Diesel engine mechanic question

Submitted: Sunday, Oct 06, 2013 at 20:31
ThreadID: 104611 Views:2193 Replies:5 FollowUps:14
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My daughter has a Peugeot 307 diesel , has an annoying intermitant fault . Once or twice each week it will start , run for 2-3 seconds and then stop . After a few more times it wont fire at all . Try again in about 1 hour and it starts and runs fine . Seems to happen when hot ,,,maybe? About 1 month ago auto elec put new fuel pressure sensor which seemed to fix it but now its playing up again . Took it to Peugeot dealer and guess what .... its started fine every time they try it
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Reply By: Ron N - Sunday, Oct 06, 2013 at 20:56

Sunday, Oct 06, 2013 at 20:56
Stevo - I found this following Pommy site a mine of information about European car problems.


Your daughters car could have a faulty connector in the wiring harness somewhere, or an intake hose that is sucking flat, or it could be just an intermittent electronic fault in a sensor, or the ECM.

The worst part of electronic faults is that they have to be faulting, to be found.
If the fault ceases and the chip starts to work again, there's no way to find it.
Working when cold and ceasing to work when hot are generally symptoms of an intermittent electrical fault in a silicon chip.

I'm presuming there's no fault code being picked up with an OBD reader, and no warning lights coming on?

Cheers - Ron.
AnswerID: 519293

Follow Up By: Member - Stevo_62 - Sunday, Oct 06, 2013 at 21:02

Sunday, Oct 06, 2013 at 21:02
Thanks for that Ron , yes whenever they hook it up to scan gauge doesnt show any faults
FollowupID: 799329

Follow Up By: Member - Keith P (NSW) - Sunday, Oct 06, 2013 at 21:27

Sunday, Oct 06, 2013 at 21:27
Sorry to be pedantic here folks...but being old school and learning the hard way ...I would check the basics first..IE...fuel filter and screens...fuel pump ...fuel cap (for a vacuum block)...and think back to maybe sumthin that was done /changed to cause it ...before charging headlong into the techno gobbley gook that these vehicles are so sweetly endowed with now.

Cheers Keith
Nothin is ever the same once I own it ...........

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FollowupID: 799332

Follow Up By: Ross M - Sunday, Oct 06, 2013 at 21:33

Sunday, Oct 06, 2013 at 21:33
Sounds like a crank angle sensor fault. Most are Hall Effect units and they don't like heat and can fail on many vehicles.

See if you can locate the crank angle sensor or any which are also cam sensors and pour cold/freezy cold water over them. If it then runs after not wanting to run, you may be lucky and have found the problem ie offending item. Buy a replacement and fit it.

Cold water makes Crummydoors go again until they heat up.

Water is cheap, just because it is European there is no need for Evian bottled water, the chilled tap stuff will do.
Chilled wine or beer will also be ok if water isn't available.
Ross M
FollowupID: 799333

Follow Up By: Ron N - Sunday, Oct 06, 2013 at 22:58

Sunday, Oct 06, 2013 at 22:58
I've got a mate with a tilt tray, and he tells me when you get a call from someone crying out, "my car's stopped! - it just stopped dead and won't go!" - you NEVER try to start anything with a likely ECM fault in it, when you get to the car.

The reason being - if he gets out to the job, and the car has cooled down - 9 times out of 10, it will fire right up again, if he attempt to start it!

So, if he does this, the client says, "Oh, you got it going again! Thanks very much! - and they hop in and drive off! - and there goes his job! (waa-aah)

SO .. he gets to the car, winches it straight on, takes it to where the clients requests .. then when he gets there, he starts the car up and drives it off!! LOL
FollowupID: 799338

Follow Up By: Ross M - Sunday, Oct 06, 2013 at 23:14

Sunday, Oct 06, 2013 at 23:14
Unethical people with tilt trays? or Ungrateful owners?
Neither tried to rectify the problem, just caused another one as well.
FollowupID: 799339

Follow Up By: Ron N - Sunday, Oct 06, 2013 at 23:42

Sunday, Oct 06, 2013 at 23:42
No, the basis of the whole problem is - there's still an intermittent electrical fault in the car - and we all know how hard they are to track down.
So my tilt tray mate has done what was requested - and it's up to the owner/mechanic to find the fault when it appears again.
The problem is trying to replicate the precise conditions under which the fault appears.
FollowupID: 799343

Follow Up By: olcoolone - Sunday, Oct 06, 2013 at 23:46

Sunday, Oct 06, 2013 at 23:46
Ron I think your mate is very smart...... time is money and with most newer vehicles trying to find a fault is like finding a needle in a hay stack...... with a bit of luck thrown in.

