I rigged everything up and took it for a drive. It stalls when you floor it or give it more than half throttle. It stalls when you put it in gear. It stalls for no reason. It backfires like CRAZY. It sputters a lot at low RPM. The timing is set between 4 and 6 degrees... AND MY TIMING LIGHT WONT WORK ANYMORE. I used it for one day and it's not flashing anymore. I'm within inches of buying a carb

Sounds like either timing or valves to me, wouldnt blame the tbi quite yet. Is the distributor hold down screwed on tight? It might not be your timing gun, maybe its just so advanced or retarded its no longer on the marker. Small **** like that is easily over looked, Ive been where you are. Check both plugs going into your distributor.

Try to reset the valves this way:

Take the bolts off the valve cover and turn the car over. When its running, take the cover off. Starting in the middle and moving outward, back off the rocker arms until you start to hear chattering, its distinct you'll hear it. Then very slowly start to tighten it back down again. When the chattering stops, go either 1/2 or 3/4s of a turn further. I used 3/4ths. Do it for all the rockers and see if that helps. It might be messy, it wasnt on my car but you never know.

Good luck man, hopefully this helps a little.

I agree with Chuck wholeheartedly... now would be an ideal time to redo the valves with the engine running. It's the most accurate way to get the rockers exactly where they need to be when using hydraulic lifters.

I think its an ignition problem- my timing light was not working at the very end of the spark plug, but it worked up on top. I think I need a new cap and rotor so I'm gonna replace those. Does the ignition coil need a strong ground or no? because it's not grounded all that well. What else, hmm... I need to set the TV cable too, and the tech article didn't help me.

I reset the lash (they were loose) and recalibrated the distributor... and still didn't run well. I put the timing light on it and it didnt flash... I put the plug wire on the manifold and didnt see a spark as often as I should, showing a WEAK spark. I'm gonna replace the cap and rotor as I mentioned and hopefully that will cure me. Any other suggestions? text my cell phone via AIM at AnthonyMCell if you get any ideas!

Cap and rotor had no positive effect. I cleaned the ignition coil's contacts and that didn't help either. I don't know what to do


If a distributor gets wet, will that permanently damage it? I left it outside in the snow the other day

HERE'S THE SCOOP
Well my problems keep growing as I touch the car more. I can get the car to run in my driveway, but it's extremely rich. I tried to turn the fuel pressure down a bit, and it works a little. Currently my distributor is out of the car because I thought I might be a tooth off on the gear. I've tried to place the *** damn thing in numerous times, and I keep getting the same results. I don't know if I'm putting the distributor in properly or what.

I know the firing order is 18436572 and that's the exact order the plug wires are in. I wasn't getting a flash from my timing gun at the #1 wire, so I moved it to the coil where it got ample power to strobe the light. Does this mean the spark is too weak? I can definitely see a blue spark coming out fo the spark plug when I remove it.

When the car runs, it's very rich as I mentioned. In fact, the electrodes of the plugs are completely black. Brand new plugs too. There's a visible cloud of exhaust. I took the fuel pressure way down as far as it would go on the Holley. When it ran, I took it on the street. It idled fine in the driveway, but stalled as soon as I put it into gear. I eventually got it out of the driveway and onto the main road. The car would bog when I gave it gas, and it stalled when I floored it. It was both backfiring and detonating in the exhaust (90% of the time in the exhaust at this point). But like I said, the distributor is out of the car now.

I don't know what to do anymore. I've spent literally more time tuning this engine than I did putting it together. I just can't get it to run. Brian assures me that the custom PROM he burned me should not be running poorly as I describe. WHATS WRONG WITH MY POOR CAR?!

When you said holley, I assume you mean 670. Which injectors are you using? They may be way too big.

the 670cfm holley, and I'm using the 350 injectors it came with

way too big.. if you're still on the stock prom, you're calibrated for 45pph injectors.. the holley comes with 55pph or 65pph (I believe it's 65pph).. that's a 50% increase in injector size.. 50% more fuel.. definitely not 50% more motor. On the down side, your stock injectors will probably run lean at anything other than idle..

I have a custom prom

oookay.. well, it's still off, then, if you're running that rich.. perhaps it was calibrated for 55pph and you got 65pph? Have you done a compression check yet? Have you done any datalogging?

Sorry to hear its not going well.

I think that you have the same mods as I do except for the tbi unit itself and maybe 1.6 rocker arms.

Do you have any fuel pressure readings (before and after)?

I am "only" running the stock tbi unit and injectors (LO3 injectors).

