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Hello everybody,
I’m a long-time-YT-watcher first-time-forum-poster to ETCG.
I have a 1990 Camry with the 2.5L V6 and I’m having a couple issues and I’d like to get your wise input.
The easy problem is that the heater won’t really heat up the cabin. Engine temp is fine but I get very little heat and it comes in spurts.
I have discovered that this car has a “heater control valve” that is in the middle of heater hose line to the heater core. I have located it mounted on the firewall and I noticed there is a cable connected to the arm/lever that operates the valve. I noticed the cable itself is a little corroded between the cable/wire and the sheath. I sprayed it with PB blaster yesterday but no love yet.
My question is whether I could dismount this cable safely to manually open the valve or to check if that is in fact the problem. I also would like to know what actually is supposed to actuate this cable/lever/arm. The HVAC controls are all buttons, nothing mechanical except the slide between cold(blue) and heat(red) on the panel.
My more serious, potentially labor intensive project is my check engine code for the knock sensor. I have verified this with the jumper wire method. I get five flashes, 1.5 second pause then two flashes. There is a 4-5 second gap and this same sequence is repeated. According to the info I have on this car the OBDI code “52” is a knock sensor fault. (http://www.troublecodes.net/Toyota/)
Another OBDI chart I’ve located suggests that a OBDI code of “5” is the oxygen sensor but it’s not the Toyota one.
I am looking to find out if I can relocate this knock sensor without taking the entire intake manifold off and all that entails. I know I would need a new knock sensor and the pigtail that connects to the engine wiring harness to do that and I can’t seem to locate this pigtail.
The symptoms of this CEL is about 16 mpg no matter if I’m driving highway or city. It should be 19-23 according to the info I’ve located.
I can start the engine and let it idle from a cold start with no CEL. However, as I take off and the tach shows about 1700 and/or the transmission shifts into second gear the CEL will illuminate again and stay on.
I worry that if I can’t locate a pigtail I will discover that the sensor is fine but the plug has completely disintegrated and I’ll be dead in the water with my intake manifold off until I find this plug/pigtail if that’s even possible. Is it? Or will I have to just have to jury-rig a new plug?
I am a pretty experienced shade-tree/DIY’er. I just replaced the timing belt, tensioners and water pump on this car with no issues.
I replaced the coolant when I did this and I made sure I bled all the air out of the system but my heat is still very sporadic and very inadequate for the 10-20F temperatures around here right now.
I apologize for the long post but that’s just how I am. :blush:
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UPDATE: The sheathed wire that actuates the heater control valve was sticking. It looked like old lithium grease that was keeping the wire from moving freely within the sheath. I finally got it to move freely in and out of the sheath. I brushed it off with a brass wire brush and lubed it with some PB blaster. I also adjusted the wire mounting clip so that the lever was in the right place for heat and cold.
Yes, the heat is a “little” better but still not right.
I checked the temp of the air on heater and recirc and it was never over 80F in the center vents. It never got over about 68 in the side vents.
The engine was at operating temp.
I’m thinking that the heater control valve is sticking/broken or otherwise obstructed internally.I think I will just bypass it for the winter and see how that goes.
As for the heat I would first start by bleeding the cooling system especially since you just did the water pump. Anytime you do any kind of cooling system service it’s imperative that you purge the air from the cooling system, if not you can get all kinds of problems including no heat. Don’t worry that you don’t have a bleeder valve, ignore that part of the video but do everything else in the video the same. Also you don’t need one of those funnels, just place a drain pan under the radiator to catch any coolant that might come out.
As for the knock sensor code you’ll have to follow the test procedure for that one. You can NOT relocate them. they are ‘tuned’ to their locations for optimum operation and they cannot be relocated. To be honest you first need to find out if you have the code 5 or the code 52. I wouldn’t do anything until you figure out what code(s) you actually have, you don’t want to be diagnosing the wrong system.
Keep us posted on your progress.
Thanks Eric.
I did bleed the radiator and I’ve noticed that when it’s really cold, like in the 20’s the heater never really works that well for some reason.
However, once it warms up into the 30’s and 40’s it blows really hot.
So, I’m assuming there’s no blockage.
I also notice that when normal operating temp is reached, even when it’s bloody cold out, the electric cooling fan will kick on.
