95 SC2 regains most of its former glory
 

I am happy to report that I have seemingly tracked down the cause of 80% of the vibration that has plagued the 95 SC2 ever since the reman Saturn motor was put in.

Fuel pressure regulator installed with small o ring at bottom stacked on top of previous one.

I believe the dealership (Saturn of Pittsburgh did this ORIGINALLY when they put in a supposedly reman engine in that car in a big hurry.
Actually, I never believed they pulled and replaced it - I think they just replaced it and filed off the VIN.
I say this because the service manager called and asked if they could reuse the aluminum valve cover from the orig engine because the "factory had no more left in stock."
Seems to me no one would ship a rebuilt engine without a valve cover.
They were also supposed to replace the clutch while it was separated nut I know they did not. But I didn;t drive the car until a month after, so I had no way to fight (wife's car, left in Ohio and swapped for a few months.

ANYWAY I replaced the fuel pressure regulator as part of basic trouble shooting 10-15 years ago. Had a *&((&*^^ time getting it to seat but it did and still ran EXACTLY as crappy so I ruled it not part of the issue.
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Fast forward to this week.

Fuel pressure regulator leaking slightly -- pressure bleeding off between starts, excessive cranking time, blah blah blah.

Went to replace it. WOULD NOT SEAT OR SEAL.

The center o ring from the previous install was still in there. It was sufficiently deep and wet with fuel such that I did not realize it was there.
The one I had put in 15 years ago pulled out with the regulator THIS time so I had no reason to think one was left behind.

Anyway, the one I pulled would seat fine -- because it was deformed such that the center was pushed up to account for the thickness of the extra o ring. I have no idea how that sealed but it did and had for 15 years.
UNTIL I RAN IT OUT OF GAS and let it sit. Seals dried out and leaked slightly.

Finally, last night, the "start simple" mantra rolled me backward in time, and the whole wrestling match of the past and now current, along with the concept that if something does not fit, forcing it is not the answer (oh how naive I was back then), I realized it had to be a physical obstruction. Sure enough, the regulator was deformed, and the extra o ring way down in there and holding its shape.

Funny enough the pressure itself was in spec -- but the flow was obviously not right.

So:

No misses, engine no longer dances from what I assume was wandering inconsistent fuel starvation, and the exhaust sounds like it should.

Also explains why the vibe was so nasty at idle -- slowest fuel flow. Even though the car has a return, it couldn't get enough fuel at the right pressure at the right flow rate to satisfy the need. Higher rpm made up for that by forcing more fuel through per unit time.
I have no idea how the PCM maintained a steady idle --gues the aVERAGE 02 was more or less the same........

The leftover vibes are likely from a more or less trashed and solidly non-vibe reducing tranny dogbone mount that was probably wrecked when the original engine blew -- it had ripped the top TAM rubber clean off --or from the vibrations afterward,
I HAD replaced the tranny mount under the tranny to the frame along with the Upper and lower TAMs. But I was told this mount didn't have any real effect on vibration and pretty much never went bad.

Yeah....... (insert naivety again)


So I need to replace that or have someone do it as it is tight quarters and frozen.

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So I guess finally going full hands-on, along with the immense amount of knowledge I have gained from the regulars here (esp Andy and Rube) regarding how things work and how to troubleshoot PROPERLY have solved a 15 year mystery.

I cannot say THANK YOU guys enough.

This is a comedy of errors to you folks, a rookie dumbass mistake, but I inherited it and didn't know any better at the time.
But you did teach me how to find it NOW. And it's over.

Derf

PS Thank you

We learn from our mistakes, derf. It's unfortunate that you've had to learn from someone else's mistake. O-rings are easily missed and over looked items on a lot of things. I was installing a new kitchen faucet a couple of weeks ago and spotted an O-ring lying in the bottom of the sink cabinet. I knew it wasn't there before I started so I had to figure out where it came from. After about 10 minutes of looking, I found out it was from the brass connector for the sprayer. I put it there and so far, so good. No leaks. Kudos to you for finding it and solving an old problem. You're a damned good student!

