Boost spike in 1st gear to 1bar?

[Kash_]

Hi guys,

Just a quick question, I was in first gear today and half throttled it from a standstill whilst turning left. My boost setting is set to 0.8 bar, but when I accelerated the car suddenly lost power, then the power came back. It did this for a very short time probably half a second. When the power came back I heard a pop like a backfire. I only took the car up to 6k, knock level was fine, inj duty was 50% but the boost said 1.16 bar. What does this mean, surely there couldnt be enough load in first to boost that high? I\'m running a mapped Power FC (upto 1bar), BNR 33 fuel pump and uprated FPR. Could it be the map sensor as on Japshow when I started the car the boost reading was 1.16 on two occasions, but fine all other times? :2Confused

[Jono FD3]

The sudden lose of power sound like fuel cut to me!! as for the boost spikes, what turbos you running??? stock twins, uprated single....... exturnal wastegate?

Jono

[royston1xx]

Check all the vacuum lines from your turbo/manifold/boost controller/wastegate etc for splits or small holes as this would cause overboost.:Thumbs-up

[Kash_]

The sudden lose of power sound like fuel cut to me!! as for the boost spikes, what turbos you running??? stock twins, uprated single....... exturnal wastegate?

Jono

Does the power FC have a fuel cut feature built in? its a to4e single turbo, external wastegate, ported engine

[Kash_]

Check all the vacuum lines from your turbo/manifold/boost controller/wastegate etc for splits or small holes as this would cause overboost.

I will have a check, the odd thing is that 99% of the time I never get boost spikes and the boost always holds at 0.8bar. If there was a vacuum leak wouldnt it boost spike all the time?

[m4drx]

not necessarily bro, many variants.

such as heat; if the pipes are very hot a tiny crack may begin open up.

also i had some ebay pipe on mine, 4mm internal diameter but a massive 7mm wall thinkness but even given this some of it by the hot side of turbos begun to shrink but i the inside was shrinking so from outside looked fine until the inside closed up completely!

[Kash_]

Just took the rex out for a spin and boost is holding 0.8 bar through all gears continuously. Also checked the boost and vacuum pipes, couldn\'t find any cuts or cracks? Now I\'m even more baffled :2Confused

[antnicuk]

when i had some wiring issues my commander showed 1.13 boost all the time, even with the engine not running,  its somekind of default.  It maybe a dodge connection on your map sensor,   just try unplugging the map sensor, switch the ignition on and see what reading you get, if its 1.16, then you may have a faulty map sensor

[Jono FD3]

Yep, power FC does have a fuel cut setting as I leart over the weekend when mine was being mapped!!! on the FC you can actualy move the fuel cut point aswell to compensate for big boost aplications!!!

Jono

[Kash_]

Just an update I\'m 100% its my map sensor going fubar as yesterday I couldnt get the Rex started, it kept cutting out and the boost on the Apexi Commander kept showing 1.16 bar all the time... I gave up trying to start it and looked at the boost reading and it was flickering between 1.13 and 1.16 bar even before I started the car. Eventually it started up and drove okay, then at a set of lights it nearly cut out again and the boost read 0.84 on idle, a huge puff of blue smoke came out as it nearly cut out. After that it drove okay the rest of the time :confused:

[antnicuk]

am i the winner  

oh, btw, the blue smoke is just the ecu giving you enough fuel for 1.13 bar of boost at idle  

I wouldnt drive it hard until you get it sorted just in case it goes faulty under boost and you under fuel

[Kash_]

am i the winner  

oh, btw, the blue smoke is just the ecu giving you enough fuel for 1.13 bar of boost at idle  

I wouldnt drive it hard until you get it sorted just in case it goes faulty under boost and you under fuel

yup looks like you are the winner :cool

[nikp]

There\'s a group buy on GM 3 bar MAP sensors going on in the members section that we need people to join!

[Kash_]

There\'s a group buy on GM 3 bar MAP sensors going on in the members section that we need people to join!

might have to look into this, although I can\'t see myself running over 1.1 bar so maybe a bit of an overkill? :2Confused


does anyone know how to check if the map sensor is getting the correct voltage on the Apexi Commander? Also what voltage should the map sensor be getting/giving?