I’m thinking about blocking off the radiator with some cardboard or something when it’s really cold out but I don’t know why I should need to do that.
I’ve triple-checked the code and it is five flashes, 1.5 second delay, two flashes, about five second gap then it repeats.
According to the page I found that is the knock sensor.
This car had a power steering fluid leak before I got it and the O2 sensor has quite a bit of this fluid on it as it sits right below the PS reservoir.
However, there really isn’t a O2 sensor code as far as I know.
Before I tear everything apart and replace the knock sensor I may replace the O2 sensor and see how that works.
Worst case scenario, I can replace the leaky valve cover gaskets, spark plugs, spark plug wires and the ignition coil while I’m in there for the knock sensor.
On an unrelated topic, do you know why my ignition coil will short out when it gets wet? The wire that comes off the ignition coil and goes to the distributor will short out if there is water standing on top of the ignition coil.
Would that be the wire or the coil itself? I’ve seen the spark myself and the engine dies. It looks like it comes from the wire down to the pool of water standing on the coil.
If you see arcing in the ignition wire then it’s likely the wire itself. It could also be that the insulation in the coil has failed which would require that you replace it. I often don’t completely remove those intakes. I leave most of the stuff connected and just hold it back with a bungie cord. This might save you some time if you understand where I’m going. The hardest part is disconnecting the bracket on the back of the engine. BTW I doubt that replacing your O2 sensor will have any effect on the knock sensor.
Good luck and keep us posted.
Just an update on this situation.
First, replaced the distributor with a rebuilt one…..but it had roughly the same resistance over the connections that the original one has. I did this because I read somewhere on the interwebs that a distributor with too high resistance could cause this code.
According to my Alldatadiy subscription for this car the resistance should be much lower than what I have now. I have 230 to 240 Ohms resistance across all of them when I should be having 160-190. I haven’t remedied this situation yet.
I replaced the distributor cap and rotor but that didn’t resolve the knock sensor code either.
I still have the arcing issue from the wire connecting the distributor to the coil…need to replace that.
My MPG was horrible, car was running rich but I had no O2 sensor code.
Drawing on my O2 sensor travails on past vehicles I ventured to actually test the O2 sensor voltage.
I tested the after catalytic converter sensor and found that it consistently read on the low end (.1V IIRC) at operating temps. The range is supposed to be .1 to .7….again IIRC.
So, this was telling the computer the engine was running lean…even when it was so rich there was some black smoke coming out the exhaust and I was getting horrid MPG even when babying the car never getting over 50 mph to conserve fuel.
I didn’t bother to check the pre-cat sensor because it was covered in power steering fluid from the previous owner’s chronic power steering leak from the hoses.
I found and bought the proper sensors (California model…..) from Amazon for $89 combined for both sensors.
VOILA!
My MPG is where it should be now.
However, my knock sensor code is still there.
Then, just now, as I was looking up some more info for this response I discovered that the 2VZ-FE engine is supposed to be running PREMIUM FUEL with an octane not less than 91…..WTH?
It sure as hell doesn’t state that on my gauges but that is what Alldata is telling me.
My next step will be to fill it with some Premium I suppose.
If I hadn’t only paid $700 for this car that has been reliable and has a working A/C I might actually be bothered by the hassle….. 🙂
Well…..91 octane makes a huge difference in performance and that surprises the hell out of me. The gas gauge just says “unleaded fuel only” with no mention of premium.
The manual didn’t come with the car so maybe it’s in there.
The alldatadiy.com spec sheet said it’s required though and it definitely makes the car run much more powerfully.
I notice it most on hills and taking off.
It’s impressive..and I figure after a fillup it basically costs me one more gallon than regular.
However, the knock sensor code came back.
The CEL doesn’t come on until I hit 1600 RPM which is when the knock sensor is supposed to be sending the voltage back to the computer.
I thought I checked the sensor at the plug and it produced the voltage it was supposed to but I’ll have to double check that.
Maybe I got the wrong plug or I didn’t rev it to 1600 or higher when I checked it.
We’ll see…I sure as hell don’t see me taking off the intake, fuel rails, injectors and intake manifold to find out.
If it does produce the voltage in the appropriate range I’ll just check the wires back to the computer I guess.
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