On the open road the car pulls to 130 very well. Plug checks and spark knock showing no problems WOT. This has been the setup for 26 months now with no major problems. BL numbers are at 126/127 cruising with around 20 mpg depending on how heavy the foot has been.

I tried as suggested so many times by others to run larger injectors. I can't relate others experiances but the larger injectors and tbi unit itself turned out to be way too much in my case.
I would try the stock tbi unit and the stock 305 chip to get a baseline setup going that you know was working before disassembly. This "should" get you at least to a point where the car will idle and run at part throttle then you can go from there.

I will try the old TBI on there. Someone mentioned that before but I was too excited.

Okay so I killed the battery with all my cranking. Anyway, I set the distributor back on, and it's for sure at TDC. I triple checked. I correctly routed the wires, still unsure if they're all flawless or not. I thought of something in my dream... The TPS sensor is ghetto rigged on there due to a different shape connector and I think that may be the cause. If the TPS was off or on the wrong way, it would be relying on the O2 sensor to give it more/less fuel, correct?


I hope this works. We'll find out in an hour or two when the battery is done charging.

AnthonyMEMU: could a disconnected/dead TPS sensor cause the car to run extremely rich?
Snflupigus: a disconnected tps shouldnt allow the car to run at all
AnthonyMEMU: what if its on backwards?
Snflupigus: Wide open throttle = idle and vise versa... think you've got your answer

dmr, where in georgia are you? i'm in atlanta. i'd really be interested in learning about your combination ... the cam in your sig is the one i want to use in my 305tbi

I'll send ya a PM

don't waste your time on this. i drove myself crazy for two weeks this summer because i believed in the old wive's tale of the distributor being "a tooth off". the distributor can be installed on ANY tooth, as long as the rotor is pointed at the #1 plug wire position on the cap. believe me, i argued and argued about this, only to have to eat crow when i found out i was wrong.

locate tdc after the compression stroke by slowly rotating the engine with your finger over the #1 spark plug hole. when you feel air trying to push out, you are on the compression stroke. stick a straw down the spark plug hole till it contacts the top of the piston. as you slowly rotate the engine, the straw will push out of the spark plug hole as the piston rises. when it stops rising, you are at top dead center.

check the timing mark on the harmonic balancer. it should be at 0. if it's not, but is still visible, you have your cam installed advanced or retarded. depending on how far advanced or retarded it is, this may be your problem. if you cannot see the timing mark on the harmonic balancer at all, then you probably have your distributor installed 180 degrees out. this is easy to do if you didn't set tdc on the compression stroke.

if all that checks out, put the cap on your distributor and mark the point on the distributor body corresponding with the lead for the #1 plug wire. now install the distributor and rotate it so the rotor points at that mark. it's now ready to start. again, the only restrictions on which tooth position it's installed in is that the distributor has enough free room to rotate to allow you to sufficiently advance or retard the timing as you tune it.

This is correct. Some poeple say it is a tooth off because they get the base of the dist so far off that they have to re-pull the dist and start over.

All of the stuff you said was right Sean, except for this, the dizzy doesn't control the phasing of the harmonic balancer. If you can't see the mark at all and your at TDC compression, you have a big problem . My car made a nice little camp fire in the throttle bores when we did cam/intake swap. It was mostly because it was running rediculously (much more-so than now) rich and the valve lash was way off.

you know what? you're absolutely right. the engine rotates twice during the 4 stroke cycle ... the timing mark would be on the right position both times the piston came to tdc. i think i got that confused with the distributor being installe 180 degrees out.

sorry

from what i understand, the whole "1 tooth off" thing started because gm had a directive that the rotor button must point at the #1 cylinder when new engines were assembled. this was strictly for consistency's sake, but turned into an automotive urban legend.

my dad worked on a gm engine assembly line when he was young and swore by that "rotor must point at #1 cylinder" till the day he died.

Haha, no problem, it's sunday (hangover day) right?

I hate to say it but your chip is way off. I spent 6 hours and 20 chips just to get my car to idle without killing me with exhaust fumes. It took me another 20 chips and 3 days of driving and tuning to get it so that it wouldn't die in traffic and justy plain behave enough to keep from killing me. I found that if I could get the car to warm up it would go into closed loop and attempt to lean itself out enough that I could drive it and do some data logging. I had to say three hailmary's and play with it till it warmed up the first couple of times untill I got my BPW in the ball park.
You need to get in touch with your chip burner and have a one on one and find out what he set the BPW for in your chip. If your off by 10 - 20 the car will just not act right at all. My guess is that it will run better with the stock tb and chip with the fuel pressure cranked up. Then you can do some data logging and realize you can burn your own chips. It really isn't that bad. It WILL BE CHEAPER in the long run.

well the car won't even start now, so I DOUBT it's the chip causing it to act that way.

