The fuel pressure on my '85 IROC was 9-14psi.... on the '87 IROC it's about 41psi.

Is this fuel pump native, or just the regulator? These cars are both 305.

I ask this because my 87 has a leak at the tank, and I want to know if just putting in my old 85 tank (pump inc) will work.

 

different pump, but if you're gonna have the tanks out, it's a 10 minute job to swap fuel pumps. In fact, since it's such a pain in the *** to swap fuel pumps, i'd buy a new TPI pump, strainer, and fuel filter while the tank is out, so you don't need to do it again in the near future.

it'll cost you like $70 - $100, but you won't have to worry about it for a few years at least.

 

I don't have that money right now. Napa has the same part Number for both years fuel pumps....

 

The 87 pump may have a different part number because they used it on the L98, but the 85 pump, if functioning properly, should still deliver 43lbs of pressure. Actually, the pump is capable of much higher pressures, but the regulator is factory-set to deliver 43lbs.

The 85 pump should be capable of delivering adequate fuel for a mildly built 350.

I'm not surprised that the aftermarket part is the same for all years. GM may have had minor differences on the 85 (*** knows they did everything else different in 85 ), but they should all interchange just fine.

 

Both the 85 and the 87 pumps have the SAME part number. So I was just checking. I thought it should all interchange, but I didn't want everything back together and have lack of fuel pressure.

the 85 only delivers 9-14lbs of pressure.

Well wish me luck~!

 

9-14lbs? That sounds like the car wouldn't even run...
My 90 Iroc-Z's pump was 8lbs rotten, so my guy swapped it for new OEM and the car is definitely quicker than with the rotten pump. So I gotta ask - you sure??

 

Look in your Chilton specs for an 85 5.0L TPI Vin F and it will say Fuel PSI 9-14lbs

BTW my 85s fuel pump runs fine in the 87.

Auto stores had them both listed as the same part number, and walah. Go GM.

 

9-14 pounds of pressure in a TPI system means you need some BIG injectors. Aren't the injectors the same 19# from 85 to 92?
Sounds like a TBI system but they didn't have TBI in 85...oh well. Maybe just a misprint.

 

Supposidly they are 19# injectors. I get the same gas milage about 23ish... 85 was the first year of TPI they changed it the next year.

 

Well if they are 19# injectors then there is no way the fuel pressure would be so low. You'd require injector duty cycles well above reality just to make the car move off idle!
Misprint...yeah the pump will work but I doubt it's running such low pressure.

 

I don't think it's the pump that has the changed pressure, I think it's the regulator. The pump is capable of running at much higher pressures, it's just the regulator says no.

 

If the chilton manual says 9-14lbs, that's just more proof that chilton sucks. 9-14lbs is what a TBI motor should have. The 85 "F" motor (i.e. the LB9) was set at 43.5lbs of pressure from the factory. the ONLY TPI motor to have a different fuel pressure was the 85 Corvette motor, which was set at 35lbs. All other TPI motors, whether corvette or f-body, whether 305 or 350, were all set at 43.5lbs.

 

That would make more sense

 

Chilton is wrong, flat out wrong. The 85 TPI was factory set at 43 PSI, key on engine off, running it was around 36 psi. Every piece of lnformation on my '85 has always said 43 psi.

 

Thats what I'm saying... 9-14lbs sounds like the car would have an idle that lopes like a bitch and cant accelerate at all.