KevinD:IIRC, the zt-2 does not read below 200C....

 

if it is showing above 200c cold, then we have a problem

 

on the "green paper" instructions that came with the zt-2, it says that the signal range for EGT = 200C to 1200C.

 

Hmm, running rich with low timing causes high EGTs doesn't it?

 

well, i wouldn't think so, but its possible. i've personally seen EGTs drop while running rich. and i wouldn't think the extra fuel would burn in the manifold because the reason it wasn't burned in the cylinder was because there wasn't enough oxygen. thus the big *** black cloud of smoke all evos have from running rich at WOT.

 

low/rich afr = cold/slow combustion = fuel still combusting as it leaves the cylinder into the exhaust mani = high egt

 

there ya have it slow combustion. however, running excessively rich WILL cause EGTs to drop. if you want an excel file of it happening i'd be happy to send one over (4 cylinders, 4 probes) . what can happen is to much fuel will blow out the spark. irratic spark means lower EGT.


jeff, you need a tune :P lets lean it out to 11.5:1 and see what happens to the EGT's.



also, it should be noted that he was running 1100 deg F at IDLE but that could be due to running lean from boost leaks/vacuum leaks.

jeff, what does the car idle at AFR wise?

 

Ok he is my last log done about 15 min ago. its colder outside and starting to snow. 3rd gear pull. max boost is 25.3 too high and i need to turn it down a bit. richest i got was 10.8 afr. ok guess you cant see the boxes very well. the top box says on 3rd gear pull afr never got below 10.8. The next one says 0psi. next to that says 25.3psi and the finial one says egt is 757deg. kevin when turned the key on but didnt start the car my egt gauge read 395deg. last time i drove the car was 12 hours ago. bad sensor i guess. the afr is not as bad as last time maybe thats due to the increase of boost?? but its not the 11.5 we are looking for.

 

hmmm it read 395 degrees Farienheit? cause that is 200 degrees C which slowcar mentioned as the default minimum. may not be the sensor as the problem

jeff, you will check the idling air fuel ratio? when just sitting idling there after the sensor has fully warmed up, what does it read? if it reads anything significantly above 14.7 you most likely have boost leaks. and then what does the EGT say in this same case?

i think you should do what slowcar is saying and lean it out and see if the EGT drops. additionally TURN DOWN THE BOOST!!! wuu! 25psi?? hahaha prolly knocking like crazy! set it at 21-22psi and see what the EGTs are at then.

 

at idle the afr is 14.5-15 mostly is stays at 14.7. at idle egt is about 600+-50. at 25psi i dont hear or feel any knock the car just keeps pulling. but i will for sure turn it down

 

ok. thats it then. the sensor is fine, there shouldn't be any significant boost/vacuum leaks either.

your running 25 psi at peak load which is in effect making 1600+ deg EGTs. turn the boost down, try again. if it is still very hot, lean it out more and see what happens. i suspect the boost being turned down alone will releive the temps quite a bit.

 

i cant tune the car at all because Al did a road tune and incripted everything. so i have no clue where to even begin

 

well, i already told you the price, but if you want me to do it for you, i can show you how to make the tables readable, as well as get you started on tuning it yourself. consider me the anti-al. haha

 

ya readable would be nice. i pay 200 bucks or so and i get a not so good tune, and then i cant even change it because its all incripted. ouch. i would like to learn how to do it my self. whens you next free day off work?

 

As previously mentioned, EGTs will go high as you get further away from stoich WHETHER LEAN OR RICH. That's why you need the A/F wideband, to make sure you know which side of stoich you're on...