tfwnoturbo

Hey dudes. Recently came into possession of a '95 SC300 with 280k on the clock. Would like to get some input on the various issues it's having from folks that have more experience with this platform than I.

I purchased it non-running, with little to no known history. It would crank up and run (poorly) on cold starts for about three minutes then stall out. Traced this to the Fuel ECU. Bypassed it, now it cranks every time and runs. Yay, one down.
Now the kicker is the thing runs like crap. Dead miss on whatever cylinder. I can hear (what I think is) injector noise out of all six with a prybar being used as a stethoscope. Interestingly I got a strobe out of all the wires with a test light. Hardly a reliable test for good spark, I know. Also worth mention that the ignition timing is clearly off, and upon looking over the distro the adjustment nut was already loose...
So due to my lack of a spark tester I decided I'd just settle for pulling plugs. I pull out the wire for plug 1 and I'm met with a pool of coolant, and all three valleys are inundated with coolant. Bingo, there's my issue.

Now for the stuff I can't fully explain to myself. Where the hell did all this coolant come from? Both the hoses that feed into the throttle body look fine and upon visual inspection neither were leaking. The heater core hose seems stout and I don't see any signs of it leaking either.
Could this have been leftovers from a sloppy previous repair? The previous owner made mention of it having a "possible coolant leak" I find it hard to believe he never saw something this serious, especially given how poorly it runs now. He told me last drove it a month or two ago and it was "running fine". Maybe he was lying? Who knows...

Finally the car has a hellish screeching at idle from around the middle of the engine. The serpentine belt is in rough shape, and I've already ordered a replacement. But it doesn't seem to be from the belt, even though it sounds very similar to a belt about to shred itself.
Putting my ear to the engine it sounds like it's coming from the injector side of the engine around the IACV. It seems to subside when I blip the throttle slightly past what it idles at (it's idling high at the moment, maybe at 1200 or so.)
I've got the intake off and will be replacing wires, plugs and valve cover gaskets while I've got it all apart. When I get it back together I'll be spraying down the thing with brake cleaner in hopes of possibly finding a vacuum leak. Aside from that I've got no clue. It's LOUD, you can hear it from several feet away. I've never heard a vacuum leak this loud, but I guess anything is possible.

I'd appreciate any wisdom you guys can throw my way. I'm hoping that cleaning off the coolant and giving her a tune up will make her run right.
IMG_2123.mov < Video of said screech. Might be too big to embed. Thanks apple.

t2d2

iTrader: (8)

I'd guess a cracked block...

Sounds like the perfect candidate for an engine swap.

Tallyhoe

As per the screeching noise, check the belt tensioner, I snapped the one on my Celica and it sounded similar to the belt squeal, but it wasn't and would quiet down when I accelerated. Addressing the coolant, there is probably 3 reasons it got there. An incorrect routing of coolant hoses into a vacuum house, especially around the IACV or throttle body area. Previous owner sat it on top of the engine with lid open and it tipped over, or like t2d2 stated a cracked block. I'd invest some time to check everything twice.

tfwnoturbo

Finally got my replacement parts in today and had an absolute riot routing the plug wires. As I was getting the throttle body assembly ready to put back on I started looking it over again as someone here suggested and noticed that there was a small bit of discoloration around the bottom.
I looked a bit closer and noticed that there was a bit of a gap between the two runners and the throttle body. How odd... I thought "well maybe the bolts are loose" given how many other loose bolts I've found throughout the engine... But the two nuts were just straight up missing.

I cannibalized two nuts from the little holder bracket that sits on the left side of the head, tightened them down and the gap disappeared. Put everything back together and the car runs like a relative dream. All cylinders firing and no visible coolant leaks. Gets up to temp fine and doesn't overheat either.
Of course it still has other issues but nothing as glaring as the ticking timebomb that is a leak in the cooling system. (One of) the previous owner(s) broke the heater control valve and simply bypassed it by sending the rear coolant line straight to the heater core... at like a 90 degree kink.

Regardless I'm still looking forward to my second SC adventure.

Edit: Also should mention this silenced the screeching, air rushing in through the tiny gap was probably the source. Two birds!

joewitafro

Be careful with the OEM front crank pully too, they love to delaminate and take out radiators.

Bad valve cover seals are very common on these old cars which typically pour oil into the center galley and cause misfires and such, but the coolant one must of been a botched job with pulling off the throttle body for a variety of reasons.

Rear heater hoses, also the heater control valve, and pretty much many plastic clips are prone to heat degradation and will fail over time and give you issues.

tfwnoturbo

Took joe's advice and went ahead and ordered a crank pulley since it has an all-the-time vibration in park and drive and it's an old part probably due for replacement at this point, as well as some other bits and bobs I could pull out from the SC recently added to the Pull a Part nearby before freezing my *** off.

