Mkiv starting , lag issue

Hi ,

I have a 96 tt manual 6 sp and have an issue that I can't resolve.

To the beginnig, I had problems with starting the car so it turned out to be a problem with fuel pump power, shorting the fp and b+ terminals at the diagnostic port solved this issue, I read that this doesn't have any real long term side effects( outside taking a couple of years off pumps life but would last years, is this correct??)

that about 100 miles ago but lately something more else emerged, from cold start it takes a bit of turning over to start and spits out plume of blue smoke but it dissipates within a 30 seconds. Smoke normal after that even under High boost, from what I can tell.

the main issue now is a stuttering/power loss if I hit throttle hard, now if I slowly go up the throttle then it has no problem,and will eventually get to full power, turbo pressuse gauge gets to 0.9 and can hold it ( making sense? :-) )

Any ideas??

I appreciate time you took to read this and look forward to any ideas. (ps still have Fuel pump powered directly to 12v through diagnostic port)

Are you getting any error codes?

Hi Tom

Thanks for quick reply, not done an error check before on ECU , I will look it up how to do it and repost

rgds

Is this a manual or auto?

Okay error 78

Ideas??

6sp manual

this error 78 probably has to do with the issue I have with fuel pump, related?

Thx again for any help

Bump

When was the last time you checked/changed the plugs

Blue smoke after starting is most likely due to leaking valve seals.

Fuel pump not coming on is most likely a faulty relay. Does the MKIV start the fuel pump for a few seconds when putting the key to 'ignition' ? If so, that would explain the extra hesitation before start. Check fuel pump relay and replace it when faulty.

Stuttering mostly means an error in your ignition department. Check plugs, plug gaps and check your ignition coils for cracks.

Thx for input,

iridium ik22 plugs fitted 5000km ago but will check them and coils tomorrow, will it be obvious if a plug is bad??

Walbro 341 fuel pump was fitted by previous owner, now the power to pump failed somehow and I put a connection from FP to B+ and now it has constant 12v supply. Is this ok to do??

Agree on valve seals but that's a minor issue for the immediate future, correct??

My first tt and bit new so sorry with all the questions, mines a japaneese tt, it has a greddy bcc and decat with restrictor but no boost controller , is this also ok??

Thx for the help

Much appreciated

 

Walbro 341 fuel pump was fitted by previous owner, now the power to pump failed somehow and I put a connection from FP to B+ and now it has constant 12v supply. Is this ok to do??

It's ok just for test, not for every day driving. Sort it out.

Walbro 341 fuel pump was fitted by previous owner, now the power to pump failed somehow and I put a connection from FP to B+ and now it has constant 12v supply. Is this ok to do??

Don't do it long term, as the wiring is not of the correct rating for this. The FP on the diag port is meant for checking the voltage not supplying. I have had to fix this on a car before where this had taken place

Agree on valve seals but that's a minor issue for the immediate future, correct??

Depends on how much it smokes, but VSVs can be left for a little bit.

My first tt and bit new so sorry with all the questions, mines a japaneese tt, it has a greddy bcc and decat with restrictor but no boost controller , is this also ok??

 

Thx for the help

Much appreciated

Don't need a boost controller unless you want to raise boost, so the restrictor should be fine, do you have a boost gauge?

Hey thx agin for advice ,

today I checked the wiring situation in relation to fuel pump, found a relay perished, changed it and fuel pump working without fp so that problems sorted, however this relay was a mod fitted near the fp ecu on back rear panel, any ideas what this is for?? I know a walbro fuel pump kit was added, is this part of that setup ?

I have a boost gauge, currently hitting about 0.9 at bar, still stuttering after 4000rpm so will investigate plugs and coils tomorrow if possible, will there be tell tale signs if there is a problem??

Rgds

john

id say it was to run the pump permantely 18v

id say it was to run the pump permantely 18v

You mean 12v

The relay probably just joins up the power wires and effectively bypasses the FP-ECU. It does mean the fuel pump is always 12v, and because a relay is used it is the safer option since the ECU can still shutdown the FP.

not sure the volt maybe its 9volt and 12v. that mod didn agree with my uk supra

It would be easy to remove it, should I ? Just unsure if it was needed as part of walbro 341 Pump kit. Any way it helps with that install? Cos it's a complicated way of doing 12v fuel pump mod , isn't it?

It also has a shift changer, what rpm should this be set at in tt?

Obi, i just had the same prob with my supe stuttering after 4000rpm. User on here (Hodge) took a look for me and it turned out it was me spark plugs.

Sounds similar to what you are experiencing mate so would start by replacing them bud

Irridiums in since only 5000miles ago bit defo check them, will it be obvious if one of them is bad?

plugs dont last long on supra 10k max ik22 ik24s

should prob notice, i would replace em either way mate.

lots of people have problems with irridium spark plugs on boost. I replaced them with copper plugs and was good to go!