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Engine Runs Rough

Tiny
KEITH W
  • MEMBER
  • 1994 LINCOLN CONTINENTAL
  • 45,000 MILES
Engine runs rough.

Replaced both Cylinder Head Gaskets...
Included Exhaust Manifolds Gaskets, Upper & Lower Intake Manifold Gaskets.

Tested Cooling System Constant Control Relay Module (CCRM).

Tested Engine Coolant Sensor.

Replaced Valve Stem Seals. Umbrella type.

Rebuilt Fuel Injectors.

Cleaned, lapped, and reseated Valves.

Replaced Spark Plugs.

Replaced Spark Plug Wires.

Cleaned small amount of oxides from distributor cap (inside) aluminum lugs.

Distributor / distributor timing has not been disturbed. Distributor housing still set at OEM chisel marks.

Replaced EGR Valve Control Solenoid. Was activating check engine light and chime. CEL now off.

Cleaned internals on IAC - Idle Air Control Valve; no difference. Then also replaced IAC; no difference
With IAC connected engine idle is a little rough. Without IAC it is the same; rough, but have to adjust idle stop to keep engine running. Installed temporary slip blind at IAC but found no difference.
Cleaned internals and tested diaphragm at EGR Valve. Remounted valve w/new gasket. Installed temporary slip blind between EGR and manifold; found no difference in idle quality. Pulled slip blind.

Tested TPS – Throttle Position Sensor.

Cleaned and tested MAF – Mass Airflow Sensor 3-times. Even disconnected with engine running and there is only a very slight difference in idle quality... Maybe gets a tiny bit worse.
(1) power circuit good. (12.34 V)
(2) ground circuit good. (12.69 V)
(3) 2nd ground circuit good. (12.69 V)
(4) * MAF electrical “signal” swings a few hundredths of a volt along with engine roughness swing at idle
= approx 0.78 to 0.810 V. Voltage numbers rise and fall fairly smoothly during rev up to 1500 rpm and coast down.

When engine rpm is increased (by hand) it will not hold at a steady rpm.

Idle rpm 510 to 520. Spec calls for 550.

Have not tested O2 sensor.

Soaked every imaginable vacuum hose, fitting, component, with carb cleaner; no change in idle.

Engine vacuum at upper intake manifold 18 to 18.75 in. At idle. Needle bounces within the range.

Now have trouble codes 56, 35, 63.

Tired of throwing money at this car / money pit.

Car only has 45,000 total miles.
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Monday, April 2nd, 2012 AT 2:28 PM

18 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
That si why ou always scanfor codes and CHECK fuel Pressure first. Low fuel pressure will causerough runing. Those codes aren't right either they need to be 3 numbers not 2. The code is 563 which means a high fan control circuit failure, check the fuse and relays fuel pressure shold be 35-45 psi.
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Monday, April 2nd, 2012 AT 4:43 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
These aren't OBD II codes. (OBD I)
These are BEFORE_OBD II.
This is a 1994 Lincoln Continental
I have an OBD II Scanner but it is not used for pulling codes on this year / model car.
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Monday, April 2nd, 2012 AT 5:20 PM
Tiny
HMAC300
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  • 48,601 POSTS
Yes I know it's OBD1, but it's a 3 digit number which is 563 that is directly from FORD.
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Monday, April 2nd, 2012 AT 8:06 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
Thank you but I have to disagree.
There are over 80 2-digit codes in OBD I.
I pulled these myself as I have done several times over a number of years. There has always been 2-digit OBD 1 codes along with the 100 thru 600 series codes for Ford vehicles as far as I've seen. Did you read thru the info in the url's I pasted in my 1st reply? This info covers the way I've pulled codes in these older cars. A Star scanner is not needed. This car does not allow the CEL to flash codes. You have to do it under the hood. The easiest way is to jumper the connections and read the flashes on a continuity tester. What do you think?
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Monday, April 2nd, 2012 AT 10:29 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
If I get 5-flashes, a very short pause, then 6-flashes, then trouble code will be 56. A long pause then 3-flashed, short pause, 5-flashed, equals 35. And, so on. I couldn't g
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Monday, April 2nd, 2012 AT 10:35 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
If I get 5-flashed, then a short pause, then 6-flashes, the trouble code is 56. A long pause, then 3-flashes, short pause, 5-flashes, equals 35. And so on. I couldn't conjure a 563 code from any of the flash sequences if I tried all day. I cleared the PCM, ran the car, re-tested several times over the last couple of weeks. Still, I do value your input.
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Monday, April 2nd, 2012 AT 10:40 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
56 MAF circuit above maximum voltage

