transam junkie

i have a 98 trans am with a 2000 motor
i need to order fuel injectors and spark plugs, i know the fuel injectors for the 98 ls1 and 2000 ls1 are different, so i need the ones for 2000 right?
and basically any part internal or external i would get for the 2000 firebird cause thats what motor i have
also if i get a tune i would tune for 2000 not 98
what about fuel pump? wud a 98 work for 2000?
thanks

RPM WS6

iTrader: (3)

Several things to cover here...

The '98 injectors are slightly bigger than the '99-'00 units, so if you are still using a stock '98 tune then, ideally, you'd want to stick with the '98 sized injectors. But the difference here is small, probably not a big deal on an otherwise stock engine.

Any internal or external engine parts, yes, you'd want to get 2000 stuff if the whole engine assembly (meaning more than just the short block) is from a 2000.

Fuel pump, you will have to get a '98 piece or do a conversion. The entire gas tank was changed for the '99+ cars, so a 2000 fuel pump module won't just drop into a 1998 tank (not that you would need a 2000-specific pump in the first place, there's nothing wrong with the the '98 module in a '98 tank - even with a 2000 engine).

As for any custom tuning, the injectors are probably the biggest consideration here. Nothing else really changed from 1998 to 2000 that would specifically impact tuning (the cam and intake update, and deletion of EGR didn't occur until the 2001 model year).

transam junkie

hmmm, my 98 gets like 10-12 miles per gallon, smells like fuel, and runs rich..
is it possible the 98 injectors @28.8 installed on the 2000 motor that are supposed to be spec'd @26.4 is just dumping too much fuel?
my buddy has a 97 lt1 and when he put 30 something injectors in his car ran like crap and he said his car felt heavy, like he had 10 people riding in it.. cause my car feels that way also..thanks

RPM WS6

iTrader: (3)

The PCM doesn't know what model year the engine is from. If you still have a stock '98 tune and stock '98 injectors (even if the engine is from a 2000), then the problem is not with the tune.

Again, there are no internal (or external) engine changes from 1998 to 2000 that would necessitate tuning changes to restore proper MPG. The only change between those years that would have any impact on engine performance was the exhaust manifolds (slight design change and material changed from rolled stainless to iron). But no significant tuning changes are needed for the updated exhaust manifolds (plus, it's entirely possible that you still have the '98-'99 exhaust manifolds in place, unless you also modified or swapped the Y-pipe and cats to the 2000+ configuration during the engine swap).

The most significant change to the LS1 came in model year 2001, with a new (LS6) intake manifold and completely new cam (LQ4/9 piece). But none of this applies to your 2000 engine. 1998 injectors on a 2000 engine will perform just like 1998 injectors on a 1998 engine, assuming the stock 1998 tune is still in place.

I'd look elsewhere for whatever issue is leading to sluggish performance and poor MPG (I'd probably start with a comprehensive cleaning of the MAF, assuming there are no codes present for other obvious issues).

transam junkie

thanks for the reply..
i dont have the stock tune, (does this change things} there is a hp tuners tune on it, i have ls6 intake, texas speed long tube headers, ory pipe, gmmg chambered exhaust, no cats, egr delete, air delete, slp c.a.i

RPM WS6

iTrader: (3)

In terms of the injectors, as long as they are still the same size as what it was tuned for, then it doesn't really matter if it's an OEM tune or has custom tweaks for various other modifications. If '98-sized injectors were in place during the tune, and that's what it was tuned for, then that's what you want to stick with for best results. 2000-sized injectors would be a downgrade, so I'm not sure why you would want to do that in the first place (unless it was tuned with 2000-sized injectors already in place, in which case you'd want to stick with that size unless you plan to retune).

If the previous tune was done poorly then that could certainly be the source of your issues. But this is no reason to move to smaller injectors, just make sure it's tuned properly for the size you currently have. '98-sized injectors will work fine, assuming that's what's in the tune, on a 2000-spec engine as there is no difference in power output, other than perhaps a marginal flow difference in the exhaust manifolds - but that's now negated as you have headers. You are better off with the bigger injectors and a proper tune for such.