robgarner

I have an olds 98 with a 455 with hei distributor. Just recently started driving it again after 3 years and drove it 2k miles with no issues. My gf drove it and when on the highway heard a popping noise and pulled over and it ended up getting towed.
I tired to start it but it spins over but no start. Check the #1 plug and no spark. check voltage to distributor and it has 12V. 12 to the module also. Distributor cap and rotor looked fine. I replaced the module int he distributor and hooked everything back up. The first time i tried to start it POW backfire was loud as a shotgun. my gf said she saw a cloud of smoke at the back of the car.
I did resistance checks on the ignition coil and pickup coil. Car has been running good, even drove it 10hrs straight, I'm out of ideas. Any suggestions? Anything I'm missing? All suggestions welcomed. Thanks

allyolds68

Have you ever replaced the stock timing chain and gear? If not it's time. You probably jumped a few teeth or chewed the gear right up

robgarner

yeah i replaced the timing chain but not the gear as it is a steel gear and looked fine. The new chain was tighter than the existing one. I did this before i drove it 10hrs as well as replaced all the gaskets except for the head gasket.

2blu442

First step double check yourself on the simple stuff. Firing order should be 1-8-4-3-6-5-7-2 and the roation is counter clockwise. Speaking from experience its easy to forget this and put the plug wires on in the wrong rotation Since you didn't have any spark at first, then when you replaced the module you had a backfire I'm hopefull the initial problem was the module.

John

robgarner

firing order seems to be good. I drove the car 2k miles with the current firing order and setup it wasnt until my gf heard the popping and pulled over and cut the car off that it no longer gets a spark. I havent tried to start it again since the backfire though

2blu442

OK, I thought you may have removed some of the wires when you worked on the module.

I'd still encourage you to remove any doubt its something related to the timing. I'd pull the #1 spark plug and find top dead center on the compression stroke. Then verify the rotor is pointing close to that plug wire.

John

robgarner

ok checked for TDC on the #1 plug and it was already there and the rotor is pointing towards the #1 plug. Now i'm not sure if its the compression stroke but seems hard to believe it was running for as long as it was and its 180 out. also took valve covers off and rocker arms looked fine.

oldcutlass

It won't run 180 deg out, it spit and sputter and pop. Have you tried to start it, does it only backfire upon start?

MDchanic

Did it start and run AFTER the backfire?

Cranking a car with no spark (bad ignition module) can pour a whole lot of gas into the exhaust, which will ignite when the car starts, with predictable results, which can be either amusing or brief-soiling, depending on the situation.

(If you don't care about your mufflers, shutting off the ignition switch, pumping the gas a bunch of times very quickly, and quickly turning the switch back on, while in a tunnel, can provide you with a moment of fun that is rivaled only by the other drivers' moments of terror .)

- Eric

robgarner

Nah it doesn't spark anymore after the backfire. So im assuming the ignition module in the distributor took a crap again. A bit of more infomation is when i changed the timing chain i never took the distributor back out and re-set it. cam and gear both set a the 6 o'clock position. I set it at 8 degrees and just turnd the distributor to the #1 plug. Could my timing be way off even thought i've driven the car over 2k miles? seems not possible but stranger things have happened.

rcrac3r

It does sound like a timing is out issue. One thing I would suggest is take the distributor cap off & just watch to make sure the distributor is spinning ok when turning over. If it pauses anwhere then you know what the issue is.

MDchanic

Ahhhhh. Now that's an important detail.

Definitely possible.

Last time I bought a module, I brought my old one to test, to be sure it was bad. I had the guy hook the new one up to his tester before I bought it - No good.

You may have just gotten a bad module. Take it back and have it tested, then you'll know for sure.

- Eric

robgarner

OLDSCUTLASS: It only backfired on start. I tried to start it before i changed the module and no spark at the #1 plug. 12V at distributor so went and changed the ignition module and on the first start it backfired and wouldnt start again

RCRAC3R: i will do that in about an hour and check it.

MDChanic: Well i did a resistance check on the old and new module and same resistence. The only difference is the new one allowed the car to start or shall i say at least backfire. The backfire was loud as all get out.


My thinking is that if i dont do anything adjustment wise and just replace the ignigiton module again i'd probably get the same result. Currently i have the balancer timing line dead ont he 8degree mark and the #1 plug TDC.

