Hey all, before I start I would like to say I appreciate all the information I have gathered before joining and making a post. I just recently purchased my 4th Z28. I have owned a 92, 99, 95, and now a 94. I have never had a major issue with any of the previous 3. I come across this beautiful 1994 for sale last week with tons of service record and a pretty sweet deal. I thought I’d snag it up so my son and I could have some bonding time with it before I release him into the wild when gets his license in 2 years. The car is bone stock with 116k miles. Runs super strong as it should, has a nice idle and sounds really nice. The problem I am having after cleaning or replacing all the common things (MAF, MAP, TPS, checking the EVAP purge and canister/lines) this car reeks of gas under the hood and is often hard to start. I have seen no signs of leaks around the injectors (records show #6 injector had been replaced along with plugs wires and opti). I disconnected the vacuum line from the fuel pressure regulator and connected a clear hose from my fuel pressure tester to see it there was vacuum pulling fuel into the throttle body and nothing. The biggest thing is each time I have removed the ductwork for the intake, it had moisture in the snorkel tube that hangs in front of the radiator. Turns out it’s gas. How is gas getting there and where should I start.

 

first off download factory service manual for your year here http://www.mediafire.com/?40mfgeoe4ctti you should consider getting a paper version. search on eBay. I would have injectors flow tested and cleaned by a injector shop. they will tell you if they are rebuildable, some times they can not. this will tell you if the injectors are all or part of your issue and is a good idea for an old high mile car even if they seem ok. have you found shbox? 4th Gen LT1 F-Body Tech Aids its a good site for 4th gen z28 info. test your temp sensors to insure they are not failing and telling system its -40 degrees or some false reading that's low, this would cause the computer to dump lots of fuel into the cylinders. if you have access to scanner scan for trouble codes, might be able to get idea where to look if its got some codes. you will want to inspect the evap system as well, find info on shbox and service manual on that. it may be fuel is getting into system from that. well there is a start for ya. welcome to the forum hope we can help.

 

Thanks for the reply. I have inspected all of the evap system but not the temperature sensor you’re speaking of. I did change the fuel pressure regulator today and while testing the pressure afterwards I found out the wrong valve stem was in the pressure release causing a drip. 72.99 for a dang new stem. After robbing one from my S10 fuel pressure is slightly low. 35-38 on prime and 30-35 on idle which seems about right. I washed out the intake duct work pretty well and cleaned the throttle body the lazy way and took it for good hard drive. Hit 3k RPMs a couple times and got up around 90. No gas in the ducts when I got home. I do have a slow start also taking 2-3 turns of the key to get started. I’m curious if O2 sensors may help with the richness. I did scan the vehicle and cleared the old codes when I purchased the vehicle. None have returned. Thanks again for your advice and I’ll check for that service manual now. Any additional information will be appreciated.

 

Regarding the slow start issue, try cycling the key several times to prime the fuel rails and see if that helps.