SPACK

XF EFI Fuel problem?

99 posts in this topic

Having a problem with my 87 XF EFI ENGINE. It starts, idles, but just a little rich. Will REV, However as you drive the car, and accelerate it carries on like crap, it does not want to go. 

Fuel pump is OK..Pressure is OK

Changed the FM and the EEC1V, As a matter of fact, the car will run, WITHOUT the AFM...At a lost where to look now, new plugs, new leads. It just sends A LOT of fuel in ...Any help would be appreciated..The ENGINE is perfect...TFI Is OK...Why would it be sending so much fuel in under LOAD/ACCELERATION??

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Fuel injector leak...?????

Bit of crap stuck in a pintel keeping it open be my guess.

Set of fuel injectors rekitted is cheap.

Or the fuel reg has a broken diaphram... or a broken vac line to it.

Making it think it's at wide open throttle

 

Try those.

 

 

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roKWiz and SPACK like this

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If you do disconnect the afm and it makes no difference to how it idels/revs, then I would start there. Should have a 5v, earth, signal from r the afm and 2 other wres that are air temp sensor. From memory... It's been a while.

SPACK, Outback Jack and deankdx like this

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Also, check water temp sensor, its the 3 wire one that feeds the ECU. NOT the single wire one in the front of the head.

I've Had one of them shit itself before and it caused the exact symptoms you described. 

It can be tested by checking it's range using a multimeter set to resistence and putting it boiling and ice water and recording that result.l and comparing to known values. I should still have the values recorded somewhere from mine if you get that far.

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how cold does the engine run? if it has no thermostat, a stuck open thermostat or locked up clutch fan it might be running rich for that reason?

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I'd be thinking it has to be related to the ECU or the AFM.

The XF EFI system needs info from the AFM to run properly, and definitely to drive.
From memory they will idle with AFM unplugged but not drive with load.

Could be a wiring issue between the AFM and ECU?

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Well hopefully its the AFM, as i have a spare one..As far as i know all the wiring has been checked, by an auto Elec..

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When my temperature sensor shut itself I took it to 3 mechanics before one of them was switched on enough to replace the coolant temp sensor and fix the car. This was back in the day when I was a young fella and had no idea what I was doing.

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Given the AFM to the mechanic, and some of your ideas here. He has already checked the water temp sensor and the thermostat. ALL good. He did think it could be crap in the injectors....but is worried why the car stays the same when the AFM IS UNPLUGGED COMPLETELY OR even with just the wires off..

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Afm has like a trap door inside that can jam shut. Have alook at that.

Have u checked spark. Have they actually confirmed it getting to much fuel? (Wet plugs). People love to jump to conclusions and miss the basics. 

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Have given the MECHANIC an S-PAC AFM that I had sitting for the last 5 years..so will see how that goes, THEN, might check the INJECTORS, to see if they are operating OK...

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If it is a sticky injector then only a single cylinder will be over fueling,simple check of the spark plugs will show if something is wrong in this manner. If all spark plugs are identical, it will be issue caused by control.

 

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When the mechanic got the car and managed to start it, it was running so rich the whole of the shop was awash in black sooty smoke, all the plugs had to be changed as they were completely black.

Outback Jack likes this

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Have you changed that air flow meter? Its something like that.

Injector leaks dont do that as stated above.

Grab a plug.... get out of the shed and put a lighter to it.
Catches fire... fuel.
If not maybe with thick black smoke maybe you are somehow sucking oil into the intake... oily plugs will be hard to get goin.
Sure the mechanic will sort it.


Sent from my GT-S7583T using Tapatalk

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A lot of the wiring, done by the restorers, putting the ENGINE back in was wrong..IE, The negative earth was wired to a positive output, the EEC-1V WIRES TO THE DISSY WAS just about to drop off, wires was S-T-R-E-T-C-H-E-D to fit, had to be re wired properly, the TIMING was RETARDED, 6 DEGREES btdc..The mechanic will let me know if the new AFM i have given him, is the problem on tuesday...

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A lot of the wiring, done by the restorers, putting the ENGINE back in was wrong..IE, The negative earth was wired to a positive output, the EEC-1V WIRES TO THE DISSY WAS just about to drop off, wires was S-T-R-E-T-C-H-E-D to fit, had to be re wired properly, the TIMING was RETARDED, 6 DEGREES btdc..The mechanic will let me know if the new AFM i have given him, is the problem on tuesday...
Good stuff mate.
Glad you found the problems.

Sent from my GT-S7583T using Tapatalk

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Just wondered if, when they changed the computer, they got the right one, ONE FOR A MANUAL .....?? I mean it starts, idles, drives...just will not ACCELERATE..

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6 hours ago, SPACK said:
Just wondered if, when they changed the computer, they got the right one, ONE FOR A MANUAL .....?? I mean it starts, idles, drives...just will not ACCELERATE..

Doesn't matter what gearbox for the computer.
@Panko swapped his XF Ghia from auto to manual years ago and still has the original auto computer. I'm not even sure there was a different computer for gearbox for EFI. There is for EST but that's completely different


But, there ARE different computers for leaded fuel (pre 86, black lid airbox), and unleaded (post 86, blue lid airbox)

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With s p o u t wire connected and a timing light on cylinder 1 does timing advance as RPM increases?

 

With spout disconnected and engine at idle timing Tribute in degrees but feel free to wind a couple extra into it.

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could it be your dizzy? 

i had a similar issue that took me forever to find. i replaced ignition module, fuel pump, fuel injectors, filters, tried another ECU, everything seemed to help but never stopped it. I finally tried another dizzy, and bam it was gone. 

sent mine in for rebuild, and the hall effects sensor had shit itself inside the dizzy. 

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the mechanic reckons its driving on the TORQUE ALONE,,,That is why i thought the COMPUTER MIGHT be a AUTO ONE..

 

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