Help Solve a Mystery! - Page 2

BAGT514 · 30-06-2011, 11:31 PM

Another cheap look would be the hotwire sensor on you Mass Air Flow meter. We found when using K&N filters - over oiling the filter would leave a residue over the hot wire sensor and make the car run bad until the O2 sensors heated up and started working properly. When the car starts up is runs on the strategy tune acording to the MAF sensor, ACT sensor & TPS sensor but as it warms up it uses the HEGO sensors to work out it's final tune.
As a cheap try - spray the hotwire sensor in the MAF with some carbyclean but make sure you hose it off reasonably quickly. Carby clean can be very agressive. Hope it works for you.

Cruise control can be affected by your brake light switch or if it is a manual the clutch switch. If you have no brake lights you loose your cruise.

Shane

P6LTD351 · 30-06-2011, 11:38 PM

Are there people here that take offense to the term "grease monkey?"
Political Correctness gone mad.

BAGT514 · 30-06-2011, 11:54 PM

The more I think about it the more it sounds like your MAF sensor is a dud. Full throttle is controlled by HEGO - start, idle & light throttle has more to do with the MAF & strategy tune.

damo76 · 01-07-2011, 12:21 AM

Inspect distributor cap for cracks and or worn corroded electrodes, mechanics these days tend to overlook the condition of these.
I know because after my 2000 vrx has been serviced a few times the engine was running sick so i took dizzy cap off and all electrodes were corroded away.

Gavin Thomas · 01-07-2011, 12:56 AM

Ok my constructive input into this "mechanical mystery" would be to agree with those that suspect that it may be related to a problem within the fuel system.... I would even narrow the seach right down to say look very closely at the fuel pressure regulator. I have worked on a vehicle with very similar symptoms, and it was quite a long process to solve a relatively simple fault.

The conditions as you have described would be expected if there was a very rich & un-metered fuel induction into the engine. The fault i had ended up being due to a faulty fuel pressure regulator - in that the internal rubber diaphram was not sealing and therefore allowing excessive raw fuel to be forced directly into the inlet manifold. This will give the engine a very, very rich "mixture" at idle & at all throttle positions. It won't be fully burn't & clear out until much higher in the rev range - even almost until WOT. It will also cause hard starting due to flooding - worse when hot.

This problem can be very hard to detect as the fuel pressure will proberly read within specs at all running conditions. Maybe the only sign to pick if you are lucky, would be to see the fuel pressure creep down too quickly on the gauge after a period of time when the engine is switched off. This may not even show at all to any reasonable degree when switched off - due to the lack of vacume from the running engine. ( Which will assist to draw fuel past the faulty diaphram ). It will leak enough to cause a flooded engine on re-start - but not enough to give a 'big' reading drop on the fuel pressure gauge.

Also in regards to the other engine sensors - ie = o2 sensor, TPS, ECT sensor, MAP sensor etc - they can all be disconnected whilst the problem is occuring and if any one of them was causing the fault then you would expect a noticable change in the symptoms. This is because the ECU would revert back to a pre-determined default setting - or limp mode - and therefore without the input from the faulty sensor you would very much expect a noticable change in the running condition. This method in conjunction with a plug in scan tool is a quick and basic diognostic practice that most Mechanics would do at times to help pinpoint a "tricky" or unusual problem.

In the case of un-metered fuel due to an actual "mechanical" fault rather than a sensor fault - it will make very little to no noticeable difference to the poor running symptoms - no matter which sensor/s you disconnect.... And as previously described above in regards to the FPR, it may also prove impossible to see the "mechanical" fault by use of standard testing gauges / tools / equippment, etc, etc. Experience & a good memory is key here,

It can sometimes be easy to over-think a problem & therefore overlook the basics. But it does happen at times to even the best / smartest "grease monkey".

Also as a few others have mentioned, a leaking injector could also cause excess un-metered fuel / rich running etc. This should have been a basic item to have already been checked. Do you know if this has been covered ? Also has the FPR been closely inspected or even replaced ? If not then do so asap - it may well be your fix. ( Also cheap & easy - especially in relation to all the other items that have already been replaced,

). A quick way to check is to pull the vacume line off from the engine side and suck on it to see if you get any fuel drawing thru. Do it straight after shut down & if it's really stuffed then you might get a good drink or taste of fuel,

Good luck & keep us posted with any progress..... Cheers.

Gavin Thomas · 01-07-2011, 01:06 AM

Quote:

Originally Posted by BAGT514

....The more I think about it the more it sounds like your MAF sensor is a dud.....

++++++++++++++++++++++++++++++++++++++++++++++++++

Do the V8's have a MAF sensor ? I thought they might have been the same as the 4.0L six that have a MAP sensor instead of a mass air flow..... It's been a while since i last worked on a EFI Windsor so i can't recall.

In any case i think he has already had most of the sensors replaced ?
( See where the original post says that previous owner has replaced the air flow meter - so maybe not a MAP sensor on the V8's ? ).

Cheers....

