Hard Starting on 03 4.0L

[thepotroast]

Truck has 130k miles on it, only aftermarket item on the motor is a KKM cold air intake. Last week after putting in a full tank of gas, it's been having a hard time starting. Once it starts, it runs fine...idles fine, doesn't die. When it cranks over, it does try to catch, and it takes about a dozen attempts before it finally kicks in and cranks up.

I have replaced the plugs (Motorcraft gapped to .052 - .056), plug wires, PCV Valve, and battery. There is no CEL so I'm not sure if it would even throw a code, but I have not tried that yet (I thought the CEL had to come on to throw codes).

I know there are a variable of things it could be...an O2 sensor, fuel filter, fuel pump, MAF, IAC, coil pack, injectors, etc...but not sure what to look for. All the shops are closed until Monday, and I'd like to maybe see if there's a few things I can look for and/or try before taking it to a shop.

I was thinking perhaps it was just a tank of bad gas, there's still 1/4 of a tank in it of 87 from Costco, I did put some Chevron/Techron fuel injector cleaner in the full tank when this all started, but that hasn't done anything at all. I thought about getting it cranked (it seems to be harder and harder to start each day) and driving it down to a gas station and throwing some good Ethanol-free gas in it (only 2 stations in my city advertise their Ethanol free stuff) and see if perhaps I just got some bad gas....but if that were the gas, would it really be running as normal once started?

Suggestions of what I can try until I am forced to take it to a shop on Monday?

 

[my pos mounty]

Why not start by cleaning the MAF and IAC. Easy and cheap to do. Get yourself some electrical contact cleaner and possibly spray away your troubles.
I would run down and get some of the "real" gas as well. Can't hurt and just might help a little.
If it was your O2's, I think it would throw codes and your CEL would be on.
While your at the parts store (buying said contact cleaner) get yourself a fuel filter (and maybe the proper tool to remove it), to change that out. Then drive home and spend some "alone time" with your truck today. Save your cash for flowers for your other half, and brag about how YOU fixed the truck yourself.

Good luck

 

[Hitchhikingmike]

Check out your idle air control valve. Mine was dirty with carbon, giving me starting problems as well.

Take off the IAC and spray the inside of it down with some carburetor cleaner. Mine was so dirty I had to use a pick to clean it out.

 

[thepotroast]

I pulled the IAC and it actually looks pretty clean inside. I have some contact cleaner in the garage and sprayed it out anyway, haven't gotten a chance to put it back together since the baby started crying and all...but I was sort of hoping to see it a little dirty in there.

I guess it could always be possible that the IAC is just bad....any way to check it by itself?

I'm guessing if the valve didn't open all the way as it should, it would prevent the truck from starting, which is exactly what it's doing. But when it does come to life, it idles just fine.

EGR Valve maybe? Or would that throw a CEL up?

 

[my pos mounty]

I'm thinkin if it was the EGR that would throw codes. But i guess it has to run first for that to happen

I think there are some codes that do not trigger the CEL, if you have a scanner, hook that bad boy up

 

[thepotroast]

Just a quick update here, handed the baby off to the wife and was able to go reassemble the IAC Valve assy. I took a 2nd look at it in the sunlight and there was some carbon buildup on the walls inside of it, so I scraped that all down as best as I could and shot some more of the contact cleaner in there. Put it all back together and it actually fired off...for about 5-6 seconds at normal RPM for a cold motor (~1200), but then died shortly after. Took a couple more cranks and it fired up. So I took it down to the local BP and filled up on quality gas, and threw some more Chevron injector cleaner in there for good measure.

I won't be able to tell if it's any better until the motor is cold again, as it seems to fire off when it's warm with no issues. Will report back in a few hours once it's cooled off...it's a brisk 32 degrees on the east coast of NC right now, so shouldn't take it too long.

Thanks

 

[my pos mounty]

This might also be a faulty ECT sensor. Was "posting" with someone else with similar problems (but he couldnt start at all) and he just came back with the fact he changed out his Engine Coolant Temperature sensor, and VIOLA fixed.

 

[thepotroast]

Coolant temp sensor was actually just replaced not too long ago, when I had the entire cooling system redone (radiator, water pump, fan clutch, etc).

So the motor is cold, just went out to crank it...and same problems...turns over, hardly a fire. I'm gonna pull the MAF sensor tomorrow morning and clean it to see if that makes any difference.

Looking into the fuel filter deal as well, but time isn't really on my side this weekend and I can't afford to have the truck sitting in the driveway all week while I find time to do the fuel filter. I need to read some more about it, but I've seen posts on here from some that have had it out quick, and others who simply haven't and have gone through 2-3 of the tools to remove it.

Still leaning on it being an ignition problem...was really hoping it was the IAC valve assembly, but besides just having some carbon buildup in it, I think it could still fail because if the actuator/relay/servo (whatever the hell is in there) doesn't pop out correctly then it won't get the correct air/idle mixture which would make sense why it has a hard time starting. If any of the parts stores had a IAC in stock I would just front the $40 for a new one, but everything is special order so I would just get it off Rock Auto if I needed it.

 

[thepotroast]

Well I give up, she's going into the shop today...will report back with the findings.

 

[Hitchhikingmike]

Okay, sorry we couldn't be any more of a help. Let us know what they say.

 

[thepotroast]

Shop called and said they traced what seems to be the problem as both the Fuel Rail Pulse Damper, and also the Fuel Pressure Regulator.

They also recommended replacing the fuel filter.

They told me that cannot be 100% sure that these are the issues, because the newer Ford's use a specific diagnostic tool to test the FPR, and that they did not have one. What they did tell me is that when they hooked a voltmeter to it, the voltage seemed to jump all over the place, or be completely dead at times.

They quoted me about $550 to do the entire job (FPR, Pulse Damper, Fuel Filter)...but with no guarantees that it will work. He suggested that I may want to take it to the stealership in town as an alternative so that they can 100% test the part(s) or trace the issue, and then bring it back to these guys so they can do the job if that's the case.

Normally I would have plenty of time to do my own work on this, however we are moving at the end of this month, and the reliability of my vehicle is pretty much necessary...so it needs to be running soon. I don't really have time to tinker with this problem in my garage. I told the mechanic that I also don't have the funds to trace the problem by replacing parts that don't need to be replaced (I had this issue with my cooling system last year...and basically I got a $1500 radiator out of it all).

So...any ideas or advice? I'm thinking about just paying this mechanic for their time in searching for the issue, and driving the truck over to Ford to have them diagnose it....

 

[miker104]

Have them or yourself change the fuel filter first. Its cheap and relatively easy. If still not working, have the dealer give you a better diagnosis.

Just my $0.02

 

[thepotroast]

Dropped it off at the dealer this afternoon...they are going to do a diagnostic on it tomorrow morning since that's when the problem occurs (cold engine....when it's warm, it cranks right up).

The service adviser just said it sounds like a bad IAC Valve by the symptoms, however he acknowledges that a bad IAC with throw a CEL and has 3 different codes it normally throws. Since there is no CEL and the shop I had it at didn't show any codes...it's all still up in the air.

If it is in fact just a bad IAC, then I can do that myself as the part is a mere $40 from Rock Auto...but with so much speculation still and the previous shop not being 100% and wanting me to just start in on a $500 job without a "for sure" statement attached to that, I am glad I am getting a second opinion from the dealer.

Will update as I find something out.

 

[thepotroast]

Dealership is saying the fuel pump is bad and to also change the fuel filter.

They told me they did a fuel pressure test and the PSI was low, and that while they were down there they would replace the fuel filter as well. The total bill...almost $900...

The 1st shop quoted me about $580 for the pump and filter (w/labor) if that was the case.

Checking RockAuto.com I can get the pump for about $200...but I'm just thinking about going with the 1st shop, having them do the pump and fuel filter.

Thoughts?

 

[jpatz18]

drop the tank and do it yourself. or pay 400 in labor...

 

[xtoolmaker]

Change the filter first. It's cheap and if it's clogged it could give a low pressure reading.I dropped the tank on my CJ-7 jeep let me tell you its no fun all those years of road grime plus it was hard getting rid of the old gas.

 

[Hitchhikingmike]

Like others said, if you do it yourself, just remember that you have to drop the tank.

 

[thepotroast]

Like I was saying earlier, I literally do not have the time to do any of the work myself to do the filter and/or fuel pump....we are moving in 3 weeks, wife just came out of the hospital in recovery, 9 month old at home...things are crazy

Ford called me back and finished the job, replaced the fuel pump and fuel filter...and said the truck runs great now. I honestly probably wouldn't have dropped the tank myself anyway, living in an HOA neighborhood they don't look too kindly on working on vehicles outside your home...but the fuel filter I know I could have done, but honestly it was only $50 extra for them to do the fuel filter (including labor) which to me seemed like a good deal considering the filter is about $15-$20, the tool price (some people say they go through 2-3 of those tools as they do break easily), and the busted knuckles. I'm sure the fuel filter would have been more to get it done by itself, but since they already had the tank off it was worth it just to throw it in there.

They bench tested the fuel pump and verified that it was going bad, not only did it not push enough fuel pressure through the system, but it was also glitching on the voltage, so it did need to be replaced.

All in all, I really wish it was something like the MAF, the IAC, or just some plugs/wires....but $883.12 later and it's all fixed.

Cheers and thanks! Hope this helps someone else out in the future.

 

[Hitchhikingmike]

glad it worked out for you.

I have a question, how many miles do you have on your explorer? how old is it?

Just wondering how long your original pump lasted.

Thanks.

 

[thepotroast]

It's an '03 with 132,x.. on it. It's already gone through an entire new cooling system (W/P, radioator, fan clutch, sensor, hoses), rear differential and clutch pack, ball joints, front hub/bearings, and now the fuel pump.

I bought the truck at 94k miles about 2.5 years ago and all of those things have been redone since I've owned it (besides the new diff and diff clutch pack). It was a corporate lease vehicle, 1 owner prior to me.

I still have the infamous rear diff whine that many in my year range complain about, but you just get used to it.

Thanks