Looking for some advice my car normaly makes 1.3 bar spike , it was fine a couple of days ago when i put it in the garage since then i have fitted an AP intake and some suspension parts. I took the car out yesterday and now im only getting .5 bar max, i cant hear any boost leaks and apart from the low boost the car drives fine. So far i have checked all the hoses i can see and also checked the actuator rods, my first thought was MAF with the new filter but i dont have any lights up and the car idles fine.

 

year? miles? mods?

 

Probably a boost leak if no warning lights present. I would make a boost leak tester like colorinc did. Try a search for directions.

 

Its an 03 with 30K on it.
Mods are K24's,manifolds,miltek system,AP intake,Forge dv's,1.3 bar spike dropping to 1 bar.
My plan for tomorrow is to make a leak test kit and try that ,if no luck will try to get it plugged into a lap top with durametic to check the sensors.

 

who did your tune. if your tune is x50 or gt2, then 1.3 is a spike and not reality, and 1 bar is your real pressure. Also what fuel octane are you using?

could be DV's.

 

I run it on shell V power which is 99 octane over here in Scotland, the tune is by one of the British tuners.
I will do a leak test and go from there , just didnt know if these cars have a lower default boost limit if a sensor goes down.

 

Do you have a code reader (any OBD-2 diagnostic reader)? Good tool for about $100 from Autozone (or your local Scotland-zone parts store). First clear codes and she may run fine...If not then try disconnecting the MAF and see how she runs (there is a base maf map that should run 90%ish and runs fine). If that helps then you need a MAF. If none helps post again. Ity doesn't sound like anything but the airbox changed so a boost leak is less likely.

Good luck,
Sam

 

0.5 bar is the "limp mode" boost level. The ECU is confused. One easy thing to do is disconnect the negative battery terminal, leave it off for 15 minutes, then reconnect. This resets the ECU. You will probably get full boost the first time, but try it several times to see if it goes back into limp mode.

If it does go back into limp mode, you could try disconnecting the MAF, and see if it makes full boost without it. Some folks here say that means it's a bad MAF. In my case, when I had similar symptoms, this test came up with 1.0 bar, but I still had a boost leak. After fixing that, boost is fine, and I'm using the same MAF.

Pressure test is a good thing to do.

Jon

 

I have tried a reset with the battery and it made .8 bar once then dropped back to .5 bar. I dont have a code reader but going to get a shot of one tomorrow, will be doing a leak test today.
At idle if i dissconnect the maf there is no change to the idle or engine note.

 

You really need to get a code reader. It is/should be required for modded cars. Without it we just guess and spend your money. Get durametric...don't settle for the cheap "readily available" readers. BTW, MAF has little to do at idle.

 

I have aranged to get a shot of a mates Durametric later this week, so just going to do a leak test untill then. Will order my own durametric but i go back offshore with work at the end of the week so no point ordering it untill i get home again.

 

Neil what kinda work you do offshore?

 

Neil, drive it with the maf disconnected (after re-set), see how it feels.

 

OS Inspector im a senior mechanic in the North Sea sector.

Looks like the MAF sensor went down and put the car into limp mode. I got a shot of a code reader and pulled the codes P1250 and P0102, P1250 reset so unplugged the MAF and the car was making normal boost . I also did a leak test from the inlet and it is holding 1.5 bar, so new sensor tomorrow and hopefully it will be sorted.

 

P0102 is MAF. Looks like that was an easy one.

I don't see P1250 in the manual.

Jon