Reece350z Posted January 16, 2016 Share Posted January 16, 2016 I have a Nissan 350z fair lady 2003 with 80k and it's an auto.. So after fitting a new conrod because I drove through deep water. I built her back up and the car started briefly for 3-4 seconds then cut out and wouldn't start again so checked for a spark by taking the plug out and putting it on the body and there was non but there was voltage to all coils so I checked resistance through the coils all ok Checked all fuses all ok. Checked fuel pump and plugs were soaked in fuel when I took them out so fuel isn't the problem. Tested crank and cam sensors all ok. Didn't remove flywheel so it has to be on the right mark, done a compressions test and all cylinders were 50psi which is really low? So it made me think I'd timed it up wrong so checked timing again before and took the chains off and done it again and it all lined up as fsm but still won't start.. Has no fault codes. Please help! Any ideas would be appreciated I'm totally stuck. Tried new plugs they didn't work. Any ideas what it could be? Quote Link to comment Share on other sites More sharing options...
richard.hezlett Posted January 16, 2016 Share Posted January 16, 2016 Pm Zmanalex. Knows these babies inside out. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted January 16, 2016 Share Posted January 16, 2016 If you have no spark, then without getting to technical I would just retrace my steps, checking all loom connections, especially at the ECU. I would also be looking a bit closer at the Crank Position Sensor and connector and whilst there check out the Cam Postion Sensors connections as well. Also check all common and related fuses to Ignition + the fuse links at the battery. Finally just thinking standing on my feet, I would also be having a look at the JDM immobiliser. Good luck. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted January 16, 2016 Share Posted January 16, 2016 Pm Zmanalex. Knows these babies inside out. :wave: 1 Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 Continuity checked all fuses. Tested for resistance through the cam and crank sensors checked all connectors all on tight and pins aren't bent I took the full loom out the car to put engine back in as it was easier so will re check soon. The imobiliser works because I have to press it into a hole before starting the car. Anything else? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 16, 2016 Share Posted January 16, 2016 Have you checked the compression since you re timed the engine? and have you checked that the crank and cam sensors actually trigger? 1 Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted January 16, 2016 Share Posted January 16, 2016 Where are you based ? Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 How do I check they trigger? I measure resistance through them and got a cranking speed when I plugged snap on solus code reader in so crank shaft must be getting a reading. Yeah compression is low but heard on another forum it's because I've rebuilt it and not run it yet, the cams and chain marks are all perfect.. Im in Whitehaven Cumbria. Far away from everywhere! Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 16, 2016 Share Posted January 16, 2016 You shouldn't have low compression just from rebuild, have you tried a little oil in the cylinders to see if it makes a big difference to compression reading? As for the cam and crank sensors its a little difficult as they are hall effect and need close proximity to a metal tooth, but I would have thought introducing something metal close to it with ignition on and coil pack attached to an earthed plug would make it trigger a spark, however I am not sure without going through the manual which sensor is responsible for ignition. 1 Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 Haven't tried that yet but heard about it. The low readings to me indicated incorrect timing or a bad valve overlap. The valves were all okay because I tested them before I put the heads on. The timing marks are perfect. I accidentally took the vvt gear pulleys off.. Could that affect timing? I've always got a leak from my vvt solenoid base so I've got a new one on order. Do you think that could make a different because it's not getting correct oil pressure? I'm grasping at straws here I know.. Quote Link to comment Share on other sites More sharing options...
350zedd Posted January 16, 2016 Share Posted January 16, 2016 Is the block well earthed and all the other earth straps refitted ? Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 Yeah I've went over them and cleaned them and re fitted them then done a continuity check to the the battery and all okay Quote Link to comment Share on other sites More sharing options...
