90 300ZX TT will not start. ECU gives code 11, Please Help!

  • 1990 NISSAN 300ZX

Engine Performance problem
1990 Nissan 300ZX 6 cyl Two Wheel Drive Manual 100000 miles

Hey guys,

I have a 1990 300zx with a JDM replacement motor.

I had a full buildup of corrosion in my radiator, so I decided to remove it and flush it with water so I can start flushing the coolant out in process of draining and refilling.

So after I reinstalled everything after a radiator clean/flush, It ran for a bit but then died and I couldnt get it to start again. The car will crank but wont start. Several sites advised me to check the ECU, and found that its giving code 11, Crank Angle Circuit.

I have the older PTU, which I read goes bad and I should get replaced by Nissan as it was on their list of recalls. Before I proceed on replacing my CAS, should I try to replace the PTU?

I also found that the ignition coil relay could also be a problem. I got the engine and some components wet under the hood which Im probably thinking I accidentally shorted out. Is there any way to short out the CAS by cleaning it on the outside, or getting water on the PTU?

Lastly I checked my fuel filter to see if It was getting fuel. I replaced it with a fresh one, and when I went to check if there was fuel in it there was. So I know its getting fuel.

Troubleshooting I checked the TPS, and sensors on the upper radiator inlet, there are two on the front of the motor. Took them off and cleaned them up. I also cleaned all connectors and pins on both the CAS, and TPS sensor to ensure that they were getting connection.

I also cleaned the MAF as well, took it off and reconnected it after cleaning the pins and connectors.

The Z cranks, and I can hear the fuel pump kicking in, but it just cranks and cranks, and does not fire.

Im also confused about the coil packs (ignition coils). When I order one I have to order 6 correct? Because these are what fire my spark plugs?

Also, if I get a new CAS and PTU can I use any of the years or a N/A version? They all look the same, or do I have to get a TT specific versions?

Thanks you for any help and for helping sort this out.

Do you
have the same problem?
Friday, May 28th, 2010 AT 4:59 AM

1 Reply

  • 42,002 POSTS

Hi Blurrz,

Thank you for the donation and sorry for the long wait.

I am no expert in this vehicle so no promise that I can help you solve the problem but I would not mind giving it a shot.

Before we get to others, I would suggest diagnosting the Code 11 problem first. I have emailed you the diagnostic files and hope they are helpful.

PTU, sorry, I do not understand this term and our database does not provide any information on it.

Ignition coils can be replaced one at a time, as and when necessary, but then again you stand the risk of others failing if not all are replaced at the same time. These items are prone to fail over time.

For parts, it is best to get the recommended parts as they might not be interchangeabls and sensors with different readings might not work as desired as the readings might be out.

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Sunday, May 30th, 2010 AT 10:52 AM

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