Lately my '97 Aerostar has required a lot of cranking to get started. Like...sometimes 15-20 seconds before it fires. If I get it started, drive somewhere, shut it down, and then a few minutes later try to start it, it starts right up.

-Interesting: I've discovered that I can start it if I crank it 15-20 seconds. But I can start it far quicker if I crank for about 5 seconds, stop, and then crank it again. Then it typically starts right up.

It has done this on rare occasion for the past few years, but lately it is becoming the Norm, so something is wrong.

Hmm. Leaking injector comes to mind, but the oil doesn't smell like gas.

What is the failure mode of the fuel pump, and do I really have to remove the drive shaft and drop the tank to change the fuel pump?

Thoughts?

N

 

Put a fuel pressure gauge on the fuel rail and see exactly how much pressure you have when you crank. When have you last changed your fuel filter?

 

Definitely check the fuel pressure.

A failing fuel pump would provide less and less pressure, and results in weak engine, or knocking while running.

You should not have to drop the drive shaft to change the fuel pump; there is a sheet metal barrier between the tank and the shaft, so dropping the shaft won't help. You do not have to fully drop the tank to get at the pump, just lower the outside enough to get at the mounting plate on the top of the tank.

Your symptoms sound like a clogging fuel filter. I had one that clogged under certain conditions, like the vehicle hitting a bump, and the engine starts to lose power. But if I shut off the engine for a few seconds, it would run OK until the next time crud in the filter got shook up again. That's a lot easier and cheaper to change.

 

Or he could just have a clogged IAC valve or bad connection to it. just take it out and clean it with throttle body cleaner.

 

Not to sound stupid, but what is the IAC valve? What does the acronym mean?

Thanx!

N

PS: Tomorrow I'm going to do the front brakes. I'm going to change the fuel filter as well...WYAIT!

 

Its on the right side of intake, behind the TPS on the throttle body. It looks like a large D cell battery with wires connected to it. it has two bolts tr 10mm holding it. remove it and clean with throttle body cleaner.

Its function is like a choke when cold till the car reaches operating temp. If it gets dirty it causes hard starting, bad idle till warm.

 

Idle air control valve. In addition to acting like the choke, it makes fine adjustments to the air intake to control the idle speed. It's been known to get stuck or filled with crud sucked in from the PCV valve.

You can test it by pulling its connector while the engine is idling with the AC on. The idle speed should slow down.

 

If none of this helps personally i would use a scan tool to check cmp/ckp synch. If not in synch that indicates timing issues. Bad crank sensor will cause a no start but bad cam sensor will cause a late start.

 

While you are cleaning the idle air control valve, clean the throttle body. I spray the cleaner on a mechanic's rag and wipe the inside and butterfly.

 

do you hear the fuel pump go "hummmm/clack" when you take the ignition switch to START ? (before cranking).

if you do, the fuel pump is good. Do it twice or three times to pressurize the system, that is how I start mine.
starts from the first crank every time.