Gavin Thomas · 01-07-2011, 01:30 AM

Quote:

Originally Posted by eb2monty

Are there people here that take offense to the term "grease monkey?"
Political Correctness gone mad.

************************************************** ***************

Nothing to do with PC BS mate..... Just about having a little appreciation & respect for those with some hard earned skills in a relatively thankless and average paid profession.... But hey i ain't complaining ---- much.

But mostly it's just about having some fun in taking the pee a little on the www.

So don't worry about your mad political correctness - rather worry more about the present bunch of banana munchers running the show right now as we speak.......

BAGT514 · 01-07-2011, 01:32 AM

Quote:

Originally Posted by Gavin Thomas

++++++++++++++++++++++++++++++++++++++++++++++++++

Do the V8's have a MAF sensor ? I thought they might have been the same as the 4.0L six that have a MAP sensor instead of a mass air flow..... It's been a while since i last worked on a EFI Windsor so i can't recall.

In any case i think he has already had most of the sensors replaced ?
( See where the original post says that previous owner has replaced the air flow meter - so maybe not a MAP sensor on the V8's ? ).

Cheers....

Australian EFI Windsors all use MAF sensors - not MAP

Gavin Thomas · 01-07-2011, 01:57 AM

^^^^^^^ No worries mate - as i said it's been a while since i've worked directly on a EFI Windsor. Also in regards to the suggestion by damo76, do they still have a dizzy - or crank angle sensor & coil packs ?

Also i see your profile of "mechanical supervisor" - are you working in a Ford dealership in the Isa ?

Also in regards to any of the sensors - you would think surely by now that with the amount of mechanics that have looked at the car, one of them would have come across something as basic as a faulty sensor. Either by way of scan tool fault code or current data reading - or even by simply disconnecting, swapping or replacing the suspect sensor. It would seem too simple, basic & common a fault to be overlooked this often by so mant Tec's....

I mean i'm not saying 100% that it's impossible they have missed the basics -but it would still make it a monumental group stuff up if that was the case.

In any case obviously it makes it quite difficult to give a fair diognosis without having access to the vehicle - but i still believe it seems more like a direct fuel problem. Hopefully we will all soon find out the answer.

Cheers.

JC · 01-07-2011, 02:04 AM

Quote:

Originally Posted by Gavin Thomas

Ok my constructive input into this "mechanical mystery" would be to agree with those that suspect that it may be related to a problem within the fuel system.... I would even narrow the seach right down to say look very closely at the fuel pressure regulator. I have worked on a vehicle with very similar symptoms, and it was quite a long process to solve a relatively simple fault.

The conditions as you have described would be expected if there was a very rich & un-metered fuel induction into the engine. The fault i had ended up being due to a faulty fuel pressure regulator - in that the internal rubber diaphram was not sealing and therefore allowing excessive raw fuel to be forced directly into the inlet manifold. This will give the engine a very, very rich "mixture" at idle & at all throttle positions. It won't be fully burn't & clear out until much higher in the rev range - even almost until WOT. It will also cause hard starting due to flooding - worse when hot.

This problem can be very hard to detect as the fuel pressure will proberly read within specs at all running conditions. Maybe the only sign to pick if you are lucky, would be to see the fuel pressure creep down too quickly on the gauge after a period of time when the engine is switched off. This may not even show at all to any reasonable degree when switched off - due to the lack of vacume from the running engine. ( Which will assist to draw fuel past the faulty diaphram ). It will leak enough to cause a flooded engine on re-start - but not enough to give a 'big' reading drop on the fuel pressure gauge.

Also in regards to the other engine sensors - ie = o2 sensor, TPS, ECT sensor, MAP sensor etc - they can all be disconnected whilst the problem is occuring and if any one of them was causing the fault then you would expect a noticable change in the symptoms. This is because the ECU would revert back to a pre-determined default setting - or limp mode - and therefore without the input from the faulty sensor you would very much expect a noticable change in the running condition. This method in conjunction with a plug in scan tool is a quick and basic diognostic practice that most Mechanics would do at times to help pinpoint a "tricky" or unusual problem.

In the case of un-metered fuel due to an actual "mechanical" fault rather than a sensor fault - it will make very little to no noticeable difference to the poor running symptoms - no matter which sensor/s you disconnect.... And as previously described above in regards to the FPR, it may also prove impossible to see the "mechanical" fault by use of standard testing gauges / tools / equippment, etc, etc. Experience & a good memory is key here,

It can sometimes be easy to over-think a problem & therefore overlook the basics. But it does happen at times to even the best / smartest "grease monkey".

Also as a few others have mentioned, a leaking injector could also cause excess un-metered fuel / rich running etc. This should have been a basic item to have already been checked. Do you know if this has been covered ? Also has the FPR been closely inspected or even replaced ? If not then do so asap - it may well be your fix. ( Also cheap & easy - especially in relation to all the other items that have already been replaced,

). A quick way to check is to pull the vacume line off from the engine side and suck on it to see if you get any fuel drawing thru. Do it straight after shut down & if it's really stuffed then you might get a good drink or taste of fuel,

Good luck & keep us posted with any progress..... Cheers.

