Hi all,

My 99, 4.0 ranger has a hard time starting when its cold out and it has sit over night. I usally have to crank it twice until it will start and when it dose start it hesitates a little and then idles fine. I have replaced the idle air control and the fuel filter. The engine runs good and strong. Could bad plugs and wires cause hard starting? Any Ideas:

thanks,

mike

 

Try moving the key to "ON" and then to "OFF" two or three times, letting the fuel pump cycle its 3-second burp. Then try to start the truck. If it starts well, you may have a leakdown problem which would leave the injectors w/o fuel to spritz. Cycling the key will pump fuel to the fuel rail and pressurize the system. If you have a leaky check valve in the fuel pump or regulator, or a leaky injector, it can cause the fuel to leak into the intake or back to the fuel pump.
tom

 

Could be a number of things Mike.

A weak battery comes to mind & your vintage is about the right time for the OEM one, if it's still in there, to lay down during cold weather.
SO, I'd stop by your favorite autoparts store & let them do a no cost load test on the electrical system, with their portable tester. It'll properly load the system & sniff out any weak components.

If the battery voltage is dropping too much on a cold start, it can affect the fuel pumps pressure, spark output & cranking speed, all of which can affect how well it'll start when cold.

If it sounds like it's laboring a little on a cold start & the cranking speed is down, or the headlights have begun to dim at idle, the battery is getting weak.

Yup, worn plugs, with too wide a gap & leaky wires won't help either, but I'd begin with the electrical system load test, especially a battery load test.

Once you know the electrical system is ok, then move on to checking fuel pressure, plug gap & condition,, wires, ect. I like tomw's idea too.

Was probably a good idea to replace the fuel filter, but why did you replace the IAC, wre you having idle problems, or did you have a code for it?????

Let us know how it goes.

 

Thanks for the replies, Yeah it was idleing rough a while back, chabged the iac and sovled the problem. I had the battery replaced as well about three months ago however, I put my prestone jump it on it for fun and it seemes to start better, may of been luck though.


thsnks,

mike

 

OK, well it would seem you've taken care of the electrical system questions, with the new battery.

I'd try toms idea, with cycling the key from "off" to "run", not "start", for three or four tmes, then go to start & see if it fires normally.

If it does start normally, I'd do a fuel pressure check & see if the pressure is bleeding off prematurely. It should hold pressure for a good while.

If it doesn't hold pressure, next question is how to best isolate the problem.

Seeing as how our vintage vehicle has the fuel pump & pressure regulator in the tank, we can't do a separate regulator check. like older models, with the regulator on the fuel rail.

So if the psi is ok, say 65 +- 8 at KOEO & it drops not more than 10 psi after the engine is started, we can probably assume the pump & regulator are ok on the delivery side of things.

If the pressure leaks down rather quickly, then it's going to be a little more tricky to determine if it's a pump end check valve problem, or injector leak down.

Seems to me you'd have to disconnect the fuel rail & dead end the pressurised fuel line some how & see if it holds psi, to determine if it's a pump/regulator check valve leakdown.

If you've noticed the mixture seems rich on start up, or a drop in fuel mileage, or are having driveability problems, maybe it's pointing to a leaky injector/s.

Your post about it hesitating a little, after the difficult cold start, sorta makes me want to lean toward a leaky injector/s right now.

When you replaced the IAC, did you also clean the throttle body inside????

Maybe some of the fuel injection system experts, will chime in with some of their "tricks of the trade" troubleshooting tips!!!!!

Just some thoughts for pondering.

 

Thanks again, Yeah I clened throttle body. I will try to cycle the pump a few times and report back.

 

Perhaps it's not relevent, but my 4liter had a bad EGR valve. Replacing it made a major difference in starting (and idling).

 

Well, I cycled the ignition from off to on three time like mentioned above and still would start, it sounds like it is trying to start but dosent. After about three tries it fires right up fast and idles great.

 

Sure sounds like a fuel delivery problem, of some kind, so now I think it's time for a KOEO & KOER fuel pressure check.

You can relieve the fuel pressure by disconnecting or tripping the in cabin inerita switch, located in the right passenger side floor board, just above the carpet, about where your right foot rests, then cranking the engine until it stops trying to fire.

Don your safety glasses.
Then hook up your fuel pressure meter to the fuel rail, rehook or reset the inertia switch & do a KOEO & KOER pressure check & let us know what you find.

 

Ok, I may have to check the pressure. on Tuesday I went out to start the truck and it was alot warmer out, about 41 degrees and it fired right away, which really suprised me. Although its only been starting hard for about a moth now. It used to start when it was negitive out.

 

Well, I havent had time to have the pressure checked, however I went out in the morning and checked to see if there was pressure at the fuel rail by pressing the pressure release and there wasnt any pressure untile I turned the key on. i heard thre should still be pressure there. Is this true. What could be the most likely cause.
Is it possible that when the guy changed the fuel filter it is leaking.
thanks

 

I have a 2000 4.0 Ranger and have the same problem.
Could it be a problem of the temperature sending unit?
Does it has one of it? Is it responsible for computer and gauges?

 

Well swisstruck, it does have separate temperature sending units, for the computer & gauges.

If your having the same kind of start problem, read through & try the above posted things & see how it goes.

 

Intake seals... leaking vacuum when cold.. once they start to warm up they swell, seal up, and everything is good... seen it dozens of times on these.

I can't say 100% this is your problem, but I've had several come in with multiple coil packs, fuel pumps, coolant temp sensors, etc replaced and these seals cured the problem.

When it DOES start it runs incredibly rough for several seconds to a minute.. then everything is great, right?

Also it almost never sets a code because computer is in open loop operation while this is happening, however a few I ran into had P0171/0174 codes as well, which were also cured by the replacment seals.

Good luck

 

MazdaRangerGuy: just for clarification, are the seals you're talking about for the lower intake or upper?