Discussion
Hi all,
As described in my other post I was having boost problems during the weekend and the last track day I had the car on, it seems to fluctuate from being under boosting to meeting the correct 1 bar boost, then on full throttle it over boosts to 1.3 bar.
When it goes over 1 bar it almost feels like its loosing power so I raced on 3/4 throttle.
Now I thought it was a vacuum leak or similar maybe from dump valve but the problem worsened over the weekend, the car was throwing big flames out from the front bank every gear change and boost was all over the place,
Now this evening I took it all apart and put it back together and it won't idle properly, it sounds like its firing twice as much as it should and plumes of black smoke are coming from the exhausts,
Is the ECU on its way out? I'm lost for ideas at the moment.
Graham
As described in my other post I was having boost problems during the weekend and the last track day I had the car on, it seems to fluctuate from being under boosting to meeting the correct 1 bar boost, then on full throttle it over boosts to 1.3 bar.
When it goes over 1 bar it almost feels like its loosing power so I raced on 3/4 throttle.
Now I thought it was a vacuum leak or similar maybe from dump valve but the problem worsened over the weekend, the car was throwing big flames out from the front bank every gear change and boost was all over the place,
Now this evening I took it all apart and put it back together and it won't idle properly, it sounds like its firing twice as much as it should and plumes of black smoke are coming from the exhausts,
Is the ECU on its way out? I'm lost for ideas at the moment.
Graham
Hollowpockets said:
Hi all,
As described in my other post I was having boost problems during the weekend and the last track day I had the car on, it seems to fluctuate from being under boosting to meeting the correct 1 bar boost, then on full throttle it over boosts to 1.3 bar.
When it goes over 1 bar it almost feels like its loosing power so I raced on 3/4 throttle.
Now I thought it was a vacuum leak or similar maybe from dump valve but the problem worsened over the weekend, the car was throwing big flames out from the front bank every gear change and boost was all over the place,
Now this evening I took it all apart and put it back together and it won't idle properly, it sounds like its firing twice as much as it should and plumes of black smoke are coming from the exhausts,
Is the ECU on its way out? I'm lost for ideas at the moment.
Graham
Is the rubber elbow for the vacuum line fitted onto the connection in the inlet manifold by the throttle body or if so pushed on too far ?As described in my other post I was having boost problems during the weekend and the last track day I had the car on, it seems to fluctuate from being under boosting to meeting the correct 1 bar boost, then on full throttle it over boosts to 1.3 bar.
When it goes over 1 bar it almost feels like its loosing power so I raced on 3/4 throttle.
Now I thought it was a vacuum leak or similar maybe from dump valve but the problem worsened over the weekend, the car was throwing big flames out from the front bank every gear change and boost was all over the place,
Now this evening I took it all apart and put it back together and it won't idle properly, it sounds like its firing twice as much as it should and plumes of black smoke are coming from the exhausts,
Is the ECU on its way out? I'm lost for ideas at the moment.
Graham
I've checked the vacuum connections a few times and all seem fine.
Spark plugs are only 6 months old, 5 of the 6 coils however are original factory fit I think.
I'll get the multimeter out in the morning and check the battery voltage as I just remembered the battery light flickering a bit during the race, god knows how i done those laps with all this crap failing around me.
Spark plugs are only 6 months old, 5 of the 6 coils however are original factory fit I think.
I'll get the multimeter out in the morning and check the battery voltage as I just remembered the battery light flickering a bit during the race, god knows how i done those laps with all this crap failing around me.
GTO600 said:
Is the rubber elbow for the vacuum line fitted onto the connection in the inlet manifold by the throttle body or if so pushed on too far ?
graham, have you checked the hose Kev is talking about here... he's NOT suggesting its loose but if pushed on too far causes similar issuesHi Graham , to reach 600+ brake it should boost at 1.3 bar , my guess is the front lambda has been damaged by the exhaust gasket failing the first time .
This has caused the front bank to ritchen up causing the flames and the front bank of plugs is sooted up causing the misfire on boost .
This also causes the idle problems .
Fit new lamda , resett adaptive maps , fit new set of plugs .
Also check front exhaust gasket to make sure still ok .
Tux
This has caused the front bank to ritchen up causing the flames and the front bank of plugs is sooted up causing the misfire on boost .
This also causes the idle problems .
Fit new lamda , resett adaptive maps , fit new set of plugs .
Also check front exhaust gasket to make sure still ok .
Tux
andygtt said:
graham, have you checked the hose Kev is talking about here... he's NOT suggesting its loose but if pushed on too far causes similar issues
Yep I'm aware of this, read it a thousand times on here so it's always one of the first things I check when boost related gremlins appear.TuxMan said:
Hi Graham , to reach 600+ brake it should boost at 1.3 bar , my guess is the front lambda has been damaged by the exhaust gasket failing the first time .
This has caused the front bank to ritchen up causing the flames and the front bank of plugs is sooted up causing the misfire on boost .