So fuel in the vac line to the FPR would indicate a dud FPR? If that's the case, then you may just have solved the rich running with my Supercharged EF!!!

sirlc6 · 01-07-2011, 11:19 AM

Quote:

Originally Posted by JC

So fuel in the vac line to the FPR would indicate a dud FPR? If that's the case, then you may just have solved the rich running with my Supercharged EF!!!

Correct any fuel in there and it is cactus.
Paul

superpursuit83 · 01-07-2011, 12:45 PM

I am a grease monkey at home, and when I cant figure it out I go and see my proffesionaly trained mechanic.... I have seen the FPR problem also. But it sounds too easy

StrokedXT · 01-07-2011, 01:21 PM

Quote:

Originally Posted by Gavin Thomas

************************************************** ***************

Nothing to do with PC BS mate..... Just about having a little appreciation & respect for those with some hard earned skills in a relatively thankless and average paid profession.... But hey i ain't complaining ---- much.

But mostly it's just about having some fun in taking the pee a little on the www.

So don't worry about your mad political correctness - rather worry more about the present bunch of banana munchers running the show right now as we speak.......

Ive spent my career in Finance and Insurance, and now big oil, I wish all i had been called was a grease monkey thats a term of endearment in comparison to what i got called.

MAD · 01-07-2011, 01:29 PM

I had a very similar problem that was fixed with a new O2 sensor. It was really strange because the one it replaced wasnt very old anyway, only a few months, but it did indeed fix the problem.

Gav,
I have no problem with you taking a little offence to the OP's use of grease money (that's your perogative) but to then basically go on and say "ha ha, I know the answer but I'm not going to tell you" is massively childish.
If you dont want to give out an answer due to being offended, fine, but dont dangle it out there.
You never had any to begin with, as everybody starts on a level playing field with me, but you are now sitting in deep 'minus' territory in relation to any respect I may have for you.
I hope to never have you respond to any questions I ever ask in future.

JC · 01-07-2011, 05:37 PM

Quote:

Originally Posted by sirlc6

Correct any fuel in there and it is cactus.
Paul

Doh! So I should have posted up in my EF thread that when I disconnected the vac line, fuel came out - here I was thinking it was normal! Doh! Doh! Doh!

LOW_NL · 01-07-2011, 08:46 PM

Quote:

Originally Posted by MAD

I had a very similar problem that was fixed with a new O2 sensor. It was really strange because the one it replaced wasnt very old anyway, only a few months, but it did indeed fix the problem.

Gav,
I have no problem with you taking a little offence to the OP's use of grease money (that's your perogative) but to then basically go on and say "ha ha, I know the answer but I'm not going to tell you" is massively childish.
If you dont want to give out an answer due to being offended, fine, but dont dangle it out there.
You never had any to begin with, as everybody starts on a level playing field with me, but you are now sitting in deep 'minus' territory in relation to any respect I may have for you.
I hope to never have you respond to any questions I ever ask in future.

++++ 1, like ^^^ it.......... nuf said

Gavin Thomas · 01-07-2011, 08:51 PM

Quote:

Originally Posted by MAD

....
Gav,
I have no problem with you taking a little offence to the OP's use of grease money (that's your perogative) but to then basically go on and say "ha ha, I know the answer but I'm not going to tell you" is massively childish.
If you dont want to give out an answer due to being offended, fine, but dont dangle it out there.
You never had any to begin with, as everybody starts on a level playing field with me, but you are now sitting in deep 'minus' territory in relation to any respect I may have for you.
I hope to never have you respond to any questions I ever ask in future.

++++++++++++++++++++++++++++++++++++++++++++++++++

If you or other monkey's want to read into it that seriously than that's your problem mate....

You might get a hint that my post was not in a serious manner by the fact that i took a quote from another member that said " i gave up reading after you said grease monkey"..... but then my post indicates that i did actually read the op's entire post. It was mean't to be taken as a p/take in contradiction, maybe it's hard to get across that "dry" sense of humor in type.
I was always going to give my experienced suggestion / advice to try and help 'ol mate out as i did realize that his remark was made in a innocent way. I was just making light of the previously made post - THAT'S ALL !

So if you want to take things so seriously, then put this in your pipe & smoke it.....

Regardless of the way my post was taken i have better things to do than explain things to people that proberly don't have a sense of humor of any type anyway. Also i don't want or need the respect of banana munchers like you & others here anyway.So Don't lose any sleep about me helping you out with any professional advice in the future mate - as it's not going to happen.

As i was always going to do, i've given my serious input into this thread so i'm done with the B/S side of it. I'll just stay within the classic section cause it's a bit more casual & real over there.

I do honestly hope that EF XR8 has a win with his problem in the very near future - cause i can understand his situation.

You guys can give what ever reply you like, cause i really don't care. I know where i'm at..... and that's all that matters to me.
I'll now await my warning of a possible ban from the mods - oh well such is life.............

Cheers & have a nice day.