Montero Hardstart

[offthepath]

Hopefully you guys can give some insight. My 2003 Montero has had an interment hard start for the past 6 years we've owned it. When it happens, it will just crank and crank, with maybe a slight attempt to catch. Generally, if you push the gas pedal a little it will start and then runs normal. This happened very seldom, so I did not look into it much.

Fast forward and the Montero spit a spark plug out. It was due for a timing belt anyway, so I pulled the heads, checked the heads (flatness, seats), lapped the valves, new stem seals, welded a cracked exhaust manifold, new spark plugs, cleaned/re-built the injectors and put it all back together. The cars runs good (just like before), but now it has a constant hard start. If you give it a little gas it starts, with about 1 second of rough/low/hunting idle and then it smooths out. If you turn it off and right back on, it starts up normally. If it sits for more than 5min, the hard start condition returns.

At this point, there are no active or stored codes, I've cleaned the MAF, checked the MAF and TPS resistance (per the shop manual), vacuum reading is steady around 19-20, I double checked the vacuum lines, and finally in an attempt to look for a vacuum leak, I spayed all the connectors with water while the car was running.

At this point, I need some more ideas and guidance on what to check next?

Thanks

 

[salbalboa]

Did you replace the seals on the fuel rail ? I just did mine and all the seals had hardened. I believe the FSM says to replace them every time you take the rail part other than that maybe a fuel pressure issue ?

 

[offthepath]

Did you replace the seals on the fuel rail ? I just did mine and all the seals had hardened. I believe the FSM says to replace them every time you take the rail part other than that maybe a fuel pressure issue ?

I did replace the upper and lower injector seals. I don't think there are any other seals on the rail, correct?

 

[Michael Brown]

It could be something with the fuel rail pressure regulator. You should be able to check the vacuum line for it easily.

 

[Walkers]

Check your fuel pressure at key on engine off, and at idle.

 

[plh]

What is the rust situation? If it is rusty, could be the fuel filler neck leaking vacuum, or even the fuel tank cap.

 

[offthepath]

Thanks for the fuel suggestions. I'll look at the regulator and see what's involved to test pressure.

I'm in the desert, so rust free. But I'll look at the fuel cap also.

 

[offthepath]

One other point I've noticed that may help. It seems like when coming to a stop, the engine idle drops (around 300-400rpm) and then comes back up and settles down around 700.

I don't think it did this before.

 

[salbalboa]

Have you tried cleaning the throttle body already?

 

[offthepath]

Yes, I cleaned the throttle body.

Today, the car started multiple times (hot and cold) without any issues, until this afternoon. Then it was long cranking and giving it gas to start. Still no active or stored codes.

It looks like I need to order a special adaptor to check the fuel pressure.

Any other ideas in the mean time?

 

[DenTar]

So, I'll throw in the random "this kinda sounds like what I experienced and this is what I did" post.

I have a 2001 Limited. A few years ago my daughter was using it as her daily to school. She reported to me that it would occasionally have a hard time starting. Just cranking, kinda catching, and then just more cranking. When she came home one day I tried it (and tried again later when it was cold) and it fired right up.

Few weeks later I drive it to work and when leaving for the day the same thing happened to me. Would not start. Just cranking and cranking (regardless of how much gas I gave it). Called for a tow, guy shows up, we try to start it and it fires right up.

Mentioning all of this because you mentioned intermittent in your original post.

Long story slightly longer I ended up replacing the ignition starter switch. This thing right here: Beck Arnley 201-1806 Ignition Starter Switch. This was over 3 years ago now and the problem has not returned, not even once, since then.

Also found this video for a Lancer that gave me a better idea generally on where it lived and how to replace it.

 

[PacS14]

Did you ever do the re-calibration or whatever it is the correct term for learning the fuel trim after removing the battery for a while?

 

[offthepath]

Did you ever do the re-calibration or whatever it is the correct term for learning the fuel trim after removing the battery for a while?

I started it and let it idle for a bit. Is there a specific procedure beyond that?

 

[PacS14]

Sorry I haven't checked back in a bit https://expeditionportal.com/forum/threads/2003-idle-relearn-procedure-for-3-8l-montero.159352/. There it is last post at the bottom

 

[offthepath]

Thanks for posting that. At this point, I don't think the idle is an issue. That may have contributed to my initial symptoms, but it idles fine now and we have about 1000 miles on the car.

Right now, it starts up cold 99% of the time. The hard start only occurs when it's hot (or warm) and if it sits for more than 30min to an hour between starts. Smaller time frames between hot starts, it does fine.

Engine runs perfect otherwise.