This also causes the idle problems .
Fit new lamda , resett adaptive maps , fit new set of plugs .
Also check front exhaust gasket to make sure still ok .
Tux
I'm not using 600bhp, this is all happening on normal wastegate pressure. If I press high boost it maintains about 2 bar, (I only tried that to see what happened boost wise and its as bad) I wasn't joking when I said I never use 600bhp setting. This has caused the front bank to ritchen up causing the flames and the front bank of plugs is sooted up causing the misfire on boost .
This also causes the idle problems .
Fit new lamda , resett adaptive maps , fit new set of plugs .
Also check front exhaust gasket to make sure still ok .
Tux
It could well be the lambda sensor BUT that wouldn't explain the excess unburnt fuel above 3k that the lambda works to.
The new gaskets and everything are all fine.
For starters I think a fresh set of plugs, coils and lambdas would be good maintenance and rule out a few possibilities. It just seems to me like something worse, both banks started chucking out un burnt fuel at idle last night.
Must admit I saw it boosting to well beyond 1 bar while at spa on track on passenger ride and you were running low boost so assumed it always did this on yours... Mine sits bang on 0.6bar and never goes above, do the other high power twins vary on low boost as much?
I have a spare mbe you could swop your map into (or use my old one as we have similar spec engines then) to test if its that but I can't do anything till weekend as I'm away.
I have a spare mbe you could swop your map into (or use my old one as we have similar spec engines then) to test if its that but I can't do anything till weekend as I'm away.
andygtt said:
Must admit I saw it boosting to well beyond 1 bar while at spa on track on passenger ride and you were running low boost so assumed it always did this on yours... Mine sits bang on 0.6bar and never goes above, do the other high power twins vary on low boost as much?
I have a spare mbe you could swop your map into (or use my old one as we have similar spec engines then) to test if its that but I can't do anything till weekend as I'm away.
I didn't realise that at the time, it should only spike at 1 bar and drop just below that. I think I may have two/three separate problems now though.I have a spare mbe you could swop your map into (or use my old one as we have similar spec engines then) to test if its that but I can't do anything till weekend as I'm away.
I've ordered a dump valve 'service kit' from forge with replacement piston, springs, O-rings and grease as the small spring in the dump valve is knackered which may be causing the underboost/overboost issue.
In terms of fuelling or ignition theres clearly something else wrong but fuel pressure is fine as I have the gauge fitted and there is a small oil field worth of fuel being dumped out the tail pipes, so I've ordered a full set of new spark plugs and coils for the sake of good maintenance.
I'll download the easymap software tonight from nobleparts and try seeing what the lambdas are doing but ultimately will turn them off for now.
I've asked Jetstream to build me one of the new MBE ecu's and load it with my map/settings and any wideband/knock/safety functions that are currently available to put the car into limp mode if the something isn't right, then we will put some switchable boost/maps onto it next time I'm down south.
If that lot doesn't fix it all then I'm goosed.
Gadge I've got the under drive pulley fitted, checked the battery voltage and its staying around 13-13.5v at idle and when revving to 2500rpm.
Graham
Hollowpockets said:
I've ordered a dump valve 'service kit' from forge with replacement piston, springs, O-rings and grease as the small spring in the dump valve is knackered which may be causing the underboost/overboost issue.
I've asked Jetstream to build me one of the new MBE ecu's and load it with my map/settings and any wideband/knock/safety functions that are currently available to put the car into limp mode if the something isn't right, then we will put some switchable boost/maps onto it next time I'm down south.
not a lover of dump valves... had to have one on mine as its a massive turbo and need it to stop the possibilty of the shaft snapping on lift but id never have one on your little turbos so have you considered removing it completely?I've asked Jetstream to build me one of the new MBE ecu's and load it with my map/settings and any wideband/knock/safety functions that are currently available to put the car into limp mode if the something isn't right, then we will put some switchable boost/maps onto it next time I'm down south.
the new ecu is a bloody good idea for your engine and application, got a timescale?
Hi Graham , the lamda probes only work up too 3k rpm and not over , you can switch these off if you want .
What fuel pressure have you set the system at ? Is it a rising rate regulator ? I e dies the pressure go up as you increase the boost ?
I take it your new regulator has a return to the tank ?
Mine will only boost at 0.7 bar on low boost , although will over boost on high .
Tux
What fuel pressure have you set the system at ? Is it a rising rate regulator ? I e dies the pressure go up as you increase the boost ?
I take it your new regulator has a return to the tank ?
Mine will only boost at 0.7 bar on low boost , although will over boost on high .
Tux
Hollowpockets said:
Yep rising rate fuel lab regulator, set to 3 bar static pressure with the vacuum line off, drops to just above 2.5 bar with it on at idle.
Do you really mean rising rate?Rising rate causes fuel pressure to rise faster than changes in manifold pressure.
I thought we needed linear rate regs - ie fuel pressure rises at the same rate as manifold pressure??
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