wouldn't start, then started, now won't start again!

[dablack]

Wife was in town running errands. Came out to the explorer and it wouldn't start. The engine would turn over but it wouldn't catch. I got there 45 minutes later and it still wouldn't start. Still turned over fine but wouldn't catch. Had it towed home and I hooked the fuel pressure gauge up to it. Showed good pressure, so I hit the key. Started up fine like nothing happened. GRRRRR! I drove it around for another five miles and let it sit for 20 minutes and it started up fine again. Let it sit for five minutes and it started up fine again.

What are the usual suspects for something like this? The car sat for a year and recently got a 09 mustang 4.0L and a new fuel pump and filter.

Any ideas of what to check?

thanks
Austin

 

[Hudsonf]

Wish i could help. I had a Ford Taurus that would do that when the temperature was hot outside and the car was driven for a few hours or so. Shut the car off, come back a few minutes later and crank and no start. Wait about a half hour and the car would start and run like I never had a problem. Had it to a couple of repair shops and there were no codes when they hooked up their computers. I finally traded it in for my Explorer.

 

[xlt03]

Had similar problem on my 04 Ranger. It was the fuel pump interia cutoff switch. Check the wiring to the switch. Mines was fried. Replaced wire and switch. Problem solved.

 

[dablack]

Thanks for the idea of the interia switch. I will check it out tonight if it isn't raining.

Austin

 

[DoraThe_Explorer]

Is your check engine light on? If so, what codes is it throwing?

 

[dablack]

No check engine light. That would be too easy.

 

[dablack]

Inertia switch is good. Now, I'm stuck on the side of the road again. Was driving along at 70 mph and it just died like I turned the key off. I'm typing this from the side of the road. UG!

What else could cause the engine to just die and not restart?

I don't have any tools with me so I don't know if I have fuel pressure or not.

 

[dablack]

Ok guys. I pulled the cap off the schrader vale, pushed in the needle with a pen and sure enough gas shot out so I did have fuel pressure. Not long after that, I hit the key and it started up like nothing happened. I had tried it about 10 times in the previous 30 minutes and it would just crank but not catch.

So I drove it home and drove the 1990 F250 to work (45 miles at 11 mpg).

I do have a NEW CLUE! After I put in the new fuel pump (after a no pressure condition after a engine swap), I drove the explorer to the gas station because I only had 4 gallons of fresh gas in it along with a gallon of old gas. I filled it up. Since then I have driven 50 miles and the gas gauge still shows full like you filled it up to the gas cap. I'm thinking I've got a wiring problem to the fuel pump.

Thoughts?

Does anyone have a fuel pump wiring diagram?

thanks
Austin

 

[05XLimited]

I do wonder if you got a bad fuel pump that quits when the conditions are right. You said that both times that whenever you used the Schrader Valve to change pressure, the vehicle started up after that. It could be that the wiring within the pump itself is messed up.

 

[xlt03]

How did the wire connector looked connecting to inertia switch? It cannot looked melted and the wire shealthing also not melted. On my Ranger I had same problem you stated. Also look at the base of the inertia switch and make sure the plastic is not melted. You'll need to remove switch to see the base of the pins. When things get hot the connection opened and my vehicle stalled. I replaced inertia switch and wires and my problem stopped.

You may want to remove the kick panel and have access to inertia switch. Now drive the vehicle and when it stalls go and feel the wire and connector to the switch to check if it's hot. Once it cools off it'll probably starts. If your vehicles stall rather quickly you can just let it idle instead of driving till it stalls and feel wire and connector. To isolate if the switch is bad, you can TEMPORARILY jump the wire to bypass the inertia switch. If vehicle stays running and not stall after your previous stall time has elapsed, I would start thinking about replacing the switch. Remember the wiring can not be corroded or burnt looking. DO NOT LEAVE THE BYPASS WIRE IN VEHICLE. The inertia switch is a safety item.

