Fuel Filter

[airguy]

I want to remove the fuel filter from above the motor to somewhere on the frame rail. has anybody done one of these with good success and do you have any pictures?

Would like to filter before the added electric fuel pump, should I run a prefilter and another filter after the pump?

[yaric008]

I bet Larry M has something he could tell you about. I would think a prefilter and a postfilter for the electric pump couldn't hurt, better to be safe than sorry. And if and/when you do that mod to move the fuel pump i would like to see it. That positioning of the fuel filter is... gay.

[Larry M]

[ QUOTE ]
I bet Larry M has something he could tell you about. I would think a prefilter and a postfilter for the electric pump couldn't hurt, better to be safe than sorry.

[/ QUOTE ]

Eric, thanks for the referral, but my understanding is the fuel systems between the IDI and DI 7.3's are very different and I'm just not familiar enough with the older 7.3's to comment from even a SWAG standpoint on this. Whatever, airguy decides I can make a few general comments for his consideration.

1. Electric and probably the mechanical lift/pressure pump systems benefit from a good pre pump filter and water separation scheme. Based on our 99+ factory pumps the internal pump clearances appear to be quite a bit less than 25 to 37 microns so a pre pump filter with a micron rating lower than that seems prudent. I run the Dahl which can accept 2, 10, and 30 micron elements. I run the 10 micron and with almost 8mo of use I have had no issues.

2. Again the IDI's don't use the "split shot" injectors like the 99+ (and some as I understand 97? Ca. Vans where this cackle thing first reared it ugly head) so the internal clearance and operation might be different for any post pump filtering requirements. But again it only seems prudent to have a filtering system geared to protecting the injectors as the last thing in the system. This will protect the injectors from pump failures and wear particles. Our 99+ factory filter is a 2 micron. My understanding that Cat uses like a 4 or 5 micron, so there are two data points.

3. Because of flow rates, I would be very, very careful in relying on a water separation scheme that relies on the filter element unless you can confirm it's efficiency at whatever flow rate you are going to subject this filter to.

4. While it might not apply to a 1991 IDI, a real added benefit of a pre pump filter for the Vans is that it should not only protect and make the in valley last longer, if you have a contamination problem, it is one heck of a lot easier to change the pre pump filter on at least the 99+ E's than that son of a gun in the valley.

Larry