Now She Wont Start!!!

[brusso]

try this

http://www.chevelles.com/techref/ftecref5.html

 

[cntrhub]

"No matter which way I do this it doesn't start and I still keep getting the pop out of the top of the carb!!!" That's right. You are way off in the timing dept. What is happening is you are firing fuel on an intake stroke. Meaning the spark is firing when the intake valve is open and the flame front is heading out the carb instead of out the exhaust pipe. Are you 180 digress out? A few teeth off will give the same effect.
Generally, when we talk about what direction to point at, it is standard procedure to talk as if you are sitting behind the wheel of the car. Use the "sitting in the car" while pointing right or left with descriptions. So here we go. Follow me if this helps. Your timing is off. Do it over again. Pull the distributor. You should be well versed at it by now. This is also why nothing (wire harness wise) lines up.
Let us start with the harmonic balancer timing mark. You will need a piece of white chalk from your kid's school. Have your child (if you have any of course) ask for a little piece. That is all you need. Keep turning the crank until you see a long stamped line in the balancer. This is your timing mark. Scribe the white chalk all over the line. What will happen is the chalk will make a mark on the surface, but will not fill the deep punched line. When you use a timing strobe light, this chalk mark will flash right at you, like a New York troll with a trench coat on. White chalk is the best marker.
Place the cap on the distributor. The harness wires are "just so long." As you move the distributor shaft (with the cap on) you will see where the distributor will sit with the harness wires attached. You need not place that distributor 180 degrees in the opposite direction, and stretch the wires just to make a wire connection. Find a natural position, where the distributor wire junction box and the ignition wire harness leads line up comfortably. Do not install the distributor yet. Now find #1 spark plug wire and see where that would naturally fall onto the cap? Next, find #1 compression and set the chalk mark line on the Zero (0) degree mark. If this is not present, then place the chalk mark line between the BTC and ATC marks.... if this is shown on the plate. Basically, you are at top dead center compression stroke. To verify, take a small hose long enough to cover the spark plug hole of the #1 cylinder, and blow into it. Make sure you have a good seal at the plug hole. Did your cheeks fill or could you blow into the hose and empty your lungs? If you have air resistance, you are on #1 TDC Compression. Install the distributor at this time. Now lift the distributor up a little and move the rotor until it drops and falls at or near the #1 plug at the cap. Remember, that when you drop the distributor, it will rotate away from or to the #1 cap. If you luck out and the rotor lines up with the #1 cap, you are finished. Note that moving the distributor in either direction (just a little) is all you need to set the timing. If you need to rotate the distributor to line up for #1 cap wire, and you see the ignition wire being pulled on, then you have to figure you are a gear or two off. Double check before you cinch things down. Wire in sequence the remaining 7 cap plug wires and light that puppy off. Maybe this might be the trick instead of everyone telling you that setting the rotor in any position will work. Of course it will, but what you are chasing now, is a natural position of the distributor to the ignition wire harness.

 

[GerryLP]

Thank you all very much for all your help I really appreciate it. This board kicks ace and is saving me tons o cash plus helping me learn everything about this sweet ride which is exactly what I wanted when I bought it!

Ok so found out how to adjust the float on the Holley adn now got it to sit parallel. So now I shouldnt drench the garage w/ gas! Hopefully. Now its onto the timing.

The problem Im having is that i cant see the mark on the harmonic balancer! Can someone shed some light on where to get. If I want it at 8degrees BTDC then thats going to be between 11 and 12 o clock if Im staring at the car from the front right? When there then the #1 piston is going to be at the top.

Then drop the distrib in pointing to the first cylinder and inthe process of dropping it and it spinning down to the bottom, when it sits it should be pointing to the #2 cylinder or the passenger headlight right!? Please tell me Im right. The part thats confusing me the most is that everyone is looking at the car from a different angle. If you could specify the angle that your perspective is please. Once I get all that done then Ill check the coil and stuff like you said robin and Bud fi it still dont start.

