BAM Boost Issues (low revs)

[fred80]

Hi,

I have a 2003 BAM engine with a Custom Code remap.

The car has been fine for over a year but has just developed a strange issue where the majority of the time at low revs it doesn’t seem to boost properly.

Usually when you hit about 3000 there would be a huge surge of power. Now nothing might happen until 4000.

If I go in a higher gear (say 4th) its not as bad, its like the car has more time to build its boost up so in terms of revs it is actually more like 3000.

Over about 4000 it seems fine so is some how related to lower revs.

I have done the following:

1. replaced the N75
2. Checked 032 (after a reset) at tickover and for 5 minutes it showed 0% which I’m led to believe means no boost leaks.
3. Checked the MAF reading at 3000 stationary and this was 9.9, which from what I have read also means to boost leaks.
4. Checked CFs in case it some bizarre timing/fuel issues and only now and then see the odd peak of 4.
5. Checked the MAF reading from 1000 to 7000 and it looks perfect, peaking about 207.

The car also has a Forge DV and a full set of the Forge small boost pipes so all of the main ones that go are covered.

The only log I have at the moment of 115 is unfortunately 2nd gear and shows its not that bad, not as bad as it feels in the car..

3.96	1040	70.7	1350	1020
4.58	1200	73.7	1400	1050
5.1	1360	73.7	1500	1080
5.71	1560	77.4	1580	1120
6.32	1760	81.2	1700	1180
6.91	2000	89.5	1980	1240
7.52	2320	103	2520	1340
8.03	2560	119.5	2540	1490
8.53	2920	143.6	2550	1790
9.03	3320	191.7	2520	2340
9.63	3960	191.7	2470	2540
10.32	4680	191.7	2430	2410
10.86	5280	182.7	2340	2250
11.44	5800	178.2	2250	2160
12.05	6280	170.7	2090	2040
12.58	6400	84.2	1000	1970

Can anybody help me or point me in another direction? I’m totally out of ideas.

Thanks in advance.

 

[8bit]

Check your Forge DV isn't getting stuck in the open position. This would still show good airflow as the turbo is still sucking in air, but it's then escaping back into the intake as the valve is open.

Take the valve off the car, hold it in your hand and push the piston in from the bottom with a pen or similar. Holding the piston in, place your finger over the vacuum nipple on the top and release the pen. The valve should stay open (look in the side port). Release your finger off the vac nipple, the piston should slam shut. Repeat about 15 - 20 times minimum.

If it sticks open, or is unnecessarily hard to open in the first place then contact Forge for a servicing kit.

 

[fred80]

Thanks, I will have a look after work.

Much appretiated.

 

[fred80]

I just managed to get out of work to try this.

The vlave is like new, no issues at all - I even opened it up.

My friend had a BOSCH one from his SAAB as well and we tried that. I know its far from ideal but did result in the same issues so I think the DV can be rules out.

Is there a way to testing fueling?

Could it be that?

 

[hara]

I had split a tiny vacuum pipe (somewhere under the inlet manifold) and had similar symptoms. Easy to replace (once you find it).

 

[SEATgod]

Are you on VAGCom as RMVB 32 is fuel trim based on lambda values!

You need to look at RMVB 11 (boost specified against actual).

Drive the car in third gear, wide open throttle and take a snapshot at 3,000rpm.

What have you got?

If you had a boost leak, you would hear a hissing noise.

But, a fuelling issues, incorrect air mass, mechanical fault, fuel issue will all back the boost off.

Any fault codes?

Where do you live?

I can help if your nearby??!!

 

[Bondiblu]

Split vacuum pipe or vanes/wastegate sticking open is what that looks like to me.

 

[8bit]

OK yeah, unlikely to be the valve then, and the car seems to be drawing plenty of air by the right time. I'd say fuelling unlikely as you'd probably see the EML and the car wouldn't make boost at all, never mind only at higher RPM.

