So I just checked the fuel pressure gauge then and it was sitting at about 10psi. I've been attempting to start the car every morning & the last week or so it has been cu-pot. So I was expecting it to be the same now, but I was wrong. Started first attempt, fuel pump was buzzing a bit longer than normal but I'm guessing that is because it had to built the pressure up. Anyway, I'm going to take it for a quick squirt around the block to clear all the cobwebs out again :bash:
Just got back from driving around the block. Still has all its power, but one strange thing did happen. I gave it some beans in first while rolling & it wheel span up to redline and stalled/engine cut out. Has never ever done that before. It was at the top of my street and I ended up rolling it the rest of the way home (100 meters or so). The engine warning light was on, but I'm assuming that is because it stalled. Once home I turned the key and it started again. I hooked the laptop up, still no ECU faults.
You want someone to watch the sensor outputs via datascan/conzult etc while you are trying to start and when driving. Or there is a recording function on datascan I think. A failing CTS (or and/or other sensors) could be fooling your ECU into thinking it needs incorrect fuel and timing maps which would explain all the problems. Also check the TPS, CAS and AFM. Erratic voltage from any of these could be a clue. Correct sensor readings for all sensors if you don't know them are on my website here. EDIT: Recall a few posts up, you reported an intermittent code 13 CTS (aux fan came on)... further evidence of a bad CTS?
could the pressure loss be from a faulty fuel pump check valve? just thinking out loud here..........
The intermittent code 13 was due to a broken wire that I have since fixed (I will still try another CTS though). Unfortunately my laptop battery is fooked, so I have to plug it in via a power point
Clue perhaps, just checked fuel pressure and it is on ZERO. No fuel pressure in the system what so ever over a 4 hour period (also forgot to add to the list of things I've done, swapped out the fuel reg and damper).
Thats NOT right. My system holds pressure right up at 25-30+ psi for over a day. I reckon you found your culpret. I would hazzard a guess and say somehow that fuel is ending up sitting in the cylinders after it is turned off. OR the car cant build pressure intermittenly to start. When you first turn the key to start. The pump starts buzzing building fuel pressure in the line. Then turns off till you start the car. Then it runs as soon as the engine cranks. I think the pressure build up phase is TIMED by the FPCU. Its not actually measuring pressure looking for 42PSI. I suggest fitting the pressure guage permanently for the moment so you can keep and eye on it when you try to start it. I went as far as sticking it out the engine bay on a pipe so i could watch it on one car i was working on for starting issues like yours.
as i understood it the fpcu can control that (correct if i am wrong), and it does sound like a problem you have. its what mine would do.
Fuel pressure regulator has got crap in it causing a blockage sometimes = to much fuel & unable to seat other times = not enough pressure. Clean out ALL of the lines as best as you can (compressed air blown both ways) & replace fuel pressure regulator - you may have replaced it already & then introduced more crap into the new one if the system is not 100% clean.
if you wanna check the system. Pull the reg and plug the return line out of the fuel rail. put the key to start ( but dont crank) let the pump bring the rail up to pressure looking at the fuel pressure guage. Turn it off and wait. see of the pressure drops away quickly. It should he holding perfectly. If it drops off quickly the fault is pre the reg. If it holds up its from the reg back. Good luck with it.
Mungy is onto something here A great observation by Mungy that the new fuel reg may now been contaminated also. Also suspect the fuel dampener and fuel filter. Put a new one on in any case. You reported way back that you had consistent fuel pressure, now its failing... Follow tekkie's post below and clean out the fuel system including the tank. Try to capture any debris that comes out so you can definitely prove/disprove this approach. I recall a partially blocked fuel line in an old VH 20 odd year ago. Got stuck during a trip in Sydney, on the way back home to Bris, the engine would die with more than 1/2 throttle. Removed fuel line from carby and used a high-pressure blast thru the lines from the tank end. The amount of crap that came out was like shrapnel. It literally coated the engine bay. Amazing that any fuel was getting thru at all...
The fuel pressure was showing 10psi this morning, which I thought was odd as it was on zero when I last checked it two days ago. Anyway, car started first attempt this morning. After shutting down, I checked the fuel pressure again about 2-3 hours later and it was on 10psi. Does this mean something is definitly wrong & my issue is fuel pressure? I'm going to do as you suggested, Graham. Remove the fuel reg, block the return and see if it will hold pressure over a longer period.