Do you think i need to pull out the destributor and re drop it in since i didnt do that when i replaced the timing chain? That's the only thing i can think of.

oldcutlass

If it ran after the timing chain then it will run again without having to pull the distributor again. I would install the new module and try again. There are many reasons an engine will back fire, loaded up with fuel, cracked valve, timing, swpped wiring, cracked cap, etc... I'd get it running and then reset your timing with a light.

robgarner

OLDSCUTLASS: that sounds like a plan i was just afriad that if i don't do anything but just replace the module it might backfire again. I'll take the module to autozone and see if they can test it or replace it for me. I'll be back with some sorta results around 8pm tonight.

FYI i checcked ther valves and they dont look cracked or damaged in any way. also check the wiring the best i could and nothing seemed out of place. That's what makes this so puzzeling.

oldcutlass

You can't see a cracked valve without removing the head. It can show up with a compression check. Let us know what happens.

robgarner

shux i was talking about rocker arms....thinking and typing incorrectly I will most definelty. I appreciate this.

robgarner

Ok I have spark and fuel but still won't start. I hit the gas more than my normal 2 times and nothing. I did get s burst of gasses shoot out the carb 6-12inches high. So now I'm thinking it might be my carb.

oldcutlass

If you did not remove the distributor, loosen the distributor and turn it one way or another slightly while cranking. Sounds like your timing is way off. Also make sure you have a good spark at the plugs.

MDchanic

This is getting curiouser and curiouser.

Car stops dead on the road (driven by the ol' lady, so it's her fault, until proven otherwise ), is found to have no spark, module replaced, backfires big time, then no spark again, now has both spark and fuel, but still won't start.

You might try to interrogate your GF further as to the exact symptoms prior to failure, but in my experience, that tends to be a dead end.

In light of the currently available information, I would theorize that the lack of spark was a red herring - either you were looking at the wrong angle, or something else got screwed up when you looked (bad wire maybe?), but there was a spark the whole time.
If that's the case, then this sounds most like a timing issue, and the only timing issue that happens suddenly and leaves you stranded would be a slipped timing chain.
I know you said that with the timing mark at 8°BTDC the rotor points right to the #1 plug tower, and that that is the way that you set it when you changed the chain, but I would suggest just making absolutely sure. If the chain has jumped, the distributor timing will have changed as well.

Have you looked at all of your spark plugs to see if anything looks odd or if they're wet?

I would also recommend making sure it's not a fuel issue (provided your plugs are dry) by pouring an ounce or 2 of gas down the primaries and giving it another crank. If it's not getting fuel, it'll start right up that way.

- Eric

robgarner

Ok that sounds about right, the spark seemed kinds weak also but was there. I'll let you know what happens.

robgarner

Mdchanic: pls don't make me devulge my stupidity and reveal the reasoning behind no spark 😄 this is where it might be the timing. The motor was sitting 3yrs after I took it out and replaced it. It was running b4 I took it out, hei distributor and all. Changed all the gaskets put distributor back it after it was set and everything. Now the engine is in the car running and all and this is when I deceided to change the timing chain b4 I hit the road on a 10hr drive and figuring it would only help. Broke the front part down and changed the chain. Lined up the gear and cam and never messed took the distributor back out just turned it and put timing gun on it. Now would that cause the timing issue? Should I hsve went back and reset the distributor? It's been running for 2k miles since until now. I only took the #1 plug out and not the others. I can though and I didn't pour any gas down the carb but that was my next idea. My spark looked ok not strong but then again I didn't wanna keep cranking on it bc that 455 will kill a battery quick.

robgarner

Sorry never messed with the distributor besides turning it after I replaced the chain. Should I hsve took it out and reset it?

MDchanic

There should be no need to remove the distributor after changing the timing chain, but you should re-time it with a timing light.

The fact that it ran fine indicates that you set it up at least reasonably well - the failure should have nothing to do with your adjustments, unless you left a screw loose and it went somewhere it shouldn't have, or something similar.

Your comments about the spark lead me to ask for more information about it.
It should be bright and blue-white, not even a little yellow or orange.
I have a neat old Snap-On tool that lets you measure how far the spark will jump very accurately, but you can do the same thing with a screwdriver stuck into the spark plug boot and propped a set distance from the block (I prefer to avoid actually holding it) - with HEI I believe you should get about ¾" to 1" (someone else may have a better idea).