The other thing is more damage can be caused or more time taken to rectify the problem..... costing the customer more money.

And toweys and roadside assist people are not there to fix a fault, just make a decision.

20 years ago you could nut out the fault quickly, these days we have a 15 minute rule, if you can find the fault with in 15 minutes by doing all the normal checks (scanning, voltage, wriggling, hitting, pulling, looking, feeling) then you seek more information like wiring diagrams and diagnostic procedures.

These days systems are becoming more integrated and a little thing can cause a big problem.

Trying to find the cause of the problem with the Peugeot is anyones guess...... could be immobiliser, ecu may not be detecting the key, faulty wiring, faulty part, bad battery,, faulty alternator, water in something (ecu or module), blown globe, loose connector and the list goes on.

FollowupID: 799344

Reply By: Herbal - Monday, Oct 07, 2013 at 07:53

Monday, Oct 07, 2013 at 07:53
That sounds very much like a relay. Fuel pump relay or engine relay.

As a new fuel pressure sensor seemed to fix it, I would suggest the fuel pump relay. The thing is that most of the time when tested the relay will look OK and so the auto elec or mechanic will not find any thing wrong. These relays do not give a ECU error code.
AnswerID: 519301

Follow Up By: Member - Stevo_62 - Monday, Oct 07, 2013 at 09:59

Monday, Oct 07, 2013 at 09:59
Thanks for that , will get it checked out
FollowupID: 799354

Reply By: gbc - Monday, Oct 07, 2013 at 08:06

Monday, Oct 07, 2013 at 08:06
We had a very similar scenario with one of our CRD fleet utes. No fault code, nowhere to start looking. Google helped and we changed out the suction control valve which fixed the problem.
Good luck finding your problem.
AnswerID: 519302

Follow Up By: Ron N - Monday, Oct 07, 2013 at 12:12

Monday, Oct 07, 2013 at 12:12
I had a new EA Falcon Ghia in 1990 with Climate Control. Dial up the temperature and the microprocessor in the dash and about a dozen sensors keep it all at the set temperature.
The CC stopped working at 19500kms, just inside warranty. Took it into the Ford dealer and the service manager told me about how fantastic all this new electronic technology was.

All I had to do, he said, was press a number of the control buttons on the CC control panel, simultaneously and in the right sequence - and the fabulous and clever little microprocessor changed from controlling the temperature in the cabin, to a diagnostic tool!

Once the test sequence buttons were pressed, the MP divided the circuitry up into 10 separate sections, tested each one for a fault, found the fault, and produced the fault code on the screen!

"Great!", says I, "let me see it in action!" So the manager presses all the buttons simultaneously in correct sequence - and the dash screen comes up with - "No Error".

I said - "That can't be right. The CC isn't working, it's that simple! There's a fault in there somewhere".
The SM was crestfallen and admitted he'd have to put the car into the shop and do further testing. 4 hours later, when I return, he says, "We found the fault! It was a dirty fuse on the A/C compressor!"

"Great!", I said - "But why didn't the MP find it?" He shrugged and said he couldn't understand why it didn't - it might have been because it was an intermittent fault that wasn't there when the MP went into self-test mode.

I took the car away. Another 4 hrs later, the CC stops working again. Pressed the buttons on the dash - "No Error" was still the message. Back to the Ford dealer, and more head scratching. Into the shop, for more intensive fault-finding.

Next day I get a call, it's right to go.
When I pick it up, I say to the SM, "What did you find wrong?". He says, "the microprocessor in the dash had totally failed!
The microprocessor can find faults in the system - but it can't tell you when it has failed itself!"

Then came the kicker - "Geez, it's lucky you got this new MP under warranty! They're $940 list price as a part! (this was 1990, remember, when the AU$ bought more).
"And you know, as I do", I said - "that there's a total of $25 worth of silicon chips in there!"
"Yeah, you're probably right", he says. "What I do know, is that the MP is unrepairable. We had another one pack up a few months ago, and the car belonged to an electrical engineer. He asked for the old MP to see if he could figure out how it worked, and how it was built, and if he could fix it.
He came back a fortnight later and said he'd opened it up, had basically figured it all out - but there was a silicon chip control unit in the middle of it, that was stamped 'VDO' - and VDO would give him no info on what was in that control unit - and it was not available as a separate part!"
FollowupID: 799364

Follow Up By: olcoolone - Monday, Oct 07, 2013 at 12:44

Monday, Oct 07, 2013 at 12:44
Ron there are companies who repair control module and ECU's for automotive.



