No Hot Start, until cool down?

kgtorino

kgtorino

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Hello Everyone, I've done a search, but can't find an exact problem like mine...(unless I missed it ) . 2006 LS, 3.9. Approx 105,000 miles. Car does not start after a run. It seems to be the longer the run, the longer it takes to cool down to be able to start again. ( I say cool down, but not sure if that's accurate or not). A 5 - 10 minute run will require a cool-down of about 5 minutes, whereas a 2 hour run, the car won't restart for up to 30 minutes. The car never stalls, and starts cold fine. (also engine runs good cold or hot ). Just can't turn it off if I run into the store. I've changed fuel pump relay ( thinking it was getting hot, with no luck ) . By the way, the car does not overheat, or lose coolant. I've changed the Degas bottle (with an OEM unit ) due to a leak, and I properly bled the system. I did have an EGR code about a month ago, (code P0406)
but I cleared the code, and the light hasn't come on since. This hot start issue has been going on long before that. It will crank, just doesn't fire up. Once it "cools down", it fires right up. Anyway, if someone could point me in the right direction as to what to try next it would be greatly appreciated !
Kevin
 
It's really tempting to recommend you replace your COPs, but lets try to diagnose this instead.
Am I correct to assume that if you could smell raw gasoline at the exhaust (when it won't start) that you would have mentioned that? If there's no smell, I would start by spraying some starting fluid into the intake while trying to start the engine.
If it tries to start then, you'll know it's a fuel issue. If it's fuel, the next thing to try is to unplug the electrical connector from the MAF sensor. If that resolves it, then it's a vacuum leak or a bad MAF. (I doubt that it will be either.)
After that, it's likely to be the fuel pump or the REM. Do you hear the fuel pump priming when you have the problem?
 
COPS..LoL....I know that's coming. .... no, I didn't notice a gas smell upon attempting to start. I do hear the fuel pump prime when attempting to start. (Fuel pump seems to act normally). I will pick up a can of starting fluid, and see what happens. Then, go on to the MAF sensor. Thanks a million, Joe !
 
Update, tried some starting fluid tonight. It did seem to ' sputter ' a bit more...then I pulled the wire off the MAF sensor, but nothing really happened when I did that. The starter just seemed to whine, while trying to start. I'm thinking it could be no fuel when this is happening. Is there a Schrader valve I can check, like older models, or is there a different procedure to check for fuel pressure. By the way, I did go towards the back of the car , and did not smell any raw gas . Thank You for bearing with me !
Kevin
 
Had this same issue with one of our 06 police chargers. Came to a point it would not start so we trailer it back to the garage and hooked up my scanner no codes no issues switched over to data stream and was watching the screen while cranking motor and I notice once I start cranking the motor the pcm would shut off fire to the coils and fuel pump system going into automatic safe mode unhook the battery reset pcm with no luck ended up taking it to the dodge house and their scanner tested the pcm itself and found it to be bad ..
 
Advice for other cars rarely helps for this one...

Some of the LSes have the fuel pressure test port, and others do not. The 06 does not. When's the last time you changed the fuel filter?

I suppose it could be the crank sensor. Hook up a reasonable scan tool and look at the engine RPM while cranking. If it stays at zero or very low, then the crank sensor would be a reasonable suspect for this.
 
Having the same issue for a long period of time. Cranks slowly after the long run, when engine is hot. Fast fire up on the cold engine. V6.
 
Thank you all for your replys....i changed the fuel filter when I first got it about a year ago... this puts it in mind to change it again. I will try a scanner, and check rpm while cranking, and report back . Thank You Everyone !
 
checking fuel pressure is a neccesity, to rule out injectors leaking down, which causes a flooded condition. hard/impossible to start when warm right after shut off, but starts great after sitting a bit or til cold.
do you try putting it to the floor when it does this?
 
HrmWrm ..thanks...Yes, no start...just crank only when hot....even from running a short hop. I did try putting the pedal to the floor...and that didn't help . It just has to wait anywhere from 5 mins to 30 minutes. I can't find what I did with my code scanner to try and observe rpm when cranking to try and diagnose if it's a faulty crank position sensor, but when I do, I'll post those results. Thank You for your advice. If you would, let me know how to do a fuel pressure test. As was stated, I don't think there's a valve on the '06...so what would be the procedure to test for leak-down on the injectors ? I'll try anything . Thanks again.

Kevin
 
I think that the "dealership" method is to disconnect the quick connect to the fuel rail and add a Tee line in between that has a fuel pressure gauge on it. Note that you can also read the fuel pressure via the OBDII, but that assumes that your problem is not the fuel pressure sensor.
BTW, I am assuming that when this happens your starter is still turning the crankshaft at the normal starting speed. Also, I doubt that your filter has clogged in a year.
 
JINT0NIC said:
Having the same issue for a long period of time. Cranks slowly after the long run, when engine is hot. Fast fire up on the cold engine. V6.
Click to expand...

Do you mean that the starter is weak and turning the crankshaft slower than normal? If so, there are a few things to investigate. First, have the battery load tested to verify it is still good and that it is being fully charged. Secondly, test the power and ground connections between the battery and the starter for excessive voltage drop while the starter is engaged. If those items are good, then the starter itself is suspect.
 
