93v6 3vz-fe spits and bogs when cold...

[Brian R.]

Only one bank having trouble is strange. That sounds most like a distributor cap.

Coil or ignitor are most likely unchanged parts, but I don't see how they can only affect one bank.

ECM is possible.

[gen3-tony]

brian, disto cap, rotor cap, wires, plugs are all new. distributor itself seems fine. also, have a good blue flame at the plugs so i'm assuming the coil is good. i don't understand enough about the igniter to rule it out - possibly if it's an oversized transistor/scr/switch that has gotten slow to switch after 14 years?

I'm also suspecting the ecm. i've found some on the auction site, but dont' know the numbers for mine. i could take it out to see if i can't find someone with my same car - a 93 v6 xle, 'j' vin, ca specs, 3vz-fe that knows the toyota numbers.

lastly, since it's the rear bank affected, would this point to a timing belt slip of a tooth now that I've discovered this?

thanks for any and all help.
tony

[gen3-tony]

now that its dark, i can see the light from the timing light better and it seems that all of the wires show 'misses', especially when i give it some throttle. the light blinks then just goes dark for a split second, then starts blinking again. i'm assuming this isn't normal behavior, but the car doesn't sound like it's missing when it's warm. it actually runs pretty well warm. i can see where missing would mess it up when it's cold though. someone tell me if they think i'm onto something or just chasing my tail.
thanks
tony

[davemac2]

Tony,

You better check your timing light on another known good car to be sure. If you are sure it is related to the camry, then you need to check the signal going to the coil itself from the ignitor to see what's happening there. Check the connectors there carefully. What kind of spark plugs are you using?

The only other things I can think of to try is to run it on cold startup without the oxygen sensor in there to reduce back pressure and see what happens. You may want to do a leakdown and compression test on the cylinders to see if it is a burnt valve or something. Maybe check the manifold vacuum too to see if you can detect a bad valve signature with it or by checking for intermittent suction at the exhaust pipe at idle.

dave mc

[gen3-tony]

dave, it's got the ngk platinum plugs. i'll try to test the light on a known good car to see if it's the light or not. thanks for the help. i'll check back in if i can figure it out.
tony

[gen3-tony]

well, i finally broke down and took it to toyota today. they ran a block test and tell me the head gasket is blown. i don't smell any coolant, and the coolant levels don't go down, but they said this is what's causing my poor running when cold and also poor idleing sometimes, hot or cold. they also said the PS pump, hoses and rack are leaking and it'd be $6,500 to fix it, assuming the block was okay when they tore it down. needless to say, i'm not going that route. i'm contemplating replacing the head gaskets myself but the most complicated thing i've attempted on this thing so far was removing and replacing the intake plenum. can someone who's replaced v6 head gaskets join in and let me know what i'm in for, share any secrets they found out the hard way, etc.? also, i'm assuming the TB & waterpump should/have to be replaced as part of this operation also?
as always, thanks for any and all assistance.
tony

[Brian R.]

The head gasket leak doesn't have to be to a cooling jacket. Did they do a compression test? What were the results? They should be on the repair order. That would tell if the head gasket leak was to a cylinder or not.

As far as the PS leak, I would first tighten (torque) the fittings to the hoses, and see if that fixes the leak. Then replace the hose that's leaking and see if that solves your problem. Hard to believe that everything in the system is leaking. They may be taking you for a ride.

I would get a second opinion from a trustworthy mechanic. Get a recommendation from a co-worker or friend.

[davemac2]

Ya, Brian has some good advice there. Check the rack and pump over thouroughly yourself to be sure. If you are willing to take on the head gasket, then you should be able to replace the rack yourself too. A new rack can be had for around $300 I think. I have never done one but I hear it's a pain to get the hydraulic lines off it. You would be better off cutting the lines and taking it all out including the pump and replacing it all.

I started a head gasket job on my wife's 93 V6 about 3 yrs ago. Same car as yours. I did a leakdown test first to identify which head/cylinder was affected since I did not want to do both heads if it wasn't necessary. I advise you do the same. Either buy a leakdown tester or make one. You need a compressor of course. I did not complete that job because when I removed the head, I found that the engine block mating surface had been pitted at the leak point from the combustion gases. It was probably driven too long with an overheated condition. I showed it to a few people and they did not recommend that I even bother with a new gasket because it would not hold with this block damage. There are some procedures out there recommended to repair this; one of them being to use JB-weld to fill the pits. Had I known that before deciding to replace the engine, I may have tried it.

Pulling the head on the V6 for a novice is going to be a big job; maybe 24 hrs of labor. I get the feeling though Tony that you are up to it. Hopefully it is the front head as it will be much easier to do. As to your questions: yes, it is recommeneded to replace the timing belt, the TB tensioner, the water pump. I would also replace the rad and rad hoses if they are not fairly new as well as the thermostat of course. You will need a full head gasket set. I would replace the exhaust and intake gaskets as well as the TB gasket. Use quality metal gaskets similar to Toyota's OEM ones. Without a head job, it will cost you maybe $300-$500 in parts (as recommended above) to do the min. job. Do get a Haynes manual as it helped me. As well, the V6 service manuals are available online under the Lexus ES300 manuals. Study the manuals and procedures for a week to familiarize yourself.

The most difficult part of this job as I recall is removing the crankshaft pulley and the overhead cams. You will need a decent impact gun for the Cs pulley or some tricks with a large socket. You just have to be real careful and keep all your parts organized and clean as you remove them. Don't mix up the camshafts or the lifters. Make a box with compartments to keep them all organized. Get the head(s) cleaned and pressure tested at a minimum, as well as inspected professionally to see if a valve job is necessary. When you re-install the heads, you must make sure the mating surface on the block and head are completely clean. I use the scotchbrite discs with an air grinder, but a lot of people don't recommend this because too much can create low spots. As well, getting the scotchbrite fibers inside the engine can cause premature wear. I don't know if I buy all these arguments, but it is wise to seal the cylinders and coolant and oil passages in the block if you do it. The final critcal part is to follow the head bolt torquing procedure to the 'T' as recommended by Toyota and/or the gasket manufacturer. It is best to ask the toyota techs or research Toyata tech bulletins for the latest head bolt torquing procedure as it can change. Not sure about the V6 head bolts being reuseable or not (ie may be TTY), but be sure.

dave mc

[gen3-tony]

thanks brian, dave, and the rest for your help. sounds like head gaskets are way too much for me to tackle. that was a great description dave. i was hoping for the front bank too, and also that i might not even have to pull the crankshaft or camshaft pulleys. not knowing the guts of the engine, i thought the head might just come off by sliding the timing belt off of it and save me some work and money as this is a 14 year old car and i don't want to put a lot into it, but i don't want to junk/trade it either - because i've had it for 14 years, since it was a baby!
maybe i'll check out the garages and see if they can put a newer 4 banger in it or even a newer 6 cylinder, but i hate working on the 6 so much. living in ca, it might not be legal to put another engine in it for emissions - i don't know. just trying to figure out a way to save my baby.
as far as the ps pump, i don't believe it's leaking cause i had it rebuilt a few years ago. i assume its a hose or the rack, but the weird part is that i only lose xmission fluid when it's hot enough to kick in the hydraulic cooling fan, so i thought it might be something in that circuit, but who knows.
thanks again for everyone's help.
i might have to be another one throwing in the towel on the gen3's!
tony