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View Full Version : Juddering / hesitation/- F7pt



James5
17-02-2016, 10:46
Ok I have struck a bit of an issue with my F7pt let me give you all a little story and see if we can help work out the cause.

Just over a week ago my F7pt was working perfectly fine other than a rather noisey fuel pump, did a few journeys to and from work without fault and no thrashing parked it up and went to use the car couple day's later and the car is juddering hesitating sounds occasionally as though running on 3.

So without even looking (as no time) I ordered all new - Bosch 044 pump, Alloy racing fuel filter, new fuel line from sender to pump, new spark plug BKR8EIX re-gapped these to .6, changing all the above made no difference. I checked fuel pressure was ok and it's sitting nicely @43.5psi, I can rev it and it hold this fine. I even removed the fuel rail and put the fuel system under 43.5psi of pressure and it holds with no leaks from anywhere.

I swapped the TDC sensor for one of a working clio 172 sport I have and that made no difference. I swapped HT leads for spares I had and in fact made it worse.

I checked the engine timing was all still aligned and that 100% fine, I then thought I will do a comp test and all cylinders were pretty much identical across all 4 (within 1+/-psi difference).

I am currently awaiting a new dizzy cap, another throttle body with working TPS and brand new VR crank sensor from Scoff.

What are other peoples thoughts

Trevhib
17-02-2016, 10:58
Blocked/broken injector or coil pack?

James5
17-02-2016, 12:05
Blocked/broken injector or coil pack?

Trev Good call on blocked injector, I've not tested injectors to see if spraying I will do that, I am still on dizzy cap but I did try and install my wasted spark setup to eliminate the ignition pack and it still does it but always had issues with wasted due to using Renault crank sensor need VR version(on order). (Back to dizzy at present).

Trevhib
17-02-2016, 12:14
Oh yeah, u have a dizzy and ht leads to sparkplugs in this set-up, which means no coil packs. Apols :o

But yeah, injectors worth a look :) :agree:

Trevhib
17-02-2016, 12:26
Btw, how do you actually check injector operation, flow rate and spray pattern? :confused:

James5
17-02-2016, 19:15
Btw, how do you actually check injector operation, flow rate and spray pattern? :confused:

The only thing I won't be able to check is the flow rate, But spray pattern they mist and I can activate them via the ECU to check

Trevhib
18-02-2016, 11:08
spray pattern they mist and I can activate them via the ECU to check

V cool :cool:

James5
18-02-2016, 11:14
Just to update this for anyone else after Trev suggested I test the Injectors it forced me to look at the ECU file to which I then found that the ECU file was badly corrupted, I uploaded a previous backup I had and hey presto the car worked. Not to sure what has caused the file to become corrupt though, I have noticed my cold start needs sorting again but that's not a problem just time to sort that but car run's fine.

Trevhib
18-02-2016, 11:38
Good news mate. :smokin:

Is all this done on a laptop then? What's the ECU file? The map or something else? I have no clue with EFI stuff. Mind you, I have no clue about carb stuff either :wasntme:

Alex
18-02-2016, 13:29
Bloody computers. At least you don't have to get your hands dirty!

James5
18-02-2016, 14:31
Good news mate. :smokin:

Is all this done on a laptop then? What's the ECU file? The map or something else? I have no clue with EFI stuff. Mind you, I have no clue about carb stuff either :wasntme:


Yeah all done via the Laptop / netbook, the ecu file contains the tuned map aswell but also has the other setting's for all other components within the file, the map is the tuning section for fuel and ignition which is a major part but their is so much more in the complete ECU file to be done.


Bloody computers. At least you don't have to get your hands dirty!

Well you say that I still replaced fuel pump, filter, fuel line, spark plugs, dizzy cap & rota, and TDC sensor. To which I am about to replace the TDC sensor with one of Scoffs VR sensor's as I have the completed wasted spark setup to install I might aswell make use of it really.

R5MJH
18-02-2016, 14:43
mikes wasted runs std 5 tdc sensor jim.

James5
18-02-2016, 14:47
mikes wasted runs std 5 tdc sensor jim.

I know mate, when I go wasted it never seems to work high rev's, maybe I should fit all I have to yours to make sure it all works leads and all

michael tierney
18-02-2016, 21:05
HI James.....which part of the file was corrupted was it the trigger settings or the map ect?

James5
18-02-2016, 21:16
HI James.....which part of the file was corrupted was it the trigger settings or the map ect?

Fuel map pic I took of it yesterday not sure why it's 0 cells. The ignition map was also in same condition :crap: no wonder it would start do what it was doing