2 Problems: Rough idle at cold start. Radiator fan not working when hot.

...really believe that the Check Engine light does not work in the 1991

Right, I lost track between 'gage' and 'engine' and now that both the '90 and the '91 are being discussed I'll need to pay better attention. I'd want to know sooner than later if it's just a borked bulb in the '91. If you need tips on a cluster pull, as always, speak up or search.

The first link you sent me for the SCCOA thread isn’t working, could you send it again?

Sorry, missed the double check on that one - try this...http://www.sccoa.com/forums/showthread.php?117378-Erratic-temp-gauge&p=914795#post914795

>I’m guessing 11111 is a combo of 11 and 11

Don't guess. To an SC, guesses smell like fear chucking your wallet down an open manhole with a big grin on it's face. Your SCs won't respect you if they smell fear. Get a code reader, pls., or... maybe whomever suggested the clip method can help you decode flashes, I'm a bit too rusty on that process ;)

Note this link for good info on both manual and code reader code pulls: http://www.amopower.com/eec-iv.htm
 
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6

Is the fan on your 91 hooked up correctly? When doing the test the fan should come on just like your 90. As for you 90, IIRC the 111 is engine designation and the 11 is pass and should be 2 digit codes as opposed to 3 digit codes for your 91.
 
Is the fan on your 91 hooked up correctly? When doing the test the fan should come on just like your 90. As for you 90, IIRC the 111 is engine designation and the 11 is pass and should be 2 digit codes as opposed to 3 digit codes for your 91.

The fan in the 1991 is not hooked up properly. Its still plugged into the Autozone temp sensor/relay kit that determines when the fan comes on all by itself. I’ll set the car back to running off the IRCM relay soon. My 1991 Tbird got put to the back burner as we worked on other projects, but it should get more attention soon.

Im only guessing about the 11 and 111 code. I only know it flashed “1” 5 times after “67”
One of those flashes might have meant something else, like the “test is over” or something. I wasnt expecting the 1990 to flash any really bad codes. After a Google search, my “67” could have been caused by the car being in 1st gear while doing the test. I’ll check again in neutral this weekend. I’ll even record it in case the spacing between the “1’s” is long or short.

There was a reason we used the crappy Autozone kit in the 1991 but we couldn’t determine why my IRCM relay wouldnt turn the fan on when the car got hot and wouldnt make the fan come on when the AC was on. Im retroactively wondering if the IRCM relay might have been ok but the fan motor was bad. I think we put the stupid Autozone kit in BEFORE swapping the fan motor. Now that I know the car has OBD-1 and that I can flash codes, I cant wait to pull that stupid relay out and just use the IRCM relay.

Hopefully this weekend my dad and I will hook up the fan normally so I can troubleshoot more easily. I think I lost my original Ford IRCM relay for the 1991 SC (I only have 2 Chinese ones) should I borrow the one from my 1990 and use it in the 1991 as a control test?
 
On the 1991 Thunderbird, I plugged the fan back into the original plug. When I do the paperclip thing with the OBD-1, the radiator fan does come on for a fraction of a second. However the fan didnt turn on when my radiator reached 190-195 degrees Fahrenheit.

While at this point, I stuck a digital volt meter into the OBD-1 plug and its voltage did bounce after I turned the key. The volt meter couldn’t reset back to zero fast enough for me to accurately count flashes, but I figure that my check engine light is not working and that I could read the flashes by using an indicator light or OBD-1 reader.

My dad told me the aftermarket fan IS a 2-speed. So we’re thinking of wiring it up so that the Low speed comes on when the key is on and the Hi speed comes on when the radiator hits 180 degrees Fahrenheit.

I’m in Charlotte NC right now for the Mustang 55th anniversary car show. I’ll get a proper tool for reading codes when I get back home.

I really appreciate all the feedback and advice you’ve given me. You guys are great :)
 
The idle problem when cold could be the iac or tps sensor, and the fan not coming on could be the ECT coolant sensor in the intake manifold by the oil fill cap..

