I was wondering if anyone has any ideas about this tricky one...it's fooled ford techs for 6 months now.
EL Fairmont Ghia V8. Intermittent starting problem. Sometimes she will fire up first go, other times she cranks and cranks but wont fire. Eventually it kicks a few times & either stalls or hunts for an idle speed. When running the engine is faultless. The only way to get her going when the fault occurs is to just hold the key on start and wait. Takes up to 10 seconds for the first kick. Fault almost exclusively occurs when ambient temperature is high (eg left in the sun)
It's had a new ECU, BEM, TFI module, distributor, coil, plugs, leads, ignition lock assembly, fuel pump, Air Flow sensor, injectors & fuel pressure regulator.
The wiring to the BEM under the dash looks dodgy (there has been a car kit AND immobiliser installed at one stage). Has anyone heard of poor wiring causing this problem?
There is a PIP signal & there seems to be spark when displaying the fault. When the motor fires, a cloud of black smoke is shot from the exhaust indicating a rich mixture, therefore there is fuel (how much we don't know). Compression is OK. Injectors are clean. Fuel pressure is rather variable but seems within tollerance.
Something interesting to consider: Ford advanced the ignition timing to about 30deg. This resulted in significant pinging at full throttle but the starting problem was much improved. Over a period of a few days, the timing has seemingly retarded itself as the pinging as gone away and the starting problem is now more frequent.
The black smoke is only evident after an extended crank.
I thought I'd hit the jackpot a while ago when I indeed found that the crappy plastic tubular chamber was not secured tightly but after fixing it, no improvement was evident!
As far as I can figure, it either has to be ignition timing (because there is spark when the fault occurs but is it at the correct time?) or a problem with the quantity of fuel being delivered (this is hard to quantify).
The ignition is only controlled by the computer above 350RPM (from memory) and everything in the ignition system but the hall-effect sensor has been replaced.
Coolant sensor and MAF have been replaced & I'm unaware of any other sensors or parts that would affect the fuel mixture (although a faulty component in the fuel system might).
It is definitely more problematic at higher (ambient) temperatures.
I tend to think that dodgy wiring would tend to cause faults more randomly and not as a function of temperature.
Spark plugs,Coil,secondry ignition wires,Spark plugs fouled,tfi,dist cap,dis/edis,Crankshaft sensers,coil packs.Check all earths esp the one at the rear of # 5 cylinder/inlet manifold, it's the earth for the injectors etc...
Thank you for your thoughts, The majority of the things you’ve mentioned have been replaced but I shall check a few of them, for instance the EGR and PCV side of things. I thought that the TFI acted as the engine position sensor on the EL and hence it didn’t have a crankshaft sensor?
No faults from EEC. The exhaust is only about 6 months old so I don’t suspect problems caused by restriction, and I use premium unleaded. It is an incredibly frustrating problem and it’s unbelievable that the amount of diagnosis conducted so far has not improved things. The injectors are very clean and the fuel pressure is fine even when playing up, perhaps the injector pulses are too short (too little fuel) – I’ll check that earth at the back of #5 (although once again, you’d suspect problems when running too).
Tell me more about this idle air flow. It seems that when playing up, the extended cranking can be (marginally) shortened by depressing the accelerator ˝ way. Would a faulty idle control solenoid explain this? Wouldn’t the idle be rough if that was the case?
I wonder, are any of these components you’ve mentioned particularly susceptible to higher temperatures?
If we could only narrow the fault to a particular system (fuel, air, ignition…) that would be a good start.
Remember, it’s interesting that the fault is EXCLUSIVELY evident when starting. The engine runs like a dream when running. Does this help to rule anything out?
so there is spark all the time when it is faulting or just sometimes?
the timing would have to be pretty far out for there to be spark and fuel while cranking but still no start...
i would be checking the wiring under the dash very carefully as well, is the immobiliser still there or was it removed? either way it could give you dramas.
also check the base idle when the engine is running, if it is too low then it might give you starting troubles. a sticking IAC (idle air control) motor might also reduce the amount of air getting into the engine at crank and reduce the chance of it starting, but the chances are slim.
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Yeah, spark is there all the time (well, I've yet to witness an occasion when it isn't) - but I found it weird that when the pinging was removed by retarding the timing, the starting got worse.
What do you suspect with the wiring? The only thing I can think of that would cause suspicion would be O/C or high impedance connections. You’d think that this would cause random or even hard faults. Would you recommend a complete rewire (how much does this cost)? The thing cranks and there is spark so as far as the BEM is concerned, everything should be un-immobilised (previous immobiliser has been removed).
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