• Sign Up! To view all forums and unlock additional cool features

    Welcome to the #1 Fiesta ST Forum and Fiesta ST community dedicated to Fiesta ST owners and enthusiasts. Register for an account, it's free and it's easy, so don't hesitate to join the Fiesta ST Forum today!

My Car Dies

Messages
18
Likes
7
Location
Medina
#1
Okay FiST Nation, I have a 2015 Ford Fiesta ST with 94,000 miles and I am now experiencing issues.

The issue I am having is that my car dies when it's running. When it dies, the engine just keeps cranking but rarely ever turns over. When it turns over, it just dies again.

I have had the fuel pump replaced and it's still experiencing the same issues. I have had my reputable mechanic look at it as well as two very good ford master techs look at it and they hook up their computer with a special computer system and nothing shows up on their end. I took the tune off of it and shortly after, she started running again pretty well with a few hiccups but nothing terrible. After driving it a few hundred miles, I have decided to put the Cobb Stage 2 tune back on it and ran it for the rest of that day. When I got safely home with no hiccups, I parked it and went inside for an hour or so. I got back into my car and it started up fine. Backing it up down my driveway and it died again. I went to start it back up and it just kept cranking.

My question is: if it is the tune that is messing this up, how do I make sure that it won't happen again. What do I need to replace in order for it to be running 100%. Any help will be much appreciated. Thank you everyone and I love this car community!!
 


Hypergram

1000 Post Club
Premium Account
Messages
1,195
Likes
710
Location
Orlando, FL, USA
#2
Okay FiST Nation, I have a 2015 Ford Fiesta ST with 94,000 miles and I am now experiencing issues.

The issue I am having is that my car dies when it's running. When it dies, the engine just keeps cranking but rarely ever turns over. When it turns over, it just dies again.

I have had the fuel pump replaced and it's still experiencing the same issues. I have had my reputable mechanic look at it as well as two very good ford master techs look at it and they hook up their computer with a special computer system and nothing shows up on their end. I took the tune off of it and shortly after, she started running again pretty well with a few hiccups but nothing terrible. After driving it a few hundred miles, I have decided to put the Cobb Stage 2 tune back on it and ran it for the rest of that day. When I got safely home with no hiccups, I parked it and went inside for an hour or so. I got back into my car and it started up fine. Backing it up down my driveway and it died again. I went to start it back up and it just kept cranking.

My question is: if it is the tune that is messing this up, how do I make sure that it won't happen again. What do I need to replace in order for it to be running 100%. Any help will be much appreciated. Thank you everyone and I love this car community!!
If it is the tune that is causing the issue (and nothing mechanical), I would suggest just flashing a different tune. The Cobb OTS tunes are known to be pretty garbage in comparison to a canned or pro tune from a reputable tuner, like stratified or dizzy. If it is something mechanical then if I had to make a guess it could be something to do with the spark, or possibly the injectors? Not really too sure though.
 


Woods247

1000 Post Club
Premium Account
Messages
1,206
Likes
1,257
Location
Atl
#4
Check your battery voltage after it sits overnight. When is the last time you replaced it?
 


kivnul

Senior Member
Messages
973
Likes
476
Location
Deer Park, WA
#6
I am no mechanic. As there are 4 injectors I doubt they are a problem as all 4 wouldn't intermittently fail at once. I don't think this car has a fuel filter. Did you replace the High or Low pressure fuel pump? I would take a look at whichever one you did not replace. I would also flush the fuel lines if possible as you may have some sort of debris that plugs things up at just the right / wrong time. Once things settle, fuel can flow again. I do not know how to diagnose spark beyond pulling a plug when it wont start and check it against the block.

EDIT: As Woods mentioned, checking the wires to / from the battery & ground wire would be warranted as well.
 


Messages
235
Likes
199
Location
Metro Detroit
#7
Go back to the basics. A gasoline engine needs 3 things to run, Air, Fuel, and Spark.

Basic test for Air is to put a piece of paper against the exhaust outlet and see if it move while cranking. If no movement in the paper suspect a busted timing belt.

To test for Fuel that is dead simple. Crank the engine for a minute or two and smell the exhaust. No smell of gas means no Fuel.

Test for spark is also simple. Remove a plug, ground the threads, and crank the engine. Suggest wearing heavy gloves when doing this or you may get a jolt.

Once you determine that you do have Air, Fuel, and Spark what you have left is the computer/programming. If you are certain that the car runs perfectly on the OEM Tune the only thing left is the tune that is causing issues. I would suggest that you call whoever wrote your tune and talk to them. I would also suggest using your Accessport and write down any codes that are showing.
 


