Idle problems....
Discussion
Hi Peeps...
Right everything was fine but i had a fuel leak on the fuel rail and the adjustable Malpassi FPR smelt highly of raw fuel..So i had the fuel rail hoses changed and a standard FPR was fitted that i bought from flea..Previously i borrowed it to someone else and when they tested their fuel pressure it was only holding 2.2bar at the FPR..However i had it fitted and it soon become apparent that the mixture was too lean as i was getting some serious pinking on hard acceleration in 3rd..Also the plug from cylinder 1 was very white.
I replaced it with one borrowed from a friend which was a standard 2.5 bar type but still retained the pinking..The timing was checked and read around 9 degrees.
Finally i replaced that one with an adjustable FPR and set the WOT pressure at 38 psi..However now I'm experiencing cutting out at idle when hot when i never before.
It seems to do it when i give it a little rev, Sometimes it happens when i stop at a set of lights.
Now i have read various forums and RV8 sites that suggest it could be attributed to the ECU...Obviously i don't want to start throwing money at parts its not..
I'm hedging my bets on the adjustable FPR...I have noticed also that when i remove the vacuum pipe off of the plenum that is connected to the FPR it doesn't cut out...
I have also noticed that the fuel pressure is a little erratic...Its set to 38-40psi then after some driving it will read 50psi..Drop it back down and drive it it then reads 30psi?
I have checked for air leaks and have removed the plugs..No.1 was still a bit white but the others were normal..I have cleaned them and put them back in.
It seems that this has come about after the Dyno run but it didn't show any faults just a little over fuelling.
Has anyone had this problem and found the solution....Cheers...Ziga
Right everything was fine but i had a fuel leak on the fuel rail and the adjustable Malpassi FPR smelt highly of raw fuel..So i had the fuel rail hoses changed and a standard FPR was fitted that i bought from flea..Previously i borrowed it to someone else and when they tested their fuel pressure it was only holding 2.2bar at the FPR..However i had it fitted and it soon become apparent that the mixture was too lean as i was getting some serious pinking on hard acceleration in 3rd..Also the plug from cylinder 1 was very white.
I replaced it with one borrowed from a friend which was a standard 2.5 bar type but still retained the pinking..The timing was checked and read around 9 degrees.
Finally i replaced that one with an adjustable FPR and set the WOT pressure at 38 psi..However now I'm experiencing cutting out at idle when hot when i never before.
It seems to do it when i give it a little rev, Sometimes it happens when i stop at a set of lights.
Now i have read various forums and RV8 sites that suggest it could be attributed to the ECU...Obviously i don't want to start throwing money at parts its not..
I'm hedging my bets on the adjustable FPR...I have noticed also that when i remove the vacuum pipe off of the plenum that is connected to the FPR it doesn't cut out...
I have also noticed that the fuel pressure is a little erratic...Its set to 38-40psi then after some driving it will read 50psi..Drop it back down and drive it it then reads 30psi?
I have checked for air leaks and have removed the plugs..No.1 was still a bit white but the others were normal..I have cleaned them and put them back in.
It seems that this has come about after the Dyno run but it didn't show any faults just a little over fuelling.
Has anyone had this problem and found the solution....Cheers...Ziga
mrzigazaga said:
Hi Peeps...
Right everything was fine but i had a fuel leak on the fuel rail and the adjustable Malpassi FPR smelt highly of raw fuel..So i had the fuel rail hoses changed and a standard FPR was fitted that i bought from flea..Previously i borrowed it to someone else and when they tested their fuel pressure it was only holding 2.2bar at the FPR..However i had it fitted and it soon become apparent that the mixture was too lean as i was getting some serious pinking on hard acceleration in 3rd..Also the plug from cylinder 1 was very white.
I replaced it with one borrowed from a friend which was a standard 2.5 bar type but still retained the pinking..The timing was checked and read around 9 degrees.
Finally i replaced that one with an adjustable FPR and set the WOT pressure at 38 psi..However now I'm experiencing cutting out at idle when hot when i never before.
It seems to do it when i give it a little rev, Sometimes it happens when i stop at a set of lights.
Now i have read various forums and RV8 sites that suggest it could be attributed to the ECU...Obviously i don't want to start throwing money at parts its not..
I'm hedging my bets on the adjustable FPR...I have noticed also that when i remove the vacuum pipe off of the plenum that is connected to the FPR it doesn't cut out...
I have also noticed that the fuel pressure is a little erratic...Its set to 38-40psi then after some driving it will read 50psi..Drop it back down and drive it it then reads 30psi?
I have checked for air leaks and have removed the plugs..No.1 was still a bit white but the others were normal..I have cleaned them and put them back in.
It seems that this has come about after the Dyno run but it didn't show any faults just a little over fuelling.
