Power Loss Rav4 54 Reg

[gonmad]

I have a 54 reg rav 4 d4d that's keeps going into limp mode (power loss) but there are no codes recorded,you can be driving on the motorway and all of a sudden it loses its power and will not accelerate after a few minutes the power comes back but it's driving me mad. Please help

[Tech01]

Hi Peter,

What engine revs are you doing when it drops into limp mode? Does this happen only when you open the throttle wide, or can it be avoided by taking the revs high, but only at very light throttle?

Bit more info, and we should be able to suggest some things to check.

Chris

[gonmad]

Hi it usaully happens between 2 and 3 thousand revs but on the odd occasion it has done it when i',m pulling off from a junction, but you really notice it when your doing around 60>70 mph when you put your foot down to accelerate it just happens,but it also goes away sometimes if i put my foot down on the clutch and try and rev the engine (this sometimes clears it) but not always. ive changed the air and fuel filters and also filled the fuel pot with diesal injector cleaner.also there is know warning lights come on when it happens.

[Tech01]

Hi Peter,

I'm not sure with your last sentence whether there is "now" or "no" warning lights coming on...

OK, so it tends to happen at high speed/highish revs, and when you put your foot down fairly hard on the throttle. If a D4D goes into limp mode (only a tiny amount of power available), then it's usual to get the amber engine management light on the dash coming on. Switching off the IGN (when stopped!) for a few seconds normally clears this light, and gets you out of limp mode. You can usually bring on the fault again by simply wellying the throttle up a fair bit of incline.

You've done right things - air and fuel filters, and some diesel cleaner.

Two things to look at now:

1: Blocked/partially blocked diesel catalytic converter (first exhaust box after the turbo). Test this by undoing the flange in front of this first box - leaving just the downpipe in place - and either remove the rest of the exhaust pipework, or tie (wire) the pipe up very securely. Test drive the car (it'll be amazingly quiet), and see if the problem disappears. If it does, then the cat box is partially or well blocked, thus strangling the exhaust. Either replace the cat, or remove its contents. (See posts elsewhere on the RAV forum.)

2: Blank off the EGR valve with a DIY plate, in place of the stainless gasket, at the engine block end, just beside the air-filter box. (See EGR blanking, also on this forum.) A straightforward job, leaving the engine running on fresh air, not partially recirculated exhaust.

I've had all the symptoms you describe on our 2003 D4D, and both of the above tweaks were needed during the last 3 years. There are other possible avenues to go down, but both of the above are straightforward to check out.

Let us know how you get on.

Chris

[gonmad]

Ok thanks for that i will try it this weekend and get back to you. there are no warning lights come on when it goes into limp mode.