So finally a smooth idle! Yeh! I’m glad the cams were in time. There is so much more information available with OBD 2 diagnostics.

Party canceled
 

Well it seems to have helped, the pressure regulator is not the only answer solution act of some deity. In my joy to hear the car run smoothly while warming up, I neglected to remember that that is at 1200 RPM, not idle at 850. The car seems to run well at the beginning of closed loop, but if you run it for an hour like I did today and everything heats fully up the operating temperature, the exhaust still has the sputtering sound. And the car shakes more violently.

I turned it off and pulled the plugs as quickly as I could. Please see the attached pictures below.
https://cimg4.ibsrv.net/gimg/www.sat...c79e73d2d7.jpg
1 to 4 top to bottom
https://cimg9.ibsrv.net/gimg/www.sat...52ac11def0.jpg
1 to 4 RIGHT TO LEFT as my camera flipped the screen upside down when I leaned over the plugs to take the picture. Way too obvious to move to the other side
Number number two and number three seem a bit oil fouled which would explain the intermittent sputtering.

The oil is not collecting in the spark plug Wells so my valve cover gasket is not leaking which is good because I just replaced it and that would suck.

I tried to look down into the cylinders to see if oil was pooling on top of the Pistons but the crank seem to be in just the right position that none of the piston tops were visible.

Anyway, I suppose we know oil is getting into the cylinders. Usual culprits on an S car sure oil control rings and or valve guide seals. I find it difficult to accept that the oil control rings are already varnished. I have kept up meticulously with the oil changes because I know better than to not. I also switched it over to 10w30 after it broke in.

I am now really thinking that the Jag up at the Pittsburgh Saturn dealership basically did the minimum amount of work he could when he rebuilt my engine as opposed to putting in a remanufactured engine that I actually paid for.

Probably did not do the valve guide seals, only the oil control rings. I suppose the only way to know for sure is to pull the head.

The engine has great compression, so I do not believe much oil could be sneaking past the compression rings to the oil control ring in the first place. The first engine in this vehicle, when it began to use oil, had the compression take a nosedive as the problem progressed.

I was thinking about that high pressure fuel injector cleaner that you mentioned Andy, to clean out any skuzz in the injectors. I suppose it can't hurt but will not affect oil usage or plug foulimg.

My Saturn dealership in New Jersey used GM top engine cleaner to free up the rings to some extent. But I have only just begun to maybe see oil disappearing. I have driven it so little I can't really say right now.

I know people use marvel mystery oil and seafoam to try to achieve the same result. I have no experience with any of those I just mentioned. I'm willing to put in the effort.

Half of me wants to fix this without having to take things apart.

Half of me wants to learn how to take things apart, how things are put together, etc as part of solving the issue or issues.

Half of me wants to transplant the 97 SC2 engine into the 95 body. I realize this is OBD2 to OBD1. I can't really use the OBD2 1997 PCM because it will always be looking for the rear O2 sensor that does not exist on an OBD1 vehicle Suppose I could install one. Then the question comes as to whether the 95 exhaust will meet 97 standards because if it does not I will get a p0420 and the exhausts are not identical although swapping one cat for another is probably not a big deal now that I think of it. Just leave the rest the same.

No clue if there is a massive wiring harness difference. All the main components are located in the same place and most of the wire colors carry through from 1993 all the way to 97. So for plug and play harness to PCM I might be able to use the 97 PCM which would be great because trying to find parts for first gen is really becoming a pain in the ass.

Breaking down at least part of an engine is on my bucket list. So is an engine swap. Call me greedy but I am 25 years behind in learning and although it is of little use to anyone else, I am strangely driven to do this. Inexplicably, not strange. I'm sure there's an explanation but I really don't care what it is.

So I am at a multi-branched fork in the gravel ditch regarding which way I should go in trying to diagnose this. I might add that the crank pulley has no rubber on it and is not a harmonic balancer it is simply a pulley and that mine has no wobble or distance travel.

GM tech I are quite inexpensive, so are GM tech 2s which can read GM's version of OBD1 or 1.5 with an adapter cable.

The thing I just don't understand is whether the issue is engine temperature related or purely RPM related.
Guidance is appreciated.