Regarding VDO and not giving information, most manufacturers like Bosch, Delphi, VDO, Denso and others own the proprietary rights to the coding and design, the auto companies purchases a licenses to use the product; passing it onto the vehicle purchaser.

So all you ABS, cruise control, traction control, stability control fitted to you vehicle you don't own....... much the same a Microsoft and the Windows platform...... you only have the right to use it.

OBD and OBD2 were developed for the USA market for emission control diagnostic, and then you have enhanced OBD that monitors other critical systems in the vehicle like ABS, HVAC......
FollowupID: 799367

Follow Up By: Ron N - Monday, Oct 07, 2013 at 13:26

Monday, Oct 07, 2013 at 13:26
Olcoolone, that's interesting. With the drive to make everything less repairable - and with low production costs of new items continually killing the labour cost input required to overhaul/repair faulty items - I'm amazed that any company can even find a market in repairing electronic components today.

I'd hazard a guess they can, purely only because of the massive mark-up on parts prices.
I've been informed that car manufacturers actually make very little profit out of manufacturing a new vehicle - it's the enormous income stream from the high-profit margin parts, over the 20 yr life of the vehicle, that keeps them going.
FollowupID: 799369

Follow Up By: Herbal - Monday, Oct 07, 2013 at 15:19

Monday, Oct 07, 2013 at 15:19
I just renewed my CV boots on my Magna...There was some confusion about the correct part number. So I got a quote from Mits in order to get the correct part number...$251.10 per side = $114.14 per boot + GST.

Repco...$14 each and that includes grease and clips and GST.

$502.20 for OEM compared to $56 from Repco...and Repco are making a profit !!!
FollowupID: 799380

Follow Up By: olcoolone - Monday, Oct 07, 2013 at 18:02

Monday, Oct 07, 2013 at 18:02
Most vehicle manufacturers will make a lot more profits from spare parts then selling vehicles, profits that the car manufactures make a quite small in the scheme of things...... maybe 20%, but on parts they can make in excess of 1000%.

Electronics are cheap to make but expensive to buy if you're the end user.

At one of the many training courses I have been too was a guy from Air International, he made a comment about a control module that Holdens sell for $1300 and is common over a range of Commodores, they went in with a sell price to Holdens of $68.00....... Holdens said it was too much and they went off shore for it.

When you look at the savings over a manufacturing life of a certain model vehicle, a saving of only a few dollars can relate to 100's of thousands if not millions $$$$$$...... so saving a few dollars here and there is a big thing.

FollowupID: 799400

Reply By: Member - Roundie (N.S.W.) - Monday, Oct 07, 2013 at 18:21

Monday, Oct 07, 2013 at 18:21
We have a Peugeot 307 that had exactly the same symptoms that your daughters vehicle. The problem persisted for several months until the offending part totally failed. It was a defective EGR valve. Sit down before you get the cost of replacement. Hope this helps
AnswerID: 519336

Follow Up By: Herbal - Monday, Oct 07, 2013 at 19:07

Monday, Oct 07, 2013 at 19:07
Sorry to say mate...Sounds like you have been had !

If a mechanic told you it was the EGR, then don't use them again !

All an EGR does is allow exhaust gas to be sent back to be burnt a second time. If your EGR completely failed, the result would more likely be that the engine would run better as it would have clean air rather than an air/exhaust mix.

EGR very rarely fail. Which has some barring as to the cost...They rarely sell them !

Chances are, they found a simple 'pull out plug in' fault and didn't want to tell you that it only cost $10 to fix !

When anything ever goes wrong, also talk to an expert first...An expert is the enthusiast (check spelling)....
FollowupID: 799402

Reply By: Eric Experience - Monday, Oct 07, 2013 at 21:11

Monday, Oct 07, 2013 at 21:11
The most likely part is the cam angle sensor, The sensor has to be buried in the cam cover because its function is to tell the computer which cycle the motor is on by looking at the cam position.because of its position it gets very hot after the motor is switched of. The crank angle sensor is on the bell housing and does not get as hot so last longer. You can test the cam angle sensor by cooling it and the motor will start. Eric
AnswerID: 519343

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