2008 Ford Focus undetectable intermittent start problem

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  #1  
Old 12-24-16, 12:54 PM
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2008 Ford Focus undetectable intermittent start problem

Hi guys,

Just opened an account here after looking at a few threads which are similar to my problem.

I really need all the input i can get and any will be massively appreciated.

This car has cost me a lot of money over the last year, nearly its whole value. Apart from seeking possible fixes from you I'd also like to know what you would do if it was your car, would you get rid of it or keep trying to fix?


So here are the details of the car to start with.
- 2008 Ford Focus Style 1.6
- Petrol
- Automatic
- 30,000 miles on the clock

Short version of whats wrong with the car and important notes:
- Mostly heat related starting problem
- The car drives perfectly
- The ECU is not the problem
- Disconnecting the ECT sensor will get the car to start almost 99% reliably although rough starting and sometimes starting then stalling out immediately will occur sometimes.
- ECT sensor has been replaced
- Crank sensor has been replaced
- No fault codes ever found
- Taken to three garages, one being the main Ford dealer.
- All wire connections from the ECU have been checked.
- Grounds have been checked.
- It has been confirmed by Ford that the fuel injectors are not getting a signal to work when not starting/cranking.

Here is some in depth detail about the problem:
The car is in pristine condition, it has never had a days problem until about 18 months ago.
One day it wouldn't start. After cranking many times and waiting for a while it started and nothing much was thought of it.
Month after month the problem became worse and worse. At first it only occurred when the engine was hot. Now it will happen when it has been sitting for a while and completely cold although it is definitely heat related since when the car warms up to operating temperature it is impossible to start unless you wait for it to cool down, or it just magically decides to start.
When this problem became quite bad about 8 - 9 months ago I decided to take it to a garage.

The garage said they had checked everything which of course might not be entirely true and after about 3 -4 weeks of diagnosis and such they deemed the ECU to be the culprit, they sent the ECU off to a testing company and it came back as not being faulty. Long story short the problem persisted and the ECU was sent off 3 more times after being received back each time having not fixed the starting problem.
Now they had actually said that they confirmed the fuel injectors were not getting a signal to open when the car was cranking.

After the last time they got the ECU back they gave up on the car and told me i needed to get rid of it because they had done everything they could.

I decided to take the car to another garage after this.
This garage immediately changed the crank sensor and of course the problem was still there.
After this I was getting very annoyed and decided to look at the car myself.
I don't know much about cars but I am handy with electrics so I started doing some online research.
After some messing around I found that disconnecting the ECT sensor will get the car to start perfectly 99% of the time with occasional rough starting and starting then stalling straight away, having found this I took the car back to the second garage and asked them to replace the ECT sensor. They did so and the problem was still there.

After this failed I lost faith in garages and decided to get an autoelectrition to look at the car. He spent about 12-15 hours on the car and gave up, he actually had a ford ECU that was compatible with my car and swapped them over to check whether its the ECU or not and surely enough the problem was still there.

I thought I'd try one more thing which was to take it to an official Ford dealer and get them to look at it. This proved to be no use as they looked at it for two weeks and gave up again. However they also confirmed that there was no signal to the fuel injectors when the car wasn't starting.


Thank you very much for helping!
 
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  #2  
Old 12-24-16, 01:17 PM
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Welcome to the forums from the UK.

You should put non-US in your bio.

I'm assuming the model of car is similar to what we have here.
I don't see what the ECT (temperature sensor) could have on the fuel injector power.

When testing there are a lot of measurements that can help in the diagnosis. Like.....
1) is the 5v (?) logic power supply failing to the ECT sensor ?
2) is the primary power getting to the injectors but not the switched power ?
3) does this car have a factory alarm system or chipped key ?

A factory alarm and anti-theft system kills the injectors when in armed state.
 
  #3  
Old 12-24-16, 01:44 PM
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Thank you for your reply!

I have put I'm from the UK in my profile now.

The answer to your questions are as follows:
1. No the ECT sensor circuit is fine, this was all checked in front of me by an autoelectrition so I'm sure on that. Also when the car does start when the ECT sensor is in everything works as normal, the temperature gauge will gradually rise as it should after a few minutes of driving.
2. Unfortunately I'm not 100% sure on this. I'm guessing it would be the switched power judging by what I've been told by the Ford mechanic.
3. Yes it does have a factory alarm and a chipped key.
 
  #4  
Old 12-24-16, 03:54 PM
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Every PCM circuit is different but there are steady state voltages that do not change. One is a regulated voltage sent to many sensors.

The chipped key is an interesting item to follow. As I mentioned... a key mismatch or problem will usually shut the injectors down. Usually if that's a problem.... the security light will be on.

I'll try to find some wiring info on that system.
 
  #5  
Old 12-24-16, 10:15 PM
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I personally love these kind of issues. (my Job). wish i could actually have a physical hand on the car. my guess would be an issue with the 5 volt reference that goes to certain sensors.
 
  #6  
Old 12-25-16, 07:35 AM
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I hate to sound cold, but rid of that car. At 30 000 miles it's already an exercise in repairs and ghost issues and more will come. It's Ford. Fix Or Repair Daily.
Folks here know me. I shall not take Ford even if it's free and I am paid to accept it.
Sorry. You actually asked for it:

I'd also like to know what you would do if it was your car, would you get rid of it or keep trying to fix?
Rid and never look back. Unless it's a re-badged Mazda with Ford logo, just stay away from that brand.
 
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Old 12-25-16, 07:38 AM
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  #8  
Old 12-25-16, 02:55 PM
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It's a 2008 ukrbyk, so neither of those listings apply, do they? It's also a UK car, which may be quite different and have it's own sets of problems or improvements.

Joe, have you looked at this page...Ford Focus 2008 - Car Review | Honest John. You know your car better than any of us, you may be able to look through the good/bad section and pick something out that fits. I did notice that there was an issue with corrosion of the fuse box due to the A/C cooled glovebox, which led to module failures and faults.
 
  #9  
Old 12-26-16, 09:20 AM
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The immobiliser definitely isn't stopping the car from starting as all has been tested and the light isn't flashing when cranking.

I would appreciate that very much if you could find any wiring info. I've tried a fair amount to get some diagrams and general information but have unfortunately not been successful!

Thank you for your input PJ!
 
  #10  
Old 12-26-16, 09:28 AM
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Thanks for your input ukrbyk.
I respect your opinion and you may certainly be right.
For better or for worse I'm the type of person that wants to get to the bottom of things and I think It would be a shame to get rid of it if the problem is as simple as a dodgy wire or sensor or something along those lines that the mechanics I've dealt with have missed.
 
  #11  
Old 12-26-16, 09:35 AM
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Thanks GunGuy I'll definitely take a look through there ASAP!

On my model the glove isn't cooled so definitely not that one. Thanks for pointing that out anyway
 
  #12  
Old 12-26-16, 09:37 AM
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That's not the problem. Problem is, Ford product is prone to all kinds of issues. Electrical or not. You fix it here - something else breaks there. Fix that - new problem arrives.
Unless you really want to become a good versatile mechanic, you do not keep those car and do not buy them. This is actually how I became a decent one - off 87 Ford Taurus.
Also, that said, you'd be absolutely best going to dedicated Focus forum or two and asking there. No disrespect to all who is trying to help you here. But ghost electirc issues with Fords are best served by Ford community.
I actually witnessed a neighbor once trying to investigate ghost electric issue on Ford Festiva. Man must have been a hell of masochist going through all the relays and fusible links and connections.
 
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