My 1983 Continental Mark VI!

[gadget73]

Its driven from the ECM, and it only gets turned on when it sees crank rotation. Slightly later ones can be hot-wired so the pump is on any time the key is on by adding a jumper in the self-test connector but I have no idea if EEC-III also has that.

Probably a couple of reasons that it works like it does. One is likely to keep the engine from flooding in case of a leaky injector. Also probably something about safety in the event of an accident. If the inertia trip didn't kick and a fuel line was ruptured it would just keep pumping even if the engine stalled. May also be to reduce current load when the engine isn't running.

[mercurygm88]

Its driven from the ECM, and it only gets turned on when it sees crank rotation. Slightly later ones can be hot-wired so the pump is on any time the key is on by adding a jumper in the self-test connector but I have no idea if EEC-III also has that.

Probably a couple of reasons that it works like it does. One is likely to keep the engine from flooding in case of a leaky injector. Also probably something about safety in the event of an accident. If the inertia trip didn't kick and a fuel line was ruptured it would just keep pumping even if the engine stalled. May also be to reduce current load when the engine isn't running.

Hmm..... There doesn't seem to be an easy way around this then. I wonder how many starters I'll go leaving it as is? Maybe I can find the correct number of times to turn the key to on to fill the lines every time.

[mercurygm88]

Do the CFI cars have a test port for fuel pressure like the SEFI cars do? I would imagine so but I haven't looked for it. That would help to confirm my suspicion.

[gadget73]

eec-iv has it somewhere on top of the CFI unit, not sure about yours but if its anywhere I'd expect it to be there. Pop the air cleaner, should be right there on top where the two injectors are.

[VicCrownVic]

Hmm..... There doesn't seem to be an easy way around this then. I wonder how many starters I'll go leaving it as is? Maybe I can find the correct number of times to turn the key to on to fill the lines every time.

There is a hack way of doing it.... I saw this on an '89 F150 I helped Derek pickup last year. Someone had put an inline fuel pump on the truck because the in tank pump presumably died. In fact, this hack job was the reason he got it for so cheap, it wouldn't start. Turns out the hack wiring was loose or not making good connection at the inline pump, the truck started right up when we wiggled that wiring and we laughed our asses off when it started after 30 seconds of work.

[mercurygm88]

eec-iv has it somewhere on top of the CFI unit, not sure about yours but if its anywhere I'd expect it to be there. Pop the air cleaner, should be right there on top where the two injectors are.

I'll have to take a look and see, at this point I can't really come up with any other ideas about what it could be. I did see some people on the Ford truck form talking about modern gas evaporating in CFI systems on hot days. That could potentially explain why it's fine when it sits in my garage over night. I suppose that could also be B.S.

[mercurygm88]

There is a hack way of doing it.... I saw this on an '89 F150 I helped Derek pickup last year. Someone had put an inline fuel pump on the truck because the in tank pump presumably died. In fact, this hack job was the reason he got it for so cheap, it wouldn't start. Turns out the hack wiring was loose or not making good connection at the inline pump, the truck started right up when we wiggled that wiring and we laughed our asses off when it started after 30 seconds of work.

That reminds me of the rumors I've heard about CFI fuel pumps. I once read EEC III CFI cars had 3 pumps in 1980. One in the tank, one in-line, and a mechanical pump on the engine. I've also read that all EEC III vehicles had the in tank and in-line pump. Another member here mentioned their Mark VI had no in-line pump but their CFI F150 did. The parts system at work lists an in tank and in-line pump, I haven't been under the car to look. I'm hoping their ends up being a simple non hack job solution once I 100% know what's going on.

I don't like hack work, even on the rare occasion that I do hack work. I'm still slightly upset about a previous owners hack radio install. It's not so much the aftermarket head unit as the fact they chopped the factory connector out and wired it to constant power because they were too cheap to buy an $8 harness, I have to take the faceplate off to turn it off. They also lost about half the dash trim screws, I fixed that, and they shot two random machine screws through the trim to the left the radio that shouldn't be there. Not to mention they mutilated the rails for the ashtray so it won't go back in. Luckily those are the only two hack jobs I've found on the car.

[slack]

My friend has an 83 CV EEC III with CFI and AFAIK, he only has the one pump in the tank. I know there's definitely none on the engine. Not 100% sure on the fuel rail, but I don't recall one. I know he has a special 83 specific fuel filter that screws on though.

Also, about the fuel boiling out on CFI. Not sure on CFI units but I thought that was the case on my 78 with a 2150 carb when I first got it because it was a PITA to start when hot. Turns out it was just the carb in dire need of rebuilding. I rebuilt it about 5 years ago and haven't had a problem starting it since (probably just jinxed myself). My experience with CFI is only second hand through my friend's car so I can't really weigh in on that. I had TBI on my 82 Deville before the HT4100 ate itself and also never had issues with starting hot.(Only mentioning because it's the GM equiv. to CFI)

[Tiggie]

If it starts nicely after cycling the key several times, sounds like the fuel pump check valve to me.

I doubt it's the fuel boiling off in the CFI unit. It's an interesting theory but I just can't see it happening. A high pressure fuel pump will usually fix that and cause the vaporized fuel to liquify. Carbs vent to the atmosphere or a carbon canister, so the vapor leaves. I don't know if CFI vents or not, I suspect not.

Fuel pump isn't the worst job in the world. I'd give it a go if you continue to have problems with it.

