Hard to start Crown Vic....

Discussion in 'Domestics' started by Pete, Nov 19, 2006.

  1. Pete

    Pete Hero Member

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    Hi folks!
    Now it's my OWN car that I'm having trouble with. I have a 94 Crown Vic 4.6L, 265K and I'm experiencing hard starting and running rough until I give it some gas just after I start it.
    There has been a valve rattle for quite a while now upon load that I just haven't been able to get fixed so I upgraded to premium and that corrected it. I don't know how else to fix it. I also unplugged that little plug that retards the timing for this a long time ago.
    Anyhow, whenever I start it when cold it starts hard. When warm it starts right up. When idling it idles very smooth.
    I recently (one year) put in a new fuel pump.
    I checked the fuel pressure reg. vacuum line to see if there was fuel in it and there was none.
    What else should I be looking for on this Ford.
    This is very similar to what a friend Suburban was having that Crunch helped me with but without the smell of fuel.
    Anyone? Crunch?
    Thanks so much and as always, may God bless you all for helping others!
    Peter
     
  2. autodr

    autodr Hero Member

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    Sounds like a typical contaminated MAF sensor. The contamined senor will cause a lean condition that cuases the spark knock. Plus, it also lowers the infered BARO reading. During cranking, there is not much air flow through the MAF sensor. So, the MAF reading is NOT used during cranking... but... Instead it uses the BARO to infer airflow during cranking. So, if the BARO is way low.. you won't get much fuel during cranking and can mimic a typicle slow to prime fuel pump. Do you have a scan tool that can veiw PIDs on this vehicle? If so, check the BARO Hz. and compare to your altitude. There is a chart for it. But if you are around sea level.. it's easy.. about 159 or 160 at sea level is fine. The Hz lower the higher the altidue is (or the infered altidue anyway).

    Sotimes cleaning the hot wires with rubbing alcohol and a q-tip (very .. very gently) will at least clear up the symtoms... but usually only a new MAF makes them completely right.
     
  3. crunch

    crunch wrench

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    Pete
    As autodr says check the baro pressure reading and match them to your altitude.
    And or do the old unplug it test
    Crunch

    BAROMETRIC PRESSURE REFERENCE CHART
    Barometric Barometric BARO/MAP Altitude Above
    Pressure Pressure PID Sea Level
    (in. Hg.) (kPa) (Hz) (ft)
    3.5 11.8 89.3
    5 16.9 92.8
    10 33.8 104.6
    15 50.7 117.0 14,000
    20 67.5 129.6 10,000
    21 70.9 132.5 9,000
    22 74.3 135.4 8,000
    23 77.7 I 138.3 7,000
    24 81.1 141.1 6,000
    25 84.4 144.0 5,000
    26 87.8 146.9 4,000
    27 91.2 149.8 3,000
    28 94.6 152.8 2,000
    29 97.9 155.8 1,000
    30 101.3 158.9 0 (sea level

    On a fully warmed ~p engine, look at Long Term Fuel Trim at idle, in Neutral, A/C off, (LONGFT1 and/or LONGFT2 PIDs). If it is more negative than -12%, the fuel system has learned lean corrections which may be due to the MAF sensor over-estimating air flow at idle. Note that both Banks 1 and 2 will exhibit negative corrections for 2-bank system. If only one bank of a 2-bank system has negative corrections, the MAP sensor is probably not contaminated..

    3. On a fully warmed up engine, look at MAF voltage at idle, in
    Neutral, A/C off (MAF V PID). If it's 30% greater than the nominal MAF V voltage listed in the Powertrain Control/Emissions Diagnosis (PC/ED) Diagnostic Value Reference Charts for your vehicle, or greater than 1.1 volts as a rough guide, the MAF sensor is
    over-estimating air flow at idle.

    4

    If at least two of the previous three steps are true, proceed to disconnect the MAF sensor connector. This puts the vehicle in to Failure Mode and Effects Management (FMEM). In FMEM mode, airflow is inferred by using rpm and throttle
    position instead of reading the MAF sensor. (in addition, the BARO value is reset to a base/unlearned value.) If the lean drive ability symptoms go away. Replace the MAF sensor
     
  4. Pete

    Pete Hero Member

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    Thanks again autodr & Crunch!
    The MAF sensor on the ol Crown Vic is spotless as I think you've told me once before to keep them clean. Perhaps it was for another car.
    I disconnected the MAF at one time and I still got the spark knock. Could it be a knock sensor?
    I don't have a tool that will tell me about BARO so I can't do that.

    Please advise cuz I'm not sure what to do here?
    Thanks again guys!
    Peter
     
  5. crunch

    crunch wrench

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    Try the MAF disconnect and post back if it helps.
    Have you checked for codes?

    Also check the pcv valve hoses all of the way back to where they go into intake.
    Look real close at the rubber elbows and hoses back there on back.
    They get mushy or soft and holes in them
    And a oem ford pcv works better.
    Also egr valve sticking or not working or passages stopped up will lead to pinging
     
  6. NickD

    NickD Guest

    I see this car had been around the block a couple of times, is it an oil burner? And when was the last time the compression was checked. Spark is weakest when cranking, and with ice cold shrunk pistons, can be blow-by blowing out what spark may be left.

    Would first check engine compression, plugs and wires and in particular the size of the spark gap when cranking, still should be about 3/8", then fuel. If compression is low and you don't want to do a ring job, can try decarbonizing the top of the engine to see if that helps, but 265K is a lot of miles, would anticipate some engine wear at that point. Heat also expands electrical connectors that may not make good contact when cold.

