gen 1 running lean after mods UPDATE

[sharkey]

injector cleaner- used it before with my old injectors, they were pintle style.

a/f gauge- im only paying attention to it as a refferance. i go by the plugs, and they are showing lean.

my car has a maf and an iat. and i have an adjustable fuel pressure regulator thats meant for a 5.0-5.7l camaro (its a holley unit, 512-501)

[sharkey]

well, after today, im battling a vacume leak. i have no clue were its comming from though. changed all the vacume lines, (even had to make a new pcv system), and still leaking. guess ill have to try some new intake gaskets.

[XLR8ING]

Just FYI, on my gen 2 3.1 I chased a vacuum leak for a year. Car ran fine, and the A/F gauge showed ok though. But the car idled like crap. Plugs always looked like there must be a vacuum leak, but I couldn't find it.
One day I'm working on the plenum, and had an extra set of plenum gaskets so I shove those in during reassembly.
Go figure, no more vacuum leak.
Plenum gaskets were new when I put them in, but just never sealed right I guess.

[sharkey]

found my leak, it was upper plenum gaskets. i had to buy a whole top end set just to get em ($40 can). car idles smooth as ever now, but im still having the lean issues.

keep in mind here, im not saying im running lean because my air/fuel gauge shows lean. im using that as a refferance, but im checking plugs at random, and they are telling me its lean (snow white and starting to specle).

im gonna see what a new mass air flow sensor is worth and try that. it seems to be working ok (no codes, tests ok) but the filiment could be fouled. ill try cleaning it and see if that helps. i have a k&n filter on a cold air intake and it could have fouled the maf. (at the last transmission seminar i was at there was something about k&n filters screwing up trannies in newer gm cars. what happens is if they are over oiled, and most are, the oil gets onto the filiment and it will read incorrectly, causeing shifting problems)

[bszopi]

You can get the upper gaskets seperately... I have the FelPro PN around here somewhere...

[sharkey]

well, to late for that. my parts guy couldnt find the upper plenum gaskets seperatly (i ranm into this before), but if you could post the pn for them, it would be greatly apreciated (i know the upper plenum will come off again).

anyways, i looked into my lean running problem today a little at work. i discovered i had a code 34 and 45, 34 being maf circuit low and 45 being rich, both can be caused by a faulty maf. i hooked our scanner at work up and managed to get the data stream up (ive had problems before getting it up) and went for a drive while watchiong the maf. it reads about 6 at idle, and at 3000rpm freereving, it goes to about 10. i took it up to 5200rpm while watching it, and it hit a max of 20. im thinking that its fouled or bad. the range is 1-155, so i think its a safe bet to say its a problem.

[sharkey]

ok an update to my problem. i cleaned the maf, and slapped it back on. it ran well for a couple days (a/f gauge 1 bar into green, plugs cleaning up and looking better), but after i changed the fuel filter, its back to being lean again. im thinking it is a coincidence, but im gonna have another look. im also gonna have a good look at the maf tomorow to see if there is a lose conection or anything noticable. id slap a new one on, but for $283, ill see if i can fix this one (if there is deffinitly a problem).

im starting to wonder if my fuel pump is dying on me.

[sharkey]

ok for anyone that still reads my threads, i think i got it fixed.

it was the exaust crossover pipe, it was cracked, and air was getting in and showing lean on the o2 sensor. now this doesnt explain why the plugs were showing lean, but they have cleaned up and it now shows 1 bar green under WOT on my A/F gauge.

im having another slight problem, but im 99.99% sure its plug wires. when i take it over 5k rpm, it kinda just hangs there and doesnt pull, and surges. ive felt this before in other cars, throw a new set of plugs and wires at it, it clears right up. i changed my plugs yesterday (put ac delcos in) and my plug wires were looking pretty sorry, and the ends were all pulling out. i tried to get a new set, but all i could get were neihofs ort autolite, and they are absolute garbage.

[Corpse]

"were looking pretty sorry, and the ends were all pulling out" - Yeah, you probably just killed 'em. You could just re-end the wires but, if they look like crap on the outside, figure the inside may not be doing so great either.

About the 5K RPM thing - I would say it is defenitely worth replacing the wires even if it doesn't fix the problem. Are you using the origional stock coil BTW? If you are, replacing the wires and the coil may be a good method of choice. I dunno what was used for a coil on those vehicles but, coils can wear out in effectiveness. especially if you have an oil cooled one that lost it's oil. Or, if it was located in a heat soaked location. Make sure also that the coil wire is as short as possible. And, that you ground the ignition system to the block, it will eliminate headaches and help promote maximum spark.

Also, ignition grounding is very important, did you know that if you were to only have a ground to the ignition system on one side of your engine (like left or right bank) that the energy will, on-average fire through your camshaft and eventually start pitting on the surface? It is a true thing that happens, I guess the gravity (?) the camshaft creates makes it more conductive and therefore, it is the easiest path for energy to flow. Best way to go is two ground wires, one on each head.

Just wanted to lay down some info. I figured you may have a coil and such though, due to the fact that, I believe you mentioned you had an MSD box earlier, so, I assume you got a coil.

-Dave

[sharkey]

i had wires on it that were a couple years old and the boots were hard and cracking, and the ends pulled out. i put on some aurora wires (bet you havent heard of them, they are a local company. they basicly buy msd wire and make the leanths themselves and put their name on it) and problem solved. it purrs like a kitten now, and has better throttle responce. now that its fixed, im going to look more into my msd 6al box.

i do have an msd replacment coil on it, and ground wires on each head (ive seen the results of bad grounds. i work on a top alcohol dragster, and once someoine forgot to put a ground onto the one head, and it welded the head studs to the heads.)