[atlantic3000]

never have hot start issues on my 83 mark 6 in fl

[mercurygm88]

Thanks for the ideas everyone. I'm still going to look when I get the chance and see if there's a port to check fuel pressure. No sense replacing the pump if it turns out I have fuel pressure when this happens. I can't possibly think of anything else though, I have spark for sure, and if it turns out I have fuel too then it doesn't make much sense. If I could replicate it at home it would be easier to diagnose but that only happened the first time. Ever since then it seems to only happen when I'm trying to leave work or stuck in some other parking lot with no tools.

[DerekTheGreat]

There is a hack way of doing it.... I saw this on an '89 F150 I helped Derek pickup last year. Someone had put an inline fuel pump on the truck because the in tank pump presumably died. In fact, this hack job was the reason he got it for so cheap, it wouldn't start. Turns out the hack wiring was loose or not making good connection at the inline pump, the truck started right up when we wiggled that wiring and we laughed our asses off when it started after 30 seconds of work.

LoL yup, $200 for a truck which ran, drove and stopped

I studied up on it and it turned out that '89 trucks still had two pumps- there is supposed to be one in the tank and then another right on the frame- so that fuel pump we thought was hacked in place is actually supposed to be there. Whoever worked on it just didn't put the pump back in the cradle and wired the thing directly to a switch. I did some tests and I never had power at the factory wiring for that pump. Didn't realize it only supplies power when the engine is cranking, but figured there should be a burst to prime it. Never heard the in-tank pump run at all, so I wanted to run it as little as possible as not to burn out that pump on the frame rail. Think those dudes were like $150...

[mercurygm88]

LoL yup, $200 for a truck which ran, drove and stopped

I studied up on it and it turned out that '89 trucks still had two pumps- there is supposed to be one in the tank and then another right on the frame- so that fuel pump we thought was hacked in place is actually supposed to be there. Whoever worked on it just didn't put the pump back in the cradle and wired the thing directly to a switch. I did some tests and I never had power at the factory wiring for that pump. Didn't realize it only supplies power when the engine is cranking, but figured there should be a burst to prime it. Never heard the in-tank pump run at all, so I wanted to run it as little as possible as not to burn out that pump on the frame rail. Think those dudes were like $150...

When you bought the truck was it advertised as not running? I've known some people who got good deals on non running vehicles only to find it was a simple fix. One was missing plug wires, another was a locked up A/C compressor, and a third that I recall was a locked up water pump. The missing plug wires were on a very very clean low mileage '92 Mustang GT that was picked up for under $1000 about 7 or 8 years ago by a buddy of mine. He bought it from the original owners widow who just wanted it gone, it was one of the very few stock fox body's I've ever seen.

[gadget73]

I've never heard of more than 2 pumps on an EFI system. Lift in the tank, high pressure on the frame rail is the usual config for multiples. I don't think the Panther cars ever had more than 1 but maybe the very earliest ones did have two. I don't see the mechanical pump being a thing though, not a chance it would handle the pressure or volume involved in a return style fuel system.

The trucks were more common with twin pumps but I think that was more about the dual tank option. Each tank had a low pressure lift pump that fed into the switching valve, then the high pressure went between the valve and the engine. Much easier to switch ~6 psi than ~35 psi. They probably kept it on single tank models just because it was less effort to use a lot of the same wiring, plumbing, and parts.

ok, two lift pumps and a pressure pump is 3 pumps, but only 2 work at a time, so you know what I mean.


shouldn't be fuel boiling. It doesn't vent to air, but at worst if it boiled it would just push some fuel back through the regulator to the tank. Just being able to keep it under pressure will considerably raise the boiling point of the fuel anyway. One pump cycle should be enough to refill the lines and build pressure. Thats really the magic trick of a return style system, the fuel moves quickly enough that it can't get hot enough to boil, and even if it happens while heat soaking the pump can shove fuel through fast enough that its not a problem. Not like a carb where you have a low volume mechanical pump that has to refill a carb bowl.

[mercurygm88]

I've never heard of more than 2 pumps on an EFI system. Lift in the tank, high pressure on the frame rail is the usual config for multiples. I don't think the Panther cars ever had more than 1 but maybe the very earliest ones did have two. I don't see the mechanical pump being a thing though, not a chance it would handle the pressure or volume involved in a return style fuel system.

The trucks were more common with twin pumps but I think that was more about the dual tank option. Each tank had a low pressure lift pump that fed into the switching valve, then the high pressure went between the valve and the engine. Much easier to switch ~6 psi than ~35 psi. They probably kept it on single tank models just because it was less effort to use a lot of the same wiring, plumbing, and parts.

ok, two lift pumps and a pressure pump is 3 pumps, but only 2 work at a time, so you know what I mean.


shouldn't be fuel boiling. It doesn't vent to air, but at worst if it boiled it would just push some fuel back through the regulator to the tank. Just being able to keep it under pressure will considerably raise the boiling point of the fuel anyway. One pump cycle should be enough to refill the lines and build pressure. Thats really the magic trick of a return style system, the fuel moves quickly enough that it can't get hot enough to boil, and even if it happens while heat soaking the pump can shove fuel through fast enough that its not a problem. Not like a carb where you have a low volume mechanical pump that has to refill a carb bowl.

Yeah I’m definitely going to have to stick a fuel pressure tester on it next time it happens. If I can get it to happen when I’m at home. If one priming cycle is enough to fill the lines then I suppose it’s possible that’s not it. Is there Anything between the lock cylinder, ignition switch, starter that could cause a random no spark event? The key is mighty sloppy in the lock cylinder.

It never stalls on me just gives me the starting issue from time to time. It hasn’t acted up since Monday “knock on wood” the only thing I’ve done different is I haven’t been pumping the gas pedal once before starting like car like the manual says I should.

Apparently CFI has some kind of high idle solenoid that that sets? I don’t see how this could be related but I haven’t had the issue since I stopped doing that.