Out of Idea's HELP NEEDED PLEASE....

[AU00XR8]

Hi All,
I have AU2 XR8 200kw. I have a problem at about 3000rpm. The car feel's like someone is holding it back it surges and shubbers. At 4000rpm it stops and takes off like someone has kicked it. This only happens when the motor is warm. From cold it is lovely it revs happily till redline through all gears.

No mechanic has been able to sort it. I have replaced spark plugs, leads, alternator, fuel filter and now the coil packs. Still there and the wallet is alot lighter.

Has anyone ever had this problem.

Thanks

[b2tf]

Try starting the car and unplugging the MAF - if it runs no different with the MAF unplugged it could be stuffed.

Also check the air temp sensor is plugged into the bottom side of the intake pipe at the bend before the throttle body. It sounds like an odd problem you're having but if you can eliminate a few things and be sure it is getting air, fuel and spark, you should be a lot closer to finding it.

[EvilChief]

since u r saying that problem only occurs once car is hot, id start with coolant temp sensor. did any of your mechanics scan teh ecu for codes? or did a live data stream of all its sensors?

as said above hesitations often point towards AFM problems, but not always, once again ecu scan and live data can be the key here

[sly]

Other things you could try... a dyno run to check the AFR's... reset the PCM.

[MNM96]

Originally Posted by AU00XR8

Hi All,
I have AU2 XR8 200kw. I have a problem at about 3000rpm. The car feel's like someone is holding it back it surges and shubbers. At 4000rpm it stops and takes off like someone has kicked it. This only happens when the motor is warm. From cold it is lovely it revs happily till redline through all gears.

No mechanic has been able to sort it. I have replaced spark plugs, leads, alternator, fuel filter and now the coil packs. Still there and the wallet is alot lighter.

Has anyone ever had this problem.

Thanks

Fuel Pump, Fuel Pump and Fuel Pump!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1 Okay!

[AU00XR8]

Where do i find the MAF???

[RG]

Originally Posted by AU00XR8

Where do i find the MAF???

It is what connects to the airbox. Metal housing with a black box on the side of it, passenger side front corner of the bay.

[AU00XR8]

Okay i will try that tonight. But i rang Brad Garlic ford today. They said leads and spark plugs which have already been done. He said he thinks it could be a valve spring??

[Punnisher_42]

Originally Posted by AU00XR8

Okay i will try that tonight. But i rang Brad Garlic ford today. They said leads and spark plugs which have already been done. He said he thinks it could be a valve spring??

There's your problem - why would you take it to a ford dealership of all places!

As if they'd know anything about a ford... :

[howesy]

Originally Posted by MNM96

Fuel Pump, Fuel Pump and Fuel Pump!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1 Okay!

Have to agree with the fuel pressure principle I would check the fuel pressure through the rev range it could even be regulator but If the pressure turns out to be dropping it would likely be pump. If pressure good all the way through then look else where but having had valve spring probs 3 times before I would be surprised if thats your problem as a broken one gives a miss all the way through and a weak one tends to keep stuffing up once it gets to the revs that cause bounce.

Anyway keep us posted will be interested to see what it is.

[MNM96]

Originally Posted by AU00XR8

Okay i will try that tonight. But i rang Brad Garlic ford today. They said leads and spark plugs which have already been done. He said he thinks it could be a valve spring??

Thats it, the broken valve spring works ok till it gets hot!

Did I mention

Fuel Pump, Fuel Pump or Fuel Pump!

I got sick of throwing money after everything, plugs, leads, coil pack, Pyro probe, filters. Even had Ford check out pressures. Car went like normal from cold, but no power at low revs when hot. Like you needed to push it to take off. Put a fuel pump in and smoked the back tyres the full length of the... um never mind! Made me realise that it was down on power when cold also, just not as bad.

Mike

[AU00XR8]

It doesn't feel like its lacking power if anything it feels better than ever(that would have something to do with all the parts i have replaced). Im at a loss its been too 3 mechanics who all stood around scatching themselfs saying that it is a strange one.

[sly]

What's cheap to check?

1. MAF (as above)
2. Catalytic converter... if it's flanged, drop it & look to see if it's blocked... x2 I suppose for a V8. That was a big part of my AU 6's lazy low-rev performance problems.
3. Get the ECU scanned for error codes ($60 - $90)
4. Fuel pump (NFI, maybe $100 or less if you can self-fit). If you have a vacc/pressure gauge you should be able to check the fuel pressure yourself. If so, do this before 3 above.
5. Dyno run to check AFR's ($60 - $70 perhaps)

Beats paying a mechanic to scratch your, errr his, balls!

