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Timing XF EFI, what could the problem be?

16K views 40 replies 6 participants last post by  atec77  
#1 ·
Today I set the timing on my xf, and it was out massively, mainly due to a place who put a new distributor in a while ago, and no nothing about cars, now I set the timing, as no.1 top dead centre etc, etc, and have the line at 8 degrees, everything has been checked, now the car runs a lot, lot smoother, idles properly (before the timing it ran really, really rough) now the problem is there is a massive lack of power, it crawls along, and has no power at all, does anyone know whayt control the timing advance on these efi's? I know the ECU has part, but there is no vacum advance on these, thats what I am guessing is causing this problem, the advance, but what controls it from the distributor? the hall effect?

and by the way the engine overheats too, so for some reason the firing is in retard, even though the engine is defenetly on the right mark.

Please help me!
 
#3 ·
yeah right said:
First things first. Have you established that TDC on the crank pully is in fact TDC on the pistons? Balancers slip. Secondly, have you timed it with the green connector to distributor disconnected and at the correct idle speed?
thanks for the reply yeah right ;-)

the thing does not like to idle at the correct idle speed,

today we had another look, and to be honest the whole thing is fu<ked, we line it 8 degrees with the V mark on the pulley, and it runs like a dog, no power at all, gutless, and secondly there is two white marks, someone previously has obviously put a white mark, and tried to time, it, yet its no where near the v, we have put the timing to both the marks, it runs, but its advanced, rough idle, and its no where near the V mark, however it does have power back. and yeah we did disconnect the green spout, it drops the revs, is this normal?


is it possible someone has put a new pulley in (timing case off etc.) and then broken off the key so they dont have to line it up, and pushed the new pulley in, so the timing mark is incorrect?

i didnt think u had to time the engine to the absoulte correct idle, in the manual, it mentions doing the idle after u have done the timing....
 
#4 ·
Disconnecting the green spout will drop the revs slightly because the advance drops back to base timing.

Do you know how to verify the TDC mark using an old plug & a metal rod, because it sounds like that's what's happened.

The biggest problem with the EFI motors is the need for them to have airtight crankbases. It pisses me off lol. The slightest air leak will cause it to run like a dog. Even the dipstick has to be a good seal.
 
#5 ·
It is possible to install the distributer out of phase with the crank and still get it to fit and bolt on. I think it is also possible to rearrange the plug leads so that they all fit and the engine sorta runs. To check it quickly:

- There should be a mark on the distributor casing which correlates to the number 1 cylinder's firing point. Turn the motor until the rotor lines up with this (best as possible).

- Look on the distributor cap, find which plug lead the rotor is pointing to now and trace this lead. If its the number 1 cylinder thats good (cylinder at the front of the motor nearest the fan.) If its another cylinder, someones pulled something on you.

- Finally check that the mark on the main pulley approxamately lines up with TDC on the timing cover (will not be perfect, could be a few degrees either way).

If thats all good the distributor has most likely been installed correctly.

If your timing with a strobe light still fails and your willing try this:

- Mark where your distributor is now so it can be returned to that timing position.

- Loosen the retainer bolt.

- Set the ECU or whatever to set the base timing.

- Start the motor.

- Turn the distributor (left or right) until the engine revs increase.

- Fiddling around with the position, find the spot where the engine idles nice and consistantly, no splutter and especially no racing. (and not too low of course).

- Do up the retainer bolt, and set ECU for normal.

- Give it a gentle test drive and see if it makes a difference.

- If its dodgy, return it to its original position.

Ive used this *freehand* timing on my moke many times, since the timing marks are practically inacessable. It works a treat when you get to know the pitch of the motor well.

Hope this is of some help!
 
#6 ·
Do you know how to verify the TDC mark using an old plug & a metal rod, because it sounds like that's what's happened
How do i do that? I have never heard of this method before? will it give an accurate method of making sure of TDC, without the aid of a timing light? I think I have been screwed here, I think your right, the harmonic balancer has slipped? Im not sure how it is possible, but for some reason I just know that may have happened if it is possible?

81foXDwagon what do you mean set the ECU to the timing, I cant do anything to the ecu. its only basic computer the xf efi ones.
 
#7 ·
I used an old spark plug & knocked the insulator ceramic out. Get a round bar that fits snugly through the hole in the centre. Screw the empty plug into the plug hole. Turn the engine over until it's over halfway to TDC then push the rod down the hole in the plug until it touches the piston top. Mark that position on the crankpulley. Then turn the motor the opposite direction by hand until the piston touches the rod again. Mark that position on the pulley. Mid way between those 2 marks on the pulley is TDC, so measure the distance with a flexible tape (like a dressmakers one) & mark the true TDC with a paintpen. I found it useful to do it with a cold engine, and hold the rod inside the broken plug with blue tac.
 