OP
BenSanta
Messages
18
Likes
7
Location
Medina
Thread Starter #8
If it is the tune that is causing the issue (and nothing mechanical), I would suggest just flashing a different tune. The Cobb OTS tunes are known to be pretty garbage in comparison to a canned or pro tune from a reputable tuner, like stratified or dizzy. If it is something mechanical then if I had to make a guess it could be something to do with the spark, or possibly the injectors? Not really too sure though.
I have a feeling its the tune but I have no clue. I started it up yesterday and started up fine. I also took the tune off of it and drove it and no problems whatsoever. If it is something mechanical, I replaced the spark plugs, no changes. Thank you for the advice tho!! I'll keep an eye on those things and hopefully come to the solution.
 


OP
BenSanta
Messages
18
Likes
7
Location
Medina
Thread Starter #11
I am no mechanic. As there are 4 injectors I doubt they are a problem as all 4 wouldn't intermittently fail at once. I don't think this car has a fuel filter. Did you replace the High or Low pressure fuel pump? I would take a look at whichever one you did not replace. I would also flush the fuel lines if possible as you may have some sort of debris that plugs things up at just the right / wrong time. Once things settle, fuel can flow again. I do not know how to diagnose spark beyond pulling a plug when it wont start and check it against the block.

EDIT: As Woods mentioned, checking the wires to / from the battery & ground wire would be warranted as well.
I had the high pressure fuel pump replaced. I had my mechanic look at the low pressure and he said it was working great. The high pressure fuel pump NEEDED to be replaced. And the we flushed the fuel line.
 


JDG

1000 Post Club
Premium Account
Messages
1,639
Likes
1,491
Location
Conshohocken, PA
#12
On my access port, but not on my dashboard. It just says fuel pressure low and engine cranking. I had the fuel pump replaced and still throwing the code
The codes on your accessport originate from the ECU. Post up the codes here and we may be able to help. Just because your check engine light is not on doesn't mean there aren't any stored codes.
 


Clint Beastwood

2000 Post Club
Messages
2,105
Likes
1,558
Location
Laguna beach
#13
havent had mine long enough to need to investigate, but does the fist have a replaceable fuel filter? if yours is gunked up or you have sediment in your tank it could intermittently block the filter and hold the gunk there, then when the vacuum dies down the particulate drops off and allows it to run fine again. This is a pain in the ass to troubleshoot, and the reason I always put clear in-line fuel filters on motorcycles I don't ride often.
 


kivnul

Senior Member
Messages
973
Likes
476
Location
Deer Park, WA
#14
I believe the fuel filter is integrated with the pump in the tank. Supposed to last the life of the vehicle.
 


Ford ST

2000 Post Club
Messages
2,187
Likes
1,874
Location
Pleasant Garden
#17
There was a thread that's well over a year old were someone was having a similar issue. Maybe worth searching for. I believe at the end the fix was the fuel pressure sensors. Don't remember which ones.

Sent from my LG-LS997 using Tapatalk
 


Messages
968
Likes
334
Location
Houston
#18
I have a feeling its the tune but I have no clue. I started it up yesterday and started up fine. I also took the tune off of it and drove it and no problems whatsoever. If it is something mechanical, I replaced the spark plugs, no changes. Thank you for the advice tho!! I'll keep an eye on those things and hopefully come to the solution.
I wouldn’t be too quick to blame it on the tune. For starters, I have been using Cobb OTS tunes for several years on my 2015 FiST (80k miles) and haven’t experienced any issues. Cobb, if anything, doesn’t make the tunes aggressive - for obvious reasons. Further, the tune would not be expected to act out intermittently - it is, after all, simply a bunch of 1s and 0s.

My money is on some kind of electrical or mechanical malfunction. Alternator? Check your spark plugs and cables. You may still have a bad pump, even though you had it replaced recently.
 


Intuit

2000 Post Club
Messages
2,209
Likes
823
Location
South West Ohio
#19
@maestromaestro - Agreed. Less aggressive typically (though not always) means less likely to result with running issues.
There was a thread that's well over a year old were someone was having a similar issue. Maybe worth searching for. I believe at the end the fix was the fuel pressure sensors. Don't remember which ones.
This was my thought as well.
https://www.fiestastforum.com/threa...d-stalling-in-idle-no-codes.17239/post-312133

Also, it would be unusual for an engine to stall and not have some code to pull prior to switching the ignition off.
 




Top