Those were my fix for my 90... not saying it will be yours but ect sensor is cheap to buy at autozone or advanced auto
 
Rick,
As it was shown earlier the fan strategies for the SC have the fans coming on at a rather high temp and with the 192 degree thermostat, it is not uncommon for the gauge to show past the M and the fan not come on until 1/2 way between the M and the H. Remember it has to get 30 degrees hotter than the thermostat opening temp before the low speed fan should be turning on. You can sort of figure between the o and R is say the 192 for thermostat to open, then figure in another 30 degree before the low speed fan kicks in. These gauges are notoriously un-calibrated and can be way off.

I didi notice in some of your pics there where wire T connectors on some of the wires coming out of the IRCM I am only guessing these are for the aftermarket temp sensor kit. I saw earlier that someone said if the high speed fan kicks on the low speed fan stays on too, but this I think is incorrect. You either get one fan speed or the other, the circuit not being used gets turned off by the IRCM.

One thing you can do is to let the car warm up until it gets to the M or a little past and measure the voltage on the low speed fan circuit at the fan to see if it getting the 12V on that connector. Of course it would all have to be back to the factory connections as other s have mentioned. I agree with Tom and others that changing out the ECT on the intake manifold with the 3 wires may help fix the issue also. if the ECU isn't seeing a high enough temp reading from the intake ECT sensor it will never turn the circuit on inside the IRCM. Make sense?

Also keep in mind that the temp sensor for the gauge just gives the driver a visual to look at but has nothing to do with turning the fans on or off, so it is really not doing much but freaking you out! LOL The important sensor is the one on the intake manifold.

Keep at it, lots of good people here to help you figure it out. Oh and getting the code reader is the way to go. I have done both and really like the simplicity of the OBD1 tester for our cars, especially with it having beeps.

Like others have mentioned when you either jumper the test connector or use the OBD1 scan tool, the fans should kick in as soon as the KOEO test starts, if not I would start there by checking voltage at the fan connector itself.

Good luck.
Smitty
 
I saw earlier that someone said if the high speed fan kicks on the low speed fan stays on too, but this I think is incorrect. You either get one fan speed or the other, the circuit not being used gets turned off by the IRCM.

Looks like both are hot when HI is energized to me: https://youtu.be/czr4g0dnYvE -- EVTM, tho, says, "Once the fan speed is determined, the EEC module energizes the High Speed Fan Relay or the Low Speed Fan Relay to allow application of battery voltage through Fusible Link B to the correct windings of the Coolant Fan Motor."

Ken
 
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Sorry if I missed it, but did you try replacing the ECT sensor? Not the temperature sending unit (for the gauge)...the one that the EEC uses for cold-start enrichment tables and electric fan turn-on settings.

Although you should have a check engine light, a bad ECT cold be the culprit for both poor cold startups/warmups (since fueling is scaled based on engine coolant temperature, among other things) and improper fan operation.

The ECT is the 3 or 4 wire sensor that screws into the intake manifold, just behind the DIS module.
 
Sorry if I missed it, but did you try replacing the ECT sensor? Not the temperature sending unit (for the gauge)...the one that the EEC uses for cold-start enrichment tables and electric fan turn-on settings.

Although you should have a check engine light, a bad ECT cold be the culprit for both poor cold startups/warmups (since fueling is scaled based on engine coolant temperature, among other things) and improper fan operation.

The ECT is the 3 or 4 wire sensor that screws into the intake manifold, just behind the DIS module.

Sorry if I missed it, but did you try replacing the ECT sensor? Not the temperature sending unit (for the gauge)...the one that the EEC uses for cold-start enrichment tables and electric fan turn-on settings.

Although you should have a check engine light, a bad ECT cold be the culprit for both poor cold startups/warmups (since fueling is scaled based on engine coolant temperature, among other things) and improper fan operation.

The ECT is the 3 or 4 wire sensor that screws into the intake manifold, just behind the DIS module.

