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Lt1 Newbie

2283 Views 21 Replies 6 Participants Last post by  Racy Roadmaster
Hey guys, like the title says im a newbie to the LT1's so im needing some help. I have a 94 Formula and im having issues with it starting. After it sits all night and i come out to start it the next day it cranks fine, but wont fire. It hesitates and sputters like it wants to start after cranking for a moment but it takes it awhile to get it started (I usually have to listen to it spit, sputter, and choke about 4-5 times before it fires). Once it starts i dont have the problem for the rest of the day and it starts fine every time. Anyone know what it might be?

On another note, i have planned on trying to get about 375-400 rwhp out of it on down the road. It is a 94 Firebird LT1 M6 that is pretty much stock. It is gonna be my dd and i wanna stay pretty cheap with it, be able to maintain respectable fuel mileage (16-20 mpg), and not get too wild with the hp so i wont be constantly breaking things. Would the LE2 package, 226/232 cam, lt's, cai, airfoil, ported intake and tb, and tune get me close to that or is it just wishful thinking? Also with the setup i mentioned would i still be able to maintain using a stock bottom end or would i have to upgrade everything? Im pretty much mechanically stupid on these, but im eager to learn. Thanks in advance and sorry if im repeating a worn out subject.
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Welcome Newbe, These cars start best when you dont touch the gas pedal before starting. You may have alot of carbon in you intake or intake valves. For starters I Would use a good fuel injection cleaner like Red Line
or the Chevron stuff in the black bottle. It may take a little while to clean up the fuel system so dont look for an overnite fix. Some folks may recommend a Sea Foam treatment,but I would only do that as a last resort. How many miles on your LT1? IF YOU WANT IT TO LAST I would
change all the fluidws and replace everything with good brands of lubricants and fluids. good luck, ed
Try cleaning your MAF sensor while you're changing the fluids Racy mentioned. If that's what you are gona do. A dirty MAF will make the car do that too. Mine did.
It has 160xxx miles. I use Royal Purple fluids and oil, and when im low on money i use the Mobil or Castrol Syntech with K&N oil filters. I've heard thats the way to go fluid and oil wise, but like i said im new to this. And is there any particular reason you think that Seafoam should be used as a last resort? I've used it in several of my vehicles and i like it...Is there something i didnt know about it?
I also use SF regulary with no issues....hmp.
well ,this is what I know about Sea Foam,when you put it in the fuel system thats ok,but when you force it,or go direct ,through your intake system you loosen up so much carbon and other stuff lining your intake system that it often clogs up your catlytic converters,which becomes a pretty large problem. ed
OH!! Ok, i know what you're talking about now. I did that on my Tacoma and after new plugs and 02 sensors im finally back running.

What about my other question about the LE2 setup? Can anyone voice an opinion on that please?
Need to get a fuel pressure gauge and see if your getting 41 psi or higher at key on prime. if fuel pressure is low car will be hard to start.

Have you changed your fuel filter, as clogged filter can cause problems.

Eliminate fuel system as a suspect, then if still hard to start, test the ignition system. First test would be to put car on obd1 scanner and see if any codes are present. Just because check engine light isn't on doesn't mean you don't have codes present. DTC 16, 41 & 42, all ignition codes, don't light the cel. But will affect running.

Go to sticky threads of this section and watch the diagnosing the optispark video there. Then run tests. also has opti testing and coil testing. Your icm can be tested at an auto parts store.
I'll have a diagnostic check done on it the next chance i get. And i dont think the fuel filter has been replaced, but it would be a good idea whether thats what the problem is or not to have it changed considering how many miles it has on it.
Forgot to add, in the ignition department, check your opti wire harness for burnt pins, loose connector and pins, bad wires.

When car is running, wiggle the wires and see if it makes a difference in how engine runs. if yes, get a new opti wire harness.

And while in ignition land, have the plugs, wires, opti cap & rotor ever been changed? And if you do change the cap & rotor, remove the inner shield and take a look at the optical sensor compartment. If it's full of corrosion, oil, or coolant your opti has seen better days.
Another question i had was on editing programs. I was wondering if someone who is mechanically stupid when it comes to programming, such as myself, could learn these programs and which one is overall easiest to use. I saw that LT1 Edit and Tunercats are pretty popular, but like i stated before i dont know how to read these programs but i would like to be able to. And also do these programs offer diagnostic checks or would i have to get another program for that? Any help is appreciated
PM me with your e-mail address and I'll send you several articles on tuning and sensor readings and what they mean.

I like tunercat for ease of use. The hard part is learning what and how much to change. As a beginner, you should read your stock pcm tune and request members to post the tunes for their cars, with similar mods to yours. That way you can compare the stock versus the tuned settings and see what others have changed on their tune.

