pipe in the tank and it will spill fuel back into the tank rather than building/keeping good pressure

To add to that dependand if that pipes been changed and whats been used, normal fuel pipe will rot in there fall apart and block the pump up

Rob Day

iTrader: (78)

Is it not easier/possible to get a fuel pressure device?

Turbotits

iTrader: (2)

there is one on there as standard but if the pump has failed or fuel is spilling back into the tank before it gets out it may never build enough pressure>


This ofcourse is all speculation you could have one of many problems relating to missfire problems> a good look via a laptop should be able to spot the problem< i know thats how my pump was diagnosed as failed

Very easy to check pull the pump out and have a look

harvey

iTrader: (48)

What boost are you running.
I suspect you are not running enough boost to blow the spark out but when I lifted boost on one particular car I had similar problems. (Classic) Changed from coils on plug to central coil pack and plug leads and problem was still there. At that point I reduced plug gap from .8mm to .65 on PFR7B and the problem went away.
Reducing the gap may help if you do not find the root of the problem.

Rob Day

iTrader: (78)

Thanks everyone, Im changing the Fuel Filter this evening to rule out dodgey fuel in the filter (water) or dodgey fuel filter itself. Then going from there really, visiting Scoobyteknix tmos, So i'll mention the Spark plug gap to them...

I noticed the car flashed the engine check at me when i was slowing down yesterday on my way home from work, and i hadnt actual hit any noticeable boost before this point. codes P0301 P0302 & P0303

Harvey im running 1.3 - 1.35 boost. The rest of the spec is on the original thread along with the STI pinks from you . The engne has covered around 4-5k now since July when it was built and fitted. New plugs went in too at this point, but which ones No idea.... What do you think?

Thanks Rob

Rob Day

iTrader: (78)

Fuel Filter changed, no difference car still the same. However ive narrowed it down to what its doing exactly.

The car in 1st, 2nd & 3rd is fine up to press, however at low revs in either 4th and 5th when the boost kicks in between 3'000 -4500max it starts flashing up misfire codes as though it is a boost issue.

harvey

iTrader: (48)

So it is happening at the point of heavy load on the cylinders.
1.35 bar is not enough to blow plugs out but reduce gap to .65 anyway and try it again and report back.

Rob Day

iTrader: (78)

Were getting somewhere

I checked the Plugs and they are PFR6B (0.8mm) so it looks like i'll be changing these anyway to PFR7B as you suggested Harvey.

Anyway the exciting part: Andrew Carr plugged up his laptop and we went for a run, however although for some reason the car behaved slighly different offering no misfire codes during the runs, it turns out the 'New' NPS isnt working correctly. The ECU reads the gears as being permanently in Neutral . So ive ordered a BRAND new one, might here today with a bit of luck.

Now the odd part. One of the codes displayed on the car yesterday was P1591. Scoobyteknix had this down as low input NPS for AT. Now i may not the most clued up guy, but im fairly sure that the pedal on the left is the clutch . lol

Anyway, I'll keep you informed.

Rob

harvey

iTrader: (48)

Yep. Only use your left foot for that one.
Some New Age cars have issues with the gear position sensor and you need to fit the correct thickness of washer to ensure the correct sensor spacing. I cannot remember if the thickness needs reduced which I suspect or increased but I can find out when I look at a gearbox in the garage.
PFR7Bs and reduced gap would be advisable anyway.

Rob Day

iTrader: (78)

Thanks Harvey. Switch (NPS) has arrived today. I'll get this on tommorow and see how we get on. Will also change the plugs early next week (one job at a time )

Rob

Rob Day

iTrader: (78)

Delayed Update: I fitted the NPS last Friday, took the battery connectors off for an hour thinking this would reset the ecu..... which it didnt

But anyway the light went of a few hours later . BONUS

Anyway ive monitored it for a while and all seem rosey. Time to fit the ported headers and remap

Rob

dunx

iTrader: (3)

Hurrah !

dunx

Rob Day

iTrader: (78)

lol

lets not forget why i was reluctant to change the NPS before opening this thread...... Ive already had two fitted prior!!! Im thinking Scoobyteknix owe me some money!!!

Going to give Andy at scoobyteknix a ring in the morning. Im not pleased with the service towards the end... all this faffing around with the NPS, turns out they fitted me a 2nd hand one from another cars tranny!!! Not amuzed especially after ive spent a few grand there last year. Anyway thats for me to take up with them. Thanks again Dunx

dunx

iTrader: (3)

I guess he thought he was helping you out....