Is the black car to become a donor due to chassis rust? Do not attempt to use OBD2 components in an OBD1 car. If the engines are the same mechanically just swap all the sensors and or manifolds as needed. Gut the rusty car and keep all the good stuff. If according to the boss you only get to keep one toy then you have to choose. I know you have two close friends there and it is often tough to choose between the two. There are lots of non rusty S cars out here, if the subframe will save the black car for a few more years I can find you parts. You just have to tell me what to look for. Trucks run from here to you all the time. 😀 I just sent Bones an oil pan after he hit a bear and ran off the road. He did not get hurt, I didn’t ask about the bear. The car is repairable.

The 97 (black car) got a reprieve and another year as my mechanic passed it -- only 500 miles on it last year, so no appreciable additional rusting.

Upside ---
the engine runs smooth as butter w 80K on it. It was a true Saturn reman. Burns not a drop of oil. Most parts still findable.
Clutch replaced with engine at 180K, now at 265k. Car will die before it wears out
Nice interior

Cons --
needs subframe
deep grooves on one side compliments of me dragging it along the side of a concrete support post in a parking garage.
small tear in back bumper,
dent on top of trunk from mailbox incident.
== body work on metal and plastic or buy replacement blanks (some are available OEM) and paint them.
Dead compressor, damage to rest of AC system unclear system still holds pressure.
Caster keeps shifting on front right. Alignment keeps drifiting -- struts likely horribly worn per alignment dude.
That nasty vibration at 60+ mph, although I SWEAR it takes five min on the highway to begin. (I pulled hard on rack -- it did not feel loose.
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The 95 (White car) is yet to be inspected since I bought it back as I had to overcome some nasty rust and seized bolts the old-fashioned way + get proper tools.
Code 26 coming from dash--have service manual will check approp circuits Had to give garage back to wife now that it's below freezing.

Upsides
Lighter -- more fun to drive even on slightly softer tires,
No body damage
no vibration up to at least 85mph
AC still works....Leaks but works
New pads/rotors all around
Subframe seemingly in much better condition esp on driver's side

Cons
Interior fabric held to doors mostly with tacks. Need professional upholstery tlc
Need snew headliner (no big deal)
Rear L caliper E brake frozen -- cable is purposely misadjusted to stop vehicle with one back wheel (cannot roll during the inspection with foot touching gas)
Needs new parking brake cables (if I can find them)
The infamous vibration (has run 50-60K without blowing up, still gets normal gas mileage
Exhaust parts getting quite scarce, have some on the shelf


Intangibles:

The 1st gen body styles -- coupe and sedan -- I have loved them from the day they came out.
Drove a 92 SL2 for 4 years then the 97.

Wife bought the 95 coupe -- I was f ing jealous. The body style was special then -- and still is now.

GM ripped off 2nd gens to style the Alero

I can't believe that I have to make this decision.

Running well with AC fix, bodywork, paint and subframe, steering wheel shakes on highway
vs
Runs bizarrely but well enough, working AC, paint, upholstery


Logic says 97
Heart says 95
Wife says make a choice already --which is why I am trying to straighten out the 95 to make the decision to keep it that much easier......................


Honest opinions needed

Andy --I appreciate your offer on the subframe and will likely take you up on it one way or another.

I know you cannot mix certain electronics between OBD1 and OBD 2 ---- communications are still Class2Serial Data (for these oldsters) and neither has a BCM---but I know things like the Baud rate will be different, the ICM is different, etc so I cannot mix and match anything that is different in that sense.

So yes, take the buttoned-up complete engine, disconnect it, transfer it over.
CPS is the same part number but don't know about reluctor ring.
If I use the 95 peripherals, then that means 95 ICM, coils (identical), no reason to touch other stuff other than to strip it for compatible spares (97)

IF 97 becomes a donor car


Apparently, the 95 PCM scene is a hot mess -- they used 2 diff PCMs for the SOHC and DOHC
AND another 2 diff for auto and manual -- so you cannot flash a junkyard 95 auto PCM to make it a 95 5 spd PCM. and a dohc man PCM cannot be flashed to an SOHC man PCM

Consequently, the only PCM that will run a 95 S car is a 95 PCM.
single year for injector model......

