I have my 1986 Camaro 305 tpi ok so here is Whats happening I put a new fuel pump in a week ago ran fine got new gas went8 miles parked tune car went to shop came back out it would start but rough idle if I touch the gas pedal it dies out imidiantly. Running fuel presure is 50 psi. Key on 48 bit drops to 10 instant its making me insane lol. Any tips would help I got 22 lbs injectors on way and new presure regulator will give update in a week but mean time im lost.

 

Pinch off the return line from the regulator, and see if pressure still drops off like a stone.

 

Im fighting a similar problem, just had my buddies put in my w-255 pump. Same story good pressure, then the pump cuts off and drops to 3-4 psi. Buds think its a wiring issue that involves the pump and ignition switch.

New 24 injectors, new diaphragm, new fuel filter. Pinched the return line, pressure hit 78-80 psi, then stone drop.

 

initial prime the fp uses the pump relay. After the engine builds oil pressure 4psi or higher the ops sends direct power to the pump through c100 out the back of the car to the sender connector.

 

Ops not shown but there should be a splice at the relay or near the relay for pump power from the ops. You might have corrosion or damage at this connected at the relay. Could be a bad pump .

 

My bud thinks its a power issue too. But why do I lose pressure after pump prime? (key unmoved, prime only)

 

I am very new to this website and I dont mean to take light away from you but i am having the same problem. But if anyone can help i am looking to start a new thread and dont know how. sorry and thanks

 

Stay in the boat, no need to jump ship.

 

A little bit of pressure drop isn't real unusual, as soon as the ECM sees the engine turning, it'll trip the pump relay again.

 

We're not talking about "a little", we're talking about nearly all of it in an instant.

 

Yup. Misread that.

 

Ok update got now parts in going to pinch the return line. What will that show. This thing won't run for nothing will be back on next week with update only get 1 day a week to work on it..... Is the egr supposed to be stiff because my old car was not this stiff?

 

Any one know how to test mad

 

iv got an update - be back

 

If he is red in the face, he's mad.

 

The only way I know is to use a scanner or tunerpro rt. And watch gps vs rpm.
Idle is 7-9 gps going up with rpm/air flow.

 

Buds said my ecm/inj driver was fried out (???) - don't know how that could have happened. An that ecm had the inj hung open the whole time, thus draining all my fuel pressure prime.

- I had tried the clamp return line (earlier) but that did nothing. Pressure hit like 78-80 psi then stone DROP.

 

Sounds more like a stuck open injector, when the injector driver fails injector pulse on each bank stops.

 

Injectors only have like 5 miles on them and I sent them to Southbay to be inspected. before and afterward same thing.

-also when I bought the set (about a year ago), one of the injectors never fired - but all the rest did

 

Sorry not mad darn phone any one know how to test maf. This thing is not wanting to idle or run

 

Bud says the car is running. Said the cylinders pored gas out and that gas shot out the exaust 3 feet. Probably gonna be a few days before I can go down there and get it.

 

Just got the car home, no more pressure problem - it runs.

 

What was the fix?

 

A new ECM.