1983 Mercury Grand Marquis Hesitates on Acceleration

[MattsLincoln]

I have a problem with my 1983 grand marquis. It occasionally will hesitate when i try to accelerate, sometimes i have to floor it in order for it to kick in and accelerate. Also when i am stopped at a red light or stop sign it will occasionally Stall. I have had the battery disconnected in the winter and i heard that the Mass Air Flow resets after doing that, would like to know how to set that. Any help here would really be appreciated.

[Brandon]

Sounds like to me that you are having CFI problems (Central fuel injection)

[MattsLincoln]

do you know what problems with the central fuel injection system. The only two things i could think of is acceleration enrichment and the ballast resistor.

[Brandon]

I can't say for sure. some one else will be able to explain to you of what is going wrong wid it.

[marquisman]

hopefully one of our CFI experts can help but, i think there is issues with the choke on CFI units

[MattsLincoln]

if im not mistaken this year didn't have an accelerator pump right. I wonder really what could be wrong with it. It is so annoying and if i can't figure out the problem i won't be able to drive it that much cause i would be sucking up gas big time.

[gadget73]

no accelerator pump. Its fuel injected, but it looks like a carb. 1983 uses the EEC III system, which is a wierd setup that not many people are familier with. Common problems are vacuum leaks, poor condition vacuum lines, sloppy timing chains, and old tuneup parts. If you haven't already, replace the fuel filter, and see what condition the plugs, wires, cap, rotor, and various vacuum lines are in. If you have no idea how old the ignition parts are, I'd probably suggest replacing at least the spark plugs, but depending on condition, do the rest as well. Any vacuum lines that are broken off, crumbly, cracked, or look otherwise sad and pathetic should be replaced.

If you get stuck, there's a guy about an hour and a half south of you thats good with these things. Contact Lincolnmania if you're in need of a mechanic who specializes in boxes.

[Lincolnmania]

test the throttle position sensor

http://fordfuelinjection.com/?p=30

[MattsLincoln]

will do

[pvillese]

Mine is CFI and I was having the same problem. There were a number of things adding to it. I have 75k on my car and everything in the ignition was original except the wires and replace plugs,wires,cap, rotor and fuel filter got me to where I am now and that is just hesitating sometimes when taking off once it is warm. I think the remaining issue is due to a bad O2 since I'm getting funky readings sometimes. I also just replaced my temp sensor and that seemed to help mildly.

If you want to know if your computer knows it is running rich or not you can splice a wire into the O2 wire and run it inside the car and then connect that to a DMM along with running the other lead of the DMM to a ground. .4V to .6V is running correct. You will only get good readings once it is up to temp though. Word of CAUTION when doing this make sure you DMM is only ever set to read voltage, if you send any type of current through the sensor you will damage it. It would be best to drive around with the DMM connect so you get a big picture of its operation. If you don't want to use a DMM you could get and air/fuel gauge and I'd guess that you could connect it to the wire mentioned above and it should at least give you somewhat of an idea of whats going on but the weird readings might not be as clear since the gauge is not going to show actual voltage.

[pvillese]

By the way, we do not have MAF sensors.

One other thing I did that helped mildly was cleaning the EGR valve. It gets lots of carbon build up and could be sticking open.

[Lincolnmania]

we found out in his readers ride thread that he converted this car to a 351w and kept the cfi............i do not think that the cfi unit can possibly supply the fuel needed to the 351w........i would consider a carb or a multiport efi conversion.......i would lean towards multiport, but that all depends on his budget........biggest cost an upper and lower intake for a multiport injected 351......a 4bbl carb swap would be cheaper........used aftermarket intakes are reasonable, olny downside i see to a carb conversion is having to use the lokar tv cable setup which i despise lol

i'm not too far away if you need some experienced help on that grand marquis mang

[pvillese]

we found out in his readers ride thread that he converted this car to a 351w and kept the cfi............i do not think that the cfi unit can possibly supply the fuel needed to the 351w........i would consider a carb or a multiport efi conversion.......i would lean towards multiport, but that all depends on his budget........biggest cost an upper and lower intake for a multiport injected 351......a 4bbl carb swap would be cheaper........used aftermarket intakes are reasonable, olny downside i see to a carb conversion is having to use the lokar tv cable setup which i despise lol

i'm not too far away if you need some experienced help on that grand marquis mang

Yeah, I suppose that would do it. When I do my 351 swap I'm planning on a carb initially to make it affordable since my brother has a 600 cfm carb I just need to rebuild that I can run on it so all I have to do is pick up a cheap used intake and it looks like if you keep your eyes open on ebay you can get a pretty good deal on one.

[MattsLincoln]

in my choice i do want to put a carb on it. I really hate the CFI System. I just wonder if connections are going to be different. The Carb that originally came on this 351 was Shot it was cracked between the Barrels and i said to myself how the hell can you crack a carb. The person obviously didn't take care of the car. It wasn't in the best of shape. I will invest in a 4bb1 carb when i get money but that is tight for me because money is a big issue for me. i like Holley carbs.

[pvillese]

Your cheapest option is probably to pick up a used carb on ebay that needs to be rebuilt and then pick up a rebuild kit off ebay as well.

I'm not exactly sure how all the linkage will line up but the ford AOD is so popular that I think I was reading that Holley has a kit you put on the carb to connect the TV cable and what not. Since we have the older style setup for our transmissions I'm not sure the bracket will directly work, we may have to switch to the cable used on the newer AODs. As for ignition I plan to ditch the computer all together and go with a duraspark distributor and then just use my MSD box as the ignition control. Then there is fuel pressure and I think I'm going to just go with a new regulator that is designed to convert injected cars to carbs that lowers the fuel pressure to where it needs to be for a carb. There are lots of options here with fuel pressure but I think this is the simplest. You could fabricate an pickup and then use an external low pressure electric pump or a mechanical pump. I think that covers the basics since you already physically have the engine in.

A side not, once you get rid of the fuel injection I wouldn't ditch the O2 sensor, I would run a wire from it into the car and connect it to an air fuel gauge or a DMM and then you can get readings to help with tuning the carb.