1999 Mercury Mystique Car Wont Start

WHITEK22

MEMBER
1999 MERCURY MYSTIQUE
4 CYL
2WD
AUTOMATIC
11,300 MILES

I have a 1999 Mercury Mystique and recently it stopped running. It was operating fine and one day I shut it off, left it for around 2 hours and came back to it and it wouldn't start. We jumped the battery but it didn't fix the problem. I called a towing company and the guy immediately told me that my timing belt had gone, which I figured was the case. Then I questioned if he was correct, as he didn't open the hood, ask any questions about it, and only tried to start it once. So I had a family member who is decently knowledgeable take a look. We took the cover off and noticed that the timing belt was fine and in fact was turning when we tried to start the car. My question is what other things might be keeping it from starting? When I turn the key it sounds like it wants to start but wont. The sound it makes is hard to explain but it does sound like it wants to start often. I've boosted that battery and had no luck. The serpentine belt is intact and working but I just cannot seem to find the root of the problem. I was thinking fuel line, fuel filter, or something of that nature? Any information would be greatly appreciated! Thanks.

Wednesday, September 8th, 2010 AT 5:39 PM

1 Reply

WRENCHTECH

MECHANIC
20,761 POSTS

Don't be so quick to discount the timing belt. All it has to do is jump a tooth and it might not start.

An experienced tech can recognize it right away by the way the engine cranks. When a timing belt jumps or breaks the cylinders lose compression and that is easily recognized when the engine is cranked as it will crank much faster with little or no resistance.

I will give you the whole diagnostic process that isolates the cause but you may want to start with a compression test on that one.

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

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Wednesday, September 8th, 2010 AT 5:58 PM