Has anyone had this problem and found the solution....Cheers...Ziga
This was a top tip I got from Craig at Dyno Torque when I chatted through my similar issues..........where is your air temp sender?...........mine is attached to the plenum in the old hole for the cold injector. As such when the engine got hot it caused heat sink into the sensor causing the ECU to freak out........the sensor needed to be on the cold air intake somewhereRight everything was fine but i had a fuel leak on the fuel rail and the adjustable Malpassi FPR smelt highly of raw fuel..So i had the fuel rail hoses changed and a standard FPR was fitted that i bought from flea..Previously i borrowed it to someone else and when they tested their fuel pressure it was only holding 2.2bar at the FPR..However i had it fitted and it soon become apparent that the mixture was too lean as i was getting some serious pinking on hard acceleration in 3rd..Also the plug from cylinder 1 was very white.
I replaced it with one borrowed from a friend which was a standard 2.5 bar type but still retained the pinking..The timing was checked and read around 9 degrees.
Finally i replaced that one with an adjustable FPR and set the WOT pressure at 38 psi..However now I'm experiencing cutting out at idle when hot when i never before.
It seems to do it when i give it a little rev, Sometimes it happens when i stop at a set of lights.
Now i have read various forums and RV8 sites that suggest it could be attributed to the ECU...Obviously i don't want to start throwing money at parts its not..
I'm hedging my bets on the adjustable FPR...I have noticed also that when i remove the vacuum pipe off of the plenum that is connected to the FPR it doesn't cut out...
I have also noticed that the fuel pressure is a little erratic...Its set to 38-40psi then after some driving it will read 50psi..Drop it back down and drive it it then reads 30psi?
I have checked for air leaks and have removed the plugs..No.1 was still a bit white but the others were normal..I have cleaned them and put them back in.
It seems that this has come about after the Dyno run but it didn't show any faults just a little over fuelling.
Has anyone had this problem and found the solution....Cheers...Ziga
Hi mate..Sorry i meant to say its a flapper and i don't have an air temperature sender..As far as I'm aware anyway...Could be the dreaded water temperature sender..I will unplug the cold start to see if that makes a difference...The bonnet was down at the Dyno.
First I'm going to change the FPR to the standard one that i bought from flea to see if it sorts out the idling issue..Cheers..Ziga
First I'm going to change the FPR to the standard one that i bought from flea to see if it sorts out the idling issue..Cheers..Ziga
Zig I didn't think you had any problem at all "being idle"!
As for the car yes there's an air temp sender on a flapper but it's in the air meter itself in the air flow.
Your varying fuel pressure sounds dodgy so I would change back to either of the standard FPR's and see if the problem goes away with a few test drives. As it's the last thing you changed it's certainly the place to start.
Before considering the ECU do set up the throttle gap and the throttle pot voltage for idle. There are procedures for this in HJ2's pages and the Epistles etc. Also check the throttle pot for continuity and smooth variation as you twist the throttle open.
As for the car yes there's an air temp sender on a flapper but it's in the air meter itself in the air flow.
Your varying fuel pressure sounds dodgy so I would change back to either of the standard FPR's and see if the problem goes away with a few test drives. As it's the last thing you changed it's certainly the place to start.
Before considering the ECU do set up the throttle gap and the throttle pot voltage for idle. There are procedures for this in HJ2's pages and the Epistles etc. Also check the throttle pot for continuity and smooth variation as you twist the throttle open.
Mark,
As Adam says, check the settings on your throttle pot and adjust if necessary.
Dead easy to do, you just need a multimeter.
Should be 0.33v closed throttle rising steadily to about 4.3v at WOT.
Also, have you checked your HT leads ? I think you have the same cheap nasty leads that I had ?
You could check the resistance of each lead too.
Hope this helps mate
Ian
As Adam says, check the settings on your throttle pot and adjust if necessary.
Dead easy to do, you just need a multimeter.
Should be 0.33v closed throttle rising steadily to about 4.3v at WOT.
Also, have you checked your HT leads ? I think you have the same cheap nasty leads that I had ?
You could check the resistance of each lead too.
Hope this helps mate
Ian
Cheers for the advice chaps..Went for a spirited drive earlier and it seems to be ok again?..The fuel pressure has settled to 30psi idle and 38psi WOT...It was a bit rough when i started it this morning but is ok..I have pushed it in 3rd and couldn't hear any pinking..Might be worth checking the continuity of the TPS and AFM...I think the leads are ok, Yes they are powerspark they cost £30 and were recommended by British V8..I will change them every year as a precaution or invest in some magnecor although i don't think its them.
It does seem to of happened after the fitment of the adjustable FPR...Although nothing untoward showed up on the Dyno?...Just gonna keep an eye on it....Cheers...Ziga
It does seem to of happened after the fitment of the adjustable FPR...Although nothing untoward showed up on the Dyno?...Just gonna keep an eye on it....Cheers...Ziga
Flapper fuelling does appear to be marginal when ambient temperature increases. Detonation or pre-ignition?
http://www.contactmagazine.com/Issue54/EngineBasic...
http://www.contactmagazine.com/Issue54/EngineBasic...
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