This is related to a problem in my previous post - https://www.thirdgen.org/forums/diy-...open-loop.html - the second issue I discussed in my initial post.

Adding to this issue: If I start the car and head to the freeway and hop on and cruise at 70 as its still warming up, as it enters closed loop it starts surging like a beating heart for about a minute. Thats all I can say to describe it, the power of the engine surges and it feels like I am rapidly giving throttle and removing throttle. After it stops the car purrs.

The issue was worse and I upped the "Closed Loop - CTS threshold" temperature to 62. What side effects (besides more time in open loop) are there to raising this farther, to say, 70? What do you suppose the REAL problem is?

 

Looking at the data log in the post you linked above, it seems as though there is too much of a difference in VE. This is between 1200 and 1300 RPM at 35 KPa. The data log shows the O2 swinging a bit too far with the INT playing catch up. Can see it between 5:44 and 5:50 inclusive. And as you say, right after it goes closed loop.

Try this: lower the VE at 1300 RPM, 35 KPa by 3%.

Raise the VE at 1200 RPM, 35 KPa by 3%.

That should help. Once this is done, if there are still issues, a short data log of it is helpful.

What is also interesting, is that this is nearly the only area in the log where you are cruising at that RPM & load (KPa). So it seems to be connected with the ECM going closed loop, when it is actually the engine RPM & load.

RBob.

 

Thats a valid observation, however in the past couple months since I've made that log it does the same thing, consistantly. Every morning on my way to work and school I start the car and drive through town it hits closed loop at exactly the same block and does the same thing. I come home on my break and drive the same path back to school with a warm engine and it doesnt do it, so I really do think that it is related to closed loop. In practice, while daily driving, the same problem exists in all types of speeds and engine loads.

When I can try your sugestion and do a datalog I'll post it up on this thread.

 

Well, I have to correct myself...I just got off the freeway here in town and it started giving me crap again, with the engine hot. It appears you are correct