I have good and bad news:

Good news: My friend and I ran some wiring and connected an adjustable thermostat to a relay to make my fan come on. I can set it to approximately whatever I want, so I used a laser thermometer and set my fan to come on once the car hit 195 degrees F. I have tested it multiple times and my fan RELIABLY comes on at that temp. I have an indicator light in my car for when the fan is on, so I’ll never have to wonder again.
The UPS Store, 1353 Riverstone Pkwy Ste 120, Canton, GA 30114
I replaced my ECT sensor and the car started smoothly and immediately idled fine without having to rev the engine. It now idles just as quietly as my 1990 SC daily driver, so I was very happy. :)

Bad news: Right as I was getting in my car to turn it off, my friend yelled “white smoke coming out your exhaust!” and I turned it off immediately :eek: I walked behind my car immediately and saw faint white-ish smoke lingering in the air. They said it started suddenly for no reason. Based on the fact my car has almost overheated 5-6 times since I’ve owned it (with coolant spewing out of my radiator) I think its possible the head gaskets blew. I’m especially suspicious because the coolant level in my reservoir did not noticably rise after the radiator was hot. I also had to top off my coolant reservoir last week when it was too low to tell what level it was at.
 
So this is the 91, then...been after you since 4.4.19 to replace the ECT...better late than never ;)

set my fan to come on once the car hit 195 degrees F. I have tested it multiple times and my fan RELIABLY comes on at that temp.

About that...too low, I think. You'll risk fighting the thermostat, running too cool, especially at speed when the fan is usually off, making it run rich, etc.

As noted up thread, the stock fan speed strategy is as follows:
Lo speed on: 222°
Lo speed off: 214°
-=-
Hi speed on: 228°
Hi speed off: 220°


About the white smoke...remind me, did you get a combustion test kit to check for gases in the expansion tank yet? AZ rents them, I think. Anything but clean oil on the dipstick? Any foam inside the oil filler cap? Milkshake in the expansion tank? Upper hose tight but not bulging when the engine is at temp?
 
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So this is the 91, then...been after you since 4.4.19 to replace the ECT...better late than never ;)



About that...too low, I think. You'll risk fighting the thermostat, running too cool, especially at speed when the fan is usually off, making it run rich, etc.

As noted up thread, the stock fan speed strategy is as follows:
Lo speed on: 222°
Lo speed off: 214°
-=-
Hi speed on: 228°
Hi speed off: 220°


About the white smoke...remind me, did you get a combustion test kit to check for gases in the expansion tank yet? AZ rents them, I think. Anything but clean oil on the dipstick? Any foam inside the oil filler cap? Milkshake in the expansion tank? Upper hose tight but not bulging when the engine is at temp?

Hello,

It's probably good timing that I changed the ECT sensor in the 1991 because my 1990 (the daily driver) starts fine when cold, but gives me some difficulty starting if the engine is hot. I may replace the ECT sensor for the 1990 in the near future because this is a similar issue that my 1991 had back when it was my regular car (and I suspected the problems were related).

The 1991 is not street legal (I just run it in the driveway), so I set the temp low (I can change it on a whim) so that I can test the wiring and thermostat I bought. When it's roadworthy, I will change it to be closer to the fan speed strategy you provided.

I totally forgot to get a combustion test kit. That's officially my new priority now. I will check the other symptoms you mentioned as well.

A part of me is upset that my headgaskets could have blown, but I've also owned this supercoupe since November 2012 and my other one since May 2015 and I haven't had to face this issue yet. I've been waiting for the "axe to drop" for years now. If it turns out my gaskets need replacing, I will be strangely relieved because if I take really good care of the new head gaskets, they should outlast the car. I will pamper these gaskets and never let the car overheat ever again. I also had a mechanic tell me that replacing the ECT sensor WITHOUT burping the system afterwards could have resulted in a tiny airbubble getting caught in the engine and blowing the gasket. I think my gaskets could have been on their last-leg anyways, but I'll definitely "burp" the system whenever I change the ECT sensor or Temp sending unit on the 1990.

Thanks for your help :)
 
So this is the 91, then...been after you since 4.4.19 to replace the ECT...better late than never ;)

About the white smoke...remind me, did you get a combustion test kit to check for gases in the expansion tank yet? AZ rents them, I think. Anything but clean oil on the dipstick? Any foam inside the oil filler cap? Milkshake in the expansion tank? Upper hose tight but not bulging when the engine is at temp?

