Rebuilt KA wont start :/ - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

136baker · 03-23-2016, 02:21 PM

I bought a rebuilt bottom end off some guy on craigslist (i know, super sketchy) but it seemed well put together. i slapped my head from my old engine (which i got rebuilt about 23,000 miles ago) but it wont turn on now.

And so I've read threads about distributor being 180 degrees off and tdc and this is where i stand right now. for some reason it wont turn on. Everything is plugged in, grounds are where they should be, but still not turning on. sounds like its misfiring for some reason.

Did a compression test and unfortunately got 155, 155, 90, 160. The guy who rebuilt it must've done the piston rings wrong on cylinder 3 or something but would that not make my car turn on? I mean I've heard of 240s running on basically 3 cylinders before.

I really just need this to run as this is my local daily. If I'm close to getting it to run please let me know! if I'm far from it, or have to take the head off again or disassemble anything please let me know! this will be the deciding factor on whether i should be broke for a couple of months to go SR or keep this KA.

Thank you guys!

Ive attached images and a link of the engines behavior below! thanks again!

https://www.youtube.com/watch?v=_xOOFTWyiiI

03-23-2016, 03:16 PM

--Deleted--

Frank_Jaeger · 03-23-2016, 03:19 PM

It's gotta be timing. Either mechanical or ignition. Get it to TDC and make sure the dizzy rotor is pointing to #1 spark plug. How confident are you the upper / lower timing are spot on?

If it's a freshly rebuilt engine the rings have to seat. I'm not sure that the one cylinder being so far out of spec is normal, however you should be sure to break it in properly once you get it running right.

136baker · 03-23-2016, 04:00 PM

Quote:

Originally Posted by Tucker240

Either way if you have 90 you will need to check that cylinder and see why you are losing pressure. Did you try a leak down test? A compression test will just let you know that you are losing pressure somewhere. A leak down will tell you from where since you are pressurizing the cylinder. But before this, yes your engine can and typically should run on 3 cylinders with no problem. Have had it happen to me and others plenty of times and will still fire right up. You need to check the basics...fuel, spark. Make sure you have that first.

i have not done a leak down test yet since i do not own a compressor

ive checked and i do have spark, not sure how to check for fuel though. other than hearing the fuel pump prime and having the fuel lines hooked up correctly and fuel running through them, idk how to check the individual injectors. Ive tried turning the car on without spark plug wires and smelled the plugs and all 4 smelled like gas. so im guessing i have fuel.

136baker · 03-23-2016, 04:03 PM

Quote:

Originally Posted by Frank_Jaeger

It's gotta be timing. Either mechanical or ignition. Get it to TDC and make sure the dizzy rotor is pointing to #1 spark plug. How confident are you the upper / lower timing are spot on?

If it's a freshly rebuilt engine the rings have to seat. I'm not sure that the one cylinder being so far out of spec is normal, however you should be sure to break it in properly once you get it running right.

i have the lower timing at TDC (second mark from the left) and in that position, the cams are pointed outward opposite from each other as you can see in the picture, i also posted a picture of the rotor in the #1 sparkplug wire spot as well. so my onlyother guess would be grounds?? are there any typical grounds that people forget to wire correctly?

Frank_Jaeger · 03-23-2016, 05:53 PM

Did you take a picture of the timing before you put on the front cover?

The cams look right to me however that doesn't tell the whole story. I recently put an engine together where the block had been decked and because I didn't make up for the difference with a thicker headgasket the cams were not in the "correct" position when I did proper timing. You have to go by the number of links in the chain.

If you try to give the motor throttle will it stay running? Have you tried keeping it WOT briefly?

Off the top of my head there are these grounds:
Driver side:
Small one goes to firewall.
Small one goes to head.

Passenger side:
Big ass one that goes to the intake manifold.
Small one that goes to strut tower.
Small one that goes to fuse box.
Small one that goes to alternator.

Those are all in the lower and upper engine harness. There are some important body harness grounds too but those shouldn't have been screwed with for an engine swap.