One bit I haven't been necessarily been able to rectify is the fact that the thing will not shift into overdrive. Shifts though 1-3 well but never wants to go past 3. The OD light circuit is good and the light operates with the switch as normal. Jumping the diag terminals reveals code 64, for Solenoid 3 (lock up solenoid) which is odd because the TC doesn't ever feel like it's stuck in either state, it shifts smoothly but still has good power when I give it gas in any gear. I pre-emptively went ahead and ordered a solenoid kit off Amazon since it was cheap and I was gonna change out transmission fluid anyway but this didn't change anything and it still seems to be throwing code 64 (or perhaps I didn't clear the computer correctly). All solenoids read at 12ohms so I kept them around just in case. Anyway I have partially disregarded the code since it seems to be kind of a ghost issue, but if anyone has any information regarding this code and possibly having a fail-safe mode where it prevents OD operation I glossed over I'd be glad to hear it.

I did some light probing that wouldn't require pulling anything other than connectors. The FSM states that the Cruise control box's OD signal may be faulty so I started there out of ease of access. Disconnected the Cruise box's connector and probed the OD terminal to body ground. Spec is 4-6v in ON position. I read 4v initially, then it slowly dropped to about 1.5 over like 30 seconds. Could this be a failing/failed capacitor? Any way to force OD by feeding this terminal voltage or am I playing with fire? The manual is pretty vague about the specifics of what the Cruise box and ECU talk to each other about, it only ever says I should see 4-6v at OD1 and that's it.

I'm not too worried about the lack of overdrive since I will eventually be converting it to stick shift but my OCD demands I knock out as much as I can before putting it under the knife.

tfwnoturbo

Well, today I decided to stop living in denial and admit I have a problem. The poor girl out of the blue developed a cold start long crank and the elephant in the room could no longer be ignored. Upon cracking open my precious ECU I discover the classic black death.
Some light research reveals 95's seem to drop overdrive when the ECU is ready to throw in the towel. I was already braced for this inevitability but deep down hoped it would not come as soon as it did! Oh well. Lesson learned, the simplest explanation is most often the correct one.

tfwnoturbo

Wasn't gonna post this but figured why not in case someone has seen this before. I put a rebuilt ECU (Bought the rebuilt ECU from ebay, place called pro-rebuild.) earlier this week and my overdrive returned, but not much else changed. the car still has the random extended cold start which I'm pretty much gonna learn to live with until something outright fails and strands me.

I was driving earlier today and I went to pass someone in a 55, floored it. Got past them and let off, and I start seeing smoke from behind me in the backseat area along with a burnt plastic smell. No drivability problem though, it was basically acting as if it was normal.

In a panic I pull over, cut it off and start pulling off the backseats to see if something's caught fire. Nothing, doesn't even look like any wires or connectors burned. The only thing i've done back there in the past is bypass the fpecu and check the voltage at the fuel pump itself. The burning smell has entirely subsided and the smoke dissipated. I crank the car back up and it starts puking smoke out the tailpipe. I know the smell of burning coolant and this was not it. Smelled kinda fuelly. like a car running lean/rich. but it was a LOT of smoke. I cut it off to be safe.

I get on the phone with my dad to see if he knows any towing companies out where I am because at this point I think the car won't make it 30 minutes back home. After about 5 minutes I crank it back up, the smoke is way less now but still slightly present. I rev it a few times and it's practically all gone. Screw it, i'll try and limp down the road to see if the issue recurs now that i've got the backseats torn apart and might be able to trace the smoke more effectively. Run down the road and the car is essentially back to normal and has remained as such the rest of the day. I have been hammering on it closer to the house to try and replicate the issue but nothing. Interestingly I undid the FPECU bypass and plugged the connector back in and the FPECU now functions as normal, which makes me think maybe it was the main ECU itself failing to deliver the 9v signal after warmup.

The only other symptoms I seem to have is an awkward low idle (around 500-600rpm) when the AC is off, like it seems to chase a certain rpm sometimes. Never cuts off though. Idles perfect with the AC on. It's not low on power, it goes all the way up the rev band with no hesitation or stumble. Don't even know if it's related. As stated above I have done plugs and wires. Anybody seen something like this before?

Ali SC3

iTrader: (10)

Grab a timing light and set the timing if you haven't already. I would also say do the distributor cap and rotor because on a neglected SC it probably hasn't been done.
When it starts to go you get random misfires on different cylinders, what you could be smelling is the plastic in the distributor burning from the arcing that happens in the cap when the rotor is too far worn down.
When it starts to go it is usually intermittent, then quickly it will leave you stranded. happened to me once on the highway where it left me stranded, then worked after 20 minutes only to finally die a few days later. The arcing and heat can also weaken the magnetic crank and cam pickups inside the distributor, so its one of those things I do when I first get a new SC300 if I am going to be using the distributor for any period of time. Otherwise the ignition is pretty bullet proof.

It could also be the rebuilt ecu, I have never personally trusted rebuilt toyota ecus as it seems lots of them still have issues after they are rebuilt, and its not the rebuilders fault its just the nature of there being so many old components on that and its impossible to check every little chips output on one of those things in a limited amount of time. Alot of the time the symptoms show when the car or ecu has gotten to full temperature.

