26 replies to this topic

[miniJJ]

No ideas?

I don't like to bump, but I want my car drivable....

JJ

[miniJJ]

Seriously? No one has any ideas?

This is getting very depressing....

JJ

[miniJJ]

Just got back from another test drive.

I've found out the problem seems to be based around part throttle betwean 20 - 35 mph, mainly when under load. For example, I'll be sitting at 30mph in third. Speed limit changes and I want to take it up to 40, so a fraction more throttle is used (honestly, like 10 / 20mm of pedal travel) and it starts bucking and backfiring.

It's odd, as when accelerating quickly (went from 30 to 70 joining a dual carrigway) I had no backfiring; although it felt like it was struggling and holding back getting up to speed (or is it just me not used to a 998 engine?)

What does this indicate? Still a fuelling problem? Or does the ignition mapping need setting up to correct these issues under load?

JJ

Edited by miniJJ, 31 May 2010 - 01:13 PM.

[01smartc]

Which of the 2 maps you have shown are you using?

Chris

[miniJJ]

Hi Chris,

I'm using the bottom map currently (998 stage 1 in title, top one is aldon yellow if I remember right).

Like I say, generally the problems occur at part throttle around 25 - 35mph, especially under load. Unfortuantly I can't post up a datalogging session as I won't have a usb adaptor for the megajolt / laptop. Hopefully I can find one this week. I can still alter the mapping via a desktop PC.

Thanks, JJ

[ACDodd]

That lower map is use-less!!!

Switch to the Aldon map. What needle are you running?

Is this engine going to a rolling road soon?

AC

[miniJJ]

Will switch it tonight! Thanks alot.

I'm running the needle wich comes with the minispares stage one kit, I can't find the code on their site.

Yeah the car will be rolling roaded as soon as funds allow (within the next month) , but I just need it set up for now to get me through until then

Thanks alot, JJ

[ACDodd]

You will just have to live with it until you can get it setup. The whole point of having it setup, is that it runs properly!!

AC

[lawrence]

hi, im just adding my contribution to this all,
my car had a problem that is similar to what you described, and it involved the needle moving up and down the jet in the carb.
my problem was that inside the jet there was a small piece of dirt which meant when you floored the accelerator the needle rose taking the dirt with it and wedging it higher up the jet.
this meant that the mixture got vastly rich, flooded the engine and did kind of what you described
so have you tried cmpletely clreaing out your carb?
L

[Kerrin]

That lower map is use-less!!!

Switch to the Aldon map. What needle are you running?

Is this engine going to a rolling road soon?

AC

Roughly what is wrong with the bottom map compared to the Aldon, are the advance figures just too small?

[miniJJ]

Yeah AC, it will be done as soon as possible; it'd be getting done right now if I had the money, payed over £1000 out this month for repairs, mot, tax and insurance.

Yeah, Lawrence, I've completly stripped the carb twice now (second time just this morning) and made sure it's all spotless inside. The first time everything was gummed up with silt, now, it's all nice and clean.

Thanks, JJ

[ACDodd]

Yes the part throttle settings are too retarded and the load bins are not used properly. The Top map the load bins are still not used properly but the engine will run much better with this map anyhoo.

AC