Hesitant on WOT

[andyg plym]

Hello all, almost got the colgate wagon working perfectly as before, some of you know I have recently had some misfire issues but have upgraded to 1.8t coils.

Oddly it seems to be hesitant in the lower gears 1-3 when revving high, if I use 4-6 from low revs and hit the loud peddle it pulls like a train cleanly all the way to the red line.

So 1-3 over 4k and it feels like its bogging down but if I hold the power long enough I can still drive through it all the way to 1.7 bar.

Normal driving is spot on and so is idle when warm, when cold first thing it splutters slightly but after a blip of throttle it sorts itself out.

Spec is:

RS2 Turbo
RS2 exh manifold
RS2 injectors
RS2 airbox
RS2 intercooler
044 fuel pump
T+S tuning chips
R201 resistor mod
1.8t coil pack conversion
new lambda
Silicone hoses and vacuum pipes

No fault codes or boost leaks, any ideas gents?

[Rusty]

Still sounds similar to my lambda issue. Have you tried unplugging the lambda and giving it a try?

[andyg plym]

Not the new one no

[Rusty]

Try it...

[mike74]

I had similar symptoms to that with my old car, turned out to be clogged injectors got them cleaned and rebuilt and it was like driving a new car again. Might also be a slightly sticky FPR not acting quickly enough or even the fuel pump!

[andyg plym]

Injectors were brand new fitted 2 years ago,I did try unplugging the lambda last week when they old one was fitted and it idled very badly.

Fpr is summat I have wondered about....

[Rusty]

Mine was perfic with the lambada unplugged, so must be something else.

What about the dump valve? What are you running?

[andyg plym]

Forge 007 mate checked it a few weeks ago when swapping springs

[mike74]

Fuel filter?

[andyg plym]

Have to be honest and say although it's got less than 90k I've never changed it, been putting it off as I know how much of a pig is it to do!

It is on the to do list but as 4-6 are no problems you would of thought you'd be sucking more fuel with the extra load

[mike74]

When I finally got round to putting my old car on the rollers to find out what was wrong with it, they found it ran horrendously lean 2.5-3k rpm (where it always seemed to choke badly at) and then richened up slightly so it was only running very lean up to redline. Was down a fair bit on power too. I also had a 044 in the boot same as you've got. Might be worthwhile pulling the injectors & checking spray pattern & for all the price, change the FPR too. IF that doesn't sort it, fuel filter next (sorry!)

[andyg plym]

Hmmm I've been thinking a lot about the fpr

[Rusty]

You got a spare 4.0 Bar one? Make sure that the pressure feed is connected and not blocked.

[andyg plym]

No spare so the hunt is on

[UrS4boy]

One missing and hesitation diagnostic

... some of you know I have recently had some misfire issues but have upgraded to 1.8t coils.

a) the 1.8t conversion (I did the first one ever in 2005) was never intended to be an upgrade, just an alternative to the OE coil on plug and separate POS system.

b) the 1.8t coilpacks, especially the early ones, do die, primarily due to heat. As they die, they might be fine puttering around town with low or no boost but once you go WOT and get some boost going, the little coil packs might not be able to produce the required spark to fire off the denser mixture. Hence, missing and hesitation.

The later red coil packs and the latest 2.0L TFSI coil packs seem to be lasting better.

You could try spark testing the coil packs (after pulling the injector electrical connectors), as suggested in this Missing and Hesitation post:

http://forums.quattroworld.com/s4s6/msgs/22611.phtml