Long story short I picked up a nice looking 02 Z28.

Owner 1 The car was tuned with a cam 228/232 600/600112 and long tubes.
Owner 2 added 243 heads no tune change drove it for 3 months like this
Owner 3 Untouched and unturned for about 3000 miles and a year and a half

I didn't know all this when I purchased the car sadly. It shows no codes doesn't smoke starts fine. smells rich and drives fine but is NOT fast at WOT especially from the lower RMP range.

Once I found out it wasn't tuned after the 243s I haven't driven it until I get it tuned on Saturday.

My questions is....what if anything other than tune could be wrong with the motor. Am I tune away from a sweet ride?

 

A friend of mine had a similar situation and his tuner said it was okay because they aren't all that different from his original heads. It wouldn't hurt to check obviously. Just my 2cents

 

Are you getting a tune on a Dyno? Before I'd let anyone tune it I would go over EVERYTHING engine related including compression, spark plug condition and read them, change the oil, fuel filter and fuel pressure. I go over the entire car invluding the trans and rear also. Tuning without having a good solid base is worthless.

 

Adding 243's won't change enough to hurt the car. I bought a car that had a ls6 with ported heads swapped in, stock tune. It was ran like that for a long time. No issues

 

Seems no one remembers that these cars were out for years being modded with heads, cams, intake and exhaust before there was even a product out to tune them with. Best we had were things like Hypertech hand helds which were crap for those kinds of mods and MAF translators. I got my first HP Tuners in July 2004 and it was V1.3.0 so you know it hadn't been out very long and I think LS1 Edit came out maybe a year before that.

 

The car feels fine at part throttle but doesn't pull like it should. I'm going to pull the plugs tomorrow and change them. I might have a compression test done before we try to tune it.

ALSO the 243s are Ported and Polished but i dont know the specs

 

Change the fuel filter AND CHECK THE FUEL PRESSURE!

 

I will changing the fuel filter as well.

 

fuel filter changed the one in there didn't look bad ...compression test and plugs and wires going in before the tune tomorrow. Trying to find a fuel pressure reader I can rent.

 

I checked the Fuel pressure today and I get 50 psi at key one and a fluttering needle between 54 and 56 at idle...where is the vacuum line located that I can disconnect to simulate WOT.

 

52/53 PSi at WOT

 

No good....replace the pump. Should be 55psi and up. I like to see 58psi. There is no vacuum boost on these cars, it single line no return from the rail. Fuel pressure is regulated inside the tank in the fuel bucket. The fuel gets pumped into the fuel filter then goes to a T near the fuel filter where it splits one line runs up to the rail, the other back into the fuel bucket to the in tank regulator.

 

Yup, grab a Walbro 255 for $100 or so and it'll be good.

 

This+++
Even if you show good pressure at idle, it can drop off under load. I have made money on these cars for this exact reason.

 

you need delete that comment so you're not labelled anything scam like on here

 

Why is that? I bought a 99' Z28 on my way home from looking at anot her car to flip and it had no *****. I got it cheap for that reason. I took it home, did my diagnosing, fixed it along with some other problems and flipped that bitch. Nothing wrong at all with that. I didn't even try and get the car cheaper. I paid the asking price.

 

It sounded pretty bad before this clarification

 

I can't fix the world's dipshits. LOL I bought a car the other day for almost nothing because the guy was just tired of getting bent by well known shops around here. I will make cash on it and gain some cool parts. I gave his asking price as well.

 

I hear you. You just don't wanna make it look like you scam people, moderators don't like that mind of thing

 

Turns out the throttle cable was messed up... was only getting 60% throttle at WOT pedal. Fixed and retuned the car and it made 405RWHP and 406 TQ. Fuel pressure was fine on the dyno...my gauge was an AutoZone rental.