odd trend with 1986 5.0 efi trucks?

[Gary Lewis]

Vinny - Was that to me? My birthday was in June, but thanks anyway.

yeah, that was to you. ok, June.

Thanks!

[Rembrant]

is there some sort of known issue with that year and engine? just seems odd that people are dumping these suddenly. its always the 1985 5.0

or is it just coincidence?

I don't follow all of the Bullnose pages and groups that I used to, but when I did there seemed to be a lot of posts about the Bullnose 5.0 EFI trucks. Usually some kind of electrical issue, or running issue related to idle, etc. Fuel pumps and fuel tank selector valves are common topics...or fuel systems in general.

I think most OBD1 vehicles fall into boogeyman territory...in the case of Ford trucks that would be 1985.5 to 1995. That's just my own opinion. I see a lot of them around here converted to carburetors. Once they start having problems, most backyard mechanics can't figure them out.

 

[Gary Lewis]

is there some sort of known issue with that year and engine? just seems odd that people are dumping these suddenly. its always the 1985 5.0

or is it just coincidence?

I don't follow all of the Bullnose pages and groups that I used to, but when I did there seemed to be a lot of posts about the Bullnose 5.0 EFI trucks. Usually some kind of electrical issue, or running issue related to idle, etc. Fuel pumps and fuel tank selector valves are common topics...or fuel systems in general.

I think most OBD1 vehicles fall into boogeyman territory...in the case of Ford trucks that would be 1985.5 to 1995. That's just my own opinion. I see a lot of them around here converted to carburetors. Once they start having problems, most backyard mechanics can't figure them out.

Thanks for getting us back on track, Cory.

Yes, the OBD-I trucks are obtuse. The systems work fine when everything is right, but when things go wrong they can be a bear to diagnose. They have a computer, so all the inputs need to be working or they get their knickers in a twist. But they aren't sophisticated enough to provide simple info on what is wrong with things, like an OBD-II system. So you have to run the key-on/engine-off tests and fix those problems and then run the key-on/engine-on tests and fix those. But of course, you just get numbered error messages, as indicated with a blinking light, that you have to look up instead of having the code reader give you the crux of the message.

As said, when everything is working they are fine. Maybe not quite as good as an OBD-II system because most of the OBD-I systems are speed density while most of the OBD-II systems are MAF. The difference is that speed density assumes that at a given RPM, atmospheric pressure, and throttle opening it knows how much air the engine just ingested. But any change in the intake, exhaust, or cam timing makes that assumption null and void. Instead, MAF actually measures the air being ingested, so can handle modifications.

But for a stock, or nearly stock, vehicle the OBD-I systems work well. They just aren't as easy to maintain as a dumb carb system or a very smart OBD-II system.

 

[85lebaront2]

Thanks for getting us back on track, Cory.

Yes, the OBD-I trucks are obtuse. The systems work fine when everything is right, but when things go wrong they can be a bear to diagnose. They have a computer, so all the inputs need to be working or they get their knickers in a twist. But they aren't sophisticated enough to provide simple info on what is wrong with things, like an OBD-II system. So you have to run the key-on/engine-off tests and fix those problems and then run the key-on/engine-on tests and fix those. But of course, you just get numbered error messages, as indicated with a blinking light, that you have to look up instead of having the code reader give you the crux of the message.

As said, when everything is working they are fine. Maybe not quite as good as an OBD-II system because most of the OBD-I systems are speed density while most of the OBD-II systems are MAF. The difference is that speed density assumes that at a given RPM, atmospheric pressure, and throttle opening it knows how much air the engine just ingested. But any change in the intake, exhaust, or cam timing makes that assumption null and void. Instead, MAF actually measures the air being ingested, so can handle modifications.

But for a stock, or nearly stock, vehicle the OBD-I systems work well. They just aren't as easy to maintain as a dumb carb system or a very smart OBD-II system.

Gary, don't you have my EEC-IV analyzer? You need to put it out for the show so people can see what it took for the dealers to be able to diagnose the systems.

[ratdude747]

Thanks for getting us back on track, Cory.

Yes, the OBD-I trucks are obtuse. The systems work fine when everything is right, but when things go wrong they can be a bear to diagnose. They have a computer, so all the inputs need to be working or they get their knickers in a twist. But they aren't sophisticated enough to provide simple info on what is wrong with things, like an OBD-II system. So you have to run the key-on/engine-off tests and fix those problems and then run the key-on/engine-on tests and fix those. But of course, you just get numbered error messages, as indicated with a blinking light, that you have to look up instead of having the code reader give you the crux of the message.

As said, when everything is working they are fine. Maybe not quite as good as an OBD-II system because most of the OBD-I systems are speed density while most of the OBD-II systems are MAF. The difference is that speed density assumes that at a given RPM, atmospheric pressure, and throttle opening it knows how much air the engine just ingested. But any change in the intake, exhaust, or cam timing makes that assumption null and void. Instead, MAF actually measures the air being ingested, so can handle modifications.

But for a stock, or nearly stock, vehicle the OBD-I systems work well. They just aren't as easy to maintain as a dumb carb system or a very smart OBD-II system.

Agreed. Which for me, made fixing/restoring/enhancing one (feedback carb, but similar challenges) that much more of a fun challenge.

But anybody wanting to go beyond stock either goes back to a dumb carb or they move up to a newer EFI setup (Gary's EEC-V, Holley Sniper, Edelbrock pro-flo, etc.). Leaving stock systems rare and sneered at (unless you're a dorky nerd like me!).

[Gary Lewis]

Gary, don't you have my EEC-IV analyzer? You need to put it out for the show so people can see what it took for the dealers to be able to diagnose the systems.

Bill - Is this what you are talking about? I think it is what I got from you.

[85lebaront2]

Bill - Is this what you are talking about? I think it is what I got from you.

There was also a bigger box labeled EEC Monitor I thought I shipped to you. I know I have the transmission one here.

That one is for all electronic ignitions. I know I sent you a DS-II tester once I converted Darth to EFI.

[Gary Lewis]

There was also a bigger box labeled EEC Monitor I thought I shipped to you. I know I have the transmission one here.

That one is for all electronic ignitions. I know I sent you a DS-II tester once I converted Darth to EFI.

I'll look again tomorrow.