'00 Isuzu Rodeo 3.2L Starting Problem

[benjamming]

Subject vehicle with 130k miles has a hard start issue. It turns over fine. The battery has been removed & tested good. The grounds from the battery seem to be clean & secure. It seems to take longer to start the longer it sits. If it only sits for 30 minutes it starts up pretty normal. Anything longer than that starts taking a while. Overnight results in quite a lot of time to finally fire up. Fuel pressure regulator diaphragm leaking? Fuel pump relay? Thanks.

 

[Colt45ws]

To test if the fuel pressure is leaking down for whatever reason, when you get in to start it go KEY ON ENGINE OFF for 2-3 seconds, OFF, back to KEY ON for 2-3 seconds again then start. This will cycle and prime the fuel pump. If it starts up quick, you have fuel pressure leaking down. Leaking injector, leaking one way valve in the tank, etc.

 

[tomcat27]

Like OE said, wait a few seconds for the fuel pressure to build before cranking. if you still experience long crank times, then I would suspect a leaking injector. that can be validated with a fuel pressure tester and also an oil analysis. dont mess with a leaking injector - you can ruin a cylinder that way since the leakdown will wash oil off the cylinder walls. I have had two coworkers lose their engines that way.

 

[benjamming]

Any other ideas of what to check besides fuel pressure leakdown or does this really sound like a fuel issue?

 

[mechtech2]

Sure sounds like fuel.
Like you thought, a pressure regulator may be faulty. Also a fuel filter problem, fuel pump, or leaking injectors.
It seems the relay is OK, since it works.

 

[benjamming]

How would a fuel filter cause this? I could see if it was having problems under load being a result of the filter (or even pump).

How do I differentiate between leaking injectors or pressure regulator?

 

[Colt45ws]

Pull the vacuum hose off the regulator. If its leaking out the vacuum connection, it is bad. If it was doing this it would have other side effects while it is running though.

 

[mechtech2]

There are many ways that any single part can be faulty.

 

[benjamming]

What are the needed wrench sizes to replace the fuel filter on this vehicle? I believe it is a quick disconnect with no special tools, just open end wrenches (flare nut of course would be best).

It is 2WD for future reference in this post.

 

[mechtech2]

With the engine running, yank the fuel pump fuse.
This will make it less messy and less pressure for your change.