Misfire, wont smog test. Need some advice

ArdWrknTrk wrote

So, look for a pair of relays near the driver's side hood hinge, and look at the center back of the engine -right up near the firewall- for the oil pressure sender.
It's a little time can looking thing, like an old time fuel filter with a wire on top.

Can you take pics of these things too?

Here are some shots:

Are these the relays?


And I believe this is the oil pressure sender but i could be wrong:

I *think* that green relay is for trailer and marker lamps.
Bill could probably confirm.

I also don't see a oil pressure switch beneath the sender, to ground 58 of the fuel pump relay.
But that convolute sleeve on the sender wire isn't stock, either...
So I cannot say for certain.

I'm going to go dive into the '85 EVTM.

ArdWrknTrk wrote

I *think* that green relay is for trailer and marker lamps.
Bill could probably confirm.

I also don't see a oil pressure switch beneath the sender, to ground 58 of the fuel pump relay.
But that convolute sleeve on the sender wire isn't stock, either...
So I cannot say for certain.

I'm going to go dive into the '85 EVTM.

Okay thanks, let me know what you find. Do you think I'm going to have to redo this whole fuel system?

Also, if I buy a fuel pressure tester, is there a easy place to plug it into the fuel system?

I know running a fuel pump continuously on a toggle switch is not safe at all - nor legal- in a road going vehicle.

It needs to stop running automatically if the engine stops or the truck is in an accident.
Burning to death in a fuel fire is not any way I want to go.

Pumping 19 gallons of gas on the ground when a line comes loose, even if there is no fire, isn't as very good idea either.

So, let's get it fixed, and get it safe.



This has to be late 1970's....
I can remember as a kid working the graveyard shift in a gas station.
It's about 4:30 am and a strange looking Ferrari pulls in.
It is Luigi Chinetti Jr. (Coco) with one of his girlfriends. (He was a Playboy, his father was the North American importer for the marque.)
I start pumping, and BSing with him.
They're on their way to Virginia or something for a car show.
This car was one off... bespoke coachwork, for him!

Yeah.
Then I realize I'm standing in a growing puddle, that's running out into the street.
He's smoking a cigarette!  So is she.

Yeah, customs had drilled multiple large holes in the tank looking for contraband.
Probably not a bad idea.
He got his nickname from somewhere...

ArdWrknTrk wrote

I know running a fuel pump continuously on a toggle switch is not safe at all - nor legal- in a road going vehicle.

It needs to stop running automatically if the engine stops or the truck is in an accident.
Burning to death in a fuel fire is not any way I want to go.

Pumping 19 gallons of gas on the ground when a line comes loose, even if there is no fire, isn't as very good idea either.

So, let's get it fixed, and get it safe.



This has to be late 1970's....
I can remember as a kid working the graveyard shift in a gas station.
It's about 4:30 am and a strange looking Ferrari pulls in.
It is Luigi Chinetti Jr. (Coco) with one of his girlfriends. (He was a Playboy, his father was the North American importer for the marque.)
I start pumping, and BSing with him.
They're on their way to Virginia or something for a car show.
This car was one off... bespoke coachwork, for him!

Yeah.
Then I realize I'm standing in a growing puddle, that's running out into the street.
He's smoking a cigarette!  So is she.

Yeah, customs had drilled multiple large holes in the tank looking for contraband.
Probably not a bad idea.
He got his nickname from somewhere...

Great story, that's amazing. Okay im all about being safe, I occasionally let my kids ride with me around the block in this thing (wont be doing that till this is resolved). Just so I'm clear, our goal is to get rid of the toggle switch and connect the electric fuel pump back up to the oil pressure sender or the relay the way it should be originally right?

Should i also ditch of the Holley red-top and replace the pumps in each tank or would it make any difference?

I don't think it makes a difference right now.

The goal is to get this truck roadworthy and past inspection, right?

Having it work with just a turn of the key, and cut off if the engine stalls or the truck is in an accident is knock on effect of setting things right.

Believe me! I'm no safety Nazi.
But I don't want to die in a fire, nor endanger a first responder to an accident. (Doesn't have to be my fault)
Or have to pay a hazmat team to clean up my environmental pollution.

I guess that is the pump relay!
I'm seeing in the 1986 EVTM that there is no selector relay.
Everything goes right through the switch.
(This system morphed over the years, and I don't have the '85 document)

Have a look here 1986 electric fuel pump control for how that's wired.

Fuel tank selector on pg 97 

Rham243 wrote

If I buy a fuel pressure tester, is there a easy place to plug it into the fuel system?

A cheap fuel gauge intended for carburetors is all you need.
Mine cost under $10
Just disconnect the line to the carburetor and connect the gauge.
Flip the switch and see what it reads.

Unlike a stock system there's no safeties to bypass.

ArdWrknTrk wrote

Rham243 wrote

If I buy a fuel pressure tester, is there a easy place to plug it into the fuel system?

A cheap fuel gauge intended for carburetors is all you need.
Mine cost under $10
Just disconnect the line to the carburetor and connect the gauge.
Flip the switch and see what it reads.

Unlike a stock system there's no safeties to bypass.

Okay, i think i might have a fuel pressure gauge somewhere in my garage. I will look around and see if i can find it. Unfortunately I have to work today (from home) so I wont have time to pull the truck in the garage today. Will get back it to it tomorrow and see if i can find that gauge and a place to hook it up. Will report back then.

I see the return line hooked up to the rear tank so you're going to have to connect where the carburetor is, to get a true reading.

Most gauges today read to 100.
Looking for 5 is not going to be accurate.
A cheap 0-15 psi gauge is the *WTG.

Jim, you are correct in the fact that the system morphed, it changed several times. The 1985 system does have a fuel tank selector relay, that diagram can be found here: http://www.garysgaragemahal.com/electric-fuel-pump-control1.html
It still uses the big tank selector valve, but the relay is for the pumps, red for front tank pump and brown/white for rear tank pump. The fuel pump cutoff relay is controlled by the oil pressure switch same as the 1986 system.

Well, that's embarrassing!
I didn't even see the 1985 EVTM when I went looking for a diagram...

When they say 'upper left corner', where exactly is it?

I feel better that I'm not going crazy when I think there's a selector relay for hot fuel in '85.

Thank you for pointing out that page, Bill!

Always glad to help Jim, after all a 22" monitor is a lot better than a phone screen.

Bill, after owning a tune up shop all those years you're the one who could really help this man.

Yes, but he needs to first get the fuel pressure issue resolved. I had already suggested getting it on an ignition scope and walked him through some of the tests needed.