Hi everyone, for some reason my Zed's gone a bit haywire lately. At first I noticed it the other day it had a very small misfire at idle after a drive, and I think it has become progressively worse. I thought the plugs might have been on their way out so I swapped out the coppers that were gapped to 0.8 (I'm running 12PSI) and put the 1.1 gapped Iridiums back in, no difference in idle. Anyway when I start the car now the idle will fluctuate between 700 and 1200 or so revs, and it misfires. Fuel pressure rises and falls between 40 and 52 or so PSI when the idle falls and rises. Adjusting fuel pressure via my sard unit is unresponsive, it doesn't do anything no matter how far I wind the adjuster out. Any ideas, anyone? Thanks once again for help in advance. :zlove:
are you adjusting the pressure with the source removed. you may have a huge leak thats causing your idle. and hence your fuel pressure 2 be all over the shop
Hey mate, what do you mean by 'source'? Are you also referring to a vacuum leak? Could be possible, might hook a compressor and tester up to it and see what the go is.
Well I'm guessing it's the original pump! I have never touched it, that would make a lot of sense actually, would explain rising and falling fuel pressure - what else could be causing it besides the fuel pump? Probably nothing right? What about thr FPCU or whatever it is, could this be the cause and would it show the same symptoms? Guessing not.
Hahaha, maybe, I might try a new fuel pump first, sounds to be the most logical explanation and see how that goes! I'd rip the FPCU out but this car's supposed to be going on the market and getting roadworthied, etc. so I probably shouldn't be deviating too far from stock at the moment!
Replace the sard FPR with the stock one for testing purposes, if it pressure stabilises then you have your culprit and also check your fuel damper, both if faulty can cause erratic fuel pressures.
Thanks again Andy for your help, noted Anyway bumping this up, I've just bypassed the FPCU and the car's idling beautifully, no fluctuations with Idle or fuel pressure. The Fuel Pump sounds very, ummm, 'Racey' However it's sitting at around 52PSI of pressure, and I can't seem to adjust the fuel pressure either down or up via the Sard Regulator. But, as soon as I turn the car off, the residual fuel pressure in the retun line sits at 32PSI, which is where it should be at right? Any ideas what's going on here? I have a Nistune ECU to chuck in anyway (Thanks HeavyTrev!) so providing the car's drivable like this I might just hike it down to Status Tuning and get them to have a look at it while they tune her up. Thanks for any help in advance. :zlove:
maybe your pumps on the way out dude. you need 2 check your pressure at idle with the vac source removed... you may need 2 adjust it down a smidge because now the pump is running at full speed all the time
Alright, now with the vacuum hose disconnected from the regulator and left open to atmospheric pressure and the nipple on the plenum plugged, the gauge didn't show any change in pressure at all. And I still can't adjust the fuel pressure down. Strange.
