Hard start when engine is hot

[floyd25]

I'm having issue with my 93 explorer. It starts fine in the morning after it's been sitting over night. But once it warms up and i turn it off and try to start it again, it cranks for about 10 to 15 seconds before it fires up sometimes I have to crank it a few times before it fires. If anyone could give me any idea on what could be wrong that would be great. Thank you guys in advance for the help.

 

[Explodr94]

Floyd,

Going to need more info. Does it turn over when it's hot? What is hot? When you have a problem like this you always start with fuel & spark. You might also want to do a computer scan. Based on the limited info you have given, I might ponder as to guess that the solenoid is going out on your starter, but it could be a lot of different things, like loose electrical connections, clogged fuel filter, etc...

Thanks, Matt

 

[floyd25]

It turns over but wont fire. It does it after i drive it around and get the engine to operating temp. After several attempts to start it if fires up and sometimes it seems like its staving for fuel. I checked the coil pack for resistance and that was good, I also checked for spark and it was getting spark. The solenoid and starter was replaced about 4 months ago. I check the crankshaft position sensor and I'm getting voltage to both wires to me that doesn't seem right. The voltage to each wire is 1.85 volts. There's two wires, the Chilton book I have says ones positive and the other is negative and I should be getting 5 volts to I'm assuming the positive wire. Could the problem be the Ignition control modular, or the fuel pressure regulator? Thanks for the reply.

 

[MrShorty]

My first thought on this is the fuel pressure regulator. One of the FPR's failure modes is for the internal diaphragm to rupture, which allows gasoline into the intake. This sometimes show up as hard warm starts, as a bunch of excess fuel leaks into the intake, effectively flooding the engine. After long enough, the excess gas disapates, so hot starts are hard, but cold starts are just fine.

Easy enough to check for this condition: Simply run the engine for a little bit, then pull the vacuum line to the FPR and see if there's gas there. Gas=bad FPR.

 

[tigercat]

maybe try new spark plugs and wires and clean the filter and fuel filter

 

[marragtop]

When it's hard starting, do you hear the fuel pump prime? If so, as previously stated, check the FRP and fuel filter.

 

[ricky8587]

I had a intermittent warm start problem a few months ago. Cranked over fine but no fire. Replaced crank sensor but still happened. After not more than 10 minutes it would start right up! Turns out it was the Fuel Pump Relay. Try swapping it with the A/C or Blower Motor relay at test/try.

After confirming that was the problem with mine I bought 3 new relays at the dealership ($18 ea) and also replaced the 2 ABS relays which also corrected my ABS light "on" problem!!

 

[bama4188]

Change those fuel relay's, when they get older they tend to stop working correctly when they get hot. They are very inexpensive and if you take it to a garage they will try to put a fuel pump or something on it. If you want to be sure take the next time it happens, like the previous post said switch the AC relay with the fuel relay or just remove the fuel relay and cool it down, and replace it. When I say cool, I had a cooler with drinks and placed it on top for about 5 minutes, it fired up so I drove to the Auto parts store and purchased 2.

 

[floyd25]

Hey, I want to thank you all of you guys for your help. I found out what the problem was, it was the ECT acting up. I'm assuming it was telling the computer the engine was to hot to start. It took me buying a code reader to figure it out. Who would of thought it would be that. Again wi want to thank you guys for your input.

 

[MrShorty]

Since diagnosis is often the better part of the battle, can you specifically describe what you went through in determining the ECT was the culprit?

 

[jmu4032]

took a trip from nj to dc on a hot day stopped at a rest stop about a hour and a half into the trip was there about 15 minutes car would not start retried for about 1 hour was towed to a ford dealer and they could find nothing wrong, the next morning it started right up. they suggested replacing the fuel pump but were not sure it would fix the problem. i have a 4.0 EFI ford explorer stock, the bill would have been $1100. a little much for a guess