3.0 TDi remap issue

[Mollygoogle]

hi all, my 3.0 221 TDi was remapped before my ownership and the map is of unknown origin. I decided to take it for mapping. It was taken from 250 to 270 on a 4wd RR.

It doesn't drive how I want which is an aside to the main problem. It bogs down a lot at low revs and is quite rattley, it limps quite a bit and flashes a glow plug light.

I've obviously contacted the mappers and it's going back but I want to rule out anything else as a cause and/or confirm that the map can be the cause of the glow plug light.

Any advice?

 

[c3nturi0n]

Diagnose it properly to start with before you start doing anything else.


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[Mollygoogle]

Thanks for the input. Iwill of course do a diagnostic as will the mapper but that doesn't answer my question. Can there be a correlation between the mapping and the glow plug light

 

[desertstorm]

There is a possibility that the two are connected however without knowing what fault codes are being seen there could be several issues. The usual siispect is the turbo on these they tend to suffer a lot with actuator problems. Get the fault codes read. If you have an android phone carista and a £5 Bluetooth dongle off ebay will read and clear codes.

 

[Simon968]

Thanks for the input. Iwill of course do a diagnostic as will the mapper but that doesn't answer my question. Can there be a correlation between the mapping and the glow plug light

I would have said that if it wasn't doing it before the remap, then there is a good possibility that the two are related.

Where did you go for the remap?
The place that I suggested previously, I believe normally run a diagnostic on the car before they map them.

 

[Mollygoogle]

It had a diagnostic before the map and was fine. I'll be sticking the reader on it today or tomorrow when I get chance.

What is the operating temperature range of the glow plug system? I know systems on other cars that are only active below specific temperatures but the car was showing 10.5 deg on the dash when the light came on and the car limped

 

[desertstorm]

Glow plugs operate below about 9 degrees. However they are only there to aid the initial start and on newer cars for 2-3 minutes to assist in reducing emissions when the car is cold. There are many other things that are likely to have caused the glow plug light to illuminate. It's slightly misleading as it's not just faults related to the glow plugs that will light it.

 

[Mollygoogle]

As an update, it's showing P0235 boost pressure control below control limit

 

[desertstorm]

I would check all the boost pipes out for possible boost leaks. You can usually see boost leaks by the wet oil patches that come from the crankcase fumes pushed through the system leaking.
Underboost faults can also be created if the map is asking for unreasonable boost figures from the turbo.

 

[Mollygoogle]

Thanks for the answers so far. After getting that code the mapper took off the boost pipes and inspected the turbo. Having refitted the pipes the car now seems to be boosting/driving much better so there is a strong chance that it was as simple as a loose pipe. I will stick some miles on it this week and see if the results are consistent.

 

[Mollygoogle]

Car is limping again. Testing has proved that the limp happens when gently accelerating at low revs or on a hill. It seems to be as you gently come on to boost. If you accelerate moderate to hard it boosts without limping

 

[desertstorm]

I would say that either the issue is with the VNT control mechanism on the turbo, a boost leak or the map specified boost request is too high. If the actual boost deviates too far from the specified boost for too long it will throw an underboost fault code. You need to try logging actual and specified boost to see whats going on to see if it's a hardware fault or a map issue.