surging flat stick first gear auto

[HARMFUL 81]

has anyone had this before. On a full spirited run in auto, the car surges (momentarily looses power, and then it returns again) at the top end of the rev range. Could this be related to a starvation of fuel due to the filter being blocked?
incedently i have just had a carbon clean and gearbox service done on this car.

[adrian k]

My XR8 did that when the tank was less than 1/2 full. i heard it was an issue with a batch of fuel pumps, so i took the car back to Ford and they replaced it with a high flow pump (which was the fix apparently) and problem gone. they were spewing cos it cost them over $2000 to fix, probably more than they made on the car when they sold it to me...

[HARMFUL 81]

i appreciate the response adrian. The only problem i have is that before the servicing it wasnt doing it at all. Im starting to think that maybe the flow has increased due to the carbon clean and hence not enough fuel. Anyone got any different ideas?

[The Monty]

Its called a rev limiter.

[HARMFUL 81]

hehe, good one. Unfortunately its a lot lower then when the rev limiter should kick in - dont know exactly, but does it from approximately 3500 and upwards

[The Monty]

Ok, its NOT the rev limiter then, lol.
Have you tried plugs and leads, or cleaning your airfilter. All these could do what you suggest is happening.

[5.0 ED]

fuel pump or fuel filter will cause this.

[HARMFUL 81]

Thanks for the responses so far. Over the weekend i replaced the fuel filter, being a relatively cheap part and that it needed replacing any how, but the surging still remains. I have also noticed that on a cold start, idling at traffic lights, it would skip every 10-15 seconds. When it warms up, it only seems to be under harder then average acceleration. I was wondering if anyone else would either support the diagnosis so for or have anything else to add. Im trying to pinpoint the problem, cause i have a feeling if i cantact ford directly they will beat around the bush and have me replace half the car first if they could. I am leaning towards swapping the fuel pump over, but i would want to be quite certain it would fix it. Over the weekend i was thinking maybe a set of leads wouldnt go astray, but i see this as quite unrelated to the probelem which seems to have occured after a carbon clean by the Ford workshop.

[HARMFUL 81]

How do you check if the fuel pump is cactus? Ive rung ford and they are playing the innocent bystanders, sugesting to bring the car in for a computer hookup and diagnos from there for a mere $90.
Any help here would be useful - its getting frustrating
The cars been super reliable to now, one of the reasons i havent touched it, now you think you do the right thing and get it serviced by ford and it develops a problem.

[burnz]

check cam shaft for worn lobes.

[HARMFUL 81]

Originally Posted by burnz

check cam shaft for worn lobes.

I realise their could be a ,million and one reasons for the surging as described before. I just find it coincidental that this has developed after a carbon clean. This is why for now i am limiting my efforts to the fuel delivery system for the moment.

Ill throw some ideas at people, feel free to knock them down as you see fit.
1. Fuel pump and filter. The increase in flow is larger due to cleaner injectors, causing the supply to run out earlier, casusinga starvation.
2. Dislodged crap blocking the so called cleaned system
3.Tuning - due to the increased flow of the 'carbon free' system, the fuel air mixture is upset causing an inbalance and surging at higher revs.

Please let us know your thoughts.

[Stav]

What sort of fuel system cleaner was used?

[HARMFUL 81]

i have no idea what the local ford workshop uses. I have since come across pages on fuel pressure regulator. Maybe this could be the cause. Seems to be placed in the right area - could be affected by carbon clean.

[RG]

I have the fix for this, it's easy and free.

Remove fuel pump carrier from tank, grab a hold of fuel pump and turn 180 degrees so that the pick up sock is facing the complete opposite direction that it was. Reinstall fuel pump and your problem will magically disappear. That is unless your fuel pump is stuffed.

There is a fault in the design of the AU tank which allows the fuel to splash back away from the pick up with mid to low fuel levels. It was most noticeable on the XR8 and T series cars and this was an official Ford fix, mine suffered the same issue and after I did this it was fine.

[HARMFUL 81]

Thanks for both your responses Stav and Russell.
Logically, what would you say is the most likely cause? wouldnt you think it would be something close to the area worked on by ford? It seems to me the fuel pump is too isolated from the injection system for it to be affected by the clean... My money at the moment is on the regulator, but ill have to see this evening.

