Very high long term offset

Very high long term offset

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Discussion

davelittlewood

Original Poster:

306 posts

133 months

Tuesday 18th August 2015
quotequote all
Have a look the screen shots gents.

The long term offset on the even bank is at -98%!!yikes



Is this normal??

OleVix

1,438 posts

148 months

Wednesday 19th August 2015
quotequote all
its overfuelling a lot, check that the vacuum hose from the fuel pressure regulator to the back of the plenum is connected

davelittlewood

Original Poster:

306 posts

133 months

Wednesday 19th August 2015
quotequote all
The even bank is much worse than the odd.
Could this be a leaking injector?

I'll get the thermometer gun out later and check the manifold temps.

davelittlewood

Original Poster:

306 posts

133 months

Wednesday 19th August 2015
quotequote all
Checked the vacuum pipe for the fuel pressure valve. All OK

We're off on a run for the weekend. I'll see what it looks like when I get back

blitzracing

6,387 posts

220 months

Wednesday 19th August 2015
quotequote all
The two banks don't fuel evenly, I dont think its physically possible with the fact that the plenum feeds air from one side, but you have another issue- number one would be a high AFM output- Ive noticed for example the AFM output can go up if the body gets really hot after a long run on the motor way- If all the sensor values where spot on, you could quite reasonably have one trim at say -10 % on one side and the other at +25 % and you would not worry about it, so you may have a single factor affecting both banks.

davep

1,143 posts

284 months

Wednesday 19th August 2015
quotequote all
davelittlewood said:
Have a look the screen shots gents.

The long term offset on the even bank is at -98%!!yikes



Is this normal??
Just a thought ... if this screenshot was taken with the engine running then the Main Voltage is on the low side, this can cause an additional adjustment value to be added to the final fuel value. In other words the injector pulse width will be increased (more fuel) to 'compensate' for the drop in Main Voltage, which is the supply to the injectors. Perhaps check that your battery and alternator are functioning as they should. Ideally you should expect Main Voltage to be 12.7 - 13.2 Vdc. I hope that makes sense.

If you ran data logging check the results for prolonged pulse width increases with corresponding Main Voltage drops.

OleVix

1,438 posts

148 months

Thursday 20th August 2015
quotequote all
davep said:
davelittlewood said:
Have a look the screen shots gents.

The long term offset on the even bank is at -98%!!yikes



Is this normal??
Just a thought ... if this screenshot was taken with the engine running then the Main Voltage is on the low side, this can cause an additional adjustment value to be added to the final fuel value. In other words the injector pulse width will be increased (more fuel) to 'compensate' for the drop in Main Voltage, which is the supply to the injectors. Perhaps check that your battery and alternator are functioning as they should. Ideally you should expect Main Voltage to be 12.7 - 13.2 Vdc. I hope that makes sense.

If you ran data logging check the results for prolonged pulse width increases with corresponding Main Voltage drops.
Davep is right! Check the alternator and or battery

davep

1,143 posts

284 months

Thursday 20th August 2015
quotequote all
I now think the screenshot was taken after a RoverGauge session and ignition switched off, engine not running, hence the trim readings are more than likely spurious. It'd be more helpful if a screenshot of the whole screen was taken with the engine running and Communications lamp showing Green.

blitzracing

6,387 posts

220 months

Thursday 20th August 2015
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Worth downloading the latest RoverGauge- One of the initial versions gave a low voltage reading.

davelittlewood

Original Poster:

306 posts

133 months

Thursday 20th August 2015
quotequote all
Gents,
thanks for all the help.thumbup

The screen shot was taken with the engine NOT running.

I'll check it again with the engine running and report back.

davelittlewood

Original Poster:

306 posts

133 months

Tuesday 25th August 2015
quotequote all
Well this is a bit weird




This is running but not warmed up yet.

Now it's the odd bank that's high

Eventually after it warmed up



Is it strange that the even bank was at -98% and now it's the odd bank?

blitzracing

6,387 posts

220 months

Tuesday 25th August 2015
quotequote all
That was a RoverGauge bug thats now been sorted.

davelittlewood

Original Poster:

306 posts

133 months

Tuesday 25th August 2015
quotequote all
blitzracing said:
That was a RoverGauge bug thats now been sorted.
Cheers, I thought it might be some thing like that!

davelittlewood

Original Poster:

306 posts

133 months

Wednesday 26th August 2015
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But are these offsets anything to worry about?

blitzracing

6,387 posts

220 months

Wednesday 26th August 2015
quotequote all
Its only a problem when it hits 100%- its no different to turning the mixture screw on a carb- its fine until the screw falls out, or the trim reaches 100%. Ideally on a new engine with a good map it could be + / - say 5%, but things change over time, and the trim compensates accordingly, In your case Id try and borrow another AFM at some point, then do an ECU reset and see when the trim re settles, but I would not worry to much at this stage- its working within tolerances.

ClassiChimi

12,424 posts

149 months

Wednesday 26th August 2015
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Dave I have an AFM off my 450 you can try.

davelittlewood

Original Poster:

306 posts

133 months

Thursday 27th August 2015
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Cheers Alun,

I'm getting a new vac unit on Saturday from TVRPower so let's see if that makes any difference.

I always said that as soon as anything expensive packs up on either the ignition or the fuel injection then the whole lot goes in the bin and I'll take it to TVRPower for an MBE.

Talking of MBE systems, have they mapped your properly yet??

Should have given them half the money for half the job!

ClassiChimi

12,424 posts

149 months

Thursday 27th August 2015
quotequote all
I saw your vac unit while I was at Powers today Dave! Dom and Jay went out on the road to tweak it. The rolling road issue is a Pita but what can you do!
It's a bit better now so I'll just have to wait until the things fixed!
The installation is good, everything's working spot on and stuck in traffic today had me bothered not a bit!
Looking at some screen shots after Dom had been up and down the motorway confirmed my temp readings on the gauge are accurate and constant at 84deg. Fans doing there job on/ off and still constant temps
That knowledge alone is a breath of fresh air,,, the car before, the fans kicked in but not until the engine seemed at boiling point sometimes,,, it's all more consistant and I actually believe what I'm seeing and hearing and smelling!

The road is a huge fustration to me to be honest,, but I'm not the only one who's suffering because if it, I really wanted a trackday before October, but not before I know the map is fuelling correctly!

blitzracing

6,387 posts

220 months

Friday 28th August 2015
quotequote all
davelittlewood said:
Cheers Alun,

I'm getting a new vac unit on Saturday from TVRPower so let's see if that makes any difference.

I always said that as soon as anything expensive packs up on either the ignition or the fuel injection then the whole lot goes in the bin and I'll take it to TVRPower for an MBE.

Talking of MBE systems, have they mapped your properly yet??

Should have given them half the money for half the job!
Unfortunately the vac' unit has no part to play in the long term trim, as the vacuum port is shut off at idle, and this is when when the long term trim is set, although if the idle ignition timing is wrong it can have an affect.

davelittlewood

Original Poster:

306 posts

133 months

Friday 28th August 2015
quotequote all
I thought that might be the case so I'll fit the new vac unit, check the timing, give it a week and see how it goes.