1990 Toyota Camry misses(hesitates) when cold.

We have owned my wife's 1990 Toyota Camry 2.0L 4door sedan with stick shift since it was new(you know, the dark gray job--must be a gazillion out there) She has 170K on it and has not abused it. About 12 months ago problems started, lets assume the same that we are currently experiencing. I would best describe it as that of a malfunctioning automatic choke on earlier vehicles. Recently returned after a trip where the car had not been driven for 3 days. Instead of a one second fire, it took 15 seconds of ignition time to fire. (My wife had previously (4 hours prior) flooded the engine on her attempt) Subsequently I had to restart at each stop for engine cut-outs about 3 times. It never has failed to ignite (restart) on these occasions. I drove for 15 to 20 mins and as before was able to eliminate the MISS, eventually to the point where I was able to FLOOR the accelerator UPHILL and get an immediate powerful response. After 15 mins this car is great! I am not detailing an isolated incident but issues when this car is cold, even, and often overnight. Six months ago we had new spark plug wires, plugs and rotor and we assume this accounts for the firepower we get when warm. (fuel filter as well) but we have never eliminated the original problem, accentuated in winter.
The mechanics that did the work (satifactory) did admit to (eventually) not having computer diagnostics so the question is will computer adjustment solve the problem or is there a part (ignition coil?) that is faulty?
Although I ,at 69 am definitely not a do-it-yourselfer I see where help has been offered in other situations.
I thank you for any help. Sincerely, Brian Peck.

 

Those have a couple things that help with the cold start/cold running.

The cold start injector provides the rich mixture for starting much like the choke would on a carburetor equipped engine. That would be triggered by the water temp sensor.

The water temp sensor will also provide the signal for the rich mixture during the period of cold running.

Since both the starting and cold running are a problem, I would look at the water temp sensor. It's just one of the players so there could be some other things, but it's a good place to start.

Hope this helps,

Bob

 

Thank you, Bob for the help. We'll start with the Water Temp sensor. Brian. Will report back.

 

I'd also consider checking the ignition consumables (plugs/wires/cap/rotor) to make sure they are OEM (Original Equipment Manufacturer) Toyota parts
These engines are pretty particular about those, and I have had to replace aftermarket (non-OEM) ignition parts in these engines in less than 6 months before (I believe some after 2 months)

 

Hello Bob, once again,

First of all, I believe all parts to be OEM. I did buy a Water Temp Sensor and I did install this about a month ago. As we have mild weather here I have been very cautious about the problem being solved. Everthing OK on daily starts etc. but from Nov 10 thru 17 we were out of town. BINGO!!!
The first start after a 10 day absence resulted in a 25-30 second ignition whirr before IGNITION!!! I then went through a 20 minute WARM UP drive with the COLD symptons being very evident--cut outs and hesitations specifically. After the 20 mins it was great as before. I have concluded that the original Water Temp sensor was OK and that the new one has not improved matters.

So you mentioned other steps if this did not work.

Would you be so kind as to suggest what I should look at next.

Thank You Brian.

 

Assuming your ignition components (plugs,wires,cap,rotor) are in good shape and the timing is correct, I would check the fuel pressure prior to starting. Less than specs would affect the fuel/air mixture.

Another possibility would be a vacuum leak at the throttle body, intake gasket, or any of the manifold vacuum lines to include pvc line.

The logic behind the fuel system issues would be that anything that would result in a leaner mixture (such as lower fuel pressure) would compound itself when the engine is cold.

When the engine warmed you would still have the same issues (unless we're talking about an air leak that sealed itself as the component material warmed and expanded), but the performance of a cold engine would be affected even more than one which had reached operating temperature.

Hope this helps,

Bob

 

Thank you very much Bob. I will copy your e-mail comments and take them into a shop and pursue it that way. It seems that if we use the vehicle every 12 hours or so, combined with our mild weather we have no trouble. When left for 3 days or more is when we have these problems.

Sincerely, Brian.