Log block 115, that'll show requested boost vs. boost measured at the MAP sensor, just before it enters the engine. That should show up a boost leak, unless it's in the hose that feeds into the throttle body. Have a good look at all the stuff under the intake manifold too, if there's any sign of grimy, oily crap in there then you're likely to have a split vacuum or breather pipe, like Hara suggests.

 

[fred80]

Thanks for all the help everybody.

Tomorrow I will go do some logging in a higher gear and report back.

I'm in Leeds SEATgod. If your anywhere near that I could drive to there are some serious beer tokens for any help

No hissing noises and no fault codes unfortunately.

 

[SEATgod]

I know some good guys in my line of work up there if you wanted some help.....

Let me know the figures when you get them!!

 

[fred80]

I managed to do some logs....

It didnt feel as bad today to be fair. The 3rd gear (up hill) runs seemed normal. Thats the the following logs were from.

In 1st and 2nd though, foot down from say 1000 it still seemed to take ages for the big surge of power. In 2nd it was coming in around 4000, which I'm sure before used to be 3000.

Problem now is I'm starting to doubt myself. Doubt if anything is even wrong. Its not my car you see, its the girlfriends and I hadnt driven it in a few weeks. Drove it and something immediately didn't feel right, so I'm sure I havent just imagined it.

Foot down from 1000 RPM on a mapped BAM does give a big sure once its hits 3000 doesnt it????????

Anyway here are the logs.

32 just stayed around -0.4% and for the second numbers between -0.8% and -1.6%.

Group A:	'115			
	Engine Speed	Load	Cmd Pressure	Press @ Intercool
TIME				
STAMP	 /min	%	 mbar	 mbar
0	1400	47.4	1000	1020
0.58	1440	75.2	1510	1050
1.19	1560	78.9	1570	1110
1.8	1680	84.2	1610	1180
2.3	1800	87.2	1710	1230
2.82	1920	94.7	1890	1290
3.4	2160	107.5	2330	1380
4.1	2360	127.1	2500	1570
4.62	2640	149.6	2550	1830
5.22	2960	191.7	2490	2320
5.83	3360	191.7	2480	2540
6.43	3800	191.7	2460	2540
7.03	4200	191.7	2430	2520
7.53	4520	191.7	2410	2420
8.14	4920	191	2320	2360
8.64	5200	186.5	2290	2250
9.24	5520	183.5	2240	2230
9.93	5800	178.2	2100	2140
10.47	6080	170.7	1970	2120
11.07	6280	149.6	1860	2100
11.67	6480	135.3	1830	1950
12.27	6640	131.6	1810	1840
12.79	6720	129.3	1800	1850

Group A:	'011			
	Engine RPM	Coolant Temp	Intake Temp	Ign. Timing
TIME				
STAMP	 /min	°C	°C	 °BTDC
1.61	1600	90	37	12.8
2.21	1760	90	36	9.8
2.72	1920	90	35	12.8
3.33	2080	90	34	10.5
3.94	2320	90	33	7.5
4.58	2600	90	33	7.5
5.2	2880	90	33	0
5.74	3240	90	33	0.8
6.34	3640	90	33	6
6.84	4000	90	33	8.3
7.45	4400	90	33	12
7.95	4720	90	34	12
8.46	5000	90	34	18.8
9.07	5320	90	36	12
9.67	5640	90	37	15
10.26	5920	90	39	15.8
10.96	6120	90	39	15.8
11.52	6320	90	41	18.8
12.09	6480	90	42	19.5
12.7	6640	90	44	21.8
13.29	6600	90	44	5.3

They mean nothign to me, but is the timing figure meant to be all over the place like that?

Again... Thanks so much for any help!


EDIT...

I checked all the pipes, even the little ones but could see no issues.

 

[8bit]

Airflow and boost both look fine. You should be feeling the turbo kick in from around 2500 rpm really, nothing in the above to suggest it's not working right. Not sure how to read the timing figures.

Tried cleaning and resetting the throttle body? Give that a shot if you haven't already. Also log blocks 001 and 020 together.