New MAF but now negative boost errors.

[Simon L]

looks like you can't meet requested boost.... got a leak? or a knackered DV?

I am in a similar situation.

Replaced all vac lines with forge hoses, and got a forge 007p.

Tried using the standard DV also, no change.

The N75 duty isnt maxed out though (ie: 95%), so i wouldnt think i have a boost leak.

What else could cause the actual to deviate from the requested?

 

[Russ_20vt]

simon how do you tell the N75 duty?

 

[Simon L]

Its either 115 or 118, and its titled "Load".

 

[Russ_20vt]

This is from 115 but how do i work out the percentage?sorry im being blonde.

 

[Simon L]

Nah, its block 118 then.

115 is actual load, not N75 duty.

 

[Russ_20vt]

Right cheers mate, going to do a log now and try the standard DV.

Thanks

 

[Russ_20vt]

Right big update, did some logging off my N75 Load and Actual vs Requested Boost

I also tested between my Forge Dv and Standard Bosch DV

I did 2 runs with my Bosch followed By 2 runs with my Forge

All runs were done with even breaks between runs and all runs were tested on the same strech of private test track.

I am posting the the best results from each DV

First of all here is my Excel Sheet of a 4th Gear run with the standard Bosch DV

And here is a Graph showing the Requested Boost vs Actual

Now this is where the fun starts,

During my 2 runs with the Forge DV i went into Limp Mode both times in 4th Gear at around 5360 rpm. But i have been around this rpm figure before and not gone into limp mode with the forge on. Further testing with the Bosch is needed to prove that the forge is at fault.

Here is the Excel sheet of a 4th Gear run with the Forge DV you can see clearly where i hit Limp ****.

And here is a Graph showing the Requested Boost vs Actual

I received these Fault codes after going into Limp Mode

18048 - Internal Contr. Module (EEPROM) Error
P1640 - 35-10 - - - Intermittent
17964 - Charge Pressure Control: Negative Deviation
P1556 - 35-00 - -


I dont have enough knowledge to be able to determine why im low on boost and going into limp mode. Help Please Guys!!!

Thanks Alot

Russ

 

[davidol]

have you done a leak test on the forge valve?

 

[Russ_20vt]

Yes and its fine,

 

[Russ_20vt]

Just been reading up on the n75% and am i right in saying that its buggered as it shouldnt be up in the 90% constantly? or is this due to a boost leak?

 

[Simon L]

As your N75 value is 95% at the top end of the range, this means that the turbo is working as hard as it can, but it still cant make the requested boost.

Similar to my problem.

Could be a leak, or the remap is asking for more than the turbo can give.

 

[Martyn]

I personally think you've got a boost leak mate. The actual fails to meet the requested throughout the rev range....your requested isnt even that high!

On a side thought...what colour spring do you have in your forge DV?

 

[Simon L]

Russ, can you do a log in 3rd or 4th gear from 2k -> 6k. most of your logs only seem to give us a small section of the rev range.

 

[Simon L]

I cant see how the spring would make a diff in the DV.

Under boost, the DV will be pressurised, so closed. Only under vacuum will it open.

So why does the stiffness of the spring make a diff? The standard spring keeps the DV closed by itself, so boost cannot escape under load.

 

[Martyn]

Because there is a chance the DV could be forced open by boost. It's not uncommon for it to happen...hence why the spring kits are available.

 

[DPJ]

Spring works against boost to keep the DV closed. The vacuum assists boost in opening the DV against the spring.

 

[Simon L]

Test for that then would be to 'jam' the DV so it cannot open, and do a couple of runs.

I know this is bad, as it cannot vent, but it would show either way if the DV is leaking.

 

[Martyn]

I'd advise againsts doing that, it's much easier and safer to get a stiffer spring from forge for nowt!

 

[DPJ]

I'd advise againsts doing that, it's much easier and safer to get a stiffer spring from forge for nowt!

I'm sure I paid about £12 for a spring kit from Forge.................

 

[Martyn]

Dave, a polite e-mail asking for a stiffer spring has works for me and quite a few others....difference is that you got a kit rather than a replacement