Help: Car Won't Start

[TriniGT]

Thought I may get more help here. I left a friend's house a while ago and came home no porblems, switched off the car and had it running on the timer. I go to close my front gate and when I turn around I hear the idle drop a little and then the car stall. Tried starting the car but it just tumbles, got it to start but then it dies. I am hearing the fuel pump priming when I turn on the ignition, the fuel tank is full (wondering if I may have gotten a bad batch of gas as I just filled it not too long ago), I changed the fuel filter and still no luck. One question, will I only get a reading on the defi oil pressure gauge when the car starts? I am hoping it is just the fuel pump, I really need to have a friend over to remove the return and ensure that it is the fuel pump by flicking the igntion and see the fuel coming out. On a side note I am gonna install a fuel gauge and check the pressure same time. Any thoughts, I don't even wanna consider oil pump .

[TriniGT]

Yeah fuel pump failed. Put in a Walbro I had but the car is hesitating now, gonna change plugs as I have not done that yet, changed the fuel filter already. Hesitation is bad enough so I am taking my time and I feel I got a combination of bad gas as well.

[TriniGT]

Okay I have replaced the plugs that were in the engine, coincidentally they were Nismo Iridiums Grade 7. The top of the plug had the inner half actually pitted and missing some material, the tip as in the spark tip itself seemed to be alright on all but the colour was light indicating that the car was running a bit lean. I got some NGK Iridiums in the same Grade 7 (BKR7EX-11) and gapped them to 0.8mm and put them in and tightened up everything and replaced hoses that were not in the best condition. Started her up and it idled fine but when driving I am still getting the hesitation.

The hesitation comes on partial throttle, like around 1/4 throttle or less, more so when I am cruising or under 1500-2000rpm but after that it is fine. On heavy throttle it will hesitate at about 1500rpm and then come into boost and holds fine, not breaking up or anything. I decided to install an AEM Uego Gauge (Wideband) I had to monitor the AFRs I had and maybe use the Pivot ACS-M Controller to adjust if needed. After installing the wideband and checking the readings my idel was at about 14.7 and under full boost would drop to 10.2 (from reading which is very rich) and when off the throttle it would swing over to 17 or thereabouts and then drop back to about 15 or so, but on full throttle it was 10.2

I adjusted the Pivot to -2 on the dial and still got around 14.7 at idle and on full boost which is 0.6 bar it would be in the vicinity of about 11.7 but off throttle would be again around 17 and then drop to like 15 or thereabouts. When cruising I saw it going from 14.5 to 17 sometimes but more between 14-16 on cruising with a vacuum of about .2 bar. My question is is my plug gapping correct and what may be causing this hesitation as before the pump failed it drove perfectly without hesitation and now with the Walbro it hesitates; is it because of too much fuel? Also what is a safe AFR on full boost and what is safe when cruising? I am tryign to save for a standalone like the Vipec or even a Power FC and have it tuned as well but if I can get by with the Pivot for now safely I don't mind. Last thing I need to get now is a fuel gauge to monitor the fuel pressure when the hesitation occurs to see if something else is causing the problem. The car does feel much stronger now as I have adjusted the AFR once in boost I may add and I even tried the high boost option on the EBC which is set at 0.9bar and the AFRs were still right around 11.7 but in third gear I could feel the clutch beginning to slip so I backed off. Let me know what you think on the problems and what suggestions please.

[Wacky Dee]

not sure if this will help since you seem to know a lot more but here goes anyway ..from all my readin on SAU, the general consensus regarding the iridiums is that they're rubbish and don't work too well in Skylines .. get the copper NGKs.

Also from my personal experience (R34 GTT), NGK coppers gapped to .8mm were missing in the lower revs (constantly) and upping the gap to 1mm fixed that and no more missing anywhere..

Also stick with heatrange 7 NGKs .. I just switched to 6s and my fuel economy took a dive (15-20% worse than with 7s)

[raps86]

Also another thing is if you got the same walbro pump that i got rated to 600hp you have to make sure you are getting 12 volts to the pump not the volts that they might have wich mite mean running power straight from the battery on a relay.

[TriniGT]

Also another thing is if you got the same walbro pump that i got rated to 600hp you have to make sure you are getting 12 volts to the pump not the volts that they might have wich mite mean running power straight from the battery on a relay.

Hmmm will measure the voltage coming to the fuel pump on tumble and see what it measures. How did you go about running a direct feed for the fuel pump and what was used to deactivate it once the car is not running. Is there any sort of wiring I can follow for this as it is a Walbro 255lph pump and I have heard horror stories of them failing because of poor voltage. Any help will be appreciated. Also I am gonna get some copper BKR7E-11 and try them but my first thing will be to investigate the pump problem as it is only since I have put in the pump that the hesitation has started. I am also thinking about changing my rubber intake setup to an aluminum setup as I felt the rubber intake and it is really soft and I am thinking it may be sucking/shrinking when under boost. I guess just trying to eliminate things in the process. It almost feels like under light throttle that it is sticking and then getting free and the car comes to life. I looked at the wideband and the moment it hesitates it goes lean and then resumes as normal.

Since I changed the plugs and tightened all my hoses and changed vacuum lines and adjust the pivot controller to a leaner state under full boost the car is more responsive and it does not pull the 0.6bar it once did, it now pulls 0.5bar and it feels really good. The only thing I am worrying about is the readings when I am cruising in vacuum I see it go from anywhere like 13.5 to 16.5 and off throttle 17 and over for a bit. Anything to be worried about?

[raps86]

i havent fitted the fuel pump yet as i only got it on friday but the way im gona run mine is through a relay. The easiest way that im doin it is mount the relay in the boot sumwhere then run a fused wire straight from the battery to the relay through the gromet behind the right hand front wheel arch with the fuse as close to the battery as possible. Then run another wire from an igniion source that only turns on when the key is in the on position to the switch terminal on the relay. Then run an earth from the relay and the last wire from the relay to the fuel pump. Hope this helps If you need more help with the wire feed send me a pm and ill try draw a pic for you and pm it to you to hopefully help. But check the voltage first at the pump with a multimetre.