need help-engine barely starts when warmed up

need help-engine barely starts when warmed up - update

1979 Mercury Colony Park with 351 engine - It fires right up when the engine is cold and has been sitting. But once warmed up, if I shut the engine off and try to restart it within 2 hours or so, it is very hard to start. Essentially, once the engine is warmed up, it is hard to start. I have to crank the engine for a total of about 30 seconds, and I have to press the gas pedal all the way to the floor. Then it barely fires up and almost dies out, but after about 10 seconds of running, the engine comes up to speed and starts running normally, and then white smoke blows out the exhaust for a minute or so. I put in a new cap, rotor, spark plugs, and fuel filter, but the problem remains. Any suggestions as to what the problem might be? All input is greatly appreciated! UPDATE - I pulled out the cold enrichment rod and cleaned it off since it was a little gunked-up. Since I did this, I have not had this hard starting problem at all! However, the engine still runs rough, and I am planning on getting rid of the 7022VV carb. Here is a link to the August 1976 edition of Popular Science which contains an article on Ford's "new" Variable Venturi carburetor. Pretty interesting graphics.
http://books.google.com/books?id=Eg...AEwAA#v=onepage&q=cold enrichment rod&f=false

 

Have you checked the timing?

 

No, I have not checked the timing. But you can't adjust the timing on this EEC-II engine, correct?

 

First, yes, timing is adjustable. Your base line timing is 12 degrees before top dead centre. Disconnect the vacuum advance and plug it. There is a retaining bolt at the base of the distributor. I use a 1/2 in socket, then a u-joint, then a 6 inch extension on the 1/4 inch drive ratchet handle to loosen and tighten the bolt. It sounds to me, though, like you may have gas cooking in the carb. The float level may be a touch high, allowing the gas to 'boil' and over flow down the throats of the carb. I would also check the gaskets and spacer under the carb. If the spacer has been replaced with one that conducts heat, there's your problem. The carb is too hot, the gas boils, and floods the engine. What gives me the idea of gas boiling out of the carb is that you have to hold your foot to the floor and it will eventually go. Holding your foot down like that closes off the fuel supply to the engine, and it fires when the air fuel mixture becomes volatile. I would certainly have the carb looked at if it is over 10 years since the last rebuild. Also, take the time to set it up properly. Most people have a nasty habit of running these cars a bit rich. Do you know which 351 you have in your 79? Chances are, it is a Windsor, and that is a sweet engine. I am on my second 78 Thunderbird with a 351M, I've had 2 79 Thunderbirds with the 302W, an 87 and 89 Grand Marquis sedans with 351W and an 88 Crown Vic with the 302. I sort of know these engines inside out and backwards.

 

Do you have the variable venturi carb?

 

Yes, it has the variable venturi carb. Mike T - regarding the timing issue, there is a sticker on the distributor which says it cannot be adjusted. Are you saying that it is still OK to adjust the timing despite the sticker? I don't want to mess anything up by doing so. The carb looks like it needs a good cleaning, and I doubt it has ever seen a rebuild. So I guess I will start with a carb rebuild and take it from there. Many thanks MikeT for your detailed and informative response. I will keep everyone updated.

 

Base timing is still adjustable. The distributor could be worn out, but I would think that would show symptoms all the time rather than just when it is hot.

If you need a carb rebuild and don't need that carburetor for emissions purposes I might suggest just swapping to a standard 2 barrel carburetor (or four barrel if you want to go that way). The VV can be very tempermental and difficult to work with. When it is working right it's a great carb, but when it is not it is not so much fun. If you don't have an overdrive transmission then the swap will be even easier.

 

Coils are very susceptible to heat. They will work when cold then fail when they get hot.

 

I spoke to a carb rebuilder today, and he actually suggested the same thing - ditching the VV and getting a standard carb. He said the VVs stink. So now my clueless question is: Where can I find a standard carb? Are there any newly manufactured ones that will fit my engine, or do I have to find an older rebuilt one? I also think I am going to replace the coil for good measure since it looks old. Can't hurt.

 

Coils are dead easy, and dead common. there are several different brands. Most are direct plug and play, and use the standard factory horse shoe connector. My personal preference is for the ACCEL coils. The do not use the horse shoe, so you have to keep the polarity correct.

With the carb, for sure ditch the VV. Either the standard 2 bbl off any old Ford, or go with an Edelbrock Performer intake and 4 bbl, 600 cfm square bore carb, number 1401. The latter will give both better performance and economy than the 2 bbl. Regardless of what Edelbrock says, their carbs do work perfectly with the CARBURETED version of the AOD transmission. All you have to do is adjust the kickdown rod under the car. Move the connector to the very back of the rod. Takes about 3 minutes.

I have never seen a Ford with a sticker saying that the timing could not be adjusted, and that included my 89 Grand Marquis with the 351W and trailer Tow III package. 12 degrees before TDC is the standard base line. If you don't hear any knock at all out of the engine, dial in an extra degree or 2, until you hear a VERY soft knock under high load. Believe it or not, the knock sensors were calibrated to allow for that. Odd, I know, but these Ford 351s seem to like just a touch of detonation. Doesn't see to hurt them, either. Seen one coming up on 1,000,000 miles, still knocking perfectly under full acceleration.

 

I am going to start off with a non-VV 2bbl carb and a new coil and see how that works. As far as the timing, I will check it with a timing light and see if it is set OK. I hope it is, because I will be hesitant to try to adjust it. Here is the sticker on my dizzy:

 

I've never seen anything like that on any of my Fords, including my 79s. If your timing is off, though, it may be due to a stretched timing chain, given that it is set at the factory, and not adjustable after. I would talk to the mechanic about possibly putting in a different distributor that is adjustable if you do need to do the timing chain. Think is, these engines are not that particular about timing, at least when it comes to starting. They are very forgiving.

 

sounds like its got a bit too much timing in it

 

Vapor lock?

 

I doubt it's vapor lock. I'm banking on the carb at this point. I plan on getting a non-VV carb and I will post my results when I do so!