1990 300zx won't start... going through the motions

[N/ayella]

OK so I picked this car up for a pretty good deal after the car at sat for a little over year the owner says it ran and drove perfectly fine before he parked it the reason it sat was due to a bad water pump. I am already planning on putting a new timing belt on the motor but wanted to at least hear run before I ripped it apart. So far I have drained the fuel tank put fresh premium in it new fuel lines new fuel filter it's got a new cam angle sensor but it's throwing a code 13 and a code 34 the code 34 is a bad knock sensor.

I pulled the coil packs that are on top of each spark plug and put a spark plug in the coil pack to test and I have no spark I do have fuel pressure and I have air so my question is would a code 34 cause the motor to have no spark. The code 13 is an engine coolant temp sensor so that leads me to believe that the reason why the car is not turning over is because of the code 34. Motor cranks and sounds like it has good compression but won't actually start...

[elecfus]

if the water pump failed it probably overheated. although it may not have been the water pump that died. the coolant temp sensor controls the coolant bypass valve. pressurized steam from low water levels kills temperature sensors. if the temp sensor isnt working then it wont open the valve normally and it can overheat.

there's a good chance it overheated. take your spark plugs out, shine a light down the bores and look for blown piston crowns and scoring on the walls. then do compression tests on each cylinder. there's a good chance head seals have blown.

a code 34 wont cause no spark but a blown ignition unit doesnt throw a code and causes no spark. common problem on the earlier z32s.

[N/ayella]

The original owner has been in contact and has been strait up through the whole thing. He said the waterpump leaked a little for awhile so he always topped off coolant and then it completely went one day so he stopped driving it. When it went he said it got hot but he didn't let it over heat. The last 2 times he moved it around his yard he started it...

So in other words he didn't stop driving due to over heating and assumed waterpump... he said you could physically see it seep coolant out of the gasket, but I will still pull a plug and check!!

[N/ayella]

A bad ignition unit won't through a code? Cause this car was made in like 1989.5 early production of z32 body style and I don't think there is internal damage... and even if the motor was over heated it would still give spark or sputter. I had a blown 427 in a Chevy that ran great until it was warm then it died

[elecfus]

A bad ignition unit won't through a code? Cause this car was made in like 1989.5 early production of z32 body style and I don't think there is internal damage... and even if the motor was over heated it would still give spark or sputter. I had a blown 427 in a Chevy that ran great until it was warm then it died

yeah, common problem on the z32. no spark is nearly always the ignition unit and there's no diagnostic for it other than to just replace it. the wires lift off the contacts and start to make intermittent contact so it can just fail catastrophically or cut in and out.

you cant really tell if it's overheating because no coolant = no temperature reading. try running an engine without coolant. your heads will melt before the temperature gauge starts rising.

there are a few tricks to get a warped or cracked motor running. you can throw in sealants that work for a little while. an egg will seal a cracked radiator if you add it to your coolant. you can join a few batteries and crank the motor for a few minutes to warm it up so the metal expands enough to seal itself until it gets cold again.

code 34 is just knock. the ECU has two sets of maps. one for knock, the engine runs rich and retarded. another for everything is fine. when it's running the knock maps, it runs rich and limits the turbo pressure. this is to stop the engine from running too advanced, too lean or at too high a pressure, essentially limiting the power output of the engine by limiting the compression forces. the knock code is unrelated to the ignition problem. code 34 can also be caused by bad engine mounts as it is basically just a microphone that listens for pinging noises.