ummm... fuel injectors on a '91

[marcusZee32]

so, for a couple of days now, when i start the car up after driving it for so and so throughout the day, the Z will turn over and start just fine. but the idle is rougher than usual, and when i get rolling, the engine is rough and kind of "gurgly" through the 2000-4000 RPM range.

also, the power is definitely lagging, but it goes away, either after a minute of steady idle, or at some point while driving, or after the car sits for a couple of hours.

this happens usually AFTER the first time i start my car.

the oil was changed about 500 miles ago. spark plugs were also replaced about 1,000 miles ago. but this sounds and feels like an injector problem. i believe my Z has the old style and i have paperwork showing they were replaced in 10/08. but they must have been replaced with the original old-styles.

if not the injectors, then the connectors may be corroded.



if anyone can relate to this, and advice on doing a plenum pull along with replacing the injectors and connectors, it'd be greatly appreciated

[BlackWidowZ]

what about the fuel filter? My injectors have never been changed and it runs fine. Did you put anything in the gas? I'm not saying that you don't have bad injectors, its just seems less likely since you say they were all changed 4 years ago.

[marcusZee32]

the filter was replaced along with the injectors, and so i don't think it would be that. i did discover that the connector for injector #1 was a little corroded. i cleaned it off pretty good and pried out the others and did the same. it started with no rough idle. i'm guessing now that it just might be the connectors.

if all 6 injectors were replaced in 2008, they should still be good up to today, so i'm gonna say the connectors and harness for the injectors may be what's causing the rough idle that eventually goes away..

[DCaff300ZX]

I think that you found your problem with the connectors, it's VERY common for them to be green inside with corrosion and as you did, cleaning them well and adding di-grease when re-installing the connectors should keep them safe for years to come.
Be sure to replace any with cracked/broken boot shrouds as well, this lets in moisture to the leads.
Also, given the age of our cars/engines and the lower octane fuel, I'd recommend running Lucas upper cylinder lubricant gas additive at least every 3rd tank as it works wonders in both of my Z's lubing the injectors...and I also recommend doing the switched injector voltage mod to remove the electrical current from an always-on state in your injectors to a switched-on scenario.
This should keep your injectors working as best possible!

[Ace2cool]

You're on the right track for sure. Please post in the tech section for tech questions, lol.

Can you replicate it in neutral? If so, try pulling connector packs when you're revving and see if it changes. If no change on a cylinder, then you've found the one with the issue. Isolate faults before troubleshooting it down to a system.