XF EFI Surging.

Got a problem.

What I have done.
1. Top overhaul with an exchange recon head with new valves, new valve stem seals etc.
2. New spark plugs
3. New Bosh plug leads
4. Checked timing and set correctly
5. Tried alternate distributor module
6. Tried alternate ECU
7. Checked for vacuum leaks...everywhere
8. Changed to Premium Unleaded.

Problem is that if I put my foot down in 2nd or third gear there is a pronounced surging. If you accelerate "softly" there is no surge. The engine has now done 122K kms.

What do I try next.

Regards

Steve

Just thought - Could the reconditioned head (now suitable for UPL) have been planned and so lifted the compression ratio. I would not have thought that this would be significant?? Is this detonation that is causing the rough running and surging under hard acceleration? Do I need to change the timing? Do I need to have the ECU tuned? Is there ANYONE IN PERTH who is competent with 4.1 EFI's?

Steve

i had a problem with my xf efi a while back. While it does sound slightly different to the problem i was having, it may be worth having a look. The only way i solved (by i, i mean my mechanic) was to replace different sensors one at a time until the problem dissapeared. The cause of my greif was the tfi (thick-film-integrated) module on the side of the distributor. Apparently these are a common fault in these motors as over time they heat and cool down a lot. My xf use to splutter, surge and carry on when the engine was warm. Sometimes it would run fine for a month and then it would happen again. I'm not saying this is your exact problem, but it may be worthwhile considering. It caused me about 6 months of greif and around $2500 of replacing fuel pumps, fuel pressure regulators etc. Anyway good luck, and if you want to know anything else about the problems i had with my xf, feel free to ask!

Check two things:
* Make sure that you have ample fuel pressure, EFI needs lots.
* Check the cam lobes arent worn... although this usually causes popping through the inlet...

Check two things:
* Make sure that you have ample fuel pressure, EFI needs lots.
* Check the cam lobes arent worn... although this usually causes popping through the inlet...


.... Cam lobes are great - next to no wear.

FUEL PRESSURE - now that somthing I did not think of. Anyone know what the output pressure of an XF pump should be. I have a gauge and could rig it up on the output of the pump.

By the way - cost me $400 for an """EXPERT""" to tell me he could not find and faults and that there was nothing wrong......."except that it surges like hell when you put your foot down"


Steve.

Hey,

There is a fuel filter under there. Never been changed from new and done 122K kms. I wonder if that could be the culprit......

Steve

Could very likely be the culprit, they're cheap enough to replace, like $30 or something. No offence man but I can't beleive you let some guy charge you $400 to hook your car up to his computer. That's like 20 minutes of work, the Ford dealership charged me about $120 which was a rip off. "All we found was a dodgy battery terminal".... literally 2 minutes down the road the thing was sh**ing itself again!

sounds like the fuel filter to me as well, my old xf done that but it got to the point where the thing wouldnt pull over 3000 rpm ideling was still good and if i feed the exelerator in slowly it was fine but it would surge under heavy exeleration, this happened over two days so i gave it a new filter then every think was fine, also i have had webber carby models that have had simalar problems from having like a crusty fuel build up in the tank

Thank you all for your comment.

First changed the fuel filter. This did very little to reduce the surging under acceleration. Next put in a new fuel pump and that has solved all the problems.

Steve

Hey. Every time I think I have the problem solved the problem comes back again.......

What I had done previously.
1. Top overhaul with an exchange recon head with new valves, new valve stem seals etc.
2. New spark plugs
3. New Bosh plug leads
4. Checked timing and set correctly
5. Tried alternate distributor module
6. Tried alternate ECU
7. Checked for vacuum leaks...everywhere
8. Changed to Premium Unleaded.

PLUS now I have........

9. New fuel filter fitted.
10. New Fuel pump fitted.
11. Exchange recon distributor fitted (with new module).
12. New distributor cap.
13. New rotor.
14. Drained and flushed out fuel tank and new fuel added. Disconnected all fuel lines and blew out with compressed air.

Now it is running on 5 cylinders. The only thing that can be causing the problem is injectors - Right - Huh - Right.

H - E - L - P

XFSteve

To check your injectors disconnect one at a time with the motor running if the rpm drops the injector is working if the motor runs the same with an injector disconnected then that injectors stuffed.

I wished my ZL would surge when I put my foot down

wish i could get my ZL STARTED for once!!!!11

PROBLEM EVENTUALLY FOUND

There is a section of fuel hose 30mm long INSIDE the petrol tank between the rigid suction side pipe and the fuel sensor module. This hose had gone very soft... There was no restriction in blowing back through the hose and petrol ran out of the pipe. At idle the pump was putting out 250kpa and 2l/m flow rate which is the specification for the XF EFI. Once the car was in motion the movement of the fuel caused either the sensor module or the fuel hose inside of the tank to move a smal amount. This caused the hose to collaps and with the suction of the pump block off the fuel supply either fully or partially. If blocked fully the engine just stopped and would immediatly restart. If partially blocked, the output pressure of the pump would drop to about 100ish kpa which would be below the minimum required by 1 or 2 of the injectors so the engine would run rough on 5 or 4 cylinders. Stopping the engine and restarting would restore the engine to full running power. The use of a fuel pressure AND flow manometer was required while driving to find this problem. There was no way of finding the problem stationary. In 35 years of working on Fords this was the first time I could not diagnose a problem the first time round or the second, or the third..... The cost in replacing all of the above was close on $600 for a 50cent piece of hose......... Did 100kms yesterday and no problems at all. We are now a happy XF Falcon driver again.

XFSteve

Good to hear, hope it has fixed the problem for good. Just remember if it has tits or tyres you've got problems.