Gerry, youve made me realise what the problem is! Yes it is the stock HEI. So the connectors for the tach, battery, and ignition are supposed to go on the left side of the engine , or the passenger side!? I went to get the wires and plugs replaced and the way its been since is that the connectors have been onthe drivers side! So #1 wire is going to plug in at 7o'clock if the windshields at 12o'clock right? maybe this is all why Ive been getting 6-8MPG in the city and 20 on the highway! Hmmmmmm...

Im almost there! Thank you all sooo much

Mac,

Please remember to orient yourself with the car. The directional cues are usually aft looking forward so that the left side is the driver side and the right side of the vehicle is the passenger side.

The harmonic balancer has a groove across it on the outer circumference. Use a silver or white marker to accentuate it. Please noctice that on the left front portion of the engine block (to the left of the balancer) there should be an index plate approximately at 10 O'Clock (again, aft-looking forward). This index plate is used to set your timing. I know that it is not simple to get under the vehicle, but if you can, then this would be the best way for you to check for the following: Check to see if the balancer outer ring is loose or rotates. If this is the case, then you'll never find the correct TDC. Over the years, oil and heat will loosen the fit of the balancer assembly. If it seems ok, then highlight the groove on the outer circumference to aid on visibility of the timing mark. If the groove aligns with the "0" mark of the index plate, then this is TDC;however, if its not TDC, then you're 180 deg away from TDC (Bottom Dead Center BDC).

Now, in a 71 Nova or Chevelle or any other car with lots of engine compartment room it is NOT important to align the distributor correctly. And like you and others have stated, it doesn't make a difference as long the wire arrangement and firing order is correct; however, in an L81 and for that matter most C3 Corvettes, engine compartment space is a luxury. Therefore, you'll find that aiming the #1 distributor post to the left-front of the engine will aid in connecting the wires to the distributor (the protruding part I mentioned on my previous post) and it will also save you hassles when fitting the air cleaner around the carburator and in between the carburator and the distributor.

The purpose of the Sharpee mark of the number one wire post is to help you align the distributor base to avoid the problems in the paragraph above. If the rotor "lands" towards where the #2 wire post is, then in effect, the amount of initial timing the distributor would have could be 30 -45 degress. Lets pretend, for argument sake's, that this is what happens, the you just simply rotate the Sharpee mark on the base towards the rotor, and when the Sharpee mark aligns with the rotor, the you have effectively obtained a zero degrees BTDC. In other words, you're at TDC on the distributor. Now remember that this is the case if the harmonic dampener (the balancer) is set with the groove aligned with the "0" on the index plate. The trick I mentioned in my previous post would allow you to set the 6 degrees BTDC on the index plate by aligning the groove with the number 6 on the BTDC side of the plate. Then you go back to the distributor and align the sharpee mark with the rotor and snug-down the clamp (hold-down clamp) on the distributor so it won't shift on you. Install the rotor if not done so already, the cap, the wires (in a clockwise direction 1-8-4-3-6-5-7-2), hook-up the C- GND B+ wire connector (brown color AND it should only fit one way. It has 3 wires going to it, and these wires come from the connection made inside the distributor and module), the TACH wire, and the BAT wire. Re-install the #1 spark plug, double check wire routing, triple check wire routing, and the you are a "go" The 4-prong connector (arranged in line, labled A,B,C,D) is for the computer hook-up.

On the fuel problem -I suspect that you are still using the mechanical pump??? Not an electrical pump?? The Holly 4150 cannot operate with more than 9 psi without the use of a pressure regulator that would keep the pressure at 9 or below. Seven PSI is best. Is the fuel coming from both bowl vents?

 

[GerryLP]

Cntrhub,

I am sorry for posting a similar post to yours. I guess it took me longer than an hour to write my posting, and by the time I posted, you had already posted. I didn't mean to repeat what your saying...

 

[Macgyver]

I had the distrib checked out and its fine. Something in the car is keeping it from sparking through the wires. He hooked it up to a test lead and grounded it and as he spun it it sparked on all points. Im going to try a combinations of things to see if I cant figure out whats keeping it from sparking. My first guess is that the computer is telling it not to since a few sensors are now missing, but it seems like it would fowl up the timing and the fuel mixuture but not keep it from starting.

