hi folks. last weekend i did the fuel pump wiring mod and fitted a second hand GTEC1 HF chip.
Today i fitted my AEM Uego wideband and i have these stats although might seem vague

tick over - between 14.3 & 15.2
accelerating steady - same as above
accelerating hard on max boost(16PSI) @ 2750RPM & above, 11.2 - 11.9.

Cant beleive how smooth, driveable and damn quick the chip has made the car compared to stock, i love the spool-up, full boost comes in exactly how i always wanted it to, (like my old R5 turbo).

even if the fuelling is good at said boost level, is there anything else i need to check or look out for? cheers guys

Perfect!

hi folks, just noticed my manifold has a small crack appearing near the turbo flange, and also along the edge of a previous welding job on the longest runner (maybe an inch long). would these 2 little leaks be enough to give inaccurate AFR readings and also mess up my fuel mixture a bit.

cheers

Yes as the afr gets its reading from the lambda sensor which is in the manifold (For the 20v engines I don't know where it is on the 16v engines, but the effect is the same).

yes on both questions .
It`s not also that gases run out of from the engine ,but also oxygen goes in...so the AFR will be very inacurate, same as the narrowband lambda wich reads a little lean all the time.
@szkom ... the afr uses a wideband sensor ,so probably a different sensor from the car,or ?

Depends on the kit fitted. Even if it does use a separate sensor it's still a lambda sensor and still fitted in the exhaust around or in the manifold.

Can you hear it blowing? Small cracks will seal once the car is up to temperature as the metal expands.

Realistically you need a big gap to give poor readings at low exhaust speeds, once the rpms pick up the effect is negligible. Reset your ecu (disconnect power for 10 mins) and go out for a couple of full throttle runs. If the fueling is still lean when you are on boost then you need to do something about this.

is it 16vt or 20v turbo?

johboy- 20vt. ideally i would love and should get a proper flea remap, im heading down near loughborough from scotland to get my belts done but think it would end up costing me a small fortune on petrol to then head over to bristol before home lmao.

hi folks. when i first fitted my gtec1 HF and pump wiring mod, i was getting afr's of 11.4 @ WOT.

For some reason now, my wideband never drops below 12-13 afr @ WOT. Is the stock ecu fighting against my gtec somehow? (im rather ignorant with the workings of the stock ecu).

I disconnected the battery for 1hr last friday and it made no difference, still terrible AFR.

im pretty gutted as the fuel figures were spot on as per the AEM Wideband anyways.

Would a 4 bar FPR make any difference as i found one in my garage that came out of a calibra V6.

cheers for any info

At part-throttle your ecu works in 'closed-loop mode'; the ecu uses the lambda sensor to constantly adjust the efr to 14.7. At WOT, however, the ecu operates in open-loop mode; it ignores the lambda signal and just follows the fuel map that's on the chip.

If you haven't made any changes and you've found that the afr has suddenly risen then unfortunately there must be a problem somewhere. Maybe that crack in the manifold you mentioned before has worsened?

thanks for that, exactly the kind of info i was looking for good techy information like that is a good help in sourcing problems, i might be able to get on top of it now.
i also noticed on the motorway yesterday on the way to johnnybravo's at lets say 70mph, im cruising along steady, afr is good, then "only sometimes" if i gave the car 3/4 or WOT, the afr went crazy and went super lean (off the scale into the red) as though my pump lost all power or pressure, i backed off instantly, tried again and all was fine. im starting to think its the pump wiring, pump its self or fuel pressure related ie regulator??

to add, the super lean, random phenomenon has only seemed to show itself in 5th gear and over about 60MPH, all other gears below this speed seem to give better figures although still terribly high at 12.5 - 13.3 WOT

I think im gonna have a busy weekend now lol

I've forgotten (and can't be bothered to read back) but do you have the Walbro fuel pump and have you also done the fuel pump wiring mod (look in the How-To section!)?

standard pump mate but with the pump wiring mod and yellow connector fix.

Fairy nuff then, it was just a thought.

Unfortunately I think the only way to start working out the problem will be to buy or go to a garage or rolling road who can test the fuel pressure under load. You might find that the fuel pup is on it's way out.

Actually, considering what it will cost to get this checked out. you could rule out a weak pump by buying a replacement. I bought this one a few weeks ago and so far its proven to flow mucho gasolino even at high pressure.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=220537044828

Incidentally, I now have a standard pump going cheap...

Might be coincidence but my hf Gtec1 ran well fuelling wise when the ecu was reset but leaned out on boost after a few miles of driving. Try disconnecting your battery for 15mins then go for a run and see what you get.

Sorry ignore me, just saw that you already tried disconnecting the battery!

i disconnected the battery again for an hour, warmed the engine up and went for a 40 mile drive. when i was nearly back home, i stopped the car and did 3 power runs through the gears.

1st, 2nd and 3rd gear had ok afr readings (roughly 11.3-12.3), 4th gear was starting to lean off a little (not really dropping below 12.2), and 5th gear was between 12.4-13.4.

i have no idea why it only seems to be 4th and 5th gear really. same boost level, and taking the engine to the same revs @ WOT.

also, the turbo is boosting to 20psi and sitting at a steady 17 after the spike, is it safe for a standard turbo to run these levels or am i waiting for my turbo to go pop.

thanks

A couple of ideas I hope may help.
1 :Charge cooling gets more efficient with car speed as more air gets to the intercooler. Cool charge = cool dense air = leaner mix if your ECU doesnt know what to do with it.Check the inlet air temp sensor is reading the correct values. As the brain uses this with the airflow meter to gauge Air weight ie 14.7Kg of air to 1 kg fuel = lamda 1
2: Low engine acceleration in high gears would remove the acceleration enricment . Acceleration enrichment often is removed at high rpm too.

3: It may be that the problem resides at low speeds and hot inlet temps causing it to be rich.
Max power should be between 11.7 to 12.45 . Sustained levels of over rich running at high rpm and load could burn out the cat igniting it on overun. It may be that the tuner had this in mind and backed it off.
hope this helps a little.
If inlet temp sensor is ok I would get a reputable tuner to check inlet and exhuast temps are ok.