Hallo,

i need some help, i have a car here that is well tuned and runs great. but sometimes we have the problem (most when it is cold and wet outside) that from one moment to another the wideband shows that the car runs extrem lean under part throttle.

the mixture jumps from 14.7:1 to 16:1 or sometimes 17:1

the closedloop is disabled and the maps are not the problem because normaly the mixture is overall 14.7:1 in part throttle till 650-700mbar after that is has 13.5:1 and a bit richer under boost.

if the problem accures the mixture goes to 17:1 in part throttle, 14.5:1 at about 1000mbar and low 14:1s under boost (we don't check the last one for a long time not to harm the engine)

the EMS is something like uberdata, but itself is not the problem because runs fine in another car. So the problem must be in the car itself.

What sensor or hardware failure can cause a lean condition over a longer period?

oh i forgot, full throttle overcomes the symptoms, but only full throttle, boost alone with part throttle at high rpms has the mixture problem.

what i can figure out is that the tps voltage is very low (aprox. 0,2-0,3v at closed Throttle)

the engine is a B16A1 engine.

has anyone ideas? i don't know more at the moment... please help us with suggestions... even stuipd one's so that we have something to check ;-)

Thanks
Malte.

 

Enable the closed loop and see if the problem persists. Adjust the TPS voltage and also if you have datalogging capabilities look at what the MAP is reading. If the tune is running fine in another car but, acting werid in yours it may be that your MAP sensor is failing (for some odd reason) and giving false readings(Showing the ECU that the engine is at different Vaucm/Pressure level where there would be less fuel). Just an Idea. Keep us informed.

Phil

 

today i run the same maps with closed-loop... you see on the Wideband that the ecu controlls against something, but the problem is still there... only that the mixtrue not drops too much anymore because of CL.

this weekend i change the TPS sensor and the Throttlebody... maybe this helps.

TPS voltage is low, but datalogging shows a normal smooth graph.
same for MAP Voltage, IAT voltage and ECT Voltage... so the TPS is the only thing i have in my mind. but as i wrote... we checked the normal things allready ;-) so we need some more ideas...

could it maybe the intake manifold gasket? (a leak or something)

Thanks for the quick answer...
Malte.

 

I'm not sure that a Vacum leak would cause the lean condition under part throttle.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mrx &raquo;</TD></TR><TR><TD CLASS="quote">today i run the same maps with closed-loop... you see on the Wideband that the ecu controlls against something, but the problem is still there... only that the mixtrue not drops too much anymore because of CL.
</TD></TR></TABLE>

What do you mean by that? It's not as lean as before?

Phil

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaguyef &raquo;</TD></TR><TR><TD CLASS="quote">What do you mean by that? It's not as lean as before?</TD></TR></TABLE>

yes, if CL is activated it runs not so extream lean as in OL, but thats only because the ECU wants to holt the mixture at 14.7:1 so it enriched the lean condition with additional fuel so i get a richer mixture. But it is leaner then 14.7:1 also in CL so the fault is still there, only the effect is not so big.

Malte.

 

definetely adjust the TPS before trying anything with your ECU