diagnostics advice

Hi all

I have an omiscan 2 which I use on my Range Rovers.

Ony my petrol P38 the live data readings are instant.

On the DSE (black top engine) there is a marked delay of 1 second or longer on live data.

Is this normal?

My reason for asking is that tha DSE seems to lag at low revs even with a chip and a new maf.
It seems that when the throttle is pressed there is a lag to 2000 rpm and then off like a rocket (turbo kicked in). I'm wodering if the ECU has an issue with slow data transfer? (laymans terms!)

However, if the throttle pedal is lifted slightly it seems to pick up quicker!

Again, many things have been changed,

Throttle potentiometer, Larger intercooler, Pump rebuilt, New timing injector (All readings correct on omiscan)Maf, EGR solenoid, EGR Cleaned thoroughly, etc.

I know these are not as quick as the earlier alloy inlet p38's but this is almost painful.

The car has been totally rebuilt now and I just want to get the last couple of issues rectified.

Any advice would be appreciated

Thanks

Ray

Normal.

They are all dead below 2K rpm

Hi,

I appreciate they are all quite slow below 2k revs.

The R plate (earlier engine) that I drove the other night was like driving a ferrari in comparison below 2k revs.

I was just thinking it could (should) be better than it is. Especially with the tuning box on.

It's just like the throttle is doing nothing. Sometimes is seems to pull like a train at low rpm only to go ack to slug mode.

Check the EGR valve is actually operating/closing fully and the pipe from the MAP sensor is in place and not leaking. If your new MAF is a cheapo not OEM that could also be the problem.

Depends on your box no? There are some you can get which are set for economy or performance, either factory set or you can move a few transistor thingy s around inside to tweak where on the spectrum you want to be. When I first got mine the previous owner left an old manual inside the handbook for one of these boxes for RR cant remember the make, but now has standard PSI fitted so threw it away.

Might your box be tuned for best economy rather than performance? Although I know most will claim benefits for everything.

Other things to consider are:

Clean vac pipe from manifold to boost sensor on top of fuel filter
Clean intercooler
Delaminating pipes on the induction
blocked injectors/filter

There could be number of reasons retarding performance even with a box working as it should.

Hi

This is a TDI tuning box. So not specific for power or economy. It enhances across the range.

On the others.

New Map sensor and vac pipe
New intercooler
new silicon pipework around intercooler
no black smoke
injectors refurbed same time as pump
new fuel filter (genuine) fitted.

As you can see I have done the normal culprits Hence why I was wondering if the electronics could be running in a delayed fashion

rayc said:

Hi

This is a TDI tuning box. So not specific for power or economy. It enhances across the range.

On the others.

New Map sensor and vac pipe
New intercooler
new silicon pipework around intercooler
no black smoke
injectors refurbed same time as pump
new fuel filter (genuine) fitted.

As you can see I have done the normal culprits Hence why I was wondering if the electronics could be running in a delayed fashion

Click to expand...

Is the box a plumbed in type or fully electronic?

As per Datateks suggestions - check the EGR Valve - they get gummed up and also if the MAF is dicky or a loose connection to it, that could cause lack of power...

aerofabrique said:

Is the box a plumbed in type or fully electronic?

Click to expand...

Hi, it's wired in with it's own harness with proper connection plugs.

Plus soldered joint to maf blue / white wire

Saint.V8 said:

As per Datateks suggestions - check the EGR Valve - they get gummed up and also if the MAF is dicky or a loose connection to it, that could cause lack of power...

Click to expand...

Hi,

MAF is spotless and works accoriding to the readings on omiscan.

MAF is genuine new and also works according to omiscan. Just a delay in moving the throttle to getting the response show on the scanner

Sorry,I was "with wine" when I posted my one word response.... It is quite normal to have a slow refresh rate when viewing EDC as live data - certainly via Testbook anyway,even the gauges take a while to actually appear on the screen,and Testbook asks you to wait for them to appear.
I think your problem lies elswhere,have you tried running the car without the tuning box in place if possible ?

