Bogging problems with Silvertop 4AG (BT ECU) under 3500 RPM

[LAC99]

I have a problem with my silvertop 4ag when it revs from idle to about 3500 RPM. I didn´t know how to describe it in english but someone just told me it´s called "bogging" (sorry for my english, by the way).
Anyway, it has a Blacktop ECU and MAP and the thing is that below 3500 RPM it has this bogging problem that I can´t get rid off. I´ve tried replacing the ECU with another BT ECU, changing the module, new wiring harness and also changed the TPS but it still does that bogging thing.

from 3500 to 8000 (according to my SAFC) it works perfectly but below that is really frustrating, specially if I give it full throttle because the engine starts knocking a little bit so I have to let go a little.

I don´t know if this helps you get a better picture but when I let go a little bit the throttle it actually revs better than at full throttle. That´s why I thought it was the TPS sensor but when I changed it, I had the same problem.

any ideas? I don´t have a oxigen sensor connected but I thought the SAFC would solve that.

thanks

[Gnugfur]

What does the bogging feel like.
Are you able to film it?

[jondee86]

LAC99 Wrote:from 3500 to 8000 (according to my SAFC) it works
perfectly but below that is really frustrating, specially if I give it full
throttle because the engine starts knocking a little bit so I have to let
go a little.

Your engine should have a "knock" sensor, and when it detects knocking
the ECU will retard the ignition timing until the knocking goes away. Then
after a short time, it will put the ignition timing back to normal.

I think you should check you ignition timing. It should be set at 10 BTDC
with the diagnosis connector "shorted" and all accessories off. If you use
low octane gas, the problem will be worse. Try and use the best gas you
can get... 95 octane or better.

Cheers... jondee86

[LAC99]

good idea, I´ll try to film it this weekend so you get the idea

the knocking is recent... I had this bogging problem since I got the car and it didn´t knock then. Still it won´t hurt to check the ignition timing.

I´ve seen in other forums problems like mine that were solved by checking the STA wire... I´ll try that also.

I only use 97 or 98 octanes gas in this engine.

thanks guys, I´ll keep you posted with the results of this weekend tests...