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  1. #1

    Petrol Engine - Injectors do they need to be cleaned or replaced.

    Hi,
    I have had my 1998 Petrol Prado from new. It has done only 230,000 Kms.

    I have decided to keep it a bit longer, so there are a few jobs on the to do list, that I hope to tackle soon.

    One of the jobs is to fix the leaky rocker cover gaskets. I have had the parts for over 12 months, so must pull my finger out and get it done.

    While the rocker covers etc are off , I was wondering whether it would be prudent to take out the injectors and have either have them cleaned or replaced.

    The car seems to go well, but it no longer returns the 11-12 litres / 100km that it used to when new.

    But then again, I do have All Terrain tyres and I did go up a size (265/75 R16).

    Typical fuel consumption is probably closer to 14-15 litres / 100 km.

    So what are your thoughts ?



    Cheers,
    Mal

  2. #2
    Not sure if mine were done before I got it at 280k but they haven't been touched since and now at 435k. Getting about 14 L/100 with same size tyres as yours running 38psi. Mostly highway use these days as the fun trips are now done in the 120!

    Edit. Pretty sure tyres are 275/70/16.

  3. #3
    Our 1999 Prado (got it new) has only done 208,000, never had any reason to do anything to injectors.
    Michael and Kelly

    1999 Prado Snowy 3.4L petrol, Ultimate Suspension 50mm lift (2013), BFG A/T, bull bar, winch, Twine hot water shower, home made rear drawers, Shippshape car top tent, UHF radio, tablet GPS & Navman GPS (both running OziExplorer), Spot 1, solar panel, second battery, inverter, Engel fridge and more

  4. #4
    Advanced Member
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    When I had the 120 V6 I used to run a bottle of Nulon injector cleaner through it before a longish trip and filled it with 98. Always went better. The injectors were fine at 160000 km when I sold it.

  5. #5
    Ive 325k and was thinking about looking at them soon

  6. #6
    Typical fuel consumption is probably closer to 14-15 litres / 100 km thats about what I get with the same size wheels as you clean the maf I don't think you need to bother about the injectors.
    Does anyone ever check the valve clearances on a 5vz fe or is it just something the manual says to do that doesn't seam to wear and no one does it I've read at least 3 blokes here fixing leaky valve covers and none of you seam to bother? Mine were in spec at 255k when I did the leaky gaskets.
    I got myself some Big Horn Maxxis and was telling my landrover lover mate he said what size did you get I told him 265/75/16 he said I didn't know they came that small.

  7. #7
    Out of control poster! Anth120playdo's Avatar
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    Quote Originally Posted by mal58 View Post
    Hi,
    I have had my 1998 Petrol Prado from new. It has done only 230,000 Kms.

    I have decided to keep it a bit longer, so there are a few jobs on the to do list, that I hope to tackle soon.

    One of the jobs is to fix the leaky rocker cover gaskets. I have had the parts for over 12 months, so must pull my finger out and get it done.

    While the rocker covers etc are off , I was wondering whether it would be prudent to take out the injectors and have either have them cleaned or replaced.

    The car seems to go well, but it no longer returns the 11-12 litres / 100km that it used to when new.

    But then again, I do have All Terrain tyres and I did go up a size (265/75 R16).

    Typical fuel consumption is probably closer to 14-15 litres / 100 km.

    So what are your thoughts ?



    Cheers,
    Mal
    No.
    Recommend never using 91
    Just use premium.
    Cheers, Anth - Technician
    Prado 1kd-ftv D4d specialist

    SYDNEY trip in April
    FRESH Injectors @ 120,000k, ONLY use NEW DENSO & pipes
    NO CHIPS NO TUNE UPS - piston crack risk it - feeling lucky?

  8. #8
    Quote Originally Posted by Anth120playdo View Post
    No.
    Recommend never using 91
    Just use premium.
    Can I ask why mate it doesn't go any further in distance I've put it in plenty of times it may give a little more power but how often do you drive at full throttle? Most of the time 91 is all I put in . The owners manual says 91 is all right.
    I got myself some Big Horn Maxxis and was telling my landrover lover mate he said what size did you get I told him 265/75/16 he said I didn't know they came that small.

  9. #9
    Thanks Guys,

    Happy to just do just the gaskets.

    Cheers,
    Mal

  10. #10
    Hey Guys,
    I fitted a 2.5inch mandrel exhaust to my 90. The fuel economy and power improved noticebly.I get about 1300km's out the 2 tanks on the highway. About 1100 around town. She's done 345000 and not touched the injectors. I run injector cleaner through every couple of tanks.

  11. #11
    Out of control poster! Anth120playdo's Avatar
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    Quote Originally Posted by pradosteve97 View Post
    Can I ask why mate it doesn't go any further in distance I've put it in plenty of times it may give a little more power but how often do you drive at full throttle? Most of the time 91 is all I put in . The owners manual says 91 is all right.
    Because 91 is the lowest quality. Many mistakes end up in that crap.
    Premium fuels have additives to keep your engine clean. The whole fuel systems says cleaner.
    Fair tests I have done on a number of vehicles show better fuel economy from premium fuels.
    Camrys get up to 1 lt per 100 better with 95. More efficiency.
    Cheers, Anth - Technician
    Prado 1kd-ftv D4d specialist

    SYDNEY trip in April
    FRESH Injectors @ 120,000k, ONLY use NEW DENSO & pipes
    NO CHIPS NO TUNE UPS - piston crack risk it - feeling lucky?

  12. #12
    Advanced Member Brett1979's Avatar
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    I've just turned over 359,000km and am getting similar figures to you. I changed the rocker cover gaskets a little while ago and didn't bother with changing the injectors. I've heard they're pretty much good for life in the 90 series. I run a bottle of Nulon injector cleaner every now and again. While doing the job it's a good time to replace your spark plugs. I found one of the spark plugs wells on mine was half full of oil when I took mine out. It didn't effect the performance in anyway, but was glad I discovered it when I did. Your kit will or should include new spark plug seals. Replace the old ones with the new. Just make sure you don't go too light on the goo when applying it to the half moons or you'll be doing this job all over again. You'll know when you have them uncovered. Clean up the metal surfaces thoroughly with metho and a rag before fitting the new gasket. It's also a good opportunity to spray your MAF sensor clean while you've got the air intake pipe off if you've never sprayed it before. Take your time and do the job right. Tape masking tape to every bolt you take out and number it and write the corresponding number next to the hole you took the bolt out of. Keep all your removed bolts in a bucket or something so you don't misplace one. If you do any of the work at night in the garage, a nice big BRIGHT light hung above the back of the motor can provide a better visual then working during daylight.

    This will hopefully be a job you'll only need to do once on your car during the time you own it for. If you're going to keep your car for another 100,000-150,000km or so you're going to be replacing your front end due to worn ball joints, this includes the tie rods, rack ends, upper and lower ball joints. Easy work to do but you'll need to expand on the tools you've got if your tool box is a fairly standard sort of set-up. If you've never removed ball joints before, I would suggest you research the tips to removing them to save yourself some frustration and panic if what should be a couple of hour job, actually turn into a 2-4 day ordeal because you can't crack a tie rod or lower ball joint loose. My tip, hammer a pickle fork deep into the coupling to be separated, then using a heavy hammer (not a light one), crack the knuckle repeatedly and hard. She'll come loose after a bit if it's stubborn. If it's super stubborn, spray it with Inox or something, let sit for 30 mins then bang it again and again. It'll pop loose. If you've got a 2 inch lift, raise your hub up by 2 inches while the car is on support stands by putting a trolley Jack under the lower ball joint part. You maybe up for a CV shaft or two as well. Usually because a rubber boot lets go after a long time. Sway bar and sway bar link bushes will be cactus by this time too if they already aren't on their way. All good fun to look forward to with a higher kilometre car. But the good news is that with the petrol 90 series it'll just be normal wear and stuff that you'll ever be fixing up on them from time to time. Theyre a very reliable car. Have you done all or most of the other maintenance on it yourself over the years?
    Last edited by Brett1979; 20-03-2017 at 07:08 PM.
    98 GXL 3.4L V6: TJM 2" lift, Airtec snorkel, TJM T15 steel bull bar, 8500lbs T-Max winch, 100w Roo Lite Spotlights, TJM alloy roof cage, Dual batteries, breathers to everything, TJM Air Compressor, Maxxis Bighorns. 359,000km and counting.

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