Frank_Jaeger · 03-23-2016, 06:01 PM

Looks like you have a massive gaping vacuum leak too in the video. That would cause it to die. Put the intake and intake hoses on, cap off anything unused, and check for further vac leaks.

When you got the short block, was the crosshatch in the cylinder bore rough or smooth?

136baker · 03-23-2016, 06:29 PM

Quote:

Originally Posted by Frank_Jaeger

Did you take a picture of the timing before you put on the front cover?

The cams look right to me however that doesn't tell the whole story. I recently put an engine together where the block had been decked and because I didn't make up for the difference with a thicker headgasket the cams were not in the "correct" position when I did proper timing. You have to go by the number of links in the chain.

If you try to give the motor throttle will it stay running? Have you tried keeping it WOT briefly?

Off the top of my head there are these grounds:
Driver side:
Small one goes to firewall.
Small one goes to head.

Passenger side:
Big ass one that goes to the intake manifold.
Small one that goes to strut tower.
Small one that goes to fuse box.
Small one that goes to alternator.

Those are all in the lower and upper engine harness. There are some important body harness grounds too but those shouldn't have been screwed with for an engine swap.

Im going to check all of my grounds then. and if going by number of links then yes, upper timing is on right. i made sure the spaces/links between cam markers were the same as all the references i saw in other write ups. im using an oem replacement gasket so i dont think my timing should be different than stock. and the surface was smooth. i made sure it was before i bought the block. Ill check for vacuum leaks. the only place i can see there might be a vacuum leak is behind the head, up close to the fire wall. since its kind of a small area to put my hands in, i might have missed one.

And yes, If i keep the throttle open, it will stay on with a slightly rough idle, but once i let go of the throttle, it dies.

Frank_Jaeger · 03-23-2016, 07:00 PM

In the video it looks like your intake is off the throttle body? And IACV isn't hooked up? I.e. your engine is pulling in 100% unmetered air.

cotbu · 03-23-2016, 08:46 PM

Quote:

Originally Posted by Frank_Jaeger

In the video it looks like your intake is off the throttle body? And IACV isn't hooked up? I.e. your engine is pulling in 100% unmetered air.

Bingo if not bullseye spot on!

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03-23-2016, 03:16 PM	#2
Tucker240 Guest Posts: n/a	--Deleted-- Last edited by Tucker240; 03-17-2019 at 11:43 PM..

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03-23-2016, 03:19 PM	#3
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 29 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	It's gotta be timing. Either mechanical or ignition. Get it to TDC and make sure the dizzy rotor is pointing to #1 spark plug. How confident are you the upper / lower timing are spot on? If it's a freshly rebuilt engine the rings have to seat. I'm not sure that the one cylinder being so far out of spec is normal, however you should be sure to break it in properly once you get it running right.

03-23-2016, 05:53 PM	#6
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 29 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	Did you take a picture of the timing before you put on the front cover? The cams look right to me however that doesn't tell the whole story. I recently put an engine together where the block had been decked and because I didn't make up for the difference with a thicker headgasket the cams were not in the "correct" position when I did proper timing. You have to go by the number of links in the chain. If you try to give the motor throttle will it stay running? Have you tried keeping it WOT briefly? Off the top of my head there are these grounds: Driver side: Small one goes to firewall. Small one goes to head. Passenger side: Big ass one that goes to the intake manifold. Small one that goes to strut tower. Small one that goes to fuse box. Small one that goes to alternator. Those are all in the lower and upper engine harness. There are some important body harness grounds too but those shouldn't have been screwed with for an engine swap.

03-23-2016, 06:01 PM	#7
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 29 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	Looks like you have a massive gaping vacuum leak too in the video. That would cause it to die. Put the intake and intake hoses on, cap off anything unused, and check for further vac leaks. When you got the short block, was the crosshatch in the cylinder bore rough or smooth?

03-23-2016, 07:00 PM	#9
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 29 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	In the video it looks like your intake is off the throttle body? And IACV isn't hooked up? I.e. your engine is pulling in 100% unmetered air.