Cut to the chase. My engine is rebuilt ground up and has great performance. After sitting a month recently (traveling) it wouldnt start. Squirted gas into the TB and she sputtered and lit. Ran fine. Then she wouldnt again and again. Cleaned the MAF - brightened up some oxidized (male) leads off coil pack, tested TPS - fine. Reset computer. Started great.

 

Two weeks later, same issue.

Tried to start over and over - no joy. Then she finally caught but sounded really really rough like it wasn't firing on all cylinders, that smoothed out and she ran well after that. After shutdown while warm I tried again and she wouldnt start, then I let the fuel pressurize longer than usual (she pressurizes and then stops as it should, but I waited) and she started a few times in a row.

 

What could be going on here!?

 

Is there a way to check if the MAF is going without using a scope (I dont have one)?

 

Since I have an 94 Forrester (same engine as my 02 on my gyroplane) should I just swap out the one from my plane and if that goes away -order a new MAF?

 

One additional note: I recently installed Iridium plugs.... doesnt seem like that would affect start only right?

 

Any suggestions!????

I'd be tempted to pull plugs after a lengthy shut down and see if any are wet with fuel. Or find some way to hook up a fuel pressure gauge for a while and see if the rails lose pressure. maybe a leaky injector?

 

I dunno.

Maybe a leaky o-ring on the fuel pump assembly leaking fuel pressure back into the tank.

 

Doubtful it's the MAF, but plugs can have a more adverse affect than you may think. Might want to pull them out and make sure they aren't fouled.

my cut down harness car is a pain to start the first time every time uses a 2.2 harness with 2.5 turbo engine have narrowed it down to air lock between injectors and pump when it sitts. It has to push all the air out before it gets feul to injectors thiss takes some cranking time. Could be fixed with a one way check valve close to injector feeds to prevent feul prehsure bleed back

Maybe a leaky o-ring on the fuel pump assembly leaking fuel pressure back into the tank.

 

Doubtful it's the MAF, but plugs can have a more adverse affect than you may think. Might want to pull them out and make sure they aren't fouled.

 

If this were the issue is it logical that then it would take longer to pressurize at start? She pressurizes quickly and then holds and stops pumping.

 

The pump is a brand new racing high pressure pump with 30 hours on it.

 

I will check the plugs.

my cut down harness car is a pain to start the first time every time uses a 2.2 harness with 2.5 turbo engine have narrowed it down to air lock between injectors and pump when it sitts. It has to push all the air out before it gets feul to injectors thiss takes some cranking time. Could be fixed with a one way check valve close to injector feeds to prevent feul prehsure bleed back

 

It used to start first time and every time.

How does one easily check for a leaking injector and wouldnt that affect mre than just start up?

 

All the numbers are perfect and performance normal once she starts.

If this were the issue is it logical that then it would take longer to pressurize at start? She pressurizes quickly and then holds and stops pumping.

 

The pump is a brand new racing high pressure pump with 30 hours on it.

 

I will check the plugs.

Correct, the newer fuel sender assemblies have a reservoir on the side with a small metal cap that can deform after years of use. The cap is sealed by a small O ring, which once the cap is deformed, will push out of the side and allow fuel pressure to bleed out and fuel to run back into the tank. This can cause slow pressure build and low pressure. If pressure builds quickly to proper spec and holds this is likely not an issue.

 

High pressure racing pump just means aftermarket to me. That could mean a pump off eBay with a clever marketing tactic. Details on this pump? Manufacturer, flow rate, etc.? Who installed it?

 

You are taking pressure readings with an analog gauge plumbed between the fuel filter and fuel rail? What is the pressure at prime? Does it remain at or near that level when cranking? If no, what is the pressure reading during cranking?

 

It is normal for the pump to operate for only a few seconds during the prime test then stop. The ECU controls the fuel pump relay and commands the relay off about 3 seconds after the key is turned to ON, but not to start. If the key is turned to start the pump continues to run, and will remain running once the ECU has a constant signal that the engine is running. (either from the tachometer or the crank or cam position sensors)

Mines in a 79 wagon with remote pump but most cut down harness cars are slow to start first time when cold