Big engine problems

[Lourens]

Hi Everyone, I'm new to this forum, but have done a few Lexus conversion.

I fitted a V8 VVTi engine with auto box and original ecu into my brother's Nissan Hardbody about 6 months ago. Everything was running great until car started to loose power and then the next moment the car started idling rough and makes a very weird sound.

It will start up fairly easily when started first time but when switched off and trying again it just doesn't start again. I have changed the ecu, spark plugs, wiring harness and all sensors except the cam sensor, but will do it tomorrow as last resort. I've also tested the coils.

I've attached the link to a video clip of the engine trying to idle and the sound it makes.

https://youtu.be/3UdWzWpK_HY

Any help would be really appreciated as I do not know were to look anymore.

 

[cribbj]

Possibly the timing belt jumped?

It sounds cam related, as though when the cam adjuster is trying to do its business, you've got piston/valve contact? Do you have access to a borescope that you could put down the plug holes to see if there's been any contact?

 

[Lourens]

Thanks cribbj.

I was thinking the same thing but the sound come and go the whole time. I can do a compression test on all the cylinders. That will tell me if the valves are bent or not.

Is there anything on the cam itself that can break and cause the engine to sound like that? Like I said, it doesn't always sound like that. If the car was standing overnight, it will start immediately but will misfire heavily. Trying to start it again after you switch it off is impossible.

Will keep you posted.

 

[Lourens]

Hi everyone, I did do a compression test as promised. All 8 cylinder 100%. I pulled in a new shielded cable from the ecu ne- and ne + pionts. Still same problem codes appearing,

They are: 12 - RPM signal
22 - Temperature Signal
78 Fuel Pump control'

The other errors wont cause the engine to behave like it;s currently doing.

Fuel pump pressure also fine;

I really like you comments on this

 

[cribbj]

Wish I knew more about the VVTi engines - JustenGT8 is your man on those. If he doesn't reply to this thread, you might try PM'ing him.

 

[Lourens]

I'm realy concert
about the wiring diagram

 

[George_R]

78 is just 2nd relay for fuel pump control. You can bypass this error code with as little as 10k Ohm resistor wired accordingly

12 and 22 codes are very serious. In fact I have never seen a vvti ecu throwing this code. With non-vvti engines however "STA" pin of ECU is VERY common reason for code 12. Check that STA pin receives 12V when cranking and reads 0v when engine running. It can cause weird engine operation otherwise

Temp signal is what it is - water temp sensor. Check the sensor and its harness.