FJ40 with GM 327 Fuel Filters

[TacoJonn]

Hey all,

Relative n00b here. Not mechanically very savvy but doing most of the work on this myself as I get this old thing running. After I parked it the engine wont turn over. I hear the fuel pump prime and the engine turns, but I think the fuel filter(s) are clogged given it has sat for 5 years. I am guessing they have not been changed in 10. I noticed what seems to be two fuel filters on my rig. Is that common in these? If so, would the fuel filter be the same for type? I have never seen two before on a car so was just curious. See images attached.

Thanks!

 

[spotcruiser]

You have an SBC and an electric fuel pump, so it's all non-stock. I don't think two filters hurts anything, necessarily.

I don't understand the "engine won't turn over", "engine turns" comments. You mean it won't fire? If it cranks but won't fire, it wouldn't hurt to change out old filters. If you pull the air cleaner and look down the carb, do you see any fuel when you work the accelerator linkage?

 

[TacoJonn]

You have an SBC and an electric fuel pump, so it's all non-stock. I don't think two filters hurts anything, necessarily.

I don't understand the "engine won't turn over", "engine turns" comments. You mean it won't fire? If it cranks but won't fire, it wouldn't hurt to change out old filters. If you pull the air cleaner and look down the carb, do you see any fuel when you work the accelerator linkage?

Yeah, it cranks but won't fire. When I picked it up from the owner it ran "okay". It had been sitting for 5 years. As I drove it into town it started to lose power when I put it under load and if let to sit idling for more than 3 min it would die. My first order of business is changing the fluids (changed oil already) and also the filters. I am guessing this filters are at least 5 years old probably closer to 10. I was wondering if maybe the fuel was so old that since it had been sitting so long that probably the fuel filters are clogged. Either way they need replaced. Someone told me on a Facebook group that the other filter looked like a pressure regulator but I am wondering if maybe the previous owner put two filters on there as an extra precaution.

I will pull the air filter and check the carb nex time I work on it.

 

[spotcruiser]

Those both look like filters to me. When you get replacements, cut the old ones open and see what they look like inside.

Fuel does go bad. Drain the old stuff, take it to your local hazardous waste drop-off place, and give the truck some new gas.

Another thing that could be an issue with a modified truck is building a vacuum in the fuel tank to where it interferes with fuel draw. Crack the fuel cap and see if that makes a difference.

Is the electric pump actually pumping?

 

[B y r o n]

It looks like the mechanical pump is still on the engine, is it still being used?

If electric pump is installed it could have a filter before the pump, and one after the pump. Other than that not sure why two were used.

 

[TacoJonn]

Hey all, I diagnosed it to being two semi clogged fuel filters after making sure the pump worked (it is mechanical). I think the added resistance of having two filters plus them being old and clogged was the reason. Fires right up now! Now I'm gonna start deleting the spring over axle conversion! Learning all of this as I go. Appreciate the replies!

 

[Downey]

So TacoJohn, now would be a good time to consider ebay #253560148230, or equivalency???

 

[TacoJonn]

So TacoJohn, now would be a good time to consider ebay #253560148230, or equivalency???

I'm thinking that is the best option if the block has good compression. If I understand the TBI correctly, it is kind of somewhere between a carb and modern EFI? So there would be no carb tuning and better at altitude I assume?

 

[Downey]

I'm thinking that is the best option if the block has good compression. If I understand the TBI correctly, it is kind of somewhere between a carb and modern EFI? So there would be no carb tuning and better at altitude I assume?

Yes, no float bowl so much better in off road steep/off camber terrain, high altitude compensation, easier starts, better managed fuel delivery for better milage, etc. etc.

 

[TacoJonn]

Yes, no float bowl so much better in off road steep/off camber terrain, high altitude compensation, easier starts, better managed fuel delivery for better milage, etc. etc.

Yeah I have been thinking about that. All I want is reliability and drivability. Next time I get a few spare minutes I'm gonna check the compression and see if the engine need any major work. TBI seems like a no brainer though

 

[RAYJON]

just one more there should be a metal screen on the carb inlet, .and remember pumps like to push not pull, if there is a filter before the pump it need to be more free flowing/larger...


on a side note ....

I would pull the float bowls and spray some carb cleaner down it, you could also do a redneck carb rebuild (spray carb cleaner down all the carb vents and orfices then start and rev it up and cover the air inlet with a piece of rubber or leather) basicly using a 300cid vacuum pump to clean out the carb....

 

[TacoJonn]

A little update on this. I changed both fuel filters and she fired right up. The bard part is about 20 min into driving it again she died again. At this point I am thinking the fuel tank is contaminated. The fuel door gasket was basically non-existent when it sat for 5 years so likely some water got in there.
I am going to drop the fuel tank out and see if I can get it re-coated. If it is too bad I will have to buy a new one or a refurbished one. Sounds like this is a pretty common issue.

 

[peesalot]

Rebuild carb may be in order. There are a lot of self contained efi systems that bolt on that you would really enjoy the increased drivability, power, economy of.