Another common failure on neglected SCs is the coolant temp sensor, you said extended cold start and issues with idle, If the sensor isn't working the ecu will read that the engine is cold even when it is at full operating temp, that causes over fueling and not entering closed loop, which shows up as different problems. It can also affect the trans if the ecu thinks the engine is full cold.
If it is just cranking for a while before it actually starts, you are likely loosing fuel pressure somewhere possibly a leaking injector but have a look all around at feed lines and return lines.

When you jumper the diagnostic connector to set the timing, it should change from like 14-16 to aruond 8-10 and you should hear it.
If you do not hear it then your tps is bad or in the wrong position (only with the stock ecu), so get the tps right, then set the base timing after you hear the change to 10 and lock down the dizzy.
It is pretty much impossible on a 2jzge to guess at the timing without a timing light, especially if the distributor has been removed it might not have been inserted on the correct tooth even which causes igniton phasing issues (basically the coil fires when the rotor is between the contacts for 2 cylinders instead of when its passing one). This also creates arcs and quickly breaks a good distributor in no time.

All I can really think of right now from what you said but def find another original ecu and check the rest of the stuff out. good luck

tfwnoturbo

Thanks for the response. I checked the distro cap a few days back and it didn't look awful but I probably should look into replacing it since you're right, it more than likely has never been done. As for timing I did set it, twice as a matter of fact. I set it once when I first got it running, then I replaced the harmonic balancer and ECU and set it again just yesterday. It was sitting at 5 instead of the previous 10 degrees when I first did it. Will probably check it again tomorrow just to be safe. I went ahead and attached a video of how it idles with the AC off because it seems to be getting worse. With the AC off it sits around 1000 RPM stable.

I have been letting it cool off throughout the day and cranking it after it's cooled off and the extended crank seems to have gone away, but I'm not gonna say it's 100 percent gone since it might rear it's head at random like it usually does. Basically it just cranks for around 3 seconds before turning over but only when it's been sat (ie sitting overnight or after work, shortest i've seen it do it is like 4 hours after sitting). When fully warmed up it turns over after like one second of cranking every time.

Either way I'll probably end up doing a distro cap for good measure, fuel filter, then seeing if any of the injectors are leaking when the car's off to start with. I'll also probably double check the TPS since there's a chance the last owner could have messed with it seeing as how he had the intake off at some point and may have messed with it chasing gremlins as I am now. Thanks once again.

Ali SC3

iTrader: (10)

Have to replace the cap and rotor together, both the rotor edge and the contacts in the cap wear down together which makes it hard to tell when its starting to go bad.
What is in the video doesn't sound like that though, that sounds like its loping for some reason. My guess is timing is wrong still, intake leak or still the ecu causing issues.

Did you notice the change in sound when you jumper e1 and te1 to set the timing? or a change in timing if you have a helper looking with the timing light?
It is the most important step cause if that didn't happen you aren't setting the base timing to 10, you are setting the full advance to 10 which is too little timing.
That usually makes it sound like a boat and down on power, pretty much exactly how your car sounds in your video.
TPS is almost always the first thing shade tree mechanics doing a quick fix will mess with, they turn it so the idle goes up some and that can cover up problems.
The thing is you can't set base timing unless the idle pin on the TPS is active, you can put the jumper in but nothing happens and you won't be able to set the real timing correctly. This also happens when the TPS is simply just bad.
If you were already doing that then ignore that but if you had 5 one time and 10 another time that makes me think you were not setting base timing.
Changing the ecu or the damper should not have any affect on the base timing.

tfwnoturbo

I jumped the diagnostic connector both times I set timing, and both times the engine would audibly change and the timing would stop jumping around. The most recent time I set it I took a look before and after putting the jumper in. Without it the mark would jump around anywhere from 15 to 5. After the jumper was put in it would stabilize at 5 and the engine running audibly changed. I did find it odd that the timing inexplicably changed after the second time setting it but I attributed it to the harmonic balancer's rubber being so worn that the crank pulley was spinning out-of-round and maybe that could have been part of it. But yeah, I'm pretty certain I set it correctly. As for intake leaks, it's entirely possible although when I did the plugs I sprayed down the mating surfaces of the intake with brake cleaner to double-check for leaks and could not find any. Won't hurt to double check though. I also replaced the PCV and valve cover gaskets while I was doing plugs, and I made sure the PCV hose sealed well and the PCV itself sat snug in it's bore. I put in denso wires and bosch iridiums.

Could the mass airflow sensor be a culprit in this situation too by chance?

Ali SC3

iTrader: (10)

If its still jumping from 15 to 5 that means something big is going on, usually fluctuates a couple degrees only at idle.
Make sure you are looking at the right mark on the crank pulley I want to say its the white one.
It sounds like the engine is pulling timing, if it is not knocking sounds like the ecu again, you know anyone with a working 92-95 ecu you can borrow as a test?
The mafs are very sensitive on these cars but shouldn't be messing up the timing so bad, it would be more of a fueling issue and stumbling or dying when applying the gas.

tfwnoturbo

Unfortunately no, I have my old 95 box with leaked caps and that’s about it. That box I feel like never had this idle issue. I’ll probably try to hook it up later and see if there’s any change. As for the timing i can confirm it is set 100 percent correctly, white mark sits pretty on the 10 with the jumper in.