#8 ·
Just take your spanner with you for a drive and keep advancing it till it pings then back it off a bit. Best way to get the most power.
Make sure it's at full operating temp tho.
And you may find it will ping on the hot days, then run premium gold in her.
 
#11 ·
the only way to do it properly might be for me to change the entire pulley over, put it in correctly, this means taking off the timing cover, which in turns means getting off the damn viscous fan, is it hard to do? ithis way when i put it in, with that little key thing, it can go in only one way- the right way...

this really is a delema, who knows what damage I have done to the engine, I have been driving it like this for 9 months+ could I have caused any damage, e.g. the valve partially opened when it fires, hence the timing being off? there hasnt been any signs of this however, fingers crossed.

EAO worm is that the best method? have u done it before? what should i accelerate too?
 
#12 ·
what if I just advance the timing to what I think is acceptable? if I just advance it, see what power gains I can get, and if there is no pinging/detonation, just keep it?
Is this safe to do? what damage can I do if I advance it too much?
i know people advance to get some power gains, so maybe i should just do this, go past the manufacturors specifications is safe right?
 
#13 ·
Yeah sure,do it all the time. Even my NH pajero kept pinging when set to factory settings so I just took it for a drive and adjusted it after every squirt of the gas utill it was right. Just keep advancing it till you start loosing power or it starts pinging. Don't worry about damage you may have done to your engine in the past, the XF engine is pretty robust.
I have to ask tho....why did you check the timing in the 1st place?
The reason I ask is we had an XF company car at work and there was no way we could get it to idle smooth unless we retarded the timing, but then it was gutless and wouldn't pull ya outa bed. It ended up having a stuffed camshaft. It had a few lobes that where worn. Fitted a new camshaft and it was like a new engine.
Does yours rev good or does it flutter around 4,500rpm?
Hope Ive helped not confused more.
 
#14 ·
nah the beast purrs like a tiger, runs hard through all rpm's, she just has a shocking idle, and I know for sure that its the timing, as when we retarded it, she smoothed out and it ran like a dream, its just had no power, and i mean none! couldnt get above 60km/h for ages!

the reason we checked the timing is because a auto place fitted a new distributor, as the car had some ignition problems (its all fixed) but the car runs really rough, in idle especially, it never had these problems, but the timing is defentely off, and 99.9% most likely the problem of the rough idle.

if the car had camshaft problems, then she would run like a dog through all rpm's whether in idle or not.
 
#17 ·
Yeah, I would be doubtfull that the timing was causing rough idle.
A worn camshaft would still run smooth thru the rpm but could be rough at idle. Just look at a car with a big cam, runs like a dog at idle but revs harder.
Not saying it's the camshaft for sure as a vacuum leak would certinately cause rough idle as would bad plugs or leads, dirty injectors or a lack of compression ie: burnt valve etc.
I would start with the vacuum test then a compression test. They are a no cost test and a good place to start.
 
#19 ·
There's lots of places for them to get an air leak. Oil filler cap, dipstick, any of the 3 inlet manifold gaskets, poorly fitted S-tube from the VAF, PCV hose, ISCV hoses, charcoal canister valve faulty & stuck open, heater control vacuum lines. We used to find vacuum leaks with a handheld gas cylinder with a hose attached. Just point it at all the possible points & wait for the engine revs to climb then you've found it. I'm a bit more aware of my own mortality these days so I prefer to use a vacuum gauge lol
 
#20 ·
thanks for the info;-) I also forgot to mention something which is very important, and may narrow it down, the rough idle only comes into effect when the car has warmed up a bit, say 3-4 mins of warming up, then it starts its little rough idle dancing, and also when I accerlerate, and then slow down it really goes rough, and seems to surge, then returns to the rough idle and stays there, it also would stall, i fixed this by upping the idle a bit, what do you think?
 
#21 ·
What rpm is it idling at now?....and is it auto or man?
How many km's on it. The oxygen sensor should be replaced every 100,000km. They can cause erratic behaviour.
BTW: Is the engine std?
 
#24 ·
There's no oxygen sensor - they're open loop. There is a temperature probe on the VAF box though. And a coolant temperatire sensor on the T connector on the right side (looking from the front) of the head at the front. Don't get that confused with the temperature sender for the gauge - that's much smaller. The crap idle when hot could be as a result of a faulty temperature sensor telling the ECU that the engine's cold when in fact it's hot. But it's unlikely. And the torque convertor wouldn't have anything to do with.
 
#26 ·
All the sensors, which are minimal on an EECIV in any case, are critical to the engine operation. The air temperature one is needed so the ECU can calculate the MASS of air flowing into the engine & adjust the injector pulse width to supply the correct amount of fuel. The coolant temperature sensor when feeding back a cooler engine does the same thing when the engine is cold & increases the pulse width on the ISCV to act as a fast idle. Timing has little effect on idle quality - it really only comes into play when the engine is loaded i.e. you try & drive away with a retarded ignition curve & it'll be completely gutless.