Thanks Gerry and cntrhub for your explanations I will run through them as soon as i figure out this problem.
Brusso that page is perfect and Im gonna start on that, thanks.

 

[Jack]

It seems you've set the timing several times ... and a mechanic says your distributor is AOK ... you think your computer is preventing fire ... I doubt it. But here ... try this to check the system. Unplug BOTH tach & power wires at distributor ... but keep the ONLY the harness/wires plugged in that runs from dist base to cap. Re-stab the dist ... DO NOT reconnect tach wire for now ... but ... do connect a discrete wire from an independent positive 12v battery to the "BATT" terminal on cap ... spin the starter & see if the motor fires ... if it don't run then make sure you're not 180 out.

If after this test the motor DOES run OK ... then that probably means you don't have steady 12v to dist or there may be a problem in the tach circuit. If it still DOES NOT run ... then there's probably something wrong with dist.

Since you've already dumped the OE carb ... and ... If the dist is the culprit ... then replace it with a PRE-81 NON-computer HEI dist ... those have 4-pin module and both vacuum & mechanical (centrifugal) advances. Those 80 & back HEI are everywhere & real cheap to acquire, fix, maintain, troubleshoot ... moreover, they're super-reliable. With a pre-81 HEI and a 4150 carb, you can sail the computer over the fence & let the neighbor's dog bury it.

...and once this ordeal's history ... you know you're gonna have to find another moniker?HA!
JACK:gap

 

[Macgyver]

So on the distributor theres the battery wire. Next to it the tach wire. Behind it the black 3 pronged ignition harness right?

Opposite of where that ignition harness comes out of the distributor is another harness that has 4 pins. I thought it was supposed to have 7 for an '81? Does that mean that this distrib runs completely separate of the ECM!? I hope so.

 

[JHL]

Will the L81 distributor work once all the computor stuff has been disconected and the carb replaced ??? My 81 has an old style HEI with vacum advance. Might be worth picking up one from a junk yard and giving it a try.


J.

 

[Jack]

So on the distributor theres the battery wire. Next to it the tach wire. Behind it the black 3 pronged ignition harness right? Opposite of where that ignition harness comes out of the distributor is another harness that has 4 pins. I thought it was supposed to have 7 for an '81? Does that mean that this distrib runs completely separate of the ECM!? I hope so.

Your wiring sequence is correct. The ignition module in a Non-Computerized large cap 4 pin HEI has 2 male terminals on one side that connect to pickup-trigger … and 2 more on other side that connect to harness. That same old reliable 4 pin HEI has BOTH vacuum advance with a conical metal vac canister located at distributor base … and a mechanical (centrifugal ) advance governed by weights & springs that are immediately visible as rotor is lifted away. That same old reliable 4 pin HEI has its ignition coil mounted atop cap and beneath a plastic cover attached with 2 or 3 small screws. Same distributor is available from GM with P/N 1104067 and also ships with some of the GMPP crate motors.

I understand all large cap Computerized HEI have either 5 or 7 pins … I’m leaning toward 7. I dunno how many pins an 81 is supposed to have … perhaps someone with more knowledge will verify (?vac or not, mech or not, pin-count?).



ALL large cap HEI modules have 2 pins on one side that connect to pickup-trigger. A 4 pin has 2 more on other side that connect to harness … a 5 pin has 3 more on other side that connect to harness … a 7 pin has 5 more on other side that connect to harness.



Perhaps yours has already been retrofitted with a more desirable, old-style 4 pin HEI having both vacuum & mechanical advances. Suggest verifying BOTH pin count at module AND at harness. I guess it’s possible to bubba it up and mismatch module to harness … I haven’t seen that little gem yet but … who knows? Check it.



FYI. Although they're very reliable ... when they do fail there are two very common HEI failures ... bad coil-to-rotor button contact (dirt-water-corrosion) … and bad ignition module. Coil contacts are easy to check & clean. A new OE-type 4 pin module can be had locally for under $20 and it’s easy to swap out. Also verify there’s no shorting between terminals at cap … pull the coil cover & inspect closely … and look at cap connections … they occasionally short across Batt & Tach terminals.