You do not seem to have checked that the EGR valve is closing properly, take it off make sure it closes fully then re-fit but do not connect the vac pipe and see if it's better.

eightinavee said:

Sorry,I was "with wine" when I posted my one word response.... It is quite normal to have a slow refresh rate when viewing EDC as live data - certainly via Testbook anyway,even the gauges take a while to actually appear on the screen,and Testbook asks you to wait for them to appear.
I think your problem lies elswhere,have you tried running the car without the tuning box in place if possible ?

Click to expand...

Hi thanks for that.

Tuning box was only fitted Sunday (Yesterday) and has made a phenominal improvement to the way it drives once the turbo kicked in.

However, lower down is still very lacklustre to the point when driving along the road and the turbo drops (below 2k revs) its kije get out and push time.

However, every now and then the car seems to spring into life lower down the revs and is quite spritely. I;ve ordered an ECU temp sensor from LR and will fit just in case its telling the ECU porkies

Also, noticed today that when it runs "flat" after pulling up to a junction and doing a rolling start there is a significant flat spot in the initial pick up and then it drags itself to 2k revs and flies!.

Today (It was warm hence the sensor comment above) it lost the flat spot and drove like a dream. Am I making sense?

rayc said:

Hi thanks for that.

Tuning box was only fitted Sunday (Yesterday) and has made a phenominal improvement to the way it drives once the turbo kicked in.

However, lower down is still very lacklustre to the point when driving along the road and the turbo drops (below 2k revs) its kije get out and push time.

However, every now and then the car seems to spring into life lower down the revs and is quite spritely. I;ve ordered an ECU temp sensor from LR and will fit just in case its telling the ECU porkies

Also, noticed today that when it runs "flat" after pulling up to a junction and doing a rolling start there is a significant flat spot in the initial pick up and then it drags itself to 2k revs and flies!.

Today (It was warm hence the sensor comment above) it lost the flat spot and drove like a dream. Am I making sense?

Click to expand...

You seem hell-bent on not checking the EGR....if this is not function and is stuck open, the Boost pressure from the Turbo will be lost.....the EGR should be closed on low revs and openning on highr revs to recirc the Exhaust....if it is stuck open you'll lose boost....

Datatek has mentioned the EGR and I reiterated it too....these do get gummed up....some people even blank it off to improve performance and economy....

Hi,

EGR has been checked, It was removed and blanked, (No difference). It has been fully cleaned and drives the same as when it was removed.

As there was no difference the EGR was put back onto the car and a new solenoid fitted. Still no difference.

Thanks for the input though.

I have also done a forced open and close on the EGR valve with the omiscan. Again all appears to do as it should.

Then you have checked everything I would do too....

Has the FIP been retimed to take into account the drive chain stretch??

Hi

Yes timing was checked 200 miles ago with the dial gauge thing that goes on the hole.

I have done just about all there is to be done. But I must be missing something very simple / obvious!

I will keep looking though. Been on it nearly 4 years getting it sorted (That wasn't the original intention I hasten to add).

Started as a DSE. Now an Autobiography (Many genuine parts).

Dont know why I do it as I have a perfectly good TD6 Vogue and TDV8 Vogue SE.

P38's just have that something special.

Looking for a limited edition to mothball now

Good job the wife is a petrol head as well!

Saint.V8 said:

You seem hell-bent on not checking the EGR....if this is not function and is stuck open, the Boost pressure from the Turbo will be lost.....the EGR should be closed on low revs and openning on highr revs to recirc the Exhaust....if it is stuck open you'll lose boost....

Datatek has mentioned the EGR and I reiterated it too....these do get gummed up....some people even blank it off to improve performance and economy....

Click to expand...

Wrong way around,the EGR will be more active around idle/low load conditions,give it welly and the EGR should be shut - which is why it makes no difference to performance IF its working properly.

eightinavee said:

Wrong way around,the EGR will be more active around idle/low load conditions,give it welly and the EGR should be shut - which is why it makes no difference to performance IF its working properly.

Click to expand...

My Bad....