Off idle timing retards badly - CA18DET

[Nissanclubman]

I have seen threads on the topic before but no final posts on the solution.

The issue is the timing once I come off idle. I set the TPS correctly and is closed at idle. Motor running at 850rpm with timing set at 15 deg on my timing light. Motor temp is 85 deg C so no cold start issues and I have duplicated both my main and knock MAPS.

What happens is this. At idle all is good but when I ease the trottle open and bring the revs up slowly (850 - 1000 - 1200 - 1500...) the flywheel timing goes from 15 - 10 - 5 - then sits at between 5 and 0 at about 2000 rpm then startes to climb as the reves build.

I have changed the Ign MAP to some very wild figures to try and solve this but it is like the low rev area of the MAP isn't being used until about 3000 rpm. Like as thorugh there is another MAP being used.

Any help would be great... Been chasing this for ages.

[Matt]

Can you post your BIN? I can check on the bench. Log file would be helpful also

[Nissanclubman]

Hi Matt,

Attached are three versions ver P, Q & R however I have tried at lease 6 variations of each.

During cold start and running the car pulls great down low off boost however something happens once the motor gets up to temp.

Anything you can find would be appreciated. Cheers Richard

[TM_S13]

what specs do your car/engine have?
what mods have you done?

[Nissanclubman]

This seems a bit of an obsession but I have been chasing this problem, off and on, now since 2010.

I have built a few motors in that time and experimented with a number of configurations. However the one thing that has been consistent through out is this off idle retarding. I saw a number of threads on the forum of others having the same problem as well as SR20 owners.

This engine setup.

Standard plenum
Custom tunes headers.
Basic T2870 turbo
Fuel is E85
830cc Injectors
GM LS3 "Truck" Coil packs fed straight from ECU. (Nissan Ignitor removed)
Std CAS
RB20 MAF
Small/Medium size inter-cooler 500 * 500

Previous motor was Std CA18DET with Std 8.5:1, 175 PSI head pressure.
This motor is Std CA18DE however has high comp head, dome pistons 210 PSI head pressure.

[Nissanclubman]

Hi Mat, any progress on your testing?

[Matt]

Not had time... will look tomorrow

[Matt]

Okay I finally got to this last night but I cant repeat the problem. I'm going from the parameters you provided in your first post but really I need a log file demonstrating the issue so I can get all the parameters correct (eg TPS voltage, MAF voltage, RPM etc at the same time) so I can repeat properly here