No start condition on 91 SC.. Any ideas?

turbokev

Registered User
I just bought this SC at a decent price because it does not start. I have and am familiar with turbocoupes, but this is my first supercharged Tbird.

The car:
sc1.jpg

sc3.jpg


1991 Automatic. 99K original miles. moonroof, keyless, ride control, etc. loaded car.

The engine compartment:
sc2.jpg


Notice how the belts and pulleys have an orangy tinge to them..almost like surface rust, but not.

The symptoms:

Car turns over with no metal to metal "bad" noises. It does make a "whoosh" noise while turning over once per revolution. I've never had a SC, so I'm not sure if this is normal or not..If my turbocoupe was making this noise, I'd be concerned.

While turning over, all the pulleys and belts are doing what they are supposed to.

The oil is full, clean and doesn't smell funny. It has no trace of coolant in it.

The radiator overflow bottle has coolant in it and is at the correct level for "cold". The fluid itself is nice and green. The radiator appears to be low as when you look under the radiator cap you can see no fluid..just the fins of the radiator.

Side notes:

The moonroof doesn't work. The drivers side power window is stuck down (motor does not appear to work). There was no battery in the car when I bought it so I'm assuming any stored codes will be lost?

From the information on the title I was able to determine that the last person who bought this car did so on March 14th of this year with the exact same mileage as it has right now. Looks like somebody else bought this car to fix up and decided to junk it instead..and that's where I bought it.

My 'shoot from the hip" theory is that the water pump may have blown soaking the front of the engine compartment (thus the orangy tinged belts/pullies) but the person kept driving the car to the point it were it was so overheated the headgaskets blew soaking/fouling the plugs. When they found out the headgasket job was over a grand, the junked the car.

Questions:

What is the best way to check for spark?

What is the best way to check for fuel delivery?

Will a Ford scanner tool be useful even though the car doesn't run?

Does it seem like the issue is headgasket related even though the oil is clean with no trace of coolant? (if that's the case, I'll resell the car or part it out..no WAY I'm tackling that job)


Thanks for any input~
 
Kev,
it turns over but wont start huh? Sounds like the old harm. bal. problem has bit you. Here is a qiuck easy way to find out.....

Check the middle of the harm. bal. to see if the bolt that holds it to the crank is still there. If it is gone you found your no start problem.
What happens is this :when the bolt shears off the harm. bal starts to vibrate and breaks right at the timing chane cover. This makes it hard to figure out when you still see and the pullys turning. The Harm. bal. then breaks and moves away from the crank sencor,causing the no start problem.
All is not lost this is a easy fix. I wont get into that until you see if that is the problem or not. I'm welling to bet that is the problem at this time.

Kurt Sr
email:GONE14S@aol.com
 
Well.. I checked the bolt, it's still there and seems to be very tight with no play..

I'm assuming it's the large bolt that goes through the center of the crank pulley (see blurry image below)

crankbolt.jpg


Also note the orangey residue on all the belts and pullies..it comes right off, but it's on every single belt and pulley.

belts.jpg



Thanks for the good suggestion though, I wouldn't have thought of that.

Any tips on how to proceed with diagnosing the issue..is there a troubleshooting guide somewhere?
 
Crank Sensor

Now that we know that the crank bolt is ok, we need to check to see if the sensor from it is working. It is very common for it to fail.
For the test, keep your eye on the lower left part of the tach for the orange UP-SHIFT light while try to start the engine. Normally, it lights up for a second or 2 when you turn the key, but when the crank sensor is bad, it will stay on the whole time while you're cranking. Its not that expensive and not that hard to replace.
 
Last edited:
check coils for spark

first pull a plug and check for spark if spark ,,then check compresssion the orangey stuff looks like rust from rad hose broke,, bad head gaskets? if no spark check wires to coils water may have got in them and made a bad contact,, if good spark and compression then its fuel,,, check for fuel pressure at fuel rail maybe pump is bad? or cloged fuel filter,,,:D
 
As you can see we all try to help. all the post above are "one step at a time alimations process". Dont give up we well get the problem figured out soon I hope. This is what the SCCOA is all about:)

Kurt Sr
 
Keep in mind that this is just another car engine. The basics still apply regardless of how much stuff is tacked onto it.

Check for spark by pulling a plug and grounding it. Check for fuel by verifying fuel pressure at the rail. (use a gauge)

With all of that, it should fire. If it has spark, had fuel, or won't even fire on starting fluid, then it would seem that there is a timing issue.

The SC is a distributorless igintion system. It uses a Crank position sensor and a Cam positition sensor to determine when to spark and when to inject fuel. Cam positition sensor failure will typically not stop starting, but will cause poor idle and odd tac fluctuations. A crank sensor failed won't allow it to start. (Engine computer won't know where TDC on #1 is.)


No spark! Check the DIS. If the car has been out of service for a while, it could be related to the DIS. New DIS components were on worldwide back order for nearly 6 months last year. A failed DIS will result in no spark.
 
OK, here's the latest.

I have fuel pressure at the fuel rail.

I have spark at the spark plugs.

The car turns over and about once every 2 revolutions 'tries' to catch. If I press the gas pedal just a little bit while it's cranking I get a pretty huge backfire in the intake manifold..again, about once every 2 revolutions.

Certainly sounds timing related.

Some more questions..

1. If the crank sensor was bad..would the car even develop spark?

2. If the cam sensor was bad, would it behave like this as well?

3. Is there anything I can test with a multimeter before I just start throwing electronics at the car?

4. Can I read the codes from the computer, even though the battery is not in the car (obviously if jumper cables are hooked up to it, the computer will have power, but will it save codes after just trying to crank the car for a few revolutions)

5. My car is an automatic, and I see no upshift light when I turn the key on, or crank.. Is there another indicator of bad crank sensor without an upshift light?

6. Is there a diagram someplace that shows the firing order of the motor so I can make sure the plug wires are all hooked up to the correct terminal on the coil pack? ( they appear to be all wired from the factory, but you never know.. )

Thanks again for the help..I fell like it's getting narrowed down a bit.
 
Trade offs on repair techniques

When Oh when to start throwing parts at the car..

If you have a shop take a look and diagnose the problem, then its a minimum of 1hour shop labor, so probably around $50.. provided they nail it right away and fix it quickly :)

For $50, IMO, go down to your local Orielly's (as Autozone doesn't carry this part), and drop $30 for a new cam sensor.
Takes about 20 minutes (if you're slow) to replace. Just be sure you stuff rags underneath the thing to catch the tiny little 7mm bolts which you WILL drop at least once during the process.

BTW, I did read part of the posted article, just enough to recall that the Ford dealer who fixed MY cam sensor problem years ago could have been the author.. They went through and replaced PCM, DIS/ICM, and eventually the cam sensor in an attempt to fix the problem. And yes, I paid for it all... except for the $30 cam sensor that is. :confused:

Codes are fine as long as the problem is straight forward.

From MY experience with my SC over the 12 years that I've owned it, I've had very few codes tell me anything which helped me fix a problem. Ok.. to be fair, the crank sensor failure, and ARC problems had helpful codes.. Cam sensor (I'm on my 3rd one!) never threw any codes.. Engine mounts causing a low idle.. no codes.. ABS accumulator.. no codes.. Ruptured IAC.. no codes..
 
$50/hr. diagnosis PLUS tow ;)

I picked up a cam sensor at the local NAPA that I'll put in tomorrow and see what happens. Worth a shot at $34 bucks now that I've determined I have both spark and fuel.

I'll let you know what happens~
 
Back
Top