250racer

ive got my 1993 z28 383 stroker gm847 ported stock heads 42lb injectors pcm forless tune and it can only run for about one min till it fouls the plugs ive been messing with it for about a yr and cant seem to figure it out soo....
i was thinking about going to a carb ive read and got the part number for the gmpp intake and i can use a HEI distributor and can get the block off plate from gm for the opti and use a low pressure inline fuel pump. but the thing im a lil confused about is where do i get power for the HEI dist from?

p.s. if anyone has a write up or and maybe some pictures of their carb conversion that would be fannnntastic!!

BigBadBlack93Z

HEI power comes from a key ON power source, this can come from a wire you put in or pull power from the starter wiring.

pretty sure you have to hack up the cowling to fit the HEI in there. on the plus side it should be trouble free once you convert it.

WS6T3RROR

You need to figure out a way to time the engine as well, the stock balancer has exactly nothing in the way of timing marks and is just pressed on any old way. You need the balancer hub not to slip and for the balancer to be marked for at least TDC

GMRL

You may be able to use this style distributor to clear the cowl.
Maybe, maybe not, just an idea though.

http://store.summitracing.com/partde...5&autoview=sku

mdacton

hei will not fit.


I have a low profile MSD. with mag pick-up so no crank trigger. Hei is like 4"+ taller than this

Why not just fix what you have? going to a carb is not going to be any better......you still have to tuyne it etc.
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96capricemgr

The GMPP LT1 carbed manifold is a low rpm manifold, not a good match for a big cammed 383.

If it is fouling the plugs like that the first two things you need to do are verify injector size ans fuel pressure are in agreement and then verify that the tune is set for that. Honestly I wouls swap to a 94+pcm before a carb. The 94+ systems are easier for the DIY'r.

250racer

ya i checked the fp with vac line off it was where it was supposed to be.... but its primarily going to be a drag car now so i was going to just throw a carb on there and be done with it im tired of the electronics and my car just collecting dust. but im glad to see im getting some help and not worthless posts asking me why i want to switch!

thanks for the help so far!

mdacton

if your going to do it....if I could do it again I would go crank trigger, crab cap, super vic intake with the SBC bolt pattern on the heads....

and acctually I woud do a dart block 434 with a good head on it in the upper 300's and spend the same money......then again I would probly just go with a bbc.

Its all up to what you want, my problem is I always get in a rush and want it back together asap......and never plan anything out so I constantly spend way more than needed and end up with a half finsihed project then change ideas half way through.

The gmpp intake is junk IMO.

96capricemgr

Honestly if I were you I would be questioning the tune. I am sure the guy who wrote it swears it is god's gift to tuning but you get someone else to look at it and they may solve this in a matter of minutes.

Since the GMPP intake is a poor choice this carb conversion you want is going to be more difficult and expensive than you think. I would encourage you to try and get a chip from another tuner or to get another tuner to look at the one you have.

mdacton

I agree 100%

Plenty of others have good running cars.....look around and do some homework. Try talking to alvin@ pcmforless

250racer

i have a moates burn1 and datalogging cable but not a tuning program... my other thought i have is maybe getting say tunercats? (if thats the best program for my 93) and try tuning it myself instead of doing the carb i cant bring myself to pay for a tune again!! and figured carb would be my best/easiest fix

i have checked fp and that was good and checked for bad grounds leaks etc.. the only thing i found was a corroded temp sensor and replaced that but have to change my plugs again to see if itll run for more than a min

96capricemgr

Tunercat is what you need, only about $90 and great support.

Like I said a carb swap is not going to be as cheap and easy as you would think so at least take this one more shot at getting the injection to work.

WS6T3RROR

Ask moates if you need the real time or "RT" version of tunercats to work with the setup you have.

What you probably have wrong is somewhere in the tune a constant like the injector size is set wrong. Seen that plenty fixing tunes for people. How hard its going to be to get dialed in all depends on how you want to run it.

Other than that i would look at the open loop a/f vs coolant temp tables. Probably set way rich. Nobody seems to touch these ever but they need it BAD with a cammed ride.

maverickmk

not to pile on, but I'm in the same camp as just about everyone here, I think your money would be far better spent to fix what you already have. I think you would spend a lot more money switching to a carb setup. It's $125.00 to get someone to program your car vs a lot of money for an intake, carb, distributor etc. just my opinion though

WS6T3RROR

I am probably the only one here that would leave the opti and pcm in charge of the spark timing and run a map and rig up the tps onto the carb.