I have acquired a 1980 302 f150 at lwb that has only 40,000 miles. The po removed the egr and smog pump leaving a bunch of unconnected hoses etc. I am in a state that has no inspection. I would like to clean up the engine compartment by removing the extra plumbing and unnecessary vacuum hoses. There is an unconnected steel pipe that goes to the back of the engine. Does anyone know which pipes and hoses can I remove and keep the engine running properly ?

 

Keep in mind every open vacuum hose or port is additional air that goes into the intake manifold leaning out the fuel mixture. When you get those plugged off, it should run pretty nice.

 

The steel line is probably the AIR system's manifold that connects to both heads. The AIR pump pushed air into a valve that determined if the air went into the exhaust directly or into the exhaust ports via that manifold and through a drilled passage into the exhaust ports. While removing emissions equipment is a crime, it sounds like much of yours has already been neutered if not removed. If so, the manifold can also be removed and the holes in the heads plugged with 5/8-11 bolts.

 

Keep in mind some of these emissions devices are controlled vaccum leaks. The original choke stove setup let air into the carb as well as the egr when it was hooked up(it did above idle).

What I have run into was a few driveability problems when I had pulled all this stuff off. Nothing most people would notice, but the exhaust wasn't as clean as it should be at idle(it smelled a little rich) and my idle screw never seemed to adjust like it should. I have driven several like this, and to get rid of the problems permanently, a small 4bbl aftermarket carb and intake always did the trick. On one truck I had, I left the original 2bbl on it, and what I finally ended up doing to that one is running a small vacuum line up and into the aircleaner area(so it would suck clean air) and left it like that. The smell went away and some of my adjustments came back.

I know that sounds a little off base, but they have a delicate tune on some of these emissions engines, and pulling stuff off upsets that. If you get the 1960's style tune in your head(get rid of the emssions carb and go with a a aftermarket) you can overcome this and get more power also. But you still have the timing to fiddle with and try to get right, that's another can of worms when you take the emissions stuff off.

 

Plug up the vacuum lines that arent hookep up to anything.

 

Dave F
Thanks for the reply. While I'd rather not change the carb and intake manifold, I may have to in the long run, as I hope to keep this truck. There is a vacuum line device on the air filter lid. Looks like a valve with 2 connections for vacuum lines. Presently there is 1 vacuum line connected. Should I run another vacuum line to the 2nd port, leave it open or cap it off ? The engine runs fairly well. The only issue is a slight continuous spark knock, mostly on acceleration. Maybe more timing adjustment is needed.
In the vacuum line from the carb to the distributor advance, there is a check valve. It tees off in another direction. Looks like from the factory. Could this affect the timing ?

 

The vacuum stuff on the air cleaner is a temp sensor in the filter chamber and a flapper valve in the snorkel. It is to regulate the air temp as the effective air/fuel ratio varies with the air temp. Originally there was a vacuum line from the carb or intake to the temp sensor and then a hose from it on to the flapper motor. Typically the hose from the carb has been eliminated, and if that that is the case I wouldn't worry about it now.

As for the vacuum advance, some of the emissions systems had two sources of vacuum depending on coolant temp. My guess is that the line from the tee goes to a thermo valve in the coolant. If all of that is working then I would leave it.

 

You are getting that spark knock because the EGR is not working. I have found that swapping a 180 degree thermostat in helps this, and getting a adjustable vacuum advance for the dist can help tune it out. You can turn the timing back to help get rid of it, but it turns the engine to more a dog than it already is.

The next time it's knocking, go ahead and floor the gas pedal and see if it goes away. When you are accelerating at a somewhat mild rate, you have a load on the engine and the vacuum advance is still got the timing bumped way up. Without the EGR it will ping. But if you go ahead and floor it, you lose any vacuum the engine has, and the vacuum advance will drop the timing back, and that will usually get rid of the ping till you let up on the gas pedal. That's why I was saying a adjustable vacuum advance sometimes helps this problem.

I would also run a simple vacuum line directly from the carb to the distributor. They had all these scenarios to control the timing, but none of that applies if you have done a lobotomy on the emissions system. Just make sure this line does not have vacuum at idle, only when you rev the engine. There should be a port on the carb somewhere that will give you this type of vacuum function.

 

My 1980 F150 has a temp and fuel guage but the battery and oil has idiot lights. While in the auto scrap yard, I reclaimed a complete instrument cluster from another compatible F150. The new cluster has guages for the battery and oil pressure. I would like to take out the idiot lights and replace them with the guages. There is one common modular plug on the back of the instrument cluster. My question is, will these new guages simply mount in the cluster and work properly or do I need to change out some sort of sensor different than those operating the idiot lights ? I could instead install the complete instrument cluster with the new speedo. All wiring is printed circuit within the cluster.

 

1980 is a one-year-wonder with regard to wiring. Do some searching here (might even be in the Sticky up at the top) as this has been covered quite extensively.