JRobling

So like the title says when I'm trying to start my car cold it takes a while for it to start firing. I noticed that it starts firing when the oil pressure gauge gets high. I don't have the cold start injector and if already replaced my oil pressure sensor. Is there a way to get oil pressure built up faster?

GeneralDisorder

iTrader: (1)

Sounds like you aren't getting fuel pump power till you build oil pressure. The fuel pump prime relay gives fuel pump power during key-on and cranking, etc. Then the oil pressure switch takes over. I would be looking at the fuel pump relay and it's power source, etc.

GD

JRobling

I just replaced the fuel pump, fuel filter, and relay

GeneralDisorder

iTrader: (1)

Do you have a test light or meter? You should check for power to the pump when you turn the key on (do not crank the engine). This will tell you if there is power there with key on and cranking before the oil pressure switch closes. It may not be the relay itself - could be the ECM isn't triggering it or it has no power going to it... etc.

GD

JRobling

I'll have to check that when I get home. I know it takes a while for the fuel pump to prime again if I turn the key to the on position and then turn it off then trying to get it to prime again for another cycle takes a while.

Vanilla Ice

I thought that was normal in thirdgens?

GeneralDisorder

iTrader: (1)

There is a relay that is designed to kick on the pump at key-on, cranking, and for a bit after start to let it build oil pressure. Then the pressure switch takes over so if it's in an accident the fuel pump power will b cut by the loss of oil pressure.

GD

JRobling

Separate relay or the same relay?

Vanilla Ice

I meant injectors firing is disabled until oil pressure comes up.

JRobling

that's exactly what I want to fix

GeneralDisorder

iTrader: (1)

It is? I wasn't aware the ECM had any oil pressure input.... are you sure? I'm going to check out the diagram on that one

GD

Vanilla Ice

I am not claiming anything. I just remember seeing that somewhere on here.
http://www.corvettebuyers.com/c4vettes/l98.htm

bjankuski

Injector firing is not related to oil pressure. My guess is you need a new chip to add in additional cranking fuel to help it start quicker.

LiveIt!

You said you replaced the oil pressure sensor, what about the oil pressure switch? Last time I checked there was 2 switches-the oil pressure sensor that gives your gauge reading, and the oil pressure switch that actually runs the pump.

RBob

iTrader: (1)

Need to do some quick & easy trouble shooting. Get a fuel pressure gauge and attach it to the fuel rail port. Place it so that you can see it while you operate the ignition key/switch.

Do a key-on, engine-off (KOEO). The fuel pressure should rise to about 43 psi. After about 2 seconds the pump should stop and the fuel pressure should drop a little. It may also bleed off quickly, but the key here is to see if the pump runs at KOEO.

In the above test if the fuel pressure doesn't increase at KOEO, then the fuel pump relay isn't sending power to the pump. Start the trouble shooting there.

If the fuel pressure did get up near 43 psi, then tap over the ignition key to crank the engine for a brief period of time. The pump should run again for 2 seconds and bring the fuel pressure up. If so then the fuel pump, pump relay, and pump wiring is OK.

Do you know whether the ECM has the stock PROM in it? Or has it been tuned?

RBob.

RBob

iTrader: (1)

Be careful of that article, lots of incorrect information in it.

RBob.

Vanilla Ice

I never saw it before, only looked for where the oil pressure is linked to fuel pump and Google found that.