My truck is a '90 and everything I've read says that the fuel return lines should be 1/4" 7mm but the lines on there are 3/16" 5mm. Did some 7.3s, maybe early IDK, come with the small lines? Should I swap out to the 1/4" when I put the new pump in?
3/16" fuel lines on a '90?
- Thread starter saburai
- Start date
I believe those were on 87 and below trucks, mostly 6.9s. It will work on your truck fine but the update design uses different style caps and 1/4” lines as you said
Thanks! I guess someone just switched them out (?) along the trucks history. Would it pay to update? I've got to do the lines with the new pump and injectors...
It could have been a roadside repair and that’s all the parts store had, I would replace it with the injectors. I believe Mel includes his return kit with every set of injectors
That's the plan. But what about the fitting on the hard line for the rubber return line? That's 3/16" as well.
You won’t use that, the new design doesn’t use it
The return line fitting on the filter cap and top of IP could be either 3/16" or 1/4", use the size whatever size those are. If you go to 1/4", you'll have to change those two fittings or they will leak or air intrusion, can't clamp tight enough.
icanfixall
Official GMM hand model
No real reason to change to the larger return lines. Both sizes will flow return fuel fine. As posted above. There are several fittings you MUST change if you are going to change the line size.. You can't mix and match sizes. the smaller lines wont fit the larger fittings and sure nuff the larger lines will leak on the smaller fittings. Easy way to determine what size you have is the smaller size line caps have the connections in the center of the caps. the larger size has the connections offset on the caps.
Macrobb
Full Access Member
88's seemed to come with the 3/16 kit stock - I've seen multiple this way and none with the 1/4 line
Though I can't say how "stock" it might be. My 91 also had the smaller, 3/16 lines on it.
If you get in a bind I have the 1/4” fittings you need
Thanks friend! I think that I've got it covered.
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