Innovate LC-1 + Bosch LSU 4.2, unstable signal

VolvoPentaMan · Post by **VolvoPentaMan** » Sat Jan 28, 2006 12:32 pm

Posted this also in MegaSquirt 'n Spark -E area, and i'll post it here too, if someone could give a helping hand. Here's the thread:
http://www.msefi.com/viewtopic.php?t=15415

Okay, here's now a videoclip of my innovate lambdasensor, on my megasquirt. The engine is a Volvo 2,5L 16v "redblock", and the sensor is placed on the end of the exchaust manifold, as it is in the 8v version of the engine.

On the 16v version of this car engine (only in 700/900seris volvos), the sensor is about 1meter from the exchaust manifold, and in 700/900 series volvo's 8v, the sensor is in the same place (almost same "downpipe"). But in 200/300 series volvos with 8v engine, the sensor is on the exchaust manifold, as in my "hybrid". The 16v engine hasn't been available from factory in 200/300 series, so that's why my "hybride".

Here are some pics of the sensor placement:
http://koti.mbnet.fi/fredrikr/Volvo%203 ... CF0077.JPG
http://koti.mbnet.fi/fredrikr/Volvo%203 ... CF0080.JPG
http://koti.mbnet.fi/fredrikr/Volvo%203 ... CF0081.JPG

And here's some videos i took with my phone:
http://koti.mbnet.fi/fredrikr/Volvo%203 ... 012006.mp4
http://koti.mbnet.fi/fredrikr/Volvo%203 ... 006001.mp4
http://koti.mbnet.fi/fredrikr/Volvo%203 ... 006002.mp4
http://koti.mbnet.fi/fredrikr/Volvo%203 ... 006003.mp4

Sorry, they are in MP4 format, I know that at least Nero ShowTime can play them...

What do you think, are the exchaust gas pressure changes making this "jumping", or is it something other i've messt' up again?

When the engine is cold (under 50Âºc), the AFR reading is MUCH more stable, goes up/down about 1AFR/sec, and i think this is normal.

But could the rising EGT, along with the exchaust gas impulses make the sensor go "wild", or what do you think?

This is the main reason, why i can't get a nice VE-table, but the engine still runs well, with my jumpy table.

So much questions, but no answers....

mops · Post by **mops** » Mon Jan 30, 2006 11:29 am

i'm not an expert, but it kinof looks to me like the sensor is in the path of gases only from the last cylinder. if that's the case then that would explain your wonky readings.

i'd move it, say 30-50 cm after the exhaust manifold, in the exhaust pipe.

VolvoPentaMan · Post by **VolvoPentaMan** » Tue Jan 31, 2006 1:39 am

mops wrote:i'm not an expert, but it kinof looks to me like the sensor is in the path of gases only from the last cylinder. if that's the case then that would explain your wonky readings.

i'd move it, say 30-50 cm after the exhaust manifold, in the exhaust pipe.

Yup, that was also what i was thinking of. But can't move it less than 60cm, because the exchaust pipes go into one first then. And then it would be under the car, altered to corrosion, water and dirt.

The weird thing is, that the sensor is in that place by default, but the 8v exchaust manifold isn't exactly the same as the 16v i have drilled the hole on myself.

But I shall try to put the sensor a bit farer away from the manifold.