Contour Enthusiasts Group Archives Forums General Troubleshooting 1996 Mystique Misfires

Got a question for anybody willing to help.

I came here from the dsm boards for some help on a 1996 Mystique I'm having real issues with.

I was rebuilding a 1996 Mercury Mystique for my brother in law that is in desparate need of a car. I got the car off a friend that knows nothing about cars because he thought that the head gasket was blown. Long story short it was a blown water-pump.

I got to work on it when I could and finally (thought) I finished a few days ago. I replaced the waterpump, timing belt, serpintene belt, a few pulleys, spark plugs, air filter, battery, changed the oil. Got finished car started, but ran very rough.

The car did sit for a year + before I ever got to it. Had about a half tank of gas in it, and being in Wisconsin, the car got cold and hot just sitting there. Figured the gas was crappy. I let it run about 2 days ago for a good 30 min, took it to the gas station and put 93 octane in it to bring the octane of the existing gas up, through in some injector cleaner and a bottle of Heet (takes water out of gas.) Drove it around for about 20 miles, highway and city. Ran GREAT!! I was very happy and proud of my accomplishment.

I have to hand the car over in 2 days to my brother in law and I go to start the car this morning (about 5 or so degrees out) and it won't start. Turns over fine, is sparking, won't start. After about 15 mins of trying and holding the accelerator to the floor it barely starts/ idles, runs very rough. Let it run is missing in the lower rpms badly. Kinda runs fine past 2500 rpms. Put it in gear and the idle falls off/sometimes dies out. Does NOT throw any kind of check engine code.

My thoughts are possibly clogged fuel filter. Any other ideas??? My buddy here at work says no way. I'm damn near positive I set the timing correctly.

Thought the very helpful people here might help a dsm'r in unfamiliar territory out.

Clif notes:

Rebuilt 1996 Mercury Mystique after sitting for 1 year +. 1/2 tank of old gas in the car. Changed spark plugs, battery, new gas, timing belt. Idles and runs like ass, nearly dies when put into gear.

After all that and you never specified if it was a Duratec (V6) or Zetec(4cyl) engine.
This is kind of important to help you.

If you've rechecked everything you've done and it's a V6 Duratec.
Check the Idle Air Control Valve, Injectors maybe leaking or plugged, maybe do a fuel pressure test.
I could very well just be the old gas and additives you threw in there.

Welcome . Yes, it could be the fuel filter too but as posted by Chongo, the IAC valve is also a good bet.

If you said you have a timing belt, then it is a Zetec.

IAC cleaning
from Ray's UIM/LIM how to in Duratec Maintenance how to.

"Replacing the IAC gasket:
(From IAC faq)
Over time, the IAC (Idle Air Control) valve becomes sticky due to buildup from the EGR and PCV systems. It can stick partially open such that idle quality is adversely affected, and engine RPM's will not drop below 1500. For a while, blipping the throttle will restore normal idle, but this only works for so long.

The fix is to remove the IAC valve by unbolting the two 8mm bolts that hold it on and disconnected the wiring plug. If you are careful enough, replacement of the gasket will not be necessary. The gasket costs less than US $1.00, so it is no tragedy if you destroy it. Once the valve is off, spray it out with some carb/intake cleaner and make sure any gunky residue is gone. Reattach, and you are done. It is a lot cheaper than a new IAC, which runs around US $70. Note: Ford claims the IAC cannot be cleaned, but this is not true in my experience." Ray.

Location of the IAC for the Zetec.

"It's on the back side of the intake plenum under the throttle body area." DESIGN.

I looked at the Haynes manual and the Zetec IAC valve is located next to the starter. It appears you need to access it from the bottom. Below are the steps from the 1996 Ford CD to remove it .

Idle Air Control (IAC) Valve


Removal

1. Disconnect battery ground cable

2. Remove the air cleaner outlet tube and resonator assembly.
3. Disconnect the main chassis vacuum line.

4. Disconnect the ignition coil and radio interference capacitor wiring.

5. Remove the fuel line bracket retaining bolt.

6. On 2.0L engine equipped vehicles, raise vehicle on hoist.
7.
7. Disconnect the engine control sensor wiring or fuel charging wiring (depending upon application) from the idle air control valve (IAC valve) at the idle air control valve connector.

8. On 2.5L engine equipped vehicles, remove retainer for engine control sensor wiring from the upper retaining stud bolt.

9. Remove the two idle air control valve retaining bolts or stud bolt (depending upon application).

10. Remove the idle air control valve and idle air control valve gasket.

Installation

1. Note: If scraping is necessary, be careful not to damage idle air control valve or intake manifold idle air control valve gasket surfaces or drop material into intake manifold.

Clean idle air control valve gasket mating surfaces.

2. To install idle air control valve, reverse Removal procedure. Tighten the fuel line bracket bolt to 8-12 N-m (71-106 lb-in).

3. On 2.5L engine equipped vehicles, tighten the retaining bolt and stud bolt to 8-12

4. On 2.0L engine equipped vehicles, tighten the idle air control valve retaining bolts to 8-11 N-m (71-97 lb-in).

Sorry guys, yes it is the 4cyl. I really don't think it is displaying the symptoms of the IAC. It is idling 700-800, but when put into gear, the idle drops off drastically and it sometimes dies out. The engine is best described as very poor revving. It stumbles alot at the lower r's.

What I really can't figure out is how it ran perfect two nights ago and today I BARELY got it started and it runs so rough????


WHERE IS THE FUEL FILTER??


Thanks guys.

Eric

That fuel filter post will be very helpful. Thank you!

Any other ideas on what to check??

Thanks again,

Eric

Might be worth scanning for codes, Auto parts stores Sometimes do it for free, write down the code numbers. Ignition wires/plugs could need replacing. Does it smooth out immediately when you take it out of gear?

The way you are describing it... it ran great on 93 octane? I had a similar problem. I would get nasty misfires under heavy acceleration, unless I ran 93 octane gas. I found my spark plugs I had recently replaced were a bad type to have in the engine, so I promptly replaced them with motorcraft OEM replacements. Champions are JUNK! I also later found out my coil pack was bad. I picked up a slightly used ACCELL coil for $20, Runs like a champ now... Another reason for running great on the 93 octane gas may be advanced timing. Normally if you advance your timining it a little, this requres higher octane gas... hentz is why it ran great on high octane a like junk on low. So First thing is first, I would suggest finding some Motorcraft spark plugs. or even the old ones you had in there before. Then a new Coil pack, then checking your timing, a fuel filter would be a great idea as well.

I would double check that timing belt. One tooth can do some strange things. I have seen this before on a ford escort, and the belt was installed one tooth out. Double check the timing, and make sure all your indicator marks line up exactly. Short of that, take a vacume reading to see if your getting proper vacume. If you find the vacume is out, which leads me to belive it is (causing the stall )
then the timing is off on the compression stroke and valves are slightly open. Good possibility that its off.

I'm going to change out the fuel filter, pcv valve, check the plugs (autolite). I will also check the timing again. I'm thinking it has got to be fuel related, why else would it have started SOOO damn hard this morning with a brand new battery (2 days old) and really good spark.

Also, somewhere on here I read that the CEL should go out as the motor is cranked to show that the cam and crank sensors are properly aligned. The car does do this, the moment the key is turned the check engine light goes out and stays off (if the car is running).