UPDATE: 19/07/10 Unfortunately I haven't had any spare time to spend on the Z. I have still been trying to start it each morning and making observations. This morning I got it to start, just. I had someone watch the fuel pressure gauge. It was showing 10psi before ignition was turned on. When ignition was turned on, fuel pressure snapped up to 60psi, then dropped to around 50psi. I got the car to start, just... with the assistance of the throttle. The idle was very rough and lumpy and fuel pressure was still at around 50psi. After a minute or two, the pressure dropped to around 40psi and the idle was a lot smoother. I gave the accelerator a few quick stabs & revved it up to 4,000rpm. The was a lot of loud backfiring (which is has never done before). I would attribute this to excess fuel. Does the above sound correct, or is there definitely something funny going on with the fuel system? What is the next test(s) I should be carrying out? Thanks in advance, Jono
You have swapped fuel reg and damper..but was it swapped with one directly from a trouble free zed/brand new reg/damper or with one that has been sitting around in unknown condition? Feel bad for you mate such a good car that is being such a pain in the arse.
Time to establish a baseline Jono You've received so much advice/opinions and tried so many things, it might be wise to collate all the things you've tried into a rough timeline. Otherwise as you change several things simultaneously, you won't know what is helping or makes no difference at all. Certain fixes can cause other issues and you don't know what has caused what after trying numerous things. An example is the classic old dead PTU issue which causes the spark plugs to get fouled due to not firing whilst fuel is dumped into the cylinder. The PTU is eventually replaced but the engine still won't start (due to a new reason now - fouled plugs). The new PTU is suspected and replaced again, still no go ... until someone thinks about the flow-on effects of no spark in the cylinder. This is not your individual problem, but just serves to reinforce the need to timeline everything. Here's what I suggest. Draw a gantt chart indicating what problems occured and what fixes were attempted and the results of each fix. I personally think this problem will be caused by a couple of issues, not just one. Intermittent fuel pressure certainly seems to be at least one possibility (so all fuel system components need to be checked). Graham's suggestion about blockages in the lines is worthy of inspection. Also check inside the tank for blockages in the fuel sock etc. You should pick one component (I'd start at the fuel tank), completely eliminate it, only then move to the next down the line. Also look at any other secondary factors which influence fuel maps such as engine sensors gibing the ECU incorrect readings (CTS, AFM etc). When you are checking the fuel pressure guage when starting- someone should also be watching datascan for any errant values. A slowly failing CTS could be contributing to the problem.
I have been watching this thread for a while now, heaps of advice from heaps of people in here lots and of things to check, I feel sorry for you. That said I have a few of questions. First up do you have a consult cable with datascan or similar? Did you cure the buzzing sound? when I got my car it was making that buz from the same spot you mentioned, as said here the TPS was the cause of mine. it was way around at .58 and one of the solenoids was going crazy on my transmission I think. I know you cleaned out the IACV but what about the AAV? (I think this is the one). The valve I am thinking of is just to the drivers side of the IACV. Again I had issues starting and mine was Jamming. This was causing major problems while the engine was cold. When the car starts what is your vacuum like while at idle?
UPDATE: 22/09/10 Gonzo was kind enough to come over on the weekend & we swapped over ECU's. My Z still wouldn't fire, where as Dave's started as normal with my ECU. Another thing that can be eliminated. Anyway, I never thought I'd say it, but I give up. I never thought it would be this time consuming to find the issue & let me tell you, I have spent PLENTY of time going over things. I'm going to drop it off at a workshop in the city & see what they can come up with. I've already spoken with the owner & filled him in with the details. Fingers crossed they will be able to find the fault quickly so that I don't have to see my place to pay for it!
Wish your zed a speedy recovery!! God Speed! Actually let us all know what the issue is when its found. Would be interesting to see. Good Luck!! :zlove:
Wow sounds like you've tried near everything, and i hate to see it end with this fustration. So I'll cast a thought, as to maybe your turbo timer (handbrake engagement/safety measure) wire isnt grounded properly. This would cause the car to crank but not fire as it isnt receiving the true signal. But this wire may on the random ocassion make enough contact allowing the car to fire up? (ie simply insulated by a painted surface or dirt/dust?)
Have you checked the AFM? The filament in these is quite sensitive and any hint of a backfire can break it. You mentioned that it ran rough for a short while then stopped and I gather hasn't started since. That rough running could have damaged the AFM and that will cause a non-start. Seems you've tried just about everything else.
