After months of head scratching, Kian finally finds the cure for his problematic S13 Silvia
You know that moment when you just throw all the toys out of the cot and completely give up on a car? Well after a year and a half of turmoil and countless tantrums like that along the way, I finally had a breakthrough with my 1990 Nissan Silvia S13.
For the irregular or new readers (welcome!), this is a car I thought I’d got for a steal at the start of 2020.
The old fuel reg (left) versus the new and adjustable Nismo unit (right)
That dream evaporated when I found the engine was toast, and after replacing it with a healthier one I went from an engine that drank oil to one that wouldn’t run properly, if it all.
After struggling for a while to get the car to fire I gave in and handed it off to a semi-professional, who after a bit of digging found the cam angle sensor was to blame.
Adjusting the fuel pressure to the correct 36psi with a temporary inline gauge
It uses a tooth that fits into the exhaust camshaft as a timing signal for the ECU, and that tooth had snapped off. That meant the ECU had no idea where the engine was at, so the car wouldn’t start.
With that amended the 1.8-litre CA18DET Nissan four pot finally fired into life, but the job wasn’t done yet.
| Read next: Kian’s Silvia engine transplant
Like some presents you get for Christmas, it looks shiny and ready to go
Even though it now ran, I wasn’t out of the woods by any means. It smelt very rich, didn’t idle very well and would barely rev over 4000rpm (which is only half the rev band on these things) without coughing and spluttering pretty violently.
The very black and fouled spark plugs were more evidence the car was running rich, and because they’re around $30 each my wallet wasn’t a fan of constantly replacing them. I remembered the previous owner telling me that he’d fitted a larger fuel pump to the car just before I got it, and some research suggested there was a good chance it could be overwhelming the standard regulator and injectors, which would explain the over-fueling.
| Read next: Nissan Silvia can of worms
The first one was toast and Kian thought the same of the second engine, not so
Luckily, genuine Nismo adjustable fuel pressure regulators made for Skylines of the same era also fit the fuel rail on the little CA18, so I got a brand new one imported from Japan.
I went with the Nismo because it’s a small, bolt-in regulator, which was super important as Nissan didn’t allow much room between the firewall and the back of the fuel rail, so squeezing the new one on was a bit of a mission.
The cam angle sensor that had unintentionally caused a bunch of grief
After busting my knuckles doing that, the next critical step was setting the base fuel pressure. To do this properly I needed to jump the fuel pump circuit so it would continuously run with the engine off.
I temporarily ran a fuel pressure gauge on the high pressure/feed side of the fuel rail, and then adjusted the regulator until it was showing a stable 36psi, the correct base pressure for this engine.
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Kian persevered with the Silva. Others would’ve taken it to the tip
With that done, I removed the gauge and fired the car up. I should note at this point I’d also installed my last set of brand new iridium spark plugs to give the S13 its best chance of a clean fire.
Joy of joys it kicked into life easily, so I took it for a few laps around the block. At first, I could feel and hear it dropping a few cylinders here and there, but after a bit more gusto they cleaned up and the car was running better than it ever had in the nearly two years of owning it. Success!
One of the many times this thing made a mess of its spark plugs, black means way too much fuel
From Unique Cars #473, Dec 2022/Jan 2023