4runner losing power

Submitted: Monday, Oct 19, 2015 at 16:56
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My 1992 4 runner is losing power on hills lately. Has anyone had this problem or could advise what may be the problem please.
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Reply By: fredwho - Monday, Oct 19, 2015 at 18:47

Monday, Oct 19, 2015 at 18:47
I had a similar problem with my '99 Hilux and needed a coil in the engine replaced. Sorry I'm not that technical!

AnswerID: 591746

Reply By: Life Member TourBoy, Bundaberg - Monday, Oct 19, 2015 at 19:15

Monday, Oct 19, 2015 at 19:15
Hi Terry, is it petrol or diesel? how many Km on the clock? original engine? filters last replaced? are you using crappy malaysian discount fuel
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AnswerID: 591747

Reply By: Member - Terry E (NSW) - Monday, Oct 19, 2015 at 19:34

Monday, Oct 19, 2015 at 19:34
Many thanks , much appreciated
AnswerID: 591749

Reply By: Member - Terry E (NSW) - Monday, Oct 19, 2015 at 19:42

Monday, Oct 19, 2015 at 19:42
Hi Dave, it is petrol, regularly serviced and both fuel and air filters replaced at regular intervals. It seems to be a problem since I last had the timing belt changed at 290,000. Now coming up to 310,000. It has never been a powerful vehicle ( seems to me the power to weight ratio was not good) It is an automatic V6 and really struggles up hills now. You have to take it out of overdrive and get a good run at a hill now and even then it hunts gears a lot. Many thanks for your inquiry.

Cheers Terry.
AnswerID: 591750

Reply By: Ron N - Tuesday, Oct 20, 2015 at 00:16

Tuesday, Oct 20, 2015 at 00:16
Terry, I'd suggest you need to have the injectors removed and cleaned and serviced.
The injectors have a little basket-style filter in each of them that needs to be replaced - and you can get a full injector service kit off eBay.

Injector service kit

The injectors themselves probably need cleaning as well. You need to put 12V power with a switch to the injectors when they're out, then give them a squirt of Carburettor and Throttle Body Cleaner.

Then put an air hose blow nozzle to the top of the injector and hit the switch momentarily and repeatedly until you get a free flow of air through the injector when the switch is hit, and the injector is open.
Make sure you have firm electrical connections with no chance of sparks, C&TBC is highly volatile.

You probably also need to check if you're getting full throttle plate opening when the accelerator is fully depressed.
Get someone to press the pedal to the floor and check that the throttle plate is wide open when the pedal is on the floor.
If it's not, look under the dash where the throttle cable is attached to the top of the accelerator pedal, and in the bracket there should be a rubber bushing that keeps full tension on the throttle cable.

This rubber bushing will degrade and collapse with age and reduce the tension on the throttle cable - and as a result, the cable will not open the throttle fully. It will need replacing, if this is the case with your vehicle.

The 3.0L 3VZE V6 engine in the 4Runner never has been a powerful engine, they have always been a bit of a slug.
Around 300,000kms of engine wear, isn't helping any.

You could also do a compression test to determine if compression is low on any of the cylinders - in which case, the valves probably need a grind as well.

Is the oil consumption still modest? It should be no more than a litre of oil every couple of thousand kms.
You can check whether any compression loss is either ring-related or valve-related, by doing an initial compression test - writing down the figures - then squirting a teaspoon of light-grade oil into each cylinder, and re-checking the compression.

If the next compression results show a decent improvement in compression pressures, then the rings are seriously worn.
If there's little difference in compression results, the valves are no longer seating properly.

Cheers, Ron.
AnswerID: 591754

Reply By: Member - Terry E (NSW) - Tuesday, Oct 20, 2015 at 09:04

Tuesday, Oct 20, 2015 at 09:04
Hi Ron, Thank you for your most detailed reply, much appreciated. I had thought it may be the injectors so I will have that checked when I put it in for service next week. It does not use oil, only occasionally I have to put in a drop between services. I will also get them to do a compression test.

Many thanks for your information

Cheers Terry.
AnswerID: 591757

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