Crap. I didn't know how the combustion test kit worked until after I had drained and removed the radiator (among other engine parts). My dad called our mechanic friend the day after my white smoke incident and he said that if my gaskets blew, we would need to drain the coolant as soon as possible. We've already removed the radiator and we have blown air through the engine to get as much coolant out as possible. The coolant is now collected in a giant Rubbermaid tub (the test kit appears to only work while the radiator is still in the car).

At this rate, should I bolt back on the parts I removed (alternator, radiator, SUPERCHARGED tube, and a couple other upper things) and refill my radiator and purge it to do the test or should I just keep going and replace my head gaskets so I don't have to worry anymore. I'm pretty sure they were JUST STARTING to go out anyways, but I don't have any concrete proof other than a little white smoke out my exhaust and an unexplained loss of coolant (I've topped of my coolant overflow reservoir 2-3 times since my last overheating incident).

Note: While my dad's mechanic friend and I were blowing air through the engine, some coolant was coming out of the radiator tube as a mist. I explained to the mechanic that the "mist" that was blowing out of the engine looked just like the "white smoke" coming out the exhaust the other day. It wasn't a thick opaque smoke, but rather just a white mist that lingers around for 5 seconds and dissipates. So I'm quite certain that coolant was coming out of my exhaust. A part of me doesn't want to refill the engine with coolant and run it again because if the gaskets ARE blown, I might damage something. However, if the gaskets are NOT blown (yet), I wouldn't know why coolant was coming out my exhaust. I will say that the white smoke happened coincidentally the same day I had replaced the Engine Coolant Temperature Sensor and I had not purged air from the system when I had done so. When I mentioned this to the mechanic friend, he said that failing to purge the air after replacing the ECT or the Temp sending unit could capture an air-bubble that could cause the head gaskets to fail (he used to own a Supercoupe, so he's familiar with some of the idiosyncrasies these cars have).

I'm about to head back to the storage unit today, I'll check for "mayonnaise" on the inside of the overflow cap, and I'll check the oil dipstick and underside of the oil cap. I feel weird saying this, but I really hope my head gaskets failed so that when I replace them, I won't have to worry about them anymore.

Thanks for your help; this is a real learning experience for me. Hopefully when my 1990 has a similar issue, I will be able to diagnose and treat it more efficiently (I'm planning on holding onto these cars for many years to come).
 
..he said that if my gaskets blew, we would need to drain the coolant as soon as possible.

If the oil on the dipstick is milky, sure, don't bother. But when it's not conclusive, testing for gases in the coolant helps being able to decide without simply jacking up the radiator cap and rolling a new car underneath it ;)

There are many ways to learn if there is an issue w/head gaskets, from reading plugs, to cooling system leakdown tests, to cylinder balance tests, to constant bubbles into the expansion tank, to ballooned/hard radiator hoses, how much history you have on the car, etc. etc. Some people go straight for the gaskets and others want to know more in case there are other issues that should be dealt with while the heads are off. Sounds like you've got plenty of advice and eyeballs now, so....

Off hand it sounds like head gaskets, and/or cracked head, and/or leaking intake, but if it were my car, I'd want to know a bit more at this point. If the intake is letting coolant into the cylinders, you might not find combustion gases in the coolant, and wonder what the issue is if the head gaskets look fine. Maybe you caught the issue before it was bad enough to dump coolant into the oil...

It wasn't a thick opaque smoke, but rather just a white mist that lingers around for 5 seconds and dissipates

There's a fine line between routine vapor being burned off, and actual steam that might be seen as an early sign. A combustion test will help decide between those. Smoke, however, is unmistakable and there isn't much point in testing.

Depending on the weather, any car that sits can see a bit of vapor/mist out of the exhaust when started from ambient moisture that has collected in the pipes/mufflers - tt won't hang around very long at all. White smoke that lingers is different, and a dead giveaway for failed gaskets. You might also see water on the ground directly under the tail pipes that doesn't seem to dry up as quickly as you'd normally expect. I wouldn't start ripping the engine down simply over a quick mist...
 
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I feel like I perhaps should have done the combustion gas test, just for peace of mind and to perhaps narrow down what the problem could be if my head gaskets end up looking ok. Lots of parts have been removed (including power steering pulley/pump, Supercharger, both Tubes, and harmonic balancer pulley), so I think we’re marching onwards to replace head gaskets now. The overflow tank cap does not have “mayonnaise” in it and the oil cap underside looks ok. My oil is pretty clear because practically no miles were put on it since its last oil change, but I could examine it closer.

