My 2003 Ford Escape will start and run for a few seconds then stall and will not start again. So far I have changed the IAC, cleaned the MAF, checked the EGR, it has new plugs and coils, replaced a couple vacuum lines, replaced the fuel filter and battery. And i still have the same issue. what to try next???
Not sure about your car but, I’ve found some vehicle that have a filter sock on the pick up inside the fuel tank and if that gets plugged, no go pal. I’ve found a few vehicle with that problem. Good luck
The problem might be with a defective Crankshaft Position sensor.
https://www.rockauto.com/en/moreinfo.php?pk=443736&cc=1414437&jsn=416
If the computer loses the signal from this sensor, the computer see’s no reason to operate the ignition/fuel systems and the engine shuts off.
Tester
I just changed the crankshaft and camshaft position sensors and now it wont even start… almost does but just not quit.
Okay.
Have you tried slightly stepping on the gas pedal when starting the engine?
Tester
One thing in your favor, when an engine won’t start at all, cranks ok but doesn’t pop & start, that is usually some simple to find problem. It’s almost always one of these
- no spark at the spark plugs
- spark ok, but at the wrong time
- no gas being injected
It could be other things, but if the engine worked ok for a long time, then suddenly developed this symptom practically overnight for no obvious reason, the other possibilities are much less likely.
Suggest to start by testing for a robust spark at the spark plugs, and go from there.
George.
This is a coil-on-plug engine.
How does the OP test for spark?
Tester
I’ve never tested for spark on a COP engine, so I’ll let you answer that question.
So there’s no method a diy’er can use to test for spark on a COP engine like this one then? That’s surprising.
Sure there is George.
If the Check Engine light is on with a misfire code, it might be caused by a faulty COP.
Tester
That’s not a direct visual test for spark tho, right? There’s many things that can cause a misfire, not just a faulty COP. So there’s no way on this car for a diy’er to confirm a visual spark at the spark plug then?
Here’s what I would do . . . this will not give you the answer, but it will certainly narrow it down considerably
Remove the engine air filter
Spray one good squirt of ether/starting fluid into the air intake . . . not too much, though
Quickly try to start the engine in the normal fashion
If it will start and run for a few seconds, you have just confirmed you have a fuel pressure problem. And now you need to figure out why the fuel rail isn’t getting sufficient fuel, or maybe not getting any fuel at all
And for all practical purposes . . . IMO . . . eliminated spark as a possible cause
But before you do all that . . . have you noticed the anti-theft warning symbol lit up lately? If the pcm sees what it considers to be an unauthorized start, it will cut the fuel, and the symptoms will be just as you described
George,
If you suspect a COP, move the COP to another cylinder.
If the miss moves with the COP…
BINGO!
Tester
What about using an inductive probe to check for spark?
Where do you place the inductive probe?
The primary current to the COP’s are low amps/voltage.
You want to measure the current/voltage on the secondary side of the coils.
And without spark plug wires, how do you do that?
Besides? I thought you were talking about a DIY’ER method?
Tester
If the voltage on the secondary side is high and the current is low, and the voltage on the primary side is low, then the current has to be high on the primary side, right? So an inductive probe should work great on the primary side. I notice via a Google search there are such devices for sale. A diy’er with a lab o’scope and some electronics experience could probably make their own. That’s how I check the spark waveform on my Corolla, just wrap some wire around the the high voltage lead and monitor the signal on my o’scope. Used o’scopes can be purchased for less than $100. This method would require the ability to isolate the + wire to the coil from the return path however, which might be difficult depending on how it is all arranged.
Of course you could also just pickup the signal directly from the coil by holding some loops of wire next to the coil, that might work. I see some probes like this available commercially too, they just light up if there’s an inductive pickup measured.
Like I say I have no direct experience w/COPs, but it seems like if it possible to install the COP onto the spark plug, it must also be possible to – for testing purposes – remove the COP from where it normally sits, then using jumper wires as needed so all the connections are still made, insert a spark tester between the COP and the spark plug, or better yet, just insert a spare spark plug into the COP and hold it against a ground.
Re: Verifying a visual spark on engines equipped w/ COP ignition systems
Would this work? Remove the COP from the plug. Leave that plug installed. Install the COP onto another spare spark plug. Hold the base of the spare spark plug against an engine ground. A helper cranks the engine, while you look for spark at the tip of the spark plug.