    You say everything is much better when the engine is warm, so working on that premise, stepping on the gas when cranking does enrich the fuel due to the TPS, but can also moisten the plugs so they won't fire.
     
  7. Pete

    Pete Hero Member

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    I'll try the disconnect Crunch.
    Thanks for the info NickD but no, it's not at all an oil burner. It's been pampered since I've had it and the state troopers had it before me. In the state of WI the state boys take care of their vehicles. Local's don't.
    Fairly new wires and plugs (within last 10K).
    Decarbing top is done by BG 44K as it's an excellent decarbonization additive along with injector cleaner and everything in the fuel system right down to the combustion chamber. I use it regularly.
    God bless,
    Peter
     
  8. NickD

    NickD Guest

    I'm in central WI, son had problems like that in the Madison area, did you know it was reported that 3,500 some gas stations have ground water in their tanks in our state. Did this problem just start after a fill up? Need more history. What I did was connect a fuel pump tester, hot wired the fuel pump and pumped gas (with water) into a container. That moisture left in the combustion chamber made cold starting rather difficult. Could be your problem, then could not, but worth checking out. His engine also started okay when hot.
     
  9. BMFer

    BMFer It only rattles when I crank it.

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    Your hard starting issue is most likely simply a worn out IAC (Idle Air Control) valve. Not nearly as easy to replace on yours as on the 96 & newer models.

    The MAF could definitely be contributing to your pinging problem, but you need a scan tool that will give you BARO readings. Also, 92-95 panthers had severe issues with the EGR and the EGR passages in the plenum and intake stopping up with carbon deposits. This is a major contributor. You have to tear into it and clean it up good to eliminate this. It will be a reoccurring problem with that sort of mileage though, unless you tear into the engine and replace the worn valve seals. 91-95 4.6's had the poorest valve seal design ever, and the oil that leaks through them burns partially and goes into the EGR system like a magnet. Also, carbon buildup in your combustion chambers will contribute to the ping, and again, I'm sure there is plenty of that on a 265K 4.6, especially if you've been driving it easy. And last but not least, what kind of shape are your plugs and wires in?

    Now you know why I have always insisted on sticking to 96 & later Crown Vics in the fleet I maintain. ;)
     
  10. Pete

    Pete Hero Member

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    Hey BMFer! Thanks for the info. I have disconnected the MAF and still get the hard start. Can't tell about the pinging as I'm running premium right now. There are no oil burning issues although I now understand the valve seals issues as if I'm idling a while I'll get a patch of blue smoke upon acceleration. EGR is clean as I've replaced it a few years back and have since cleaned out the passages since. I'm aware that this is a problem. I'm not sure what you mean about the intake. What do I clean on the intake? Also, I use a chemical called BG44K which cleans the combustion chamber of carbon as well so that may or may not still be an issue. It's the only stuff that does it.
    Plugs and wires new.
    The pinging I can live with (well, I use premium so there is none) but it's the hard starts that I'm all of a sudden getting that I want to rid myself of.
    I'm most grateful for the advice!
    May God bless,
    Peter
     
  11. Ford_Dude

    Ford_Dude wrench

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    When you say its hard to start, is it every time you try to start it ? Or is it just the first start of the day. If you have a fuel pressure gauge it might be worth putting it on the car to see if the fuel pump is taking a long time to prime, or if the injectors are letting fuel in to the combustion chamber when they are not suposed to.

    Ford_Dude
     
  12. BMFer

    BMFer It only rattles when I crank it.

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    Where the lower intake and upper intake (AKA plenum) meet, there are two small EGR passages that clog up quite quickly, especially if you see a puff of blue smoke after extended idle periods. BG 44K is good stuff, but it won't clean EGR passages when it is run through the fuel system. It may help cut down on carbon build up in the combustion chambers, but only marginally.

    Let me make sure I understand your cold start issue fully. You say when you start the car when cold, you have to give it a little throttle to keep it running, right? Replace the Idle Air Control valve if this is the case. They are a common problem.
     
  13. Pete

    Pete Hero Member

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    Hey Ford Dude! Any relation to Hondadude?
    It's always the first start of the day. After that no problems unless of course it's been sitting for a long time say, 8 hours.
    Yes BMFer, it's when the car sits and is cold when it has to crank quite a while and then I may have to give it a bit of throttle to get it going but not always. You still think IAC?
    I'm most grateful for all of your help folks!
    Peter
     
  14. Ford_Dude

    Ford_Dude wrench

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    If you haven't got a fuel pressure gauge try this:
    First start after a long sit cycle the key from off to just Run a few times and then try to start it. If it fires up much easier you are having a problem with your fuel pump priming. Just because the pump is pretty new doesn't mean that it can not be bad. Be even better if you could beg borrow or steal a fuel pressure gauge.

    Ford_Dude

    P.S. yeah there is a relation, he likes Hondas, I like Fords, and we are pretty friendly, so I kind of copied his idea.
     
  15. BMFer

    BMFer It only rattles when I crank it.

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    ^^^ Yes, try what FD suggested. Also, how old is the fuel filter? All that premium gas and cleaner you run through the tank also cleans the tank & lines out, and all that stuff goes into the fuel filter. I misunderstood your cold start issue. I appologize. I believe FD has you on the right track with fuel pressure.
     

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