Thread: TD5 EGT's.

Whoa, hang on. You file just changed. Where did your ambient pressure go it's all 2.79 now?

Can you upload the original again?

Your ambient pressure column was about 100 all the way. It sometimes goes up to 101.?? and ofter goes down to 98.?? or further when you first hit the accelerator.

Happy Days.

I haven't changed my uploaded file. My file says 2.79 for ambient pressure.
I have checked my TD5 diagonstics info, this should read ambient pressure in kPa, which should be around 100kPa. I may have a sensor error here?

Originally Posted by joel0407

Whoa, hang on. You file just changed. Where did your ambient pressure go it's all 2.79 now?

Can you upload the original again?

I don't know what I had but the first time I opened it there was now yellow or anything.

Hopefully "Tombie" will chime back in here. I think that's your problem. If your ambient pressure is low it thinks you have lots of oxygen in the air so it puts lots of fuel in. That's just how the ECU works, nothing to do with the tune. Well a little to do with the tune. The tune will decide how much "lots" is.

Maybe your ambient pressure sensor if stuffed. Your vehicle is a EU3 being a 2a so yours will actually read an ambient pressure. I think mine just estimates a figure.

Happy Days.

Progress made.
I have investigated why the ambient pressure reading was not as expected (thanks Joel). The vehicle was services 3,000km ago and it appears that the mechanic did not refit the plug on the air box for the ambient pressure sensor.

I took it for a drive and the EGTs have dropped at least 50 degrees. A hard accelerate from 80-110km/h now goes from 600-700 and just touch 800 degrees. Still way too high by my liking but big progress over earlier in the afternoon. (I suppose ambient air temperatures were lower than earlier in the day though, but not much.)

The next step may to wind up the wastegate to increase boost (and hence lower EGTs)???

Will increasing boost adversely affect longterm engine reliability?

I can't help with engine long livery but I'mInterested, what's your boost at now?

Originally Posted by cjc_td5

Progress made.

I have investigated why the ambient pressure reading was not as expected (thanks Joel). The vehicle was services 3,000km ago and it appears that the mechanic did not refit the plug on the air box for the ambient pressure sensor.



I took it for a drive and the EGTs have dropped at least 50 degrees. A hard accelerate from 80-110km/h now goes from 600-700 and just touch 800 degrees. Still way too high by my liking but big progress over earlier in the afternoon. (I suppose ambient air temperatures were lower than earlier in the day though, but not much.)



The next step may to wind up the wastegate to increase boost (and hence lower EGTs)???



Will increasing boost adversely affect longterm engine reliability?

If your headgasket is already marginal increasing boost pressure will speed its demise. This is caused by the increased cylinder pressures that result from increased boost.

This why vendors suggest only winding up boost if you are sure your engine is in good condition and recommend only 18-20psi as the upper limit.

I know it's not a TD5, but I have run my 4BD1T at 750C sustained for several minutes at a time and even hit 900C on occasions of inattention (dropping off boost while towing and not watching).

I had the head off on the weekend and the pistons have survived this fine. No signs of melting or cracks yet.
Just to give those of you scared to pass 650C a bit more confidence.