35 EVP circuit above maximum voltage

63 TP circuit below minimum voltage
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Monday, April 2nd, 2012 AT 10:45 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
What's the fuel pressure
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Monday, April 2nd, 2012 AT 10:47 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
Haven't had time to get that yet. The car is outside. It has been raining off and on. And I had med appointments to keep. I will check that soon. Though and let you know.
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Monday, April 2nd, 2012 AT 10:52 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
OK !. Here's what I got. (Fuel Press. @ Rail)
Key-On-Engine-Off = 40 # Fuel Press
Engine at Idle, bouncing between 500-520 rpm = 32.5 # Fuel Press
Pulled vacuum hose off top of press. Regulator and stopped vacuum leak on the hose with finger. Fuel Press. @ Rail went to 40 # and there was no change in the rough idle. Regulator increased pressure w/no vacuum hose as it should.
Any ideas appreciated.
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Tuesday, April 3rd, 2012 AT 8:35 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
Ok. 5-minute static pressure test = 2 # drop
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Tuesday, April 3rd, 2012 AT 8:45 PM
Tiny
HMAC300
  • MECHANIC
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Ok see if the vacuum line going to teh carbon cannister is open on both sides, meaning if the valve is open. It shold only open around 30 mph. There will be vacuum to one side but not the other until speed is reached. Clean egr valve if you can and check for a cracked/broken holes when egr mounts. Other than checking compression I can't think of anything else.
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Tuesday, April 3rd, 2012 AT 8:54 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
(1) I replaced 1 vacuum hose on the Canister Purge Valve Solenoid that merges into the PCV tubing. The hose on the other side of the valve goes to the canister, was hard to get to, looked ok, but I didn't replace it. I can remove the hose where it merges into the PCV system and plug the port there and the idle does not change.
(1) I've removed the EGR Valve 3-times. Remounted with a new gasket each time and a tiny bit of high-temp rtv. I've cleaned the inside of the EGR Valve though it was not really dirty. The pintle rises and falls smoothly w/vacuum against the diaphragm. The diaphragm does not leak down with a static vacuum test. Very, very slight leak across the seated pintle when I suck on the outlet hole on the valve body.
(3) I used OEM Motorcraft spark plug wires.
(4) A compression test was my thought too.
(5) And, also, see if I can find a plug not firing by using a timing light inductive pick-up on each spark plug wire. The back 3-cylinders and plugs are extremely hard to get to. Especially without getting burned.
(6) Possibly one of the new spark plugs is bad.
(7) Bad spark plug gap somewhere. Maybe I unknowing hurt it.
(8) Worst fear is there's a compression leak across/between some cylinders or a cracked head.

This car was inherited but I poured much money and effort into it. If I had known. It would not have gone this far. I purchased and drove Ford products for 42 years until I finally got wiser. Ford has screwed the American public so bad. I have not had a good model, when I think about it, since 1969. I still have a 1966 Mustang. I told my wife to one time to shoot me if I ever wandered too close to another Ford dealership.
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Tuesday, April 3rd, 2012 AT 9:31 PM
Tiny
HMAC300
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One other thing I forgot to meniton is the firing order correct? And have you checked the dist cap for carbon tracking or cracking. Ireally can't think of anything else. Alot of times if a plug doesn't fire then if you pull the wire just a bit away from the plug it will start to fire. One of the plugs could have soem crap between the electrodes causing this. Firing order pic enclosed.
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Tuesday, April 3rd, 2012 AT 10:39 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
> Firing order good. Checked, re-checked. I marked the cap with a permanent marker also. No tracks or carbon in the cap. There was only a very small amount of oxides on the aluminum lugs which I removed.
> Wiggled all boots. Pulled, re-positioned wires, but they are run and lay in the best possible way.
> A timing light flashes with a regular frequency on all wires but No. 6. I get some funny blips on 6. Moved the inductive pickup to 4-spots along the wire and no change. Going to pull the plug and investigate. At least it is in front.
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Tuesday, April 3rd, 2012 AT 11:09 PM
Tiny
HMAC300
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Bet it's got a piece of junk in it
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Tuesday, April 3rd, 2012 AT 11:13 PM
Tiny
KEITH W
  • MEMBER
  • 12 POSTS
No, it's clean except for a short dark brown horizontal streak on the porcelain near the ground strap. And, the gap was about 0.044" instead of the 0.054" spec. I'm going to buy a new one tomorrow. No. 5 cylinder looks normal, No. 4 looks entirely unused but the gaps are a little tight on those too. I may have overlooked gapping the plugs (?). I check the others tomorrow. And, probably check compression at least on the front cylinders.
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Wednesday, April 4th, 2012 AT 12:34 AM
Tiny
HMAC300
  • MECHANIC
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I have no other ideas on how to help you
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Wednesday, April 4th, 2012 AT 2:34 PM

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