Prado V6 fuel consumption

Submitted: Tuesday, Jul 02, 2002 at 00:00
ThreadID: 1403 Views:3498 Replies:5 FollowUps:6
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I have a 97 RV6 Prado that runs around town mostly, with a good highway run most weeks. It does get to the bush every now and then.
I have been averaging 14 –15 lts/100k, for nearly four years. I believe that the economy was going west before my recent changes (full length roof rack, OME lift 30mm, Coopers 235/85/R16, the tyres give 105 k when speedo reads 100). I thought the roof rack would hinder the fuel econ, however with the slightly larger tyres it would help. (runs 110 k @ 2850rpm). The fuel econ is now 20 lt/100k on the highway!
I believe the car maybe running too rich, as smell soon after pulling up is quite strong. Any suggestions or similar experiences?
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Reply By: Mal58 - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
Anthony,
I have a Prado GXL. I achieve typically around the 14-15 lt/100km. Fuel economy, however does occasionally take a dip for the worse (18-19 lt/100km). I believe that I can correlate it to a couple of things,
1) Disconnecting the battery for an extended period of time (ie. while working on electrical things eg dual battery system, driving lights etc),
2) Particular brands of petrol,
3) Using the Air conditioner in stop start city traffic.

Having taken the above into account, I would check your calculations for the change in speed. I did a quick check based on the RV trye size (215/80/16) cf your new tyres. I did this at,

http://www.fernblatt.com/longhurst/tyre_bible.html

This is an increase in 7.4%. You have to take this into account when working out how many kms you have actually covered compared to the speedo reading. (ie speedo = 100 km, actual distance = 107 km)
The other thing you should check to, is tyre pressure as I have found that this makes a big difference. I assume the Coopers are an A/T and should be run at a higher pressure than the ADR placard states for the original Grandtreks.

Hope some of the above helps,
Rgds,
Mal58
AnswerID: 4588

Follow Up By: Anthony - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
Mal58.
Thanks for your comments. I can exclude most of the items on your list, including taking into account the distance travelled (I used speedo +5%).
I do agree with your calcs.
The last trip did not have aircon on, and tyre pressure at either 40 - 45 psi.
- Extra RPM on road (simular to old RPM with original tyres) does not work.
- Brands of Petrol is one I have considered, and am presently trying alternate supplier, as past 8 months has been 90% with one outlet.
- I am also trying fuel addative to ensure injectors are clean.

Not too many different things at once.
I will let you know how I am getting on.
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FollowupID: 1966

Follow Up By: Anthony - Friday, Aug 09, 2002 at 00:00

Friday, Aug 09, 2002 at 00:00
Ray,
I have had a 120,000 k service, and asked the tech to check the points raised by you. He indicated that he found nothing wrong & ran on road fuel econ checks. His results came up good, like my past results.
He even worked out that the tyres were larger, and made corrections when calc fuel econ.
I have taken the car on two long runs, and the fule econ is back to 15.5 l/100 k, with the roof rack on.
I have also changed fuel supplier, and tried injector cleaner. The service has made the difference.
Regards
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FollowupID: 2401

Reply By: Rob P - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
Anthony,

You probably have already checked this but make sure that your air filter is clean. Recently I was suffering very high fuel consumption (18 to 19L/100Km around town)in my Prado. After giving the air filter a thorough clean, my consumption dropped down to around 14 to 15 L/100km which is normal town driving. Hope that helps...

Cheers
AnswerID: 4602

Follow Up By: Anthony - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
Thanks for suggestion.
I have not checked, as car is serviced every 10,000 km. I will check, and I hope it is that simple.
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FollowupID: 1967

Follow Up By: Rob P - Thursday, Jul 04, 2002 at 00:00

Thursday, Jul 04, 2002 at 00:00
I've had my vehicle serviced regularly since new, as per the standard service shedules, but I have found that they are not that thorough.....it pays to check these things yourself !!
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FollowupID: 1986

Reply By: greg - Thursday, Jul 04, 2002 at 00:00

Thursday, Jul 04, 2002 at 00:00
Anthony a roof rack can make as much as 1-2 kpl difference depending on the wind direction. Driving technique can also make a big difference along with wide tyres.
AnswerID: 4657

Reply By: Mal58 - Friday, Jul 05, 2002 at 00:00

Friday, Jul 05, 2002 at 00:00
Anthony, I am a memeber of the toyota prado discussion group on yahoo. I new post came in the last few days about toyota deisel owners having poor fuel economy. Within the reply, was some information concerning Petrol as well. I have copied and pasted for your info. "....and the sensor reading inaccurately causes increased fuel consumption. Many petrol Toyotas also have had problems with oil hitting their MAP sensors (a pressure sensor on the intake side). How do you check for this? Unplug and Unscrew the air intake temp sensor carefully (Its the 24mm hex thing sitting above the throttle valve) and look at the bottom side of it for any black oil. I would be surprised if you didn't have oil smeared over the sensor....." The reply also mentions that the problem can get worse if doing four wheel driving where the vehicle is on acute angles. Possibly worth a check.
Rgds, Mal58
AnswerID: 4672

Follow Up By: Anthony - Saturday, Jul 06, 2002 at 00:00

Saturday, Jul 06, 2002 at 00:00
Mal58,
Once again thanks for info. I have received basically the same advice from others, as well as dirty injectors etc. I can now confirm that on the open road, running the same trip twice, we obtained 17.2 lt/100km ( I was driving the first time, the wife second). The test was over a full main tank.
I am giving a fuel additive a chance before I let mechanics have a go.
I have been told to de gunk the head and injectors will cost a penny or two.
I will however check the sensor and air intake system.
Thanks.
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FollowupID: 2001

Reply By: Mark - Tuesday, Aug 06, 2002 at 00:00

Tuesday, Aug 06, 2002 at 00:00
Hi Anthony

I have a 97 RV6 as well. It has OME, no racks, and exactly the same tyres! I have only had the car for a few months, and when I first checked the economy it was about 22l/100km!! around town driving conservatively. The last check I did was 18l/100km around town after a highway trip. I have just put some injector cleaning stuff in the fuel and plan to get Toyota to do a gas test on it - apparently there is an adjustment that can be easily made to fix mixture problems. Also there is a hot-wire oxygen detector behind the air filter casing that can be checked for dust etc.(hope there is none there!).

It has done 112000km now and I am considering a comprehensive service to try to get much better fuel consumption.

On another matter, Toyota has agreed to install a boom vibration kit free of charge! I get the 2800rpm vibration in all gears. All I did was ask!!

All the best
Mark

AnswerID: 5442

Follow Up By: Thommo - Tuesday, Aug 06, 2002 at 00:00

Tuesday, Aug 06, 2002 at 00:00
Hi Mark,
I have just had a 120,000 km service, and I asked them to check the system thoughly. They said they found nothing wrong, however subsequent trips to Mt Hotham and Melbourne have given 15 lt/100 k. That is after adjusting the klm covered by adding 10% to the speedo.
The service guy was up to speed on this, and said even though the tyre specs should give 7% error, the actual diameter measured indicates 10%.
As indicated, they said they found nothing wrong, but its all working much better.
I did give the car 2 hits of the injector cleaning liquid.
I have not had the "boom"problem at all.
Thanks for you reply.
I hope you enjoy the Prado.

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FollowupID: 2346

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