turbotim

Hi, I own a 85 zxt. I changed from 260 to 460 cc high impendance injectors. Car seems to run fine at part throttle or cruising speeds with correct afr's. When I come to idle I get a hanging idle and also a high idle, but with correct airfuel ratios. When I lean her out the idle goes down but I don't want to be idling lean. While this is happening vacumn is about 20 to22! And there is no leaks around the injectors! Any thoughts!

turbotim

Could be a possible vacuum leak at injector seals. I don't see why I wouldn't see fuel leakage there too! But, I am on my way to pick up a bottle of carb cleaner to see if this is a vacuum leak situation. I'm also getting abnormal readings in vacuum on my boost gauge now!

turbotim

Okay, started her up, she's running lean afr's gauge is of the charts. Cars idling like crap, boost gauge is supposed to be reading 20 to 22 at vacuum and its reading 10. At that moment I step over to the engine and spray carb cleaner in the direction of injector O-rings. It's idle goes up as soon as I spray it, then goes back to running like crap. So I think I found the problem. The car will get good afr's when warmed up, but that's because I can tune it. Its idle will also go up as it warms up if I try to keep the fuel there. Sounds like a vacuum leak. These injector seals were bought of e-bay. And they seemed to be to small for the hole of the engine, but still fit over the injectors, something didn't seem right about them from the get go! Looks like I will be going oem seals now!

turbotim

It was a vacuum leak at injector O-rings. Put the ones in from Nissan, and she runs good now!

turbotim

Anybody know if when putting in bigger fuel injectors, do I keep the fuel pressure at the stock 37psi. I have the ability to add fuel through injectors or take it away via airflow map.

Skully

When tuning for different injectors you want to do it through the fuel map and not the fuel pressure.

turbotim

Ok, thanks for the reply!

turbotim

I felt change in power after I managed to get car to run right. I did not turn up the boost. The same 9 psi and grunting power. My injectors must have been shot! Our cars could be really fast!