I'm with the previous post...

Find TDC#1, previous post explained it well.

Also make sure ur TDC mark is right on the balancer ( it hasn't slipped )..this is pretty common with higher mile engines.

Easiest way I know is to unbolt the crank pulley and see if the mark on the balancer is close to the keyway in the crank...

If that's the case, rotate the engine until the mark on the balancer lines up with 0 on the timing tab. Now pop the driver's side Valve cover. Look at the first two rocker arms ( towards the front of the car ) this is cyl #1. IF you're on TDC#1, BOTH valves should be close. That means the springs are NOT compressed. If this is NOT the case, rotate the engine 180 degrees, so the balancer TDC mark lines up with 0 on the timing tab and THIS will be TDC#1.


NOTE: This is What I do to get REALLY CLOSE On initial timing on first firing of an engine without having to break out the timing light...

NOW you're at TDC#1..now turn the balancer to make the line match up with where you want your initial timing to be...for example 8 degrees BTDC.


Yank the distributor.

Shine a flashlight down the dist hole to see how the slot in the oil pump driveshaft is facing. Make the groove in the bottom of the distributor face the same direction NOTE: you will need to turn the rotor a bit farther CCW...because as you lower the distributor, the gears will mesh and actually turn the rotor a bit CW.

Make sure it's seated all the way. Put the cap on. Is the rotor facing to #1 on the cap? If not, there's two ways to proceed.

You can simply make whatever spot the rotor is pointing to on the cap #1, and run your spark plug wires accordingly, following the firing order.

OR - if you want number one to face forwards like it's "supposed" to ( doesn't matter really )...pull the distributor again, and turn the slot in the oil pump driveshaft w/ a long screwdriver to match where the slot needs to be to get the dist installed like you want.

Once that's done bolt the dist down enough to hold it down so the timing won't jump.

Now adjust the valves again.

The easiest way I know is this...

1. Engine at TDC#1. ( remember u moved the balancer to set initial timing before u installed the distributor, so now rotate it again until it's at 0 on the timing tab ).

2. Loosen the rocker arms on #1 cylinder. Grab the pushrod with one hand with a socket and rachet on the rocker arm nut. Move the pushrod UP and DOWN while tightening the rocker arm. When there is no vertical movement anymore of the pushrod ( assuming stock valvetrain geometry ), that's ZERO lash.

3. Turn the balancer clockwise 90 degrees ( mark the balancer off if you need to ) and then adjust the next set of valves in the firing order, the same way as listed above.


4. You will adjust ONE cylinder per each 90 degree turn of the balancer, until you complete all 8 cylinders...7 turns at 90 degrees = 360 degrees, so you should end up back at TDC#1.

Me personally, I go through it one more time.

Now it's time to tighten the valve to give it it's "preload". I like 3/4 of a turn on stockish valvetrain....if it's new parts, you might want to go a full turn, cause you'll normally get some wear during breakin that can "loosen" the lash.

Seal it back up. Pop the cap on, hook up the wires and fire it off.

just FYI... i was doing somthing, (i dont recall what) to my car last summer, and i had to run to the parts store real quick.

i forgot to reconnect my TPS sensor... but i assumed it was the light from what i was doing... (i think i was renting a 2 sensor socket or somthing..)

anyhoo, i get back and do some more stuff.. start it and goto drive, and i have a SES light... pull the code.. and walah.. no TPS...

car ran perfectly fine... i mean just like always as far as i could tell.
so if its not wired backwards, then its not your problem.






my first guess would be timing slip.. the times when the distrib likes to slip the most is when you start and shut down the motor.

check your timing first... you KNOW its not the fuel pressure or settings because it was running yesterday.. dont throw more variables in there, figure out what it is systematicly.

cgb, I've already reset lash in the manner you've described, as well as the Haynes manual's directions told me to. I've also found TDC at #1 a dozen times, and made sure the distributor was lined up and the rotor was pointing to #1. I honestly don't think I'm doing that much wrong.

It has to be something to do with my WEAK SPARK I think. My timing light doesn't even flash. That's indicating low resistance in the spark path... meaning it's either getting a weak *** spark, or it's grounding out prematurely...right?

It stopped running when I had the Holley on it. I've since put the old TBI on, as everyone suggested I do. The TPS is connected, as well as the other sensors, all perfectly. It still won't start.


