Random CEL and Hesitation resolved

[RitzyFestiva]

As I had posted on here I was having issues with my 93 Festiva hard starting and random CEL generation followed by engine hesitation when the CEL cleared. After monitoring for some time, I noticed that the issue appeared only after the engine started getting warm up till normal operating temperature. Once stopping and turning the engine off, I would have difficulty in starting the car, requiring holding the accelerator all the way to the floor and after 8-10 attempts the engine would finally begin to catch acting as if it was only firing on 2-3 cylinders until finally running. Random CEL during warm up as well and as the CEL cleared, the engine would hesitate. The smell of raw fuel was always present when running at idle and would also run up the rpm randomly. Lacked power on hills (yeah I know pretty much all of cars do that! LOL) but more so then normal.

After chatting with a few friends, people at Auto Zone, and my son, who by the way is a wizard with these little cars, (but as he said, only with the carbureted engines), came up with common issue was temperature related and the only sensor that was common to the temperature issue was the coolant temperature sensor. Now my understanding as was related to me was that sensor is located under the intake manifold on the carbureted engines. So I was not eager to start this project. After checking my misplaced Festiva shop manual, found out it is actually on top and using a deep socket, 6 inch extension and ratchet, was a breeze to replace! Took me all of 15 minutes including putting my tools away! Only lost like a table spoon of coolant, replaced the washer and probe and reconnected the sensor wire and wham! Done!

Did a quick check and started right up and no hesitation, better acceleration, smoother running and right now I’m doing a gas mileage check and already seems to be better. So if you are experiencing the same symptoms, replace your coolant temperature sensor. It was $15 at Auto Zone.

[bravekozak]

I solved that problem by throwing out the CTS and the feedback carb and the computer along with a mile of hoses, wiring and solenoids. No more problem.
Your son is very knowledgeable with diagnostics based on symptoms.

[GenevaDirt]

Awesome your son was able to cross over to the FI engine and help you diagnose the problem.... glad it worked out and is running better.

[drumnerd33]

Makes sense because the temperature sensor your talking about tells the computer when your engine is up to proper temp and then goes into closed loop mode which uses the sensors to adjust your a/f ratio, so if your sensor is bad and it stays in open loop it will be running rich and hurt your fuel milage and not run the best. There is another temp sensor that is in your thermostat housing, that one controls your temp gauge in the dash.

[RitzyFestiva]

Makes sense because the temperature sensor your talking about tells the computer when your engine is up to proper temp and then goes into closed loop mode which uses the sensors to adjust your a/f ratio, so if your sensor is bad and it stays in open loop it will be running rich and hurt your fuel milage and not run the best. There is another temp sensor that is in your thermostat housing, that one controls your temp gauge in the dash.

Exactly and understanding some basic auto mechanics helps and I do use electronic controllers in my work. I just needed to understand what was needed to make the system work the way it does.

As for my son, well let me tell you he is the one who got me started on Festiva's as when he was in high school he told me "Dad, the car I want is a Festiva." He stands at about 6'4"! So when I got him his "first car" it was a white 88 Festy he named "Steve". Steve has moved on after an accident in which he repaired the car pretty much back to roadworthiness and still is out there. His second one was also an 88 in blue which we picked up from a lady whose son had been using it to move fire wood so it was pretty beat and abused. I bought a Ford Factory Service Manual for it and over the course of a summer he completely gutted the car literally down to the shell and between Steve and Blue Steel he made two cars that were usable and rebuilt Blue with the help of one of his buddies, swapped engines, transmissions , dash, the interior down to the bare floor boards. And using nothing more then Dad's tools and that shop manual! I was surprized to see what he had done as I was away in SoCal and when I got home I found both the cars in various stages of disassembly. It was amazing to see what he had learned and on his own! I'm pretty proud of him. We are hoping to do the Aspire suspension swaps this summer.

[200KGPGTP]

What a heartwarming thread all around!