HELP! 94Z Lack of low end torque, hesitation, stumbling!
So I picked up a 94 Z28 LT1 Auto. Ran pretty good, some classic signs of Opti starting to go with a little hesitation here and there. Added a 100 shot wet kit which worked great. Car was a burnout monster and a riot to drive...
Well, then I left my nitrous switch on and punched it from a stop. Massive burnout I was not expecting and immediately let off and there was a huge backfire that blew up the MAF and sent the air filter flying! Very embarrassing lol.
Replaced the MAF and it ran but definitely never the same. Stumbles badly under 3K. It is better when cold but gets worse when it warms up but the earlier signs of Opti going were the same way. Will not do a burnout even with a brake torque. Runs good up top though. I replaced the following:
MAF - Stock unit
Opti - Brand New Delco full unit
Plugs - 1 step colder for Nitrous
Wires - Stock
Timing cover gasket, pulled pulley
It also has a K&N CAI, Catback exhaust. I did all the bushings, coilovers, brake upgrade, tires, rims, etc., before the incident so I have quite a bit of time and money invested into this car so I need some help figuring it out PLEASE.
A couple things to note. The coolant temp sensor is unplugged and lying in the engine bay. There is a secondary temp gauge from a port in the water pump. This has been this way since the beginning so not related. I checked for vacuum leaks spraying carb cleaner and did not hear a change in rpm. I'm stumped. Only things I found are there is an EGR solenoid vacuum port that is unhooked? See pic attached. Can't find out where it goes? Also, there is a loose connector lying in the engine bay that I can't find a home for. This has been there all along though too. Perhaps there was a hose for that EGR port that got knocked off when I blew the intake off?
First place to start would be to check for codes (one pops up every once in awhile but it has always done that even when it ran strong). I took it to my buddies Midas and the tech could not get his OBD1 scanner or the paperclip trick to communicate at all! Maybe something is wrong with the wiring from the ECU.
Any ideas on what to look at next considering I cannot get any codes?
EGR solenoid unhooked?
Secondary ignition coil
There has to be some relationship to the work I did or NOS backfire event. I'm fairly certain I performed all the work correctly so what on this list could have malfunctioned due to the event or my work? Thinking EGR or the MAP or IAT sensor? How can I test these? Or should I start somewhere else? Thanks in advance!
Last edited by mschmidt33; 04-21-2017 at 10:39 AM.