If the spark is weak, that could cause all of the problems you have described.

- Eric

Delmont 88 PA

I've seen bad ignition modules in Fords (back in the late '70's) that would cause the car to run rough and then blow the muffler apart. We always figured that the module was allowing the car to run (somewhat) but was failing intermittently and when it wasn't firing it allowed raw gas to load up in the exhaust and then ignite--what a thrill!

I would have the new module tested as recommended above. Also, your coil could have failed. An ohmmeter does not induce a significant load and may not show a break in the windings that only occurs under actual load.

Another component that could have failed in the distributor is the pickup. It's been 30 years since being a practicing mechanic but, if I remember correctly (and that is a big if) pickup usually work or don't.

robgarner

I'll try that it doesn't take much effort. I'll also check the plugs. Not sure if I can get to it tonight but def within 24hrs. Need to get back on the road. Def appreciate your suggestions.

robgarner

Delmont: I did a ohm check on the pickup and ignition coil and both checked out good. I've been told to replace ignition coil bc it's cheap enough.its easy enough to get the module checked and it can't hurt any. Give me some time and I'll come back with some results. Thanks

oldcutlass

Do you know of anyone with a known good distributor? Pop that one out and see if it will start.

robgarner

Well that was kinda my backup plan. To get a good known distributor and carb in the meantime while I'm doing all this troubleshooting. Good idea.

Rickman48

Pop the cap, grab the rotor, and see if your distributer bushing is worn out -
ANY play is nfg, and you should replace the distributer!
Tell-tale sign is inside of cap showing wear marks, and/or tip of rotor worn bare.

robgarner

Ok sorry for the delay, family and stuff took over. I've learned lots since last time. SO here is where i'm at.

I changed the plugs, the ones i had r46sz and i put in r45s. My engine is stock never ben re-built the only change is the hei distributor. Next was got another carb. rochester quadrajet off a running 425 i believe.

I set the timing degree at 8 degrees on the balancer at #1 TDC and re-dropped the distributor so that the rotor inside the distributor lined up with the #1 plug wire spot on the rotor cap. Then tightened down the distributor just enough where i could move it by hand a bit.

So i go to start the car and nothing. I rotate the distributor clockwise more and more until the car will just start with one turn ( the sweet spot i believe). This is where it gets hairy. I put the timing light on the balancer to make sure i get it dead on, the balance notch and the 8 degree mark. Well the balancer notch for some reason is at the 0 mark. and the engine is runnning with one turn. How could that be? I tried to start the engine initially before rotating clockwise and it didn't want to start. I'm confused. yes i did have my vacuum advance hooked up. Could that be the reason? Could it be because of the hei distributor? My car is running but it doesn't add up. Any ideas?

allyolds68

Is there a chance your balancer has spun and you're setting the timing way off?

oldcutlass

Disconnect and plug the vacuum advance. Set your idle to around 650 rpm, and then time it. Make sure your timing gun is hooked to the #1 spark plug. Let us know what happens.

robgarner

allyolds68: that's what i was thinking also.

oldcutlass: my timing gun doesnt have a tach so i'd have to go to the store and get one. i could plug the vacuum and see what the timing would be but i thought the vacuum advance worked when not at idle so i left it hooked up figuring it would have no effect.

oldcutlass

Just turn the idle down low enough to ensure your still in the idle circuit on the carb, time it and see how it does. Disconnect the vacuum advance to be on the safe side.

robgarner

allyolds68: the balancer didn't spin but the gasket was seeping from its seal so i replaced it just in case.

oldcutlass: did what you said and it runs good. shifted into reverse and back into drive and runs good. carb needs adjusting but running smooth.

the timing gun still says either 0* or the mark before that which would be retarted. I'm still puzzled but it runs good. I'll adjust the carb and drive it like it is. I'm all out of ideas.

robgarner

Ok i had a thought. When you turn the distributor (hei dirstributor) which way is advacing it and which way is making it retarted? CCW or CW.

If clockwise is retarted then would it be correct to say that if my initial was 8* and i turned it a lot CW then it would make sense for it to be 0* when i put the light on it.

If that's true then i would need to set my initial at 0* then shine the light on it and the 0* and notch on the balancer should line up directly.

oldcutlass

Set your gun to 8 and align the mark to 0. Then your initial timing will be 8.

MