91 explorer hard starting

[wildstang]

Hello everyone. As the title of the thread says my 91 explorer starts hard, especially as the weather gets colder, I live in Vermont. I did do a search and found some previous topics, but no one seems to reply back if they got the problem fixed. If I do the on and off with the key switch some it does seem to start easier. Would this indicate dirty injectors or bad pressure regulator. I just recently replaced the fuel pump because it was leaking gas because the metal lines rusted, but still same start up problem. It has around 168000 miles and is my back up rig. I also have a 92 ranger with the 4.0 and that start great. I don't want to dump a lot of money into it because it is my back up rig, but if I have to then I have to. Thanks for any help.

 

[Rhett]

If I do the on and off with the key switch some it does seem to start easier. Would this indicate dirty injectors or bad pressure regulator.

Well as you already know, you need fuel and spark to fire off the engine and you must not be getting one or both of them.

First thing I would think would be that the fuel pump is going bad--because each time you do key on, key off, the fuel pump is activated. If it's a weak pump, the activating 2 or 3 times can get enough fuel into the rail--if the pump were strong, 1 prime would be all it needed. But you say you replaced the pump...so that's not it.

Can you hear the pump when you turn the key to accessory?

I just recently replaced the fuel pump because it was leaking gas because the metal lines rusted, but still same start up problem.

Start with cheap fixes since it's your backup rig...I'd buy a can of Sea Foam ($5) and run that through the intake, and put some in the gas as well. Well wait, you can't do Sea Foam if you can't get the truck started, can you! hmm.

I'd look at the condition of all of the vacuum lines under the hood. Make sure none of them are blown off the manifold or cracked out, etc.

Pay particular attn to the vac line from the fuel pressure regulator. Pull the line and see if there is raw gas in it.

Get the alternator, battery, and starter tested...

I'd probably change the spark plugs, and the plug wires too if they have not been changed out in a long time.

Maybe change out the fuel filter too if it's due, and check the fuel lines from tank to engine.

 

[Glacier991]

was just gonna comment on the fuel filter. Also the fuel pump relay.

 

[wildstang]

Rhett, it does start, but needs to crank over a lot more then my 92 ranger with a 4.0. That sea foam you mentioned, does that work good for cleaning injectors?

 

[Rhett]

Rhett, it does start, but needs to crank over a lot more then my 92 ranger with a 4.0. That sea foam you mentioned, does that work good for cleaning injectors?

Well before the injectors I'd look into having the starter, battery, and alternator load tested. I'd also think about replacing the battery cables. All of that is cheap stuff and more commonly causes hard starting than the injectors.

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Regarding Sea Foam, it works GREAT for cleaning injectors. Now keep in mind if your injectors are very badly clogged, then the best way to fix that is to pull the injectors and manually soak them. Or replace them.

Here's a good sea foam procedure for a 1st gen:

Do this in a well-ventilated area.

I'd recommend you go to a hardware store and buy a 2-foot long piece of clear plastic tubing, about 3/16" ? (not sure) inner diameter. The idea is to get a tube that will fit fairly tightly around your truck's throttle body vacuum port. Then get your bottle of sea foam. Get a cup or glass jar, and pour about half to 3/4 the can of sea foam into the glass jar.

Start the truck. Attach one end of the tubing to the vacuum port on the bottom of your throttle body (you will probably have to remove the intake tube to reach under there--but don't worry, the truck should not die when you do this. Keep the MAF and breather attached, just undo the intake tube from the throttle body to allow yourself room to access the vac port on the underside of the throttle body). If the tubing doesn't fit fairly tightly around the port, you need smaller tubing.

With engine running, BRIEFLY put the other end of the tubing in your jar of seafoam, then quickly pull it out. You don't want to flood the engine, just let it sip a little at a time. Work the throttle butterfly on the side of the throttle body to make sure the truck doesn't die while you are treating it.

Truck may smoke quite a bit. This is normal. Then again it may not smoke much at all. I've seen both.

Once it's sucked in all of the Sea Foam, shut down the truck. Re-attach the vac fitting, and re-attach the intake tube. Let truck sit for 10-15 minutes.

You can dump the remainder of the Sea Foam into your fuel tank (using a funnel for no mess).

Start the truck, and drive it BRISKLY for about 15 minutes or so. That means get on it. When you first get on it, after leaving your driveway, you may well see a big rooster-tail of smoke. This too is normal. I always take mine to the interstate and run up and down in "D" at about 80 mph. Cleans it out nicely.

Solves pinging problems, idle problems, restores pep. I have found that I need to do it about every 8000 miles.

 

[wildstang]

I think I fixed the problem with having to excessively crank the explorer over. I did do the sea foam treatment which did seem to help, but the thing got to the point where it would only crank a few times and then act like the battery was flat. I tested the battery and it had plenty of cranking amps. So I swapped starters from my ranger and it fired right up. So I rebuilt the starter and it starts much faster. Appearently the starter wasn't spinning it over fast enough, but so far so good.

 

[Rhett]

Good to hear. Are the tree leaves looking good in Vermont yet?

 

[wildstang]

The leaves are turning, but so far I don't think the colors are very bright. They seem like a lot of dull orange and yellows. It has been a really warm fall so far and we just had a lot of rain this weekend so alot of leaves that had turned were knocked off. There still appears to be a lot of green leave yet to turn. I think if we can get a good frost, it might help brighten up the leaves that haven't turned yet.

 

[410Fortune]

weak starter can do that for sure, as they get this old I often find the wires to the starter get old/weak/corrode too. I also like to solder everything if I redo the wiring, including the male crimp on connection for the starter relay feed wire (small wire) dirt gets in there and it comes loose/etc.