Loss of power in 5th and 6th gears! - SOLVED

[Ryno91]

So my ute has just started losing power in 5th and 6th when accelerating past 90km/h, I've read about people having this problem at lower speeds and even stalling going into limp mode? Mine is a manual and has EGR block. Accelerating through the gears up to 80kmh is fine and idling is smooth so I don't know what it could be.

The mechanic looked at it and put a new air filter in and cleaned out the EGR pipe which didn't fix the problem at all, gonna rip into him tomorrow! Anyone else had this problem, should I be suspecting the suction control valve?

 

[Malicious]

Have you done an ecu reset?

 

[Ryno91]

Pretty sure the mechanic did that already, ecu relearn?

 

[lookskyward1]

Neutral Position Switch on the gearbox?

Try pushing the gear leaver to the left when in 5th or 6th; If this sorts the power delivery out you either need a new switch or you can trim a wee bit off the shoulders of the switch so that it goes a bit further into the box.

good luck

 

[Ryno91]

Ah I've never thought of that I'll give it a go on the way home this afternoon

 

[Ryno91]

Also tried driving with the fuel cap loosened and that didn't make a difference

 

[Ryno91]

UPDATE

The battery was spiking up to 15 volts which was throwing out the alternator and in turn this was giving the MAF sensor an out or range fault and was telling the turbo to stop boosting at a certain point.

New battery has solved the problem, can accelerate right through each gear no problem

 

[Tappet]

That is handy info.

 

[Old.Tony]

It's a very unusual reaction to a weak battery. It also calls the regulator into question - the battery itself isn't capable of producing that high a voltage (2.3V/cell tops = 13.8V peak but nominal stable power 2.2V/cell = 13.2V peak).

 

[Malicious]

Tony is correct, it is very possible though that the battery could have been going open circuit , with load on it the alternator is putting out 14ish volt disconnect the battery with the engine running and voltage can spike drop and do all sorts of very strange things,