[Stav]

Ford remove the fuel lines at the front of the car on the passengers side firewall.This is where they inject the cleaner.They use the quick fit connectors.Did you ever think that they have not been reinstaled properly and leak at high speed? Failing that get the injectors removed to be checked. One other thing...the fuel regulator has an internal fuel filter.It is a green plastic with metal meshing..

[HARMFUL 81]

Yes stav i was aware of the internal fuel filter of the fuel regulator, i was actually just reading up about it. Turns out you can open it up and clean that out - i intend to have a go at that this evening. as for the leaking fuel, i havent actually checked to be honest - that wouldnt hurt either.

[HARMFUL 81]

I am happy to announce that the problem has been fixed. I took of the Fuel pressure regulator and cleaned out sediment in there and reassembled. problem gone. Have found the throttle body to be fairly dirty so thats the next thing, but for now im stoked with this simple fix. Cheers for your information guys.

[shazaam]

nice work, well done for finding the solution :

[HARMFUL 81]

Well, the problems still there unfortunately, i jumped the gun thinking it was fixed. Ive cleaned the FPR with vastly improved results, however it isnt totally gone. Im thinking that its been detroyed by the Carbon Clean and needs replacing. im contemplating getting new leads for it too, as well as maybe an intector removal and clean. See if that fixes it totally

[burnz]

the injector have micro fine filter them self.
if all else fails possably a reverse flush of the injector when removed from the throttle body.

[HARMFUL 81]

Ive had another thought.
What affect does a collapsed cat have on a car?
How do you work out if it is gone?

[burnz]

Originally Posted by HARMFUL 81

Ive had another thought.
What affect does a collapsed cat have on a car?
How do you work out if it is gone?

bit of a coincident, but yes it will do the what you are experiencing.
same if the wool dislodge in the resi.

[HARMFUL 81]

what leads me to think of the cat is a number of reasons

1. there seems to be a lose of power that never seemed to be that noticable from 0-3000rpm
2. would the crap they flush through the system for a carbon clean not be detrimental to the operation of the cat?

[HARMFUL 81]

any more thoughts guys- im hoping to slove this coming weekend if at all possible.

OK i will try to explain the symptoms.
Start the car - all fine, idles ok, revs ok in neutral, maybe a hint of bogging down, but that could just be me.
Put the car into gear - thats fine, slow speed acceleration to reverse out of drive way all ok. Select drive once your on the road and take off normally and you would think all things are like they supposed to be.
However, at our place we are on a low point of the road, so we would accelerate harder then normal getting up the hill. And that is where you notice it. I would say anything from 50% acceleration upwards form 2500-4000rpm (approximately) and there is a surging (car slows and speeds up again momentarily - fluctuating). above 4000 the car seems to be fine.
I have tried numerous things to rectify it - firstly replaced the fuel filter.
i have taken out the FPR and cleaned the mesh - the first time there was a fair bit of crap there, and things improved quite dramatically when i put it back in - although it wasnt eliminated.
I have cleaned the TB and the idle controller on top and the air filter - no change
I have since cleaned the FPR a few more times, and last night i took out the injectors and sprayed them with a bit of carby cleaner. At the same time i have ceared out the fuel rail up to the quick connectors under the passengers side firewall. for a while there it actually was worse, but now is back to the original condition.
I have also reset the computer - no change.
So what do you recomend to be next?? I have 4 areas i assume it could be:
1. fuel pump
2. replace FPR
3. remove and service injectors
4. Cat convertor

any help would be appreciated.

[SIKSIX]

I have had simular problems and found that one of my leads wasn't plugged in properly.i fixed it on friday and went away for the weekend done 500k's and so far so good.

[HARMFUL 81]

For the second time now - i can tell you that the problem is sorted. On the W/E i replaced the fuel rail along with new injectors and a new fuel pressure regulator, so that was eliminated. I removed the tank and inspected the furel pump , but it all seemed to be in order so i reinstalled it. These things combined only made the problem worse. Then i replaced the leads on the car - and hey presto - problem gone. Oh how sweet it is to drive with a smooth power delivery. Testing the old leads found lead No. 4 to be faulty.
The car now runs better then it did before the problem, so im reaallly stoked.