I will say that the white smoke was big enough to be noticed from within the car (I briefly saw it in my rearview mirror). It was a warm, dry day and the car had been running until it was hot enough to send coolant to the radiator (my fan came on:)). So the car was close to normal operating temp when it happened. The car has been started and idled more than normally the past couple weeks, and it never spit out white smoke like this before, so it seemed really serious.

In a few days, I’m going to order some parts (after the heads are removed). I was wondering what the best head gaskets for the 1991 SC 5-spd would be. Should I go with MLS head gaskets or are those only for the 1994/1995 SC? I also saw some people recommending Fel-Pro head gaskets.
 
I've only used Fel-Pro and had good luck. I also had my heads refinished to RA20 (a smoothness factor).

Others can chime in on MLS gaskets, but they should be paired with ARP studs vs. bolts, and the block should be similarly machined, as I understand it. If you're going to significantly increase horsepower, MLS is the way to go.

See: http://www.sccoa.com/forums/search.php?searchid=3077073
 
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I've only used Fel-Pro and had good luck. I also had my heads refinished to RA20 (a smoothness factor).

Others can chime in on MLS gaskets, but they should be paired with ARP studs vs. bolts, and the block should be similarly machined, as I understand it. If you're going to significantly increase horsepower, MLS is the way to go.

See: http://www.sccoa.com/forums/search.php?searchid=3077073

I’m absolutely getting the ARP studs (already ordered). I’m leaning towards getting MLS gaskets. I’m keeping the car mostly stock, but I like knowing they could handle some extra performance mods, should I ever go that route.

I removed both exhaust manifolds today. The drivers side was no problem but 2 bolts snapped off on the passenger side. Not sure what exactly to do about that yet, but I still need to remove the heads in the next couple days. In the picture included, you can see a little piece of one of the snapped off bolts (hopefully enough is sticking out to be removable).

Edit: Crisis averted. I happened to have spare heads from a 1990 Supercoupe engine that I forgot about. My mechanic friend thinks they will work fine. I’ll hang onto my heads with the rusty bolts snapped off just in case there is a way to remove them when I have some spare time.
 
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A tree fell in my yard yesterday, so I didn’t remove my heads today like I planned. Howevever, something just crossed my mind that I feel like I should share. When I bought my 1991 SC over 6 years ago, I think I remember the guy telling me he changed the head gaskets (I could be wrong). If that’s the case, I’m concerned he MIGHT have re-used the stock headbolts instead of buying new ones (the previous owner did some sketchy things to the car that I’ve had to undo over the years, so anything is possible). Wanting to lean on the side of caution, what would be the best thing I could do to minimize the possibility of snapping head bolts? PB blaster and a steady hand? Using a torque wrench so that I don’t apply too much pressure removing them? Again, I can’t remember for sure if the guy said he changed them (at over 130,000 miles, I assume he did) let alone if he re-used the original head bolts (you can look at the picture above), but I’m an amateur and thought it was better to ask a stupid question than possibly snap a bolt in my block.
 
TTY bolts are 'springy', meaning they can act funny when you try to remove them, especially by hand.

Save yourself the struggle, use an impact to pull them, and don't worry about what someone may/may not have done during previous repairs.
 
Heads and head gaskets removed. My mechanic friend said that the heads on my 1991 (the one I snapped 2 rusty bolts in when removing the exhaust manifold) look better than the spare ones I found. He says we may have to drill out the two snapped bolts and re-use my 1991 heads.

I tried to examine the old headgaskets that I removed from my engine. I can't tell for sure where it failed, but I noticed a little area where the gasket looked like it was tearing away from the metal ring. I don't know for sure if this happened when we removed the gaskets, but it looks like a soft area that could have been compromised and that became more obvious after pulling on it. There's also a thick, black tar-like blob stuck to the inside of the metal ring near where the tear is. What do you guys think?
 

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You've identified at least one fail, no doubt. I've got a used gasket that looks just like it ;)

What cylinder is that? Passenger side rear?
 
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