hey guys, got a bit of delimma here.... iv got a project happening at the moment. iv put the twin turbo 300zx engine in...everythings seems ok, however wont start. the engine would turn over a few times then it gets stuck. i found that there is to much petrol in the piston chambers, and i feel this is the reason why the engine gets stuck. so much petrol enters the chambers to the point where the engine jams! have no idea whats wrong. the other issue was that the engine that was in the car prevoiusly was doing the same thing. we thought it was a valve but now that the new engine is doing the same thing im starting to wonder... any suggestions guys? what should i look for? iv changed the petrol regulator and disconnected the MAP sensor and tried starting it but the same problems comes up. is there an issue with the computer?
could be an electrical fault and injectors are staying open or stuck. thats a lot of fuel to hydrolock a motor? is it a replacment ecu or originale may have wrong tune if you have fitted a new one for your project.guiessing that you havent . try the old one if you have. also series 1 or series 2 ptu ? s1 ptu's die without notice how much and what have you done with the project.anything new that you have done since you started would help to diagnose what may be happening. old motor same fault ecu or elec gremlin my first thought. then again im no exspert.. but i am an EX as in has been. and i am a SPERT drip under pressure.!!!!
yeh it is!! i took all the spark plugs out and turned the engine over and so much petrol came out it soaked me and the car but its only happening on the drivers side engine of the car, which from looking from the front is the left side. haven't changed any computers around. basically at the start when we got the car, the engine would lock up when you tried to start it. we initially thought starter motor. changed it and still same. then we thought valves. we loosened the engine by manually turning it and it became loose. the engine then started but something was loose on the bottom end which gave way and that was the end of that! we then got another engine, installed it, and this same problem is still there. the engine is a working engine so not sure why this is happening. ill change the ptu and computer and see how that goes. thanks for the advice mate. much appreciated
I would pull the plenum off again and get the injectors checked because it sounds like they stay open listen to them through a screw driver before you pull it off are they making a clicking sound. sometimes they can get bits of fine stuck in them
Dont hydrolock it If it were me I would pull the injectors out, have them cleaned and flowtested, changing all the orings inide the rail and between the rail and lower plenum. Its electonic fuel supply so its gotta be the injectors, loom, ecu etc. Just curious if you had the markers on the fly and cams lined up when you attempted to start for the first time? (ie the ECU knows where all the pistons are at and its not out of sequence)
Ok, so your injectors are putting too much fuel in. I guess you already know that much. The ECU may be at fault - keeping injectors open. Unlikely as it is mostly one side only. It could be an earth fault. Your injectors always have 12v applied and are negatively pulsed. That means the ECU supplies an earth to each of the injectors in turn to open them. If you have any of the injector connector lines earthed out, then they will be constantly open. This is most likely. You may have big injectors and a standard ECU. This means that too much fuel is being supplied. Not likely as it is only one side. If the fuel rail has been out of the car is it possible the wrong injectors have been installed on one side? The tops of the injectors (pintles?) should all be the same colour. Very unlikely.
Hey guys thanks so much.... will look into compression, negative wires and if worse comes to worse will have to take out injectors..... will keep you posted on the outcome. thanks for all you help guys!!
Didn't read all posts so not sure if it been mentioned but check the lower o rings on the injectors as well. If one is gone it will fill the cyclinder quick smart. Easy way to check is to pull the rail off then prime the pump and look for leaks.
hey guys.....compression good. i swapped the ECU and still same problem. i checked all the earth's and i guess it seems ok. cant see any earth's that are out. i want to check the injectors to see if there functioning but dont know how. does anyone how to check it? mholt mate, how do you listen to it with a screwdriver? i tried but cant hear anything. how do you do it? thanks sevenangrypenguins..... will have to do that now i guess.....not looking forward to it.
screwdriver right on top off the injector (helps if the shaft of screwdriver runs through the handel as compaired to plastic incassed shaft screwdriver) and put your ear to the end and listen for the rappid clicking of the injector opening and closing. no good in your case unless someone turns it over while you listen to them but you may not hear it over the starter motor winding it over havent tryed it that way should be able to hear it should only if it were runing you can pick it out quite easy. give it a try with a helper turning on the ignition for you as you listen if the side that's flooding is not ticking away your injectors are stuck open and filling the bores with fuel and then hydrolocking as you try to turn it over has to be a short to the engine manigment part of wireing loom to(is it the drivers side)sorry forgot which side. maybe strip back the loom on that side and check it right along its length becase it is neg current that triggers the injectors any earthing to the motor on any injector lead will have them open and stay that way till the earth is broken . so look hard tiny cracks after twenty years are hard to spot. just an uneducated guess as you can probably tell from my spelling and grammer. cheers wayne
The way I check injectors is using the manual gravel filter for my fish tank, I just put the tube in my ear and use it like a stethoscope, should be like $2 from any aquarium:
X 2 Had the exact same issues as the OP, and you hit the nail on the head. (I've also had fuel spewing the other way on another occasion) leaking or damaged injectors wont fill a cylinder rapidly enough to cause a compression lock on cranking, a blown Oring however WILL Blown Orings will either fill a cylinder or dump a large amount of raw fuel over the inlet manifold. To locate as to which injectors Oring has failed or to check for a failed Orings in general, simply remove the coil paks, remove the sparkplugs, turn ignition to ON for a few seconds, crank engine over and watch for massive fuel spray from effected cylinder. NB: dont let anyone stand near the side of the car when doing this, raw fuel and lots of it will be exiting the cylinder at a fast rate. :br:
Do not do this at all ! The slightest spark can set the fuel vapor on fire. On the old Jag MK2 I had a badly leaking carb. I was cranking the engine and the fuel was spurting out. Looking down past the squirt of fuel, I could see those little blue sparks. The connection of the 12V to the starter was a bit loose and there were sparks flying when I was cranking. It did not catch fire - phew - I was lucky there
