Changed injectors to 555cc, fuel in cylinder engine locked up

[MJD5SS]

G'day, I changed my 370cc injectors to 555cc yellow nismo injectors on my N15 pulsar.

I used the "resize injector function" which did adjust my K constant

Now when I was cranking over, the engine locked up, I inspected the cylinders and the 3rd cylinder was full of fuel.

I proceeded to crank the engine over with injectors disconnected and spark plugs out to clear out the fuel.

after doing a bit of research, I found that "710ms" or "0.71us" is correct for the 555cc yellow injectors, for reference the 370cc red top injectors were running at 600ms

Is this because I didn't adjust the injector latency and left it at the settings of the 370cc?

please help & Thank you!

[Matt]

Such a change to the latency would not cause the injectors to fill cylinders full of fuel (particularly if its just the one). Were the injectors flow tested before you used them? Are they new, second hand? Where were they purchased from.

[MJD5SS]

Yes according to their listing:

http://www.ebay.com.au/itm/131905292675 ... EBIDX%3AIT


Hey thanks matt for replying, I have a feeling one of the Orings was pinched and was leaking into the intake manifold, I re-fitted the 370cc's and fired it up. (all is ok)

I will fit the 555's back in and remove the rail and check while the injectors are in and primed if there are leaks.

[Matt]

I would not purchase injectors like this from ebay.

'PROFESSIONALLY re-manufactured' which means they took some JECS injectors (check does it have the JECS stamp and part number on there) and then drilled them out to flow further.

Didnt you say that the cylinder was full of fuel? If the O-ring was pinched then I cannot see how this would result in more fuel being added to the cylinder...

[MJD5SS]

Yes, if the secondary lower smaller O-ring is pinched it will Piss out fuel into the cylinder. I had it happen when I installed the 370ccs back in. luckily I heard it hissing and the pressure in the rail dropped.. Could of locked up the engine AGAIN! lol.

These sr20's are pretty strong. Have almost 300k on the clock and see's full boost and limiter every time I drive it.

[MJD5SS]

Ok, quick update, I fitted the 370cc's back in and fired right up.

Now, after confirming the motor is still OK, I went ahead and installed the 555cc's back into the rail making sure 100% I did not pinch any O-rings.

I primed the fuel pump and it is holding 30+ PSI, checked inside the cylinders. And it is completely dry.
I will fire up the car once I install the rocker cover again.

Markings on the injectors are:

[MJD5SS]

yay car fired up. all working. E85 in.

would anyone happen to know the correct latency for these injectors? I entered 0.62ms they worked, and also I changed it to 0.72ms and worked ok aswell.

quite smokey. but air fuel ratio is OK! (probably cause I haven't driven the car in 6 months.)

I'm thinking of adding a few degree timing from the distributor..

cheers.

[Matt]

Not for these since they are not branded injectors. You will need to adjust the latency until idle is fine (assuming you have base fuel adjustments all in the right place at cruise and is good on boost)

[MJD5SS]

Thanks matt, idle seems fine, yet to take it for a spin.

[MJD5SS]

took it for a spin, it is lagging \ missing when coming onto boost before 4000rpm, I'll play around with the injector latency, see if it fixes the issue

[Matt]

Latency will only resolve issues around idle. If it is missing going on boost then check the AFRs right the way through. Make sure you are not going lean anywhere. check fuel pressure also in case of lazy fuel pump

[MJD5SS]

Thanks matt will do, I'm running BKR6E plugs gapped to 0.88... so if the above doesn't resolve the issue, I'll be gapping them down to 0.7

[MJD5SS]

https://youtu.be/yTA2bEeLKb0

All fixed. =)

[Matt]

Excellent!