Fuel pressure(running rich) (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Badad

Badad

Joined
May 2, 2021
Threads
6
Messages
65
Location
Fulshear, Texas
1979 2f with electric fuel pump. Just rebuilt the carb. Vehicle runs rich and blows excess water/fuel/ carbon out the tail pipe. It is not oil. It has been desmoged by p.o. the fuel pump specs are 1-4.5 lbs pressure. Compression is good in all cylinders. Valve adj. Just done.
Could the desmog cause it to run rich?
Could the fuel pressure be too high?
When I got the vehicle it did have some fuel in the oil. Flushed system. And has fresh oil now so will watch for that issue returning.

Any feedback is appreciated.
 
Sort by date Sort by votes
Does it still have the factory fuel pump, or is that gone with the electric pump addition? Does it have the factory (or any) fuel return still installed?
 
Upvote 0 Downvote
hobbes said:
Does it still have the factory fuel pump, or is that gone with the electric pump addition? Does it have the factory (or any) fuel return still installed?
Click to expand...
Factory fuel pump still on engine with the return line in tact but there is no return line for the electric pump.
 
Upvote 0 Downvote
Since you have a stock pump in place, I think I’d start by bypassing the electric pump to see what happens.
 
Upvote 0 Downvote
If fuel in the oil it’s probably either leaking from the fuel pump into the engine or maybe down the carb.
 
Upvote 0 Downvote
If it has a sight glass in the carb it will be easy to tell if the pressure is too high for the float needle valve. The level will not remain half way in the glass, and will fully cover the window, and flood fuel down the carb throat . If you have a pressure regulator, it might need adjusting to a lower pressure setting.

*** Most electric pumps have too much pressure if used without a pressure regulator, unless you use a T with an adjustable flow rate going to the fuel return line.
 
Last edited:
Upvote 0 Downvote
OEM pumps can fail in such a way as to let fuel into the oil. Sorry, wasn’t referring to the electric pump.
 
Upvote 0 Downvote
And luck solving this?
 
Upvote 0 Downvote
Badad said:
Could the desmog cause it to run rich?
Click to expand...

Not if was done competently.


Badad said:
It probably has something to do with vacumme emissions systems being ripped out.
Click to expand...

Not likely at all; there is nothing there that would affect fuel pressure or delivery.

As has been said, reconnect/replace the stock mechanical fuel pump. If that doesn't fix it, then it is a carb issue, most likely the float level or a bad float needle seat.
 
Upvote 0 Downvote
1911 said:
Not if was done competently.




Not likely at all; there is nothing there that would affect fuel pressure or delivery.

As has been said, reconnect/replace the stock mechanical fuel pump. If that doesn't fix it, then it is a carb issue, most likely the float level or a bad float needle seat.
Click to expand...
I just rebuilt the carb thinking that was the problem. Adjusted the float level. And replaced float needle seat.
I don't think it's a pressure issue but by going back stock will eliminate that variable. I did not do the desmog so can't tell if it was done correctly. If not done correctly can it cause it to run rich? Tons of black soot is blowing out tail pipe with a heavy gas smell.
 
Upvote 0 Downvote
Which rebuild kit did you use?
 
Upvote 0 Downvote
So, it came in a box/bag with no identification?
 
Upvote 0 Downvote
You must log in or register to reply here.

Similar threads

Kschep
fj running rich
2 3
Replies
45
Views
2K
Kschep
Kschep
T
Oil pressure conundrum
Replies
2
Views
550
45Dougal
45Dougal
truckfighter
1980 FJ40 fuel pressure regulator / inline bypass fuel filter
Replies
8
Views
1K
GLSisk
GLSisk
T
fuel gauge issue
Replies
11
Views
867
45Dougal
45Dougal

Users who are viewing this thread

Total: 2 (members: 0, guests: 2)

Share this page

Back
Top Bottom