We'll tackle it if we have to.

Supposedly a home garage swap can be done in a weekend if you know what the caveats are.

Code 26 eradicated. Light corrosion on contacts of connectors that plug into back of instrument cluster. That was fun.

Also, since fixing fuel pressure regulator, the engine coolant temperature behaves normally. It no longer flies up quickly and hovers near the fan kick on temp. I am thinking that the limited fuel flow was causing the combustion temperatures to be way too hot.

Replaced the tranny strut mount. Minor imimprovemt.

Saved up a brand new 02 sensor until other stuff addressed. Goes in today.

Exhaust note changes dramatically as vehicle warms up. Recordings to follow.

It’s coming around, sure feels good to make progress! Maybe a little drive when the roads clear?

Maybe now I can pass inspection without a service engine light. It has passed emissions running like crap for many years. Personally I don't think it is running rich but I'm changing the o2 sensor anyway so I might as well do it before inspection.

I am torn but not torn on the next step of troubleshooting.

The only thing I have never actually done troubleshooting on on this car other than swap and replace with new OEM is the ignition control module. That and fuel injector pulses.

The fact that the vehicle seems to fire properly from a cold start (exhaust is even and smooth at 1200 RPM) but vibrates like an MF tells me there is probably something wrong internally.

The fact that as things warm up and the engine gets down near idle 850, the exhaust starts getting goofy , and at idle, the exhaust is thoroughly irregular in tone, tells me something is probably not firing at the right time or the valves are not staying closed or are sticking open intermittently. ( Will stop wildly guessing)
. The tiny bit of oil on those plugs in 2 and 3 in my experience is not nearly enough to cause misfires in an S car dohc. can't tell you how much oil it uses right now because I haven't driven it in four years but it's not much. I'm the fact that it runs fine at cold start per the exhaust note kind of supports that in that the plugs, when cold, can still fire with whatever oil is on them that was deposited when the engine was last hot.

I think I finally remember where my fuel pressure gauge is. Suppose I should hook that up. Been looking for it for a month.

The escort does not have an external harmonic balancer. The pulley on the crank is just that. A metal pulley. There is no wobble.

The s car dohc has always had a known nasty resonance around idle RPM, 800 to 900 RPM. This is why the upper torque axis mounts were consumables on these vehicles, and now that all the OEM ones are gone, aftermarket is ****, people go to junkyards for 3rd generation S cars to get the truck access mounts. Anyway that's how you always knew when your Tam was worn out. The car would vibrate too much in the cabin.

But not like this. Plus I have swapped a known good OEM t a m with zero difference.

Sorry that was a wandering whatever.

Just kind of covering some background stuff and things I've already tried that don't help that should.

Even when the exhaust sounds fine, I can feel the vibration on every firing while sitting in the driver's seat. And it's not subtle. It shakes the car. I do not believe there are any misfire codes for the aldl obd1ish system, but I bet a tech one or tech two could easily tell me some of what the hell is going on in there. For example, timing advance, fuel pulse width / duration, oxygen sensor voltage. The corn temperature sensor seems fine. I already replaced it once when it seemed fine just to be sure. OEM.

Purge valve solenoid now reattached and functional I assume.

one of the few things I have never considered whatsoever is that the PCM is corrupted and determining completely bogus firing timing and sending that to the ignition control module.

The idle is rocksteady at the expected 850 so I do not believe there are any vacuum leaks no can I find any when spraying. There is no hesitation when I put my foot on the gas. There is no measurable exhaust back pressure. The car runs no different with the O2 sensor removed. I have not pulled the EGR and it should be closed at idle anyway.

The change in performance as the engine heats up is something I do not have the experience to understand. And the massive vibration when the exhaust sounds fine sounds like a destroyed TAM or transmission mount but it's not. Those have been changed.

Tech one and tech 2 are available for about 200 or 250 on eBay with all the cartridges although I only need one. My question is will this help me to sort things out if this is an internal physical issue?

Please advise.

I will go to inspection in the meantime.