[jimbojuicebox]

Hi guys

just recently fitted my JR MAP controller... everything seems to running fine... massive improvement in day-to-day usage...
however sometimes when accelerating hard if i let off the gas where normally the car would come off boost and deccellerate smoothly, its not smooth at all... hard to explain... when coming out of boost it sometimes chokes i guess... like its suddenly been restricted or something...
any ideas?
cheers

jimbo

 

[AcidLotus]

Are you still running the JR FMU? I would think that might have something to do with it if the fuel pressure is still high after you let off the gas. I never had that problem, but then again, the Cartech FMU also had a check valve for the purpose that vacuum is required to pull the preload spring under the center screw away from the valve so stock fuel pressures can be achieved under manifold vacuum conditions. This allows venting the boost signal to atmosphere in order to adjust the rate of gain, while maintaining a seal under vacuum conditions.

 

[jimbojuicebox]

ha ha cheers Acid... after reading that about 5-6 times i think i understand it! well a cartech (begi???) fmu is next on list! only other thing i could think of was the bypass valve? getting stuck or not working properly maybe? but that would be a massive coincidence that it happened straight after fitting the MAP controller... i am assuming if i had wired the MAP controller in wrong then the car would run a lot worse/not at all?? because other than this blip that sometimes happens it runs perfectly...

 

[Mac8008]

probably has to do with the signal interference between the map and ecu caused by the JR map controller.

back in the day when my friend had the afc hack, if was real ruff on decel especially when you got back on the gas with narrow throttle angles.

 

[AcidLotus]

Cartech is also called Begi, yep. I don't it's the bypass valve, but if you have longer vacuum hoses than you need, you could shorten them a bit.

 

[jimbojuicebox]

yeah there's a lot of vacuum hosing going on now! lol
is it worth getting a vacuum manifold? or does this just tidy things up a little...

 

[AcidLotus]

yeah there's a lot of vacuum hosing going on now! lol
is it worth getting a vacuum manifold? or does this just tidy things up a little...

I don't think a vacuum manifold is necessary, as some items should only see Vacuum, and others should see both Vacuum and boost.

 

[jimbojuicebox]

not sure what they are called... but some boost gauges come with a restrictor you put in the vacuum hose to smooth the reading and stop it bouncing all over the place... would this work at all? smooth out the boost being read by the map sensor?

 

[AcidLotus]

not sure what they are called... but some boost gauges come with a restrictor you put in the vacuum hose to smooth the reading and stop it bouncing all over the place... would this work at all? smooth out the boost being read by the map sensor?

I've not seen or heard about anything like that. It doesn't sound like it's a problem with the boost that it's seeing, but rather a fuel pressure issue when going from boost to vacuum.

 

[jimbojuicebox]

but it only started when i installed the map controller... going from boost to vacuum was smooth before... the only fueling component that has changed is the map controller...

 

[AcidLotus]

Check your Vac lines and make sure that there are no leaks anywhere. Also, in step 3 of the instructions, did you lower your tip-in fuel pressure? Add timing?

 

[jimbojuicebox]

no vac leaks... base timing is still stock other than the boost timing controller which is currently set a few clicks off minimum. only thing i havent cheked is the fuel presure... i dint raise the fuel pressure when i first installed the supercharger so it will still be stock. i gather i want it set between 45-50psi - is this likely to be stock pressure? i will put a fuel pressure gauge on at somepoint to check...

 

[AcidLotus]

Stock fuel pressure should be around 42 PSI. tip-in fuel pressure should be around 45-50 PSI, according to the map controller instructions.

 

[jimbojuicebox]

yeah i think something else is up... can timagine 3-8 psi fuel pressure gonna be causing so man problems... took it for a long drive today on a motorway... not very good... seems really inconsistent going into and out of boost... i get massive flat spots going into boost sometimes... where normally i'd get a kick from the supercharger i'm getting a massive dead spot that requires i let off the throttle then it corrects itself... seems lacking in power too...

if i drive sensibly and dont push it then you wouldnt know anything was wrong... its only when i put my foot down everything seems a little messed up :-(

 

[AcidLotus]

It's running too rich. Do you have an A/F gauge, preferably a wideband one to tell you what's going on when you get on it? You'll need to shed some fuel pressure to get it running better.

 

[jimbojuicebox]

i have my eye on a ne begi regulator at the moment and the guy is willing to ship to the uk... would the map controller make it run richer than the "fuel enrichment relay"?because even though it was rich with the relay it didnt have these problems...

 

[AcidLotus]

Yes, it should run richer, hence why they suggest lowering your FP and raising your timing.

 

[jimbojuicebox]

ah.. makes sense... as my base timing is stock still is it wise to increase the timing?

 

[AcidLotus]

ah.. makes sense... as my base timing is stock still is it wise to increase the timing?

As long as you're not detonating during summer time temperatures after a couple of back to back runs, it should be fine to increase it little by little. Pull it 2 degrees at the first sign of detonation.