Tunercat has a side by side comparison mode for 2 different tunes. Don't know if lt1 edit has this feature or not.
New issues have come about. About 15 min. ago i took the car to spray all the pollen off of it. While i was washing it i left it running and sprayed it off. The only thing i did different this time was spray around the from edge of the hood to get the settled pollen out. When ever i got it out of the car wash i drove it possibly 3 miles to another gas station to put some air in the tire. I shut it off and spent possibly 3 minutes tops hitting the tires with a little more air. When i went to start it back it spit, sputtered, and abrutly shut off (not like it usually does, as previously mentioned). Cranked it a few more times and it fired up. However, when i got back on the road as i started to get into the throttle it popped and backfired so hard that im not sure that the old man at the gas pump didnt have a heartattack. Figured i may have gotten something moist so i kept the pace pretty steady and figured whatever it was would dry off after a few minutes of driving, WRONG! Tried to turn around and it died on me. Started it back and it rattled and knocked and then made a whizzing sound like a supercharger spooling under the hood then back off she went. Got her fired up and got it back home but its idling somewhat smooth, but as soon as those rpms start to climb quickly it backfires like mad...only does it when you start to hit it quick, you can ease into it and it'll rev pretty high without backfiring. Its still sitting in the driveway idling and im praying that i might have just gotten a little moisture around the Opti and its drying out. Any ideas on what it might be?
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Went outside to see if the problem had ceased, No dice. Backfired, rpms shot down to nothing, and she quit. Started it up, it beat, rattled, and knocked and then it was like it was running but not running if that makes sense. I could hear it sucking air very hard and then that spooling sound again, but the rpms werent moving and the car wasnt shaking like it does at idle. Im at a loss. And i forgot to mention that before i washed it it was running like a scalded dog so i dunno if this is something that the water affected or what. Just trying to put as much info out there as possible.
Start it up at night, in a place where there is as little light as possible. Watch for spark leakage from plug wires. Use a spray bottle to get them damp and watch for the light show.

If that's a no go, check for codes, as ignition codes are silent, watch diagnosing the opti video in sticky threads, this section. Do tests.

If all is well in the optical section, your not going to like this next suggestion. That is to remove water pump so you can take cap & rotor off to check them out for wear, corrosion, moisture. While your in there pull off the shielding and check the optical section for moisture, oil, corrosion. If you find oil or water, carefully try to clean it out, keeping in mind that optical wheel is a very delicate part.
I cant tell you whats wrong ,but if you used high pressure water spray from a car wash, you might have ,probably got the opti wet. They are very very sensitive, especially if they are kind of old and warn. We always talk about it on this thread and we are not joking,the opti is a sensitive component. I would keep the hood open foe several hours and see if it dries itself out, If not one of the guys has already instructed you on what to do. good luck, ed:craz28:
Thanks for the help guys. Tried to let it dry out...A no go. Now it wont start at all. Guess it may be the Opti. If i were to replace it would it need the whole new assembly or just the cap and rotor? Seems like they're pretty dang expensive for what they are.

On the other hand i dont think this is the problem, but the hose on the bottom of the tb had severe dry rot and was cracked open. What kind of issues would that cause or is it even a super significant part? Gonna get it replaced, but i was just wondering.
If you have that bad of a vacuum leak or it's pulling air in where the hose is, that could be a factor. I had my intake pulling a little air in after the MAF and it ran like crap because of it. Don't know if it would make it not start, though.
Thanks for the help guys. Tried to let it dry out...A no go. Now it wont start at all. Guess it may be the Opti. If i were to replace it would it need the whole new assembly or just the cap and rotor? Seems like they're pretty dang expensive for what they are.

On the other hand i dont think this is the problem, but the hose on the bottom of the tb had severe dry rot and was cracked open. What kind of issues would that cause or is it even a super significant part? Gonna get it replaced, but i was just wondering.
i believe you have found the problem...but, i would still check fuel pressure.
there are two lines on the bottle of the throttle body that are the TB coolant lines. the "bypass" is very common, and in your case, those lines you are referring to under the TB that are dry rotted might be leaking coolant directly to the top of the optical dist.
if this is the problem, my only solution would be to purchase a REAL opti i.e. dealership, not a re man. or ebay special. unless you go aftermarket, which for the price, its just about the same. MSD, ACCEL, ect. great products. i have my accel dist. since it was stock lt1, to the now new stroker turbo lt1, without a problem. driven in the rain, lived in salty humid florida and now texas.
heres the link fro the bypass.

Intake Oil Leak Repair and Throttle Body Bypass Mod
Everytime i've opened the hood while idling or after long trips i've never even seen a drop of coolant. Not saying that isnt what it is, just saying i havent seen it and i figured it might be flowing while the engine was running. Like i said new to these engines so i dunno. It just kills me how it ran perfectly before i washed it and then crapped out. I heard the opti's were sensitive but really? It only got mist on it, at best. /End rant

Are the MSD's or Accels a little better or they all just polished turds? And again would i just need to replace the cap and rotor or the whole thing? Any places to get a deal on em cause they seem to be pretty pricey. Also are there any other items to replace, maintanence wise, while in the process of replacing the opti? Thanks again guys
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