Also replace the fuel pump relay, it's only about $10.00 at Autozone. Or you can swap it out for one of the other relays in the junction box. I did this first on my Ranger but still had stalling issues. I replaced fuel pump and still had stalling problems. Finally checked inertia switch and saw burnt wires. Replaced switch and wires and connector and no more stalling. My understanding that fuel pump failure can cause an overheating issue with switch.

Post back with your fix.

 

[pzy3339]

Have you checked the ignition during a no start period? Any chance the anti theft system is not operating properly and sending power to the ignition system when you turn the car on?

Seen it happen before. It runs and starts fine when it runs, but if it wont start it just plain wont start.

I have never owned a 3rd gen, does it have a coil pack or coil on plugs? If its a coil pack just keep a spare spark plug handy for the next time it wont start, hook one of the spark plug wires up to it and ground it and have someone turn the key. Wear gloves, ive had this shock me even while only holding the boot of the spark plug wire. If you get spark and the engine wont try to fire this is not the issue. However, if the plugs are not receiving spark you will want to look into whats preventing the ignition system from getting power. Which is often an issue with the anti theft system. And believe it or not, that can be nothing more than a bad(or improperly programmed) key!

Did the engine control module come from the donor car? Is the key from the explorer? There may be some programming issue between the computers.

 

[dablack]

Thanks guys. I have been researching like crazy and really appreciate the input.

I will respond to the comments and then add aditional information.

05X,
Yes, a bad new part is a possibility. I was getting zero pressure before the new pump. I'm hoping to get the problem to repeat at home so I can check pressure. I'm even willing to take it on the road with the pressure gage hooked up and taped out of the way so if it happens again, I can pop the hood and see!

XLT03,
I found a couple of your old posts about your inertia switch. I pulled the panel and unhooked the switch. Everything looks great. I'm going to leave the panel off and try to repeat the no-start condition. When it happens again, if I don't have pressure to the rails, then I will check at the inertia switch to see if I have power there. I think I will since I can hear the pump prime after the car dies.

pzy,
You are getting to the heart of it. Right now since it only happens out on the highway, I don't have tools with me. This next time I will! Right now I don't know if it dies due to the computer pulling spark or fuel. I'm going to leave a fuel gage hooked up and also have my spark tester ready. I'm going to figure this out! Only the mustang long block, pan, water pump and crank ballancer were used. Everything else is explorer.

Extra info: After checking the IAC last night (it is clean) and the MAF (also clean), I rechecked the relays and swapped some around. I rehooked the battery and cranked it up. I was surprised to see my gas gauge read 3/4 instead of full. I believe 3/4 to be the correct reading. So I drove the explorer up and down the driveway a couple of times (600ft of gravel). I thought maybe one of the relays had caused the problem and it was now fixed since my gas gauge was reading correctly. In that time on the driveway, the gauge went back to full. I spent the rest of the nigh researching that. I found that the more resistance in the line, the higher the gauge will read. I think I might have a bad ground down by the pump.

Tonight I'm going to pull the seats, pull back the carpet, open up my "pump door" in the floor and see if I can spot anything obvious. I will check the grounds there and at the connector on the outside of the framerail. If I can't find anything I might take it on a little road trip with my test light and multi-meter in one hand and my fuel pressure gauge in the other! The dieing on the highway with no restart and the fuel gauge might be two different problems or the same one.

Sorry for the long post. I've been thinking about this one alot. I have found two other places in the forum where people reported the exact same problem and never reported back on what the fix was! UG!

thanks
Austin

 

[pzy3339]

Something I always find myself overlooking and under emphasizing when messing with electrical issues is grounding. A bad ground can do funny stuff.

Considering what you have said I think its computer related. If the engine was sputtering to a stop I would suspect the fuel was cutting out, if the fuel pump died the pressure in the system wouldn't drop so fast the engine would die like the key was tuned off I don't think, it would sputter out.

I still suspect the ignition system. Not sure how to help you figure out why it would be going in and out though.