Will the L81 distributor work once all the computor stuff has been disconected and the carb replaced ??? My 81 has an old style HEI with vacum advance. Might be worth picking up one from a junk yard and giving it a try. J.

With a non-feedback carb & non-computerized dist it should run OK. Most carbed street cars w/ large cap HEI need both vac & mech advances. Does yours have BOTH vacuum AND mechanical advances? If so, it should work ok. Seem to recall yours is cammed up … if too little manifold vacuum then a vac advance dist may not work out so well.

JACK:gap

 

[Macgyver]

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

SHE RUNS AGAIN!!!


Tada!!! Being plugged into the computer was keeping it from firing. ****in piece of ****!

The timing seems to be about right. Now all I have to do is adjust the Holley which I know jack about, but just learned a little.

Once I figured it out I had to go back and use everyones post to get the distrib right and the timing close. Thank you everyone I really really really appreciate it! Its very nice to know that Im not alone in my struggle to build one Bad Ace Vette.

Jack, just Macgyver (the greatest), I finally figured it out.

 

[brusso]

That's what I'm talkn bout!!

 

[Macgyver]

Herumph Herumph!

Thanks bro.

Anyone got any Holley info that I could read, especially on tuning that sucker?

 

[GerryLP]

Congratulations! What a feeling! huh?

 

[rgtrough]

Hey Mac, CONGRATULATIONS!!!!!
Bud

 

[JHL]

Mac

Great that you got it going and that it was something simple.

With a non-feedback carb & non-computerized dist it should run OK. Most carbed street cars w/ large cap HEI need both vac & mech advances. Does yours have BOTH vacuum AND mechanical advances? If so, it should work ok. Seem to recall yours is cammed up … if too little manifold vacuum then a vac advance dist may not work out so well.

JACK:gap

Jack,

You are right mine does have both vac/mech advance although I found in my particular use it ran better without the vacum advance, I just set it up with a lot of intitial avance (16* btdc) and used the other 20 or so degrees in the mechanical side to take care of the rest. Did the 81 computor HEI`s have vacum advance or was the advance all handled by the engine management system ???

J

 

[Jack]

Jack, Did the 81 computor HEI`s have vacum advance or was the advance all handled by the engine management system ???J

John:

So you disconnected the vac can ... lotta guys do that because they can't get it to work so well with bigger cam's lower manifold vacuum. This condition can often be remedied by installing a different vac can ... one that has lower threshold ... or one that can be adjusted to come in at lower pressures. If you haven't tried that already ... I'd suggest it ... may help out cranking & performance in lower ranges. But it won't help power brakes, vacuum-modulated auto trans, lazy C3 wipers / headlight doors.



I'm not certain, but I believe 81 vette w/ 350ci came OE with large cap HEI that had only mechanical (centrifugal) advance while the computer handled what had been the vac advance job. Wish someone with more direct experience w/ OE 81 vette distributor will confirm or deny.



There is also a vac can lockout that is available from several ... Moroso & Crane come to mind. Many plain, off-the-shelf "rebuilt" vac advance HEI from parts house come from rebuilder with a vac advance lockout installed. It simply bolts in place of vac advance can ... prevents pick-up assembly from rotating about reluctor. A disconnected vac can holds it in place fairly well but there remains some slight rotation/movement. Our circle track car has a converted HEI ... has vac lockout & mech adv is welded ... runs total advance ALL the time ... crank it by spinning starter motor first & then switch on ignition ... motor runs continuously above 6K rpm.



BTW, Crane has a new distributor for under $300 http://www.cranecams.com/?show=newProdDistributor ... has no vac can nor weights nor springs ... has screwdriver-programmable curves for both mech AND vac advances ... has both onboard electronics & MAP sensor to "mimic" both vac can & mech advances. Requires a box such as MSD 6 or Crane Hi6 ... another $150. Looks like it might be helpful for NON-computer street cars that have vacuum-challenged ignitions. Again, maybe someone with more direct expreience with OE 81 vette ignition will chime in to confirm exact configuration(s?) of 81 vette dist.

JACK:gap