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I have 165000 kilometers (approx 100000 miles) I am thirds owner so have no maintenance records. Mileage is terrible also but changing 02,s tomorrow and will see but i also notice that while the car starts easily and idles very smooth with no noises or ticking BUT if u press hard on gas under load while driving the engine will rattle or tick bad,almost sound like a Desiel.Would that be the valves need adjusted and if so are they shims in pots (cams have to be removed) or are they a nut with a screw that can be adjusted like hondas or earlier Toyotas.Will valves being too loose effect mileage or power.I did a compression test and got 208/210/215/220 HOT which i thought was excellent!
 

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Sounds like you are getting pre-ignition from a build up of carbon. I would run some Sea Foam thru the engine. It does a good job of removing carbon build up. I beleive all Ravs have hydraulic lifters and are self adjusting. Some one may correct me if I am wrong
 

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Discussion Starter #4
I did run a can off seafoam thru the tank when i got the Rav plus i ran some direct as per directions.Should i do it again,will it take a few tanks and a few bottles to get the results and remove all the carbon.By the mileage and years this car was prob ridden very little and in town mostly,was a lady driver from new till i got it!!
 

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I have a 96 Rav4, front wheel drive auto tranny. Mine rattles like a can full of marbles on regular gasoline. I have to run premium (93 octane USA) in the summer with the air on. Right now I'm getting away with mid grade (89 octane) because I'm not using the AC much this time of year and the weather is much cooler. When I'm running premium there is no pinging at all.. I'd love to get to the bottom of the problem myself. A lot of people recommend Sea Foam but I have yet to read about anyone with a Rav with a pinging problem actually correct the problem by using it.
 

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I agree this is most likely pinging, I haven't had this problem with my rav but I have used Seafoam in it and it did reduce the carbon on the piston crowns (you can see them looking down the plug hole), I then used distilled water, sucking it in to the TB the same as you do with Seafoam and it completely removed all carbon from the Pistons. Which way you go is up to you, one or the other or both methods.
That said, it could be the knock sensor, I have also replaced that too but not before removing all the carbon which is much easier and cheaper.
The valves are not self adjusted but adjusted using shims.
 

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Discussion Starter #7
Thx everyone,after installing the new 02,s today,will try another can of SEAFOAM since i have one on the shelf
plus will try running some high test 93 octane thru the tank.Those Compression numbers are pretty high for this lil motor.I have approx the same compression numbers on my Harley 1200 Sportster and have to run min 91 or it will ping and knock u can here it under hard throttle in high gear at low rpms.Pretty much the same with this Rav.
Why would Toyota make the compression so high yet state in the manual that u can run 87 octane.I can adjust my timing on the bike with a fuel controller,retard or advance and adjust the fuel mapping BUT cant do that
on this old Rav.I think that the timing may be to advanced and or with worn parts,ie:weak fuel pump,valve lash slightly out off spec,carbon build-up ect even the TPS could be out slightly (need to check that) all could contribute to ping and rattle under load.Im sure these 4.1 Ravs dident ping when new so somethings not tuned or running right.Im not giving up just yet.Will advise if i figure it out.
 

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Sounds like you are getting pre-ignition from a build up of carbon. I would run some Sea Foam thru the engine. It does a good job of removing carbon build up. I beleive all Ravs have hydraulic lifters and are self adjusting. Some one may correct me if I am wrong
What is this Seafoam i already heard alot of it but i dont now what it is ?

I am from belgium can i get it here to ?
 

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Please do update. BTW. Mine is also relatively low mileage. It had 70.000 miles on it when I bought it last winter. The Carfax said it averaged 4000 miles a year for the last 10 years.There's no record before that. I suspect it belonged to a winter only resident of Florida. The paint is shot from sitting in the sun but aside from the pinging and the paint it's like driving a newer vehicle. The engine otherwise runs great and has plenty of pep. Here's another twist to the story. I bought it from a new Toyota dealer. When I was signing the paperwork the sales person told me she had driven it to the gas station and filled it up. The pinging didn't start until after that tank of gas when I put regular gas in it. I can only assume the dealership knew about the problem and told her to put premium gas in it. At first I thought I put bad gas in it but after trying other brands it didn't change a thing.........until I put the premium gas in it which stopped it totally. I took it on a couple highway trips which should have cleared away most carbon build up if there was any..
 

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If you have a 96, does it have a distributor? I don't know much about these yet, but can the base timing be altered by moving the dizzy, or is it all controlled by the ECU?

Otherwise, it could possibly be faulty/clogged injectors, fuel filter or fuel pump. Also worth trying an injector cleaner with PEA.
These are US ones I know of *
* Chevron Techron Concentrate* (32% PEA, based on an older published MSDS spec sheet)
* Gumout Regane (30-40% PEA content based on published MSDS data)
* Redline SI-1 (30-50% PEA based on MSDS data)
* Amsoil Performance Improver (28-37% PEA based on MSDS data)
* BG Products 44K (unknown PEA content since they reformulated—does anyone have this data?).

*Info copied from this thread What % pea? | Fuels and Fuel Additives: Gasoline and Diesel | Bob Is The Oil Guy

*Also found another thread which says Techron has the highest PEA% Chevron's Response on PEA in Techron | Fuels and Fuel Additives: Gasoline and Diesel | Bob Is The Oil Guy
 

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Discussion Starter #11
UPDATE: OK i got the 2 02 sensors changed and after a quik ride noticed smoother engine running and slightly more responce.But deisel sound still there so i then added a full can off Seafoam to 1/2 tank and then let car idle for 1 hr,after that i added 1/4 can thru the brake booster hose then let car sit for 1.2 hr.Then i ran the engine hard till no more smoke came out exhaust and test rode car,mileage has definately improved as the needle before would drop before your eyes now it really takes some time before u see the gas needle move.Still a bit off rattle though so i exhausted the 87 octane and ran a 1/2 tank off 91 octane and finally very lil noise noticed on throttle as before.I thing a combination off everything has definately helped.I am now testing to see what my milage is and i will advise when i run thru a half tank.I really hoped i wouldent have to run super 91 to get the engine to stop pinging but that looks like the case.I think theres to much compression for the timing set-up.
I still think that the TPS may be out slightly .I di read that 96/97 Ravs had TPS issues.Toyota changed some engine stuff in 98 on 4.1 models.even the 02 sensors are different,there were many small changes to the entire vechicle from 98 on,most for the better.
 

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1. From my limited DIY motoring & mechanical knowledge... poor fuel consumption and pinging/pinking under load would have me looking straight to ignition timing.
2. Fuel octane value does play a role... I assume you are using unleaded fuel. Leaded or heavy metal fuels were less prone to pinging / pinking in the earlier years before being discontinued. The octane rating is an index of a fuel's ability to resist engine knock at high compression ratios. This makes sense of less pinging with the premium fuel vs the regular lower octane.
3. With electronic ignition systems usually there isn't a vacuum advance on the distributor... a leak on the vacuum hose would affect timing and would most definitely give a sluggish acceleration. Electronically , the sensor in the distributor could be giving incorrect feedback resulting in timing change.

Just a few ideas...
Andy


https://en.wikipedia.org/wiki/Compression_ratio
 
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