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Chasing this flat spot / starting issue in my xr8... 

 

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 Post subject: Chasing this flat spot / starting issue in my xr8...
Posted: Sat Jan 07, 2012 9:09 am 
Getting Side Ways
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Age: 38

Posts: 771

Joined: 20th Nov 2005

Ride: AU XR8 220 Manual

Hi guys,

I have an auto EL XR8 II. I have been cleaning it up since I bought it recently with:

- new plugs/leads/rotor button/dizzy cap
- cleaned MAF and TB out
- set TPS to 0.97
- new air filter and fuel filter (and oil not that that will help this)
- checked timing at 30 degrees
etc

The car has an unusual fault. Before I got the leads and set the TPS it would sometimes start really quickly, ie only crank once or twice then fire and other times (I think only from a cold start) it would have to crank over for 5 seconds or so then it would fire up and wasnt very happy about it.

It would also have a flat spot / hesitation from idle sometimes.

I then changed the leads and set the TPS as well as resetting the ECU and it went away!

Since then the fault has returned so I am now unsure where to go next. I do also think the car is running rich? Just by the exhaust smell and the occassional black exhaust puff under power.

So Im starting to think maybe MAF or coolant temp sensor? But I want the opinion of people with this experience before I start shelling out any cash.

Thanks guys
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Sat Jan 07, 2012 10:11 am 
Parts Gopher
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Age: 43

Posts: 76

Joined: 23rd Jul 2005

Gallery: 2 images

Ride: FBT002

Location: Perth
WA, Australia

how long ago were your O2 sensors changed? They will only last a max of 100K and as they die the engine will run rich.
Also check for any small vacuum leaks.
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Tue Jan 10, 2012 10:23 am 
Getting Side Ways
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Age: 38

Posts: 771

Joined: 20th Nov 2005

Ride: AU XR8 220 Manual

Yeah I will change them, cheap on ebay these days. Would they affect the idle to power setting though? I thought these were all done by ecu maps and the o2 sensors were only for cruising?
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Tue Jan 10, 2012 7:37 pm 
Parts Gopher
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Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

{USERNAME} wrote:
Hi guys,

I have an auto EL XR8 II. I have been cleaning it up since I bought it recently with:

- new plugs/leads/rotor button/dizzy cap
- cleaned MAF and TB out
- set TPS to 0.97
- new air filter and fuel filter (and oil not that that will help this)
- checked timing at 30 degrees
etc

The car has an unusual fault. Before I got the leads and set the TPS it would sometimes start really quickly, ie only crank once or twice then fire and other times (I think only from a cold start) it would have to crank over for 5 seconds or so then it would fire up and wasnt very happy about it.

It would also have a flat spot / hesitation from idle sometimes.

I then changed the leads and set the TPS as well as resetting the ECU and it went away!

Since then the fault has returned so I am now unsure where to go next. I do also think the car is running rich? Just by the exhaust smell and the occassional black exhaust puff under power.

So Im starting to think maybe MAF or coolant temp sensor? But I want the opinion of people with this experience before I start shelling out any cash.

Thanks guys


Mate - My NL Fairlane has a very similar issue. I've done exactly what you have done too as listed.
Even replaced the O2 Sensors. It's helped but still a slight flat spot and stutter on acceleration. It's doesn't annoy me that much, because I know how to drive her, but still it's not right. I've even replaced the MAF as when the engine was on LPG it backfired many times and blew the guts out of it. :roll:

I had an on-car injection service done a while back which also helped, but I'm thinking taking all the injectors out maybe the only fix!
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Thu Jan 12, 2012 8:37 am 
Getting Side Ways
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Age: 38

Posts: 771

Joined: 20th Nov 2005

Ride: AU XR8 220 Manual

very interesting, please keep me posted on your progress and I will to you if I have any luck
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Thu Jan 12, 2012 8:54 am 
Parts Gopher
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Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

Cool. I haven't worked on the Fairlane for a while. Late last year I drove to Sydney > Melbourne return and apart from blowing out the cob webs, I was able to achieve quite good fuel economy from 18.5l to 11.3l per 100km... The engine is running and idling smoother, slight more power :roll: but still that noticeable stutter and flat on acceleration...

I have the reply notification set on this thread, so I'm all ears mate :)
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Thu Feb 02, 2012 10:35 am 
Getting Side Ways
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Age: 38

Posts: 771

Joined: 20th Nov 2005

Ride: AU XR8 220 Manual

I had a look for vaccume leaks and nothing obvious but I may need to pull the top manifold off and check under there as I know they can fail under there due heat.

The car occassionally does not start well when cold (only when cold) it may fire up then stall then fire up again with no problems or not start at all then on the second attempt start fine. Im sure this is related. Any thoughts.

