Thread: 1984 efi 302 stall issues

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I got a hold of an old Grand Marquis. A 1984 model with a 302cid v-8 and throttle body fuel injection. Its got a huge issue though. It stalls all the time. When I start it it stalls unless i keep a foot on the gas, it stalls when I shift into drive, it stalls when I try to accelerate (engine dies and then comes back sometimes) and it stalls when I come to a stop.

I've replaced the cap, rotor, wires, plugs, o2 sensor, fuel filter, air filter pcv valve and so far nothing has helped. The exhaust on the vehicle is new but there are no catalytic converters, if that might be causing issues. It does better once the engine warms up but not by much. I'd appreciate any help I can get on this one, as the only thing I know it isn't is warped heads.

check fuel preassure. test for codes, and make sure it's injecting fuel correctly... that is the old CFI, and while it is a very simple setup. it is crude and somewhat finiky .. if needed you could hook up a holley 2bbl on that manifold with a factory duraspark II distributor and basicly have the same setup as the '83 version of that car.. IIRC it only lasted '84 and '85

Actually the 83 had the same setup just about. Same throttle body injection and everything. I owned an 83 before I bought this 84, but I'll test fuel pressure all the same.

fuel preassure should be 15 psi, and the regulator is internal with the CFI

I ground hopped it with another fuel pump from another fuel cell and the engine still refuses to thrive. A friend said I was running in rich conditions, and I can smell unburned gas in the exhaust. I just dont know what other part it could be that would cause this, given what I've changed out.

the fuel preassure regulator in the CFI

pull the egr and check to see if the gasket is burned through and check and make sure there is not a piece of carbon or other debris holding it open....ted

I would check the TPS (throttle position sensor). Sounds to me like the ECU could be out of synch with throttle demand.

I'll get on all of those things tomorrow, thank-you. If nothing seems to pan out I'll start pondering the purchase of a propane conversion.

It sounds like the engine coolant temp sensor is bad. It will tell the pcm the engine is alot colder than it is. Sometimes showing -20 degrees. This will cause it to run rich & stall. Also make it hard to restart. As the engine warms up it will run start to run a little better. You can check the voltage to verify this. I don't remeber what the readings should be as they will change with engine temp.

Originally Posted by rspears

I would check the TPS (throttle position sensor). Sounds to me like the ECU could be out of synch with throttle demand.

We had an 84 Town Car, same engine, same problem. Had it back to Lincoln dealer bunch of times and they couldn't fix it. Finally found a little garage where the guy knew Fords. Kept the car for a few days and drove it home so he could see what was going on. He replaced the throttle position sensor and it ran like a clock. Roger may be right about what you have going on.

Don

Nope, it was the fuel pressure regulator. Now that I think about it its about the same as when the regulator died in my 83 a few years ago. In the 83 though the regulator spat fuel everywhere and started a fire. At the time I can remember wondering if I should be driving towards an autozone or a firehouse.

Thanks guys. Now I have a vehicle that runs solid, came with enough spare parts to build most of a second car and it only cost me 800 bucks.