My '96 Saturn SC2 was idling rough recently. Replaced the coolant temp sensor (has been the cause of problems in the past), which didn’t fix it. Had some diagnostic work done, and was told that it was the spark plugs and/or the spark plug cables. Replaced those, and the stuttering has gone away. However, now it will hesitate to accelerate from a dead stop when I give it some gas.
I noticed that one of the distributor connections (that connects to the spark plug wire) was covered with some white corrosion, which I removed with some steel wool…could this be indicative of a distributor problem?
The corrosion indicates that you need a new distributor cap and probably rotor.
The hesitation would tend to indicate that your ignition timing is off. Did anyone loosen the distributor when wires were changed?
No distributor - just “ignition coil packs” - just tested those and they seem to be functioning properly. Sorry for the confusion (the corrosion was at one of the coil pack towers)
The hesitation wasn’t there prior to me replacing the spark plugs and wires…at least not that I noticed (could have been covered up by the rough/stuttering idle)
Either it has a distributor (with rotor and cap) or it has COPs (Coil-on-plug) or it has coil packs. Which is it? You said distributor, so I assumed that it had one.
Just edited my last post - sorry for the confusion. Coil packs are what it has.
Then its probably not a timing issue.
quick update: I found the stutter/hesitation/hiccup happens whenever I give the engine some gas while in gear - this will still happen even if I’m already moving, take my foot off the gas, and the give it some gas.
Thinking this might be throttle bidy injected, I attempted to look it up…and, to my surprise, found carburators for 1996 Saturn SC2s.
If this is carburated, you may have a problem with the accelerator pump. With the engine off, manually open the throttle plate, manually and quickly operate the acelerator linkage, and look for a good strong spray of fuel. You should have one. When you punch the gas pedal the throttle suddenly opens wide allowing a huge surge of air to be pulled into the cylinders. Without adding that rich spray you get a temporary “lean-out” and the engine will stumble. A momentary “lean-out” with carbs is not uncommon, but I’m assuming this is a change in the way the vehicle is running, and change always has cause.
If this is throttle body injected, I’d want to look at the manifold absolute pressure sensor. That’s the sensor that first and most dramatically senses the punching of the throttle by registering the sudden dramatic drop in manifold vacuum caused by the sudden removal of the throttle plate from the path through which the cylinders are trying to draw air.
This vehicle also has an OBDII system. You may want to check for codes. You may not find any, but the check is free at most parts stores.
It’s fuel injected. I’ll have to take a look at the manifold absolute pressure sensor.
I just had the codes pulled a few days ago, and the only things that came up were “cylinder misfire” and then something to do with the ABS system (separate issue - much more expensive to fix, too!).
Incidentally, I also just had Saturn update my PCM firmware…could this possibly be the culprit?
The throttle position sensor tells the engine computer when the throttle moves from the idle position (and, anywhere else). It should be checked for smooth voltage change from idle to just off the idle position. Voltage spikes, or drops, won’t get smooth response from the engine computer (to the fuel injectors, and ignition timing).
It’s possible for a mechanic to check the fuel injector pulse width (which indicates fuel injector injection), and ignition timing change when the throttle is moved.
Using a throttle body spray cleaner could be beneficial.