(note the car has new leads, plugs, coil, dizzy cap, rotor button etc so its not the ignition and it did this before I changed all them over)

Thanks
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Sat Feb 04, 2012 9:48 am 
Getting Side Ways
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Age: 71

Posts: 3555

Joined: 7th Nov 2004

Gallery: 4 images

Power: 482 rwkw

Location: Penrith
NSW, Australia

Check your relays and connections .. Check the relay base also..
The wire's / connectors often come adrift ...

 

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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Tue Feb 21, 2012 7:38 pm 
Parts Gopher
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User avatar

Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

{USERNAME} wrote:
Check your relays and connections .. Check the relay base also..
The wire's / connectors often come adrift ...


I don't mean to be naive but check which relays/connections and relay base? 8-)
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Mon Jun 25, 2012 10:18 pm 
Parts Gopher
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Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

{USERNAME} wrote:
very interesting, please keep me posted on your progress and I will to you if I have any luck


Any luck? What's the latest?
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Tue Jun 26, 2012 2:37 am 
Smokin em up
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Age: 55

Posts: 205

Joined: 8th Dec 2009

Gallery: 1 images

Ride: EB XR8, Now Blown 1977 Mini S

Location: Toowoomba
QLD, Australia

Check the EGR spacer and gaskets. I found my issues with the EB XR8 was leaking coolant into the intake airstream and gummed up the whole manifold with gunk. Replaced the gaskets and put a can of Subaru upper cylinder foam through the intake. Works a treat now and intake is now clean and shiny.

Dont park anything behind your car if you use ths cleaner - it will be covered in soot!!

Hooroo
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Tue Jun 26, 2012 7:05 pm 
Parts Gopher
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User avatar

Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

{USERNAME} wrote:
Check the EGR spacer and gaskets. I found my issues with the EB XR8 was leaking coolant into the intake airstream and gummed up the whole manifold with gunk. Replaced the gaskets and put a can of Subaru upper cylinder foam through the intake. Works a treat now and intake is now clean and shiny.

Dont park anything behind your car if you use ths cleaner - it will be covered in soot!!

Hooroo


The EGR hey? I shall check it out... This cylinder foam only can be bought from Subaru?
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Wed Jun 27, 2012 5:19 pm 
Smokin em up
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User avatar

Age: 55

Posts: 205

Joined: 8th Dec 2009

Gallery: 1 images

Ride: EB XR8, Now Blown 1977 Mini S

Location: Toowoomba
QLD, Australia

The yanks call it seafoam but I use the subaru stuff as I know it works(owned an L series 4WD with a 2.5 WRX drivetrain transplant - including low range!!)and I use it every 12 months. Just keeps the carbon/gunk buildup at bay. DO NOT!!! put it through the MAFF/MAP or it will destroy the wires(this stuff is pretty heavy handed)and follow the instructions to a T. It costs about $17 a tin but it works a treat. Even use it on the mini(just takes longer as the inlet distance is bugger all - the poor brick looks like it has rabies when I try to get half a tin in the inlet!!).

The EGR leak really stumped me - I spent thousands chasing every possible(and most expensive)path to fix my hunting idle but it was a $20 gasket that ultimately fixed it - go figure that one!!

Hooroo
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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Fri Jun 29, 2012 6:43 pm 
Parts Gopher
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Age: 41

Posts: 91

Joined: 8th Sep 2011

Gallery: 3 images

Ride: NL Fairlane

Location: Brisbane
QLD, Australia

Well I've had a closer look at the EGR valve. So, one electronic connector and one vacuum hose.
Whilst the engine is running, should it stumble or noticeably change revs when I disconnect either of these? Because it didn't make a difference at all...

I think I also found the PCV valve... Right at the back of the engine? One end of the hose is connected underneath the inlet manifold and the other is the PCV valve? Which just sits in a groove, it's almost has like a grommet or stopper on the end...?

:?

 

 

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 Post subject: Re: Chasing this flat spot / starting issue in my xr8...
Posted: Fri Jun 29, 2012 11:26 pm 
Stock as a Rock
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Location: sydney
NSW, Australia

another thing is fuel filter,also pull the tank cover off and have a look at the in tank filter/pump,i did and found a hole in the intank filter on the bottom of the pump,also check your fuel pressure on the shrader connector, i did and found the pressure regulator spat the dummy and was giving 20 psi instead of the required 40 psi at idle,you can turn it down a bit if you put a adjustable unit in there,86-93 mustang unit is the go from jegs-summit etc etc,lots more tricks :twisted: but i wont blind you with science <<< joke. :lol:
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