Occasional violent starts?

[arrfep]

I've got a 95 Saturn SW2. It's never had starting issues for the few years I've owned it, even through Chicago winters. Lately I've been experiencing an occasional issue when starting. When I turn the key, the engine begins cranking like normal, then sometimes I get a severe stutter which makes the entire engine buck, and is usually accompanied by a loud engine noise. Not sure how to describe it, other than sounding like the engine is "over-starting." Not quite an explosion/backfire, but louder than a normal engine noise. Anyway, after that, the engine turns over just fine and car starts no prob. Whole sequence takes 1.5-2 seconds tops.

Happens maybe 1 out of 10 times, and if I turn the car off and then back on again, it starts up no problem.
Sometimes, there is a split second of no response upon initially turning the key, which is making me suspect the starter. Could a bad starter cause the stumbling problem described?

Recently changed plugs/wires, ECTS, new PCV valve, cleaned TB and EGR valve. Thoughts?

 

[brblx]

could be a timimg belt missing a tooth or a damaged chain guide (dunno which setup that car has).

is the SW2 one of the V6's of the 1.9L? if the latter, definitely research the oil comsumpsion issues inherent with that motor, you could also be describing valvetrain clatter, piston slap, or something else internal and often caused by oiling issues and general engine wear.

could also just be an intermittent starter issue or a missing flywheel tooth.

lots of options. get a digital camera from the past five years and capture the noise (seems like most 5-6MP+ have decent 'youtubing' capabilities, though the mics are a crapshoot).

 

[brblx]

also- no engine light ever? does it come on during the key-on self-test?

 

[CraigRT]

Go to Saturnfans.
I am knowledgeable in Saturn (s-series) but without hearing the sound or somehow being more descriptive there is nothing I can tell you.
I've owned 3 S-series including one wagon (and looking at buying a 95 SW2 soon actually)

 

[brblx]

Go to Saturnfans.
I am knowledgeable in Saturn (s-series) but without hearing the sound or somehow being more descriptive there is nothing I can tell you.
I've owned 3 S-series including one wagon (and looking at buying a 95 SW2 soon actually)

i have no experience with said saturn forums, but in the same vein as this man, i reiterate- be more descriptive of the exact circumstances and nature of this noise. try your best to capture the sound on some kind of recording device. having video immensely helps, too, so we know where you're standing while you record the noise.

this is just one of those situations where having someone with a decent amount of experience on hand to evaluate the symptom can be infinitely useful. atm all anyone can do is guess.

 

[TakeNoPrisoners]

I had an issue like this at one time. It turned out one of the bolts holding the starter to the block had fallen out.

The starter would make a horrible sound and grind gears and stuff.

 

[arrfep]

could be a timimg belt missing a tooth or a damaged chain guide (dunno which setup that car has).

is the SW2 one of the V6's of the 1.9L? if the latter, definitely research the oil comsumpsion issues inherent with that motor, you could also be describing valvetrain clatter, piston slap, or something else internal and often caused by oiling issues and general engine wear.

could also just be an intermittent starter issue or a missing flywheel tooth.

lots of options. get a digital camera from the past five years and capture the noise (seems like most 5-6MP+ have decent 'youtubing' capabilities, though the mics are a crapshoot).

1.9L twin cam. I've tried to catch a recording of it, but, of course, it never makes the noise when I want it to. Will continue to try it though.

I had an issue like this at one time. It turned out one of the bolts holding the starter to the block had fallen out.

The starter would make a horrible sound and grind gears and stuff.

The thing is, it's not really a grinding or mechanical noise. More of a combustion noise...I'll try and grab some audio.

 

[LTC8K6]

Leaky injector?

 

[brblx]

could be a brief misfire that is not happening often enough to get the MIL to turn on. especially in an OBDI car...though i'm no GM expert and many brands had 1995 models that might as well be called OBDII...often just had small technical differences that might cause issues with generic 1996+ scan tools, but may be functionally similar.

still though, i've seen modern GM's (aveo, go sit in the corner) that will misfire constantly under load without even turning on the engine light (when it kinda seems like it should be flashing it, given that you're destroying the cat). aveos had common issues with both cracked plugs and bad coil pack assemblies (one big epoxy turd lays across all four cylinders).

fuel issue is also possible. i think that engine has a pretty standard fuel system that is mechanically regulated at the fuel rail. first suspicious would be a leaky regulator- it's vacuum operated, and depends on a sealed diaphragm between engine vacuum and fuel pressure. if it gets old and tears, the engine starts roughly due to a lack of initial fuel pressure, plus there may be a decent amount of fairly stagnant gas pooled up in the intake after a night's rest.

 

[twinrider1]

Leaky injector?

This was my first thought, just based on the thread title. But after reading the post I think I'd check the starter first...sounds like the starter gear not disengaging properly. Hard to diagnose further without actually hearing the sound.