Joegr.... no , starter spins normally hot or cold. As soon as i locate my scanner, ill be able to check the rpms, and see if the crank position sensor is o.k. Thank You , everyone.
Kevin
 
joegr said:
Do you mean that the starter is weak and turning the crankshaft slower than normal? If so, there are a few things to investigate. First, have the battery load tested to verify it is still good and that it is being fully charged. Secondly, test the power and ground connections between the battery and the starter for excessive voltage drop while the starter is engaged. If those items are good, then the starter itself is suspect.
Click to expand...
Hi Joe,
It's correct, starter is weak on hot engine. The battery was replaced not a long time ago and is being charged from time to time, so its not the problem. Second test should be redone, I have done it couple years ago and didn't find any excessive voltage drop. Have to check that again, before going for a starter. Thanks for advice.
 
Update on my issue. RPM is registering from about 176- 195 rpm upon cranking. A buddy of mine was cranking the engine while I sprayed the starting fluid in the intake. ( Which was difficult to do myself the other day) it does "run" for a bit , though roughly, with the starter fluid. I'm definately thinking I'm not getting fuel for some reason when car is hot. Wouldn't the REM throw a code if there was a problem ? The only code I'm getting is the P0406 ( which started up again this week, with a check - engine light). So that's the latest. Please let me know what you would check next. Thank You !
 
If the REM wasn't powering the fuel pump, then you wouldn't hear it running. You could use a test light to verify that the injectors are firing. I think you are going to have to verify fuel pressure. Maybe your fuel pump is failing?
 
without a port, yes, checking pressure can be tough. :)
scanner on datastream, or as said, a T put inline, probably easiest at the disconnect.
or, if you have someone with you, remove the filler cap and have a listen at the filler for the pump when it's not starting.
don't remember the years the fuel pump control modules came in, but they can be a problem as well.
an intermittent thing like this can be crank sensor too.

but i would think that if the crank sensor was bad, it wouldn't even run at all, even with starter fluid, since the coils wouldn't be firing without a signal.
do you have a cam sensor? try unplugging that. see what happens then. they cause occasional problems like this.
 
hrmwrm said:
...
do you have a cam sensor? ...
Click to expand...

There are two cam sensors on his 2nd gen. A problem with either would generate a DTC. I wouldn't mess with those connectors. They are a bit of a pain to get to, and the plastic latches may break when disturbed (brittle with age and heat).
 
Update on no start when hot issue : ... Finally got a chance to work a little on the LS this past weekend. There is power at the injectors with ignition on. ( I was suspicious there would be none, when it doesn't want to start, but was proven wrong ) . A buddy of mine insisted I change the fuel filter, even though I changed it when I first got the car a little over a year ago, and surprisingly to me, there was brownish fuel, and a few small bits and pieces that came out. So, I'm glad I changed it. Thought that it might have solved the problem as well, because the car acted normally in the driveway . Ran it at idle for a good 10 mins, with the temp gauge at normal operating temperature, shut it down, and the car restarted fine, every time. I was happy. Then, after a 20 minute round trip, sadly, the problem is still there. Although, oddly , it seems to restart with less down-time now with the new filter. ( it could be my imagination though lol ) ....Any way, it seems to me, we're on the right track....in my mind, maybe the fuel pump is failing ? Should I throw a fuel pump at it, and hope that cures it? Should I go to a mechanic and see if he can pressure-test the fuel pump? The darn thing runs so great, otherwise. I'm stumped. If you suggest a fuel pump, what would be your choice to purchase a replacement one...are there ones you would stay away from? I'm sure one from Ford would be costly, but if that's what you'd suggest, so be it. Thank You All for your input, it is greatly appreciated. While we're at it, the car has 106000miles, and I'm sure I'm going to need COP's, and plugs soon. They are likely original. (not too sure). What brand, and who to purchase from would be great to know, as well. Thank You again !!

Kevin.
 
If your one year old filter was that dirty, I would wonder about the filters in the fuel tank. It's probably worth the effort to pull the modules up and have a look. There should be a filter sock on the inlets of each. You can clean those. Reportedly on at least some LSes, there is also an in-line fuel filter in the module after the pump. If you have one, it might be a part of the problem.
 
Thank You, Joegr...I will check those out next time I get a chance. I think that would be a good thing to do anyway for a 12 year old car .
Thanks ,
Kevin.
 
Hello All...a quick update, just started up working on the Lincoln again ...I am 99 % sure its the fuel pump. ( not transfer pump) One strange thing is, when the weather here got hotter, it wouldn't start until late evening / early morning. And, I hadn't even driven it. Now, it doesn't start at all. I picked up a Delphi Fuel Module from Rock Auto for about $200.00. I hope it works out. I'll post back, and let you know if it works ! Thanks !
 
Hello, and Happy Labor Day to Everyone...…..well, I installed the new pump, Car started and ran great for one drive cycle. Pulled it in the driveway, waited 10-15 seconds, would not restart. Hasn't started since. I'm really stumped. Tried gas pedal 1/2 way down, no luck....inertia switch was not tripped...O well...back to the drawing board. Just thought I'd post an unfortunate update. :mad:
 
You really need to measure voltage at the pump when this is happening. Measure between the Green/orange wire and the Black/red wire and see what the voltage is. It has to be between the two wires (black probe on one, and red probe on the other).
This will quickly tell if the fuel pump relay and the REM are good or if the problem is with one of them.
 
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