350zedd Posted January 16, 2016 Share Posted January 16, 2016 You're getting a cranking speed via the code reader. I assume this is mirrored on the tachometer as well. You have 12v at the coil pack...is this voltage being interrupted when you crank, to induce a high voltage spark Not sure if you can see this bounce with a multimeter or not, maybe see a flicker with a test lamp. 1 Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 Yeah I am.. Yeah it is.. I haven't checked when I crank it but I'll try a lamp tomorrow on it. Think I could of fried the ecu going through the puddle or anything? I'm just hoping it's the vvt solenoid but don't think anybody knows? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 16, 2016 Share Posted January 16, 2016 Haven't tried that yet but heard about it. The low readings to me indicated incorrect timing or a bad valve overlap. The valves were all okay because I tested them before I put the heads on. The timing marks are perfect. I accidentally took the vvt gear pulleys off.. Could that affect timing? I've always got a leak from my vvt solenoid base so I've got a new one on order. Do you think that could make a different because it's not getting correct oil pressure? I'm grasping at straws here I know.. Aren't the VVT sprockets keyed to the cams? if so you should have no problem, the VVTs don't actuate during start up and low RPM so that wont effect things, low compression will hinder starting, so re check that. If the ECU has got water into it its entirely possible that this is causing no start as well, but check out the compression first. 1 Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 16, 2016 Author Share Posted January 16, 2016 Haven't tried that yet but heard about it. The low readings to me indicated incorrect timing or a bad valve overlap. The valves were all okay because I tested them before I put the heads on. The timing marks are perfect. I accidentally took the vvt gear pulleys off.. Could that affect timing? I've always got a leak from my vvt solenoid base so I've got a new one on order. Do you think that could make a different because it's not getting correct oil pressure? I'm grasping at straws here I know.. Aren't the VVT sprockets keyed to the cams? if so you should have no problem, the VVTs don't actuate during start up and low RPM so that wont effect things, low compression will hinder starting, so re check that. If the ECU has got water into it its entirely possible that this is causing no start as well, but check out the compression first. I think so but I was just thinking outside the box really just incase. I don't know what could be causing low compression. Gonna do a leak down test then after that it must be timing. Just had new head gaskets and bolts so I'm really puzzled. Still doesn't explain no spark though.still need help with that! Quote Link to comment Share on other sites More sharing options...
350zedd Posted January 17, 2016 Share Posted January 17, 2016 Yeah, you need to test the switching signal at the coil pack Quote Link to comment Share on other sites More sharing options...
Ebized Posted January 17, 2016 Share Posted January 17, 2016 Given your engine sucked in water I would have thought it likely the ECU (and other electrics in that area) got a drenching too? Only saying that as once bought a s/h Audi that had various intermittent electrical faults and quickly got the dealer to exchange for another (that was OK) and at the time there was suspicion on the part of a mechanic I knew that the car had been flooded at some time beforehand. Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 17, 2016 Author Share Posted January 17, 2016 Yeah, you need to test the switching signal at the coil pack How do I do that? Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 17, 2016 Author Share Posted January 17, 2016 Given your engine sucked in water I would have thought it likely the ECU (and other electrics in that area) got a drenching too? Only saying that as once bought a s/h Audi that had various intermittent electrical faults and quickly got the dealer to exchange for another (that was OK) and at the time there was suspicion on the part of a mechanic I knew that the car had been flooded at some time beforehand. the ecu is inside the car wasn't wet in there but it could of. I'm thinking it could of sent a spike bike to the ecu Quote Link to comment Share on other sites More sharing options...
350zedd Posted January 17, 2016 Share Posted January 17, 2016 Take a look at this. It may not be exactly the same as the zed, but hopefully point you in the right direction http://easyautodiagnostics.com/misc-index/coil-pack-testing-tips-3 Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 18, 2016 Author Share Posted January 18, 2016 So today I tested all the signal wires from the ecu pins to the coils and all okay. Continuity wise that is. Going to change the crank and cam sensors next then will be going down the ecu road and it's my last option.. Unless someone has an idea on something I've missed? Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted January 18, 2016 Share Posted January 18, 2016 As per my post #3, did you check the pins on the ECU connection to the loom ? Quote Link to comment Share on other sites More sharing options...
Reece350z Posted January 18, 2016 Author Share Posted January 18, 2016 As per my post #3, did you check the pins on the ECU connection to the loom ? yeah checked them just before. All have good continuity too all 6 Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted January 18, 2016 Share Posted January 18, 2016 As per my post #3, did you check the pins on the ECU connection to the loom ? yeah checked them just before. All have good continuity too all 6 Crank Position Sensor then ? Quote Link to comment Share on other sites More sharing options...
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