Is there ever anything noteworthy in how the electronics in the dash or interior behave when the engine dies or wont start?

I would check all grounds and leads to everything you can under the hood. Something may be hanging by a thread and about to fall off and sometimes makes enough connection to keep things going and then it gets bumped just right and cant flow enough power to maintain operation until it gets bumped again and makes a better connection.

Who did the engine swap?

 

[dablack]

I just got home so I don't think I will be doing any troubleshooting tonight!

I did the engine swap and yes, I believe it is the computer "turning off" the engine as well. When the car does it, it took me a second to figure out it happened. As far as car movement, it feels like you pulled your foot off the gas. The car just coasts in drive. I threw it in neutral. The radio and ac were still on. While I was coasting to a pull off I was able to turn them off.

The only other clue is the fuel gauge showing full the whole time.

The thing that is still confusing me is unhooking and rehooking the battery temporarily fixes the fuel gauge. Weird!

I have a wiring diagram for the 8 pin plug at the tank. I will start by checking grounds there or the big plug on the outside of the frame.

I will keep everyone up on the progress.

Thanks
Austin

 

[dablack]

Well, I have another update from the road. I checked all the grounds in the engine bay and found a slightly loose one. Thought for sure I had found the problem. No joy. Drove to town and I'm stuck. Same thing as before. The gas gauge still reads full. Also, this is three times now that it goes 15 minutes and then dies. That has to mean something. Tomorrow I'm pulling the seats and checking the grounds around the tank.

Austin

 

[dablack]

This morning the explorer cranked up just fine. Drove it home. Sure enough about 5 minutes after getting home, it died. This time I was ready.

1. Put the fuel pressure gauge on it. 60 psi
2. Used the bleeder valve from pressure gauge to get some gas from the rail. No water or junk in gas.
3. Then I shot some starter fluid in the intake. Hit the key and it ran for a second. That means I have spark. To be sure, I'm going to pull a plug and check.

At this point I don't know what to do. The fuel gauge has come down some with the use so I no longer think it is related to this problem.

I'm wondering if the computer is losing power. I know what relay powers the computer. What wire sends power to the computer? I really want to make sure it is getting juice.

Also, what sensors would tell the computer not to open the injectors? Since I have spark and fuel pressure, it has to be the injectors not firing and if the computer is getting power (not sure yet), then something is making the computer think it would be bad to open the injectors.

Also, even though I don't have a check engine light, I ran the codes anyway. My reader showed no codes.

Any help would really be appreciated.

Austin

 

[dablack]

Well. That's it. I give up. It has power to the PCM relay. The check engine light comes on when I turn the key to on and then goes out during start. So I think the computer is getting power. I guess I'm out of luck. I will most likely part it out in a month or two. I can't keep putting money into it blindly.

Thanks
Austin

 

[05XLimited]

Another thing that it could be is a crankshaft position sensor going bad. It sometimes throws codes when it is bad, or in the case of a Mustang that a buddy of mine had, it would just stop working on him and take a while to restart. He replaced many different things before checking his (PCM, Fuel Pump, Injectors) and found out that his was not working properly.
http://www.explorerforum.com/forums/showthread.php?t=85965 is someone who has a test procedure for testing the CPK sensor.

 

[dablack]

I am so pleased! I found a great trouble shooting guide online (troubleshootmyvehicle) and checked everything. Plus I had a spare CPS and coil pack from the mustang engine. Even with the new parts it would still get hot and die. It was acting liked bad CPS but the parts were checking out good. So, since I knew all the parts were good, I traced my CPS wires. Sure enough, right between the PS pump bracket and head, the wiring was pinched. When the engine was cool, there was enough room and everything was fine. When the engine would get hot, it would pinch the wires TIGHT, causing a short.

I just got back from a long drive and everything is good. Wife is pleased!

05X,

I will have an address for you tomorrow.

Austin

 

[pzy3339]

Good to hear you got it figured out!