89 SHO Will Crank, Won't Start

[CardinalGopher]

My '89 SHO died on the freeway suddenly at about 75 mph in 5th gear on Friday night. I got the car onto the shoulder and towed home.

Here's what I know about the problem: I get codes 11 & 66 from the EEC. 11 is the System checks OK code and 66 is the Mass Air Flow Signal Low code. The engine cranks fine and the fuel pump, which I assume is the high pressure pump, runs when the key is turned to the on position. I've put a timing light on all six plug wires, and all six show that they're receiving spark when the engine cranks.

I haven't checked the fuel rail yet to investigate if it's actually getting fuel when the pump turns on. My thought was to loosen the fuel pressure relief valve and then ground the self-test pin to cycle the fuel pump and qualitatively verify that the fuel system is working.

The bigger question I have surrounds the 66 code. I have the OEM 1989 Car Shop Manuals for the car (both Vol. 1 & 2), but not the Engine/Emissions Diagnosis Manual. What does that manual say to do in the event of a 66 code? Is a bad MAF sensor enough to totally **** the engine at highway speed and prevent it from starting again?

I also have yet to try clearing the code by disconnecting the battery cable and then running a key on, engine off test. Does anyone know if the engine would fire on cold start if it had previously found a 66 code that had been cleared?

Any thoughts?

Adam

 

[.RaMpAgE.]

mmm when u crank the car with the starter does the tach move..... im guessing crank sensor

 

[Vnuk1]

mmm when u crank the car with the starter does the tach move..

Vital info there^^

 

[CardinalGopher]

Wouldn't a faulty crank sensor prevent the spark from firing at all? I suppose it could be an intermittent failure of some sort, but I would expect that the engine would run intermittently since the spark is at least intermittently working. The manual doesn't list the crank position sensor as an input for the fuel injection system, but I would believe that the EEC uses engine speed as an input for fuel metering anyway.

I replaced the cam sensor, front crankshaft oil seal, and timing belt in August about 500 miles ago. I was being cheap and left the crank position sensor in there, which may turn out to be my undoing.

When I get home tonight, I'll watch the tachometer while I crank the engine. Still, I'd like another method for verifying which sensor failed before tearing apart the front end of the engine again.

 

[Vnuk1]

A misconception that just because a part is new doesn't mean that it is not a faulty one and took a dump prematurely. Check everything, and then check it again...

 

[rubydist]

If there is spark, as was described, then it should not be the crank sensor, since when that is bad there is no spark. However, if the cam sensor is bad, it can mis-time the spark, which will make it not run even though there is fuel and spark.

A bad mafs should not make the engine die.

If you have cleared the codes, the pcm knows nothing about what may have happened in the past.

 

[.RaMpAgE.]

if it was me i would replace both the cam and crank sensor it did the same thing to me but it would come back to life in a second or two cam sensor 25 buxs crank is like 60 buxs on ebay...

 

[shobote]

After cranking with no start, do you smell gas ? Is it the original fuel pump ? Check the fuel pressure at the schrader valve.

 

[CardinalGopher]

I didn't think about it at the time, but I did smell some gas Monday night after cranking the engine for a while to check the spark signals. I didn't see any leaks on the top of the engine and didn't really look anywhere else, but that gas vapor could have been pushed out through the exhaust system unburned. The two things I'll check tonight will definitely be making sure I have fuel pressure in the rail via the schrader valve and checking the cam position sensor. I still have the sensor that I swapped out; that sensor would always let the car start, but would occasionally cause the car to miss. The missing went away after I changed sensors, but it's possible that the new sensor failed in a less graceful manner.

As for the fuel pump, my father replaced one of the two fuel pumps (I believe the low-pressure pump) in 2000 at around 100,000 miles. The car currently has 145,*** on it.

 

[aar_man]

I am having the same problem with my 95.
Have spark, have good fuel pressure...won't start after I stalled the car pulling out.
The car had the 60,000 major and 120,000 major and only has about 17,000 mi after the latest major. If I get it solved or you do, please let me know or I will do the same.
I smell gas, the plugs are wet and I had a higher volume fuel pump installed in the car a while ago. I have 42 psi at the rail.

 

[CardinalGopher]

Update

Tonight I played around a little bit more. I checked, and there was some gas at the fuel rail after activating the pump by cycling the key to the on position. I checked by pressing the needle in the schrader valve with a screw driver and releasing the fuel pressure in the rail, so I don't know the exact pressure, but I do know that there was enough pressure to shoot a column of gasoline about 2 inches into the air.

I also swapped out cam position sensors. I put the one I replaced back in August on to see. Switching sensors did not solve the problem. Additionally, I removed the crossover pipe on the manifold to gain access to the sensor. I could smell gasoline in the manifold, meaning I'm getting some gas into the it.

It might be time to check again with the timing light, just to be certain that I am getting spark.

Again, does anyone have the Ford Engine/Emissions Diagnostics manual out there?

Adam

 

[xshoel93x]

well, maybe this helps. my car did the same thing, 93atx. randomly. would die out on the highway and sometimes wouldnt start back up. CCRM was a p.o.s. and once i replaced that everything went fine. got it for about 100bucks.

 

[CardinalGopher]

Pinout for CCRM

Does anyone have a pinout for the CCRM for an '89 SHO? Similarly, does anyone know what the typical resistance should be between the ground pin(s) and the negative battery terminal. I measured all the resistances between the pins and ground this morning, and some of them were on the order of 2.5 Ohms. I was in a hurry, so I didn't take notes, but the tests are simple enough to run again when I get home.

Thanks in advance,

Adam

 

[rubydist]

One other thing to check before you start spending money to guess at things:

turn the engine over until the crank pulley is at 0 degrees (TDC). then pull the top timing cover off and make sure the dots on the cam sprockets line up with the marks on the rear timing cover. its possible that the idler on the timing belt came loose and the cam timing got off.

 

[CardinalGopher]

Fuel Rail Doesn't Hold Pressure

I tested the fuel system pressure tonight. I had the fuel pump running continuously by wiring the fuel pin lead on the EEC connector to the ground pin. While the pump was running, I measured the pressure in the rail to be 38 psi. As soon as I shut off the pump, the fuel pressure started falling and was back at 0 after about a minute. I haven't found any leaks in the engine bay, and there aren't any puddles of gasoline under the car (it's been sitting still a week). The Ford manual says to disconnect the fuel return line, plug it, and run the pressure test again to check the fuel pressure regulator.

 

[rubydist]

the regulator can let it bleed down or the checkvalve in the pump can let it bleed down or you could have injectors that don't shut off that let it bleed into the engine.

 

[CardinalGopher]

Whoops!

I finally found the problem. I neglected to properly tighten the timing belt tensioner nut when replacing the timing belt in August. The tensioner fell off (and landed on the subframe, fortunately) on the interstate. The car needs a new timing belt, needs the tensioner stud drilled out, a new tensioner stud and nut, and new middle and lower timing belt covers. The engine died because the valves stopped moving with the crank. Thanks for your input.