Thread: High exhaust temps on vnt install + Maf faulty?

sounds like you need a new fuel map to suit the mods you've done.
I'd trade the msb on a nnn

I got a Allisport Intercooler and other mods (but no VNT) and my EGT's were still too high with my Tombie map, so Jose (Td5Inside) wrote me a new map and it wont even get anywhere near 650 now, and it goes much better than I had hoped.

I'm surprised the VNT has caused higher EGT as the extra air should have the opposite effect and cool the combustion temperatures. On a diesel richer equals hotter temperature, lean equals cooler.

I'd record the inputs using the Nanocom and then speak to Jose from TD5 inside. He should be able to advise you if he can provide a tune that would fix it.

Mikey, 700deg after caning it uphill at `130km/h I would say that is quite low.

JC

No reading on the MAF is the first issue to sort.
The TD5 ECU will default to a base fueling parameter without MAF.

A VNT does not mean more boost ( though it can)
it primarily gives a better range of boost for variable operating conditions, so unless your boost pressure is down, won't be the issue.

Importantly, what have the EGT's been previously to this?
Boost pressure?

Twr7cx, TD5inside contacted.

Justinc, that was only on the flat roads. I really do not think that there was much more left in it to be honest. It seemed just about out of puff. D2 has never been capable of 130 uphill ever. Not even with the work i have done to it.

Egt's have been an issue since the BD remap a few years back. I thought that the intercooler upgrade, vnt and exhaust mods would have lowered them somewhat but it has not made much difference, I just seem to hit the high temps a bit quicker these days.

Mike

Edit: Boost pressures are spot on from the factory settings for the vnt. I get a spike to 22 sometimes and it settles to 19-20 when held at wot.

If you disconnect the MAF then the vehicle ECU will use default settings. If it runs better like this it would indicate a MAF issue.

I will be doing some more investigating tomorrow afternoon. We only do short days on Sundays.

I will check wiring at first and disconnect maf for a run and see how it goes. Incidentally I did check with a Fluke meter the resistances of both the maf's I have and they give close to identical readings to each other which is close to the expected readings as per another thread I read on Aulro somewhere.

Not sure if the resistance measurements are definitive indicators of a faulty/good maf or not (not enough experience on my part with maf's) but I will look at all the known problem areas first in order of easiest to hardest. It should not take to long to sort it out.

Mike

Well, I installed a new Maf and all is good again except for a bit of a hiccup every time I take off and that only started to happen about three weeks ago. Not quite sure what the hiccup could be as it has never happened before.

Before replacing the Maf I read a thread on this forum that listed resistance readings between the 3 pins of the Maf. The installed Maf and another I had were reading about the same as each other. This was different to the thread in question which made me think the Maf was faulty.

The funny thing is, once I got the new Maf I put the meter on it right away and it too was giving about the same resistance reading between pins as the other two I had so I installed it and started the car and, hey presto, airflow readings.

What to make of this? Well for me the resistance readings were NO indication of whether a Maf is faulty or not. All the Mafs I have are VDO Seimens in branded packaging. Two are obviously faulty and one is not.

Cheers,
Mike