1993 CVPI - running rough

[GarageMahal]

So my sister has been complaining about my old Crown Vic so I drove it for the day to see if I could get a handle on what is wrong. Now that I know what it is doing I thought I post my observations and seek advice/opinions.

First off it started slow this morning, I had to crank it for 5 or so seconds. This car always used to start in under 3. I let it warm up for a couple minutes before I drove off and all was well.

A few times during the 20 mile drive at highway speed to work, the engine light came on for several seconds. I didn't notice anything wrong with the performance or unusual sounds.

At each of the stoplights encountered during the last mile to work, there was a stong smell of raw fuel. It was too windy at work to isolate it.

After work, I just started and went. It took over 5 seconds to start again and was hesitating badly with some occasional pops (backfires maybe). I was unable to give at much throttle at all until it warmed up after which it behaved the same as the drive in.

At home I tried to locate the source of the raw fuel smell without success. There is no visible leakage along the fuel rails and nothing dripped to the driveway at all.

We had it at a dealer once for the problem and they cleaned "heavy carbon deposits" from the intake manifold. This did not fix the problem however.

I thought there was an access port so I could read the codes but have been unable to find it. Is it possibly behind a dash panel?

Any and all suggestions are appreciated.

Details:
1993 Ford Crown Vic Police Interceptor
4.6 SOHC V8
155,000 miles

Thanks much,
jta

[LNYTUNS]

On the 93 the connector for reading codes is under the hood in a wiring harness by the air box and wiper fluid reservoir, at least that is where it is on the civilian cars. You have to read the codes with an analog voltmeter and count the needle sweeps to get the numbers for the codes.

I attached a pic of the connector and which pins get jumpered and which one is connected to the voltmeter and battery.

Now for how to get the codes. Run the car until it is warm. Then turn it off and wait at least 10sec. before starting this procedure.

Connect the jumper shown in the pic. And connect the meter as shown in the pic. The meter should read about 12V. You will need an analog meter as a digital autoranging one will not respond to the pulses from the PCM fast enough.

Next turn the key to the ON pos, don't start the car. The meter should go to 0 volts.

Get back over to the meter and start watching the needle pulses, you will need a pen and paper to write them down, they come somewhat fast.

The first code will be a "seperator code" to tell you the process has begun, on the 93 the sep code is 111. The needle will pulse three times in a row with a 1/2 sec. pause between each pulse. Then the stored codes will begin coming. There is only a short pause 1/2 sec. between pulses and a long pause 2 sec. between numbers, between code numbers there is a 4 sec. pause. The codes on the 91-94s are 2 digit codes. Then you will most likely get another seperator code 111 and then the codes may repeat one more time and then another 111 code at the end. The needle will stop sweaping when the codes are done. Then find a list of all of the codes, it is too long for me to list here, there are about 90 different ones.
To erase the codes, which I would not do until you fix the problem, you have to pull the jumper wire out of the grey connector while the codes are pulsing on the meter.

You can find the code list in a cheap Hains manual publication 36012 for the 88-2000 Crown Vic.

It actually sounds like the PCM is compensating for an EGR valve that may be stuck. You said there where heavy carbon deposits on the intake and the EGR is also a good place for carbon to build up and not allow the pintle to move freely. EGR codes are 31-35.

Good Luck.

[LNYTUNS]

Oops dumb me, correction to my previous post. On the 4.6L the check engine light on the dash will flash the codes, no voltmeter needed. Sorry all of my GMs have been 5.0L, little different, need a voltmeter.

[merc406]

That^^ and change the plugs.

[jobrien8]

When you fill the tank do you top it off, fill until the auto shutoff, on pump, won't let any more in? If so you have probably filled the evaporator cannister. This can give you an interrmittant check light and a heavy fuel odor. Best to remedy this condition is, when fueling and the pump shuts off, don't add any more. It will take maybe two fillups to empty the cannister of liquid fuel. There is no way to empty cannister, easier to just drive. Hope this helps. Reason I know, did it myself.

[jobrien8]

Checked in the garage and found my diagnostic codes for the '93 model year Ford/Lincoln/Mercury vehicles. List the codes and I will relay the interpretation.:up:

[Krytin]

I had this same problem with my "92 CV. Turned out to be one bad plug. Get the diagnostic tool that plugs in under the hood @ the EEC port. Available @ AIDS Auto Stores or Pep Boys - usually under $40. You can run engine on and engine off tests that check all the sensors and cylinder balance. Flashing light on unit coresponds to codes in book that comes w/tool. Also reads stored codes.

[GarageMahal]

Thanks for the suggestions so far :) I think I will be able to get the car again for a day later this week to try some of them out. I plan to pick up a code reader if I can find one cheap in town.

The overfilled tank might be a possiblity however I did discover some gas spots on the driveway in the daylight today. Looks like the tank may be leaking :(

The plugs were all just replaced at a dealer and did not solve the problem.

Hopefully the codes will reveal something.

I drove this car for four years before getting my MM. I must say I miss it a bit but the MM runs circles around it and it soooo much more comfortable. I used to the think the CV made driving my '96 Caprice feel like I was sitting on a 2x4. The MM has me thinking the same about the CV.

Thanks again,
jta