I am pretty sure it's a spark problem but I just can't put my finger on it.

Okay let's go back to basics.

Do you have a spark at the spark plug when trying to start the car??

Have you doulbe-checked the grounds on the car? Those hard to see one's on the rear of the passenger cylinder head?

Double-checked the wiring that plugs up to your distributor and coil?

Spark, not sure. I was cranking for a while, and only the #1 header tube was warm. The grounds could be off... However the car started at one point so unless they got ripped off their bolt, they should still be there. The coil-to-distributor wiring is fine, no breaks or exposed wires.

I ordered the new coil and ignition module, which are part of this wiring system, so we'll see what it does.

this past summer, my car was running perfectly, then just died. no spark. replaced the module, distributor (where i ran into the whole "1 tooth off" issue), cap, etc. car had fire, but would not run right. acted like it was out of time. finally ended up replacing the msd blaster coil with a stock one. apparently, the coil had gone bad, but not completely. wonder if this could be your problem?

No offense, but before you start replacing parts, check the grounds.

Then check to see if you have spark. Do a search on this site, sure u'll find a ton of ways to do it.. I won't post how I do it, I don't want to get sued.

sued, eh? lol
you can always PM it to me and nobody will ever know! hahahahahha

i think it has something to do with what digit he uses to check for spark

This guy thinks I may have bent my pushrods


http://www.sallee-chevrolet.com/Cyli...ds/Vortec.html
http://www.chevyhiperformance.com/howto/97458/

Dont know if anyone has mentioned this yet but are you disconnecting the est wire when you are setting your timing.. .??

yes.

I don't think the LT4 cam is too much...BUT

Yank a valve cover and pull some pushrods. Just loosen the rocker arms and swing them out of the way.

Then take 'em and roll the pushrods on a piece of GLASS or something you KNOW Is flat. They will have an obvious "jump" when you roll them if they are bent.

Still don't think that's it.

[QUOTE]Originally posted by Token
[B]This guy thinks I may have bent my pushrods

QUOTE]

The acceptable lift on stock vortec heads is much higher than the 0.410 383 Monte mentions. There are a few values floating around out there, but I'd feel safe with 0.450.

I'm interested to see what the new coil and ignition module do for you.

Best luck-
S-D

I am too

I just can't afford to nickel and dime this engine any longer... I don't even know how much I owe Visa. Scary.

If you havn't already, check your fusible links down on the starter! I accidently grounded out my electrical system and one of them fried. More than likely not the case but wouldn't hurt to check em out!

Bruce (90RS305)

good call, but the engine turns fine... it just doesn't catch :-/

There are 3 fusible links that come off the starter. You could still be getting power to the starter, but one of the other ones could be fried. They are REALLY easy to see from under the car. Just make sure you run your fingers down the wire a lil' ways to see if there are any lumps/ridges in the insulation that would suggest the inside was fried. Mine just completely fried in half my car grounded so bad!

Oh? I did not know this... hmmm. I'll feel around for those fusable links. Will it be a definite sight/feel when I find one that's fried?

More than likely. A fusible link is basically just a wire that works like a fuse. If it blows, just like a regular fuse the wires will no longer be in contact, meaning they had to move somehow...

Like I said, mine had COMPLETELY seperated...AIM me if you have any more questions about them. Unfortunatly I know more about them than I'd like to...

Boys, check your ground wires. According to this link my stainless steel intake bolts are a horrible conductor of electricity, and that's precisely what my ground wires are mounted on! I'm going to move those ASAP when I get home to an iron bolt on the head, instead of the stainless one on the manifold! I also have a poor ground to begin with- it's just stripped wire wrapped around this bolt!

"what, no recognition for clueing you in on your grounds? I see how it is..." --90RS305


I'll let ya know :lala::

With the vortecs you will be into coild bind at .440-445 lift and your retainer will be touching your seal at .450-4.55 lift. I checked these numbers on a set of vortecs myself. .410 lift is what you would want with the proper clearance between the seal and retainer. Which is .05. How much lift does your cam have anyway?

that's on stock vortecs, isn't it?. i'm pretty sure the sdpc vortecs are good to .550" lift, as are the pro toplines

he just discovered that he had the least recomended casting number for his heads and he is running the LT4 cam that has about .480 lift with 1.6's. So with 1.5's he is at .450". There is a slight chance he actually has the hotcam which would put him way off with coil bind and his pre-burt tune. That is my final geuss why he is having problems. It may be time to pull the heads and have some machine work done.