[EvilChief]

$140 for a wallbro gss342, direct replacement

[AU00XR8]

Okay have unplugged the MAF and the car ran like a pig so i am guessing it is not that. I put it into another mechanic who like all the other one's has no idea. It is not giving any error codes or that is what they are telling me anyway.

[MNM96]

Fuel Pump!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!

[autickfordfairmont]

Sounds very similar to mine (except I'm 2 cylinders less than you). Mine does what you have described above, and my fuel pump isnt that old (although they can go pretty quick. Strange thing with mine is when on LPG it doesn't do it (so points towards fuel system) however if I reset the computer (disconnect the battery over night), then it runs perfect for about a week or so then starts doing it again. Mine was overheating when it would do it, but that was fixed with a coolant flush & change and new thermostat. Im still searching with mine, I have replaced Leads, plugs, cleaned air filter, cleaned throttle body and ISC, general service. At the moment I have other bills to pay and need tyres etc etc etc, so the searching is on hold for a while. Hope you figure it out soon.

Cheers
Col.

[FGII-XR6]

Originally Posted by MNM96

Fuel Pump!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!

so are you trying to tell us it's the fuel pump????????????????????

[MNM96]

Originally Posted by au3xr6

so are you trying to tell us it's the fuel pump????????????????????

Hard to pass a hint around here!

[mik]

if every thing checks out can you unbolt the cat/cats and see how it runs with no back pressure? do you have lpg?

[bodes-sh]

on another thought, have you been able to go to anyone with a scantool and take it for a spin with that hooked up? mainly to check engine readings, just to see what the ecu is seeing from the motor...

[au2sw]

forget fuel pump...itd do it right through rev range. not just drop out at mid range then kick in at high revs. im going with the cats and or o2 sensors.however, it doesnt take long for these items to heat up and if you have time to drive while the motor is cold and there is no problem....unlikely to be exhaust. but as you have tried everything else, it is possible. definitly go to Ford and get them to check ALL codes for you. they will be the only ones who will have the programmes for the entire ECU. other scantools will get the main items like has been suggested in here, but for more deeper problems, "public" scantools wont pick it up. i know we have had to send some cars to dealers to get hard codes checked out as our scantool wont read them.
good luck

[MNM96]

Originally Posted by au2sw

forget fuel pump...itd do it right through rev range. not just drop out at mid range then kick in at high revs. im going with the cats and or o2 sensors.however, it doesnt take long for these items to heat up and if you have time to drive while the motor is cold and there is no problem....unlikely to be exhaust. but as you have tried everything else, it is possible. definitly go to Ford and get them to check ALL codes for you. they will be the only ones who will have the programmes for the entire ECU. other scantools will get the main items like has been suggested in here, but for more deeper problems, "public" scantools wont pick it up. i know we have had to send some cars to dealers to get hard codes checked out as our scantool wont read them.
good luck

I had the exact same symptoms, replaced the exact same parts, only to find it was the fuel pump. Admittedly, my car is a six, but the likeness of symptoms is uncanny!
Ford had the car for 2 days, found an old inactive Coil Pack code, but nothing else. this led me to replace a coil pack which was in perfect working order. (if you were to search 'threads started by me', you will find I gave the spare coil pack away to a member here) A shop with a scantool didn't find the coil code. another shop was requested to carry out a fuel pressure test. Another shop carried out a Carbon Clean. Add up the costs. $150 for plugs, $200 for CC, $80 for Coil Pack, $60 for Leads, $80 for Pyro. Filters, etc, + labour costs when used. Exhaust and Cat where less than 12 months, so I was confident they were ok.
Ford had replaced the Throttle Body, as the Idle Sensor was shot, and they couldn't undo it. I was starting to worry it was the problem, then a rep came into work with a specials list, with a fuel pump on it. Ordered one, fitted it, drama gone!

Mike

[AU00XR8]

Okay, HINT takin and i will order a fuel pump. Now the question is what type would we go with??? Since i am getting one may as well get a nice, one that will handle a few extra KW's as next year i want to put a stroker kit in it.

[AU00XR8]

Hey was just reading another post -xr8 220kw cuts out in 1st- and one of the post talks about the cam sensor????? Where is this and can i do it myself???? The squel that he talks about makes me thing that as mine make a squel as well???

[Stav]

The problem sounds to me that the ego sensors to ecu ..or ecu reading of the ego sensors may have an issue. Have you reset the ecu?

[AU00XR8]

Yes i took power off the ECU overnight. Have also check the MAF. The squel is the thing that got me and everyone who has put there 2cents in.

[Stav]

Squel?

[au2sw]

sque A l
i think he means

[AU00XR8]

sorry yes Squeal shouldn't of been drink typing....