Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

ITB Trumpet Tuning BOGS and oscillating Lambda

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads



I've hit a problem with a customer car...

Customer comes in with a volvo and have a Maxxecu street installed.

Car does not have any good location for IAT or for MAP and since it's an ITB we set everything up for TPS as load.

However if i tune everything on the dyno using steady state everything looks crisp.

However as soon as i started a ramp run it bogs down and the lambda oscillates from lean to rich like 1.2 - 0.7 Lambda at 1600-2000 RPM.

Load points is 0,1,2,5,7,10,15,20,30 etc.

Any ideas or tips

If the set SS points are correct, have you checked the smoothing/interpolation options?

Could it be an ignition misfire?

Is there some untuned acceleration enrichment? Perhaps a bit too much when you quickly move the throttle?

Good point, David.

Pontus, does the ramp rate make a difference - is it worse with faster acc'n or about the same?

Hi, what camshaft does the engine have? Is it stock or with too much overlap?

Good point about the acc enrichment. I did try that but it had almost no change but it could be one of the gremlins.

the the cam is a KG8 with 12.8 Lift 104 nock angle 315 Duration.

But i don’t think i will get another shot at this car. Customer just said that it felt slow and bogs so i don’t know what i am doing….

i wanted to have the car over night but customer insisted to take it home…

well you win some and loose some.


of course it feels slow with 17 degree of timing at WOT and is basically ”untuned” at higher rpms…

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?