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Discussion Starter · #1 ·
Hi just bought a 1998 rav4 four door from a guy who couldn't get it running ( 380 kms on body 160 kms on rebuilt motor ) I know the fuel pump is working hooked up the battery charger on jumpbdtsrt so there's lots of juice and it just doesn't seem to want to start. Romived sosrk plugs black and sooty one wasn't even screwed in really black and sooty compression is 150 in 3 if the cylinders 180 in the other one. Towing it home on Saturday just wondering where to start? I'm thinking the timing belt jump? Any ideas?
 

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Discussion Starter · #3 ·
I yes it cranks over fine no problem there haven't checked for spark yet it tryes to start and kind of backfires a bit. The previous owner said it was running really rought and back firing just before it died it progressively got worse I was able to drive just was running rough till it wouldn't run anymore.
 

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if the timing is off then it would explain the backfiring, it will be igniting fuel with the valves open.
I would also get a noid light and check the injector pulses, I have a 3SFE ECU in my graveyard that suffered a failure and forced all injectors to stay open continuously, flooding the engine, its the second time that has happened in a Camry, I have no seen it happen in a RAV, but its the same engine and ECU so its possible.

If the ECU is bad the plugs will be very wet, and the noid light will come on and stay on, rather than flashing then the injector is supposed to be pulsed.
 

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Discussion Starter · #5 ·
Funny thing is the plugs were dry,just sooty. I was thinking maybe a fuel filter but what are the chances its totally plugged? I'll crack open a fuel line when I get it home tomorrow. Hopefully it's not to hard to fix, I did only pay $100 bucks for it and there's new front rotors and pads for the front brakes in the back seat. I'm not sure if they will fit on my 98' 3 door 2WD convertible or not.
 

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Discussion Starter · #6 ·
So ya it never really started so to speak the guy said it got progressively worse till it wouldn't run one day. I'll check for fuel first then if its got fuel I'll take off the timing belt cover and see what kind of shape the belt is in.hopefully its not some expensive computer part!! Oh well.
 

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Discussion Starter · #7 ·
Ok so I've been trying to diagnose my new rav 4 ( 1998 ) it just won't start!! I've checked the compression 150 in three cylinders and 180 in the fourth. Changed the spark plugs and wires , charged the battery, checked fuel at the filter and the pump. When I turn it over it it tried to go , if I pump the accelerator it sort of starts a bit and I can hear little backfires like poping sounds from the exhaust manifold. I've seen spark at a spark plug. Right now I've got the timing cover off and was thinking about replacing the CPS but its $130 before tax a lot if money on a maybe but I've got it apart now, also I do have another rav 4 runs great I could swap some parts out like the coil pack maybe? The guy I bought it off said it had an air cleaner code but it could have been a old one, any ideas?
 

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This sounds like it was worked on by someone who didn't know what they were doing. I have found when this happens, in addition to the original fault, another fault may have been introduced in the puzzle. Are you sure it is fuel? I had an old man dump 3 gallons of kerosene in his tank to clean the injectors. There might be a lot of alcohol in the fuel.


I skimmed over your posts. Did you ever check the timing marks? If the belt jumped, it shouldn't backfire. Backfire is spark at the wrong time, but just one tooth. The belt would have to be off many teeth for it to backfire. If the firing order correct? You said a plug was loose, so someone has been in before you and gave up, or found the problem, told the owner and the owner decided it was too expensive to repair.


The compression readings seem ok, but I'd like to see 170-180 across all 4 cylinders. If a cylinder is washed with fuel from cranking with no spark, the rings will be washed with fuel and won't seal as well.


If the timing marks are lined up (might help to get a second set of eyes on it), put a set of fresh DENSO Iridium plugs in and try it again. Black means rich - too much fuel.


Another thing to consider that has burned me more than once over the years is a plugged exhaust. It's worth considering, and only requires dropping the exhaust pipe from the manifold a few inches. It's far fetched.


Could be the distributor. I have seen these go bad. Is there an accumulation of oil in the cap? Check closely for carbon tracks. This will cause a no-start and backfire. The rotor is suspect also. I've seen the spark eat a hole in the center of the rotor and find the ground at the distributor shaft.


Could be a bad MAF sensor causing the sooty plugs.


I have yet to replace a crank sensor on any Toyota product. Nissan/GM/Ford/ lots but not Toyota/Lexus/Scion. A lot of their parts are made by DENSO which is high quality. I have never had a DENSO part fail that I have replaced.
 

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Discussion Starter · #9 ·
And the plot thickens lol. No I haven't lined up the timing marks yet that's next thing I guess. The spark plugs seemed kind of black and sooty also does it have a distributor? The four spark plug wires go into two coil packs I think? The guy who had it before me said it got progressively worse over a short period maybe it's not getting enough air? I changed out the plugs and wires from my running rsv4 I should try a cidecresder maybe after I check the timing the belt looks fine BTW, thanks!!
 

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I'd suspect (at least) the timing belt too.

Read the FSM and various threads on here (including mine) about changing the timing belt.

The top timing belt cover should come off fairly easily, and with the crank at TDC the cam's sprocket has a little hole next to its mounting bolt in which to insert a tiny flat-bladed screwdriver (engine off, of course -- be safe!) horizontally with the blade tip almost vertical. There's a little detent cast into the head that the screwdriver will push into if the timing is correct.

If the belt didn't jump, it's also very easy to install it wrong. Fortunately the 3SFE is a non-interference engine I hear.

Many other things could cause this too, as mentioned above. Stuck/bent valve, etc.
 

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Discussion Starter · #11 ·
Hey thanks for your reply. Just a thought, if there was a stuck/bent valve wouldn't that show up on the compression check? Maybe the lower compression in the three cylinders is because of that.Anyway I hope I'll find out what's wrong through process if elimination , thanks!
 

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And the plot thickens lol. No I haven't lined up the timing marks yet that's next thing I guess. The spark plugs seemed kind of black and sooty also does it have a distributor? The four spark plug wires go into two coil packs I think? The guy who had it before me said it got progressively worse over a short period maybe it's not getting enough air? I changed out the plugs and wires from my running rsv4 I should try a cidecresder maybe after I check the timing the belt looks fine BTW, thanks!!

I have a foggy memory about it having a distributor or coil packs. If the plug wires go into coils, then I am mistaken about it having a distributor.
:serious


I didn't understand this sentence "I should try a cidecresder maybe after I check the timing the belt looks fine BTW"


I see you have fat fingers like I do, so are the timing marks lined up?


A code reader would be helpful if a code is set. A scanner that can read data would be better, but you would need to know what you are looking at, and if what you are looking at is good or bad.
 

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Discussion Starter · #13 ·
I think it was I should try a code reader lol yes very fat thumb, talk to a mechanic buddy if mine today and he says its more than likely the timing belt skipped a couple teeth, even though the belt looks fine the tensioner might have loosened off and it skipped. Also with the poping sounds from the intake that could be it I'll keep you posted thanks again.
 

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Go buy a code reader and see what comes up.

Progressively getting worse. Getting fuel and spark. Black plugs. Sounds like a clogged Catalytic convertor. Disconnect the CAT ans see if it fires up. It will be loud but for a few moments, but it will tell you if the cat is blocked.

My Rav4 had slack in the timing belt and was slapping the plastic cover. And still it didnt skip a tooth. Unless someone installed it wrong, I doubt it is the TB. If the CAT is clogged. You can gut it and get the car running again. Not sure where you live but I just bought a cat from rockauto.com for around $100.
 

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Discussion Starter · #15 ·
Hey you know you might be right , the motor has been rebuilt but probably the original CAT there's 380,000 kms on the body so could be a good possibility. I guess a code reader would say something about that hey?
 

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Take off the oil filler cap, and have someone else try to start the car. Pretty obvious, when the valves don't move.

Also, you can remove the top two bolts of the timing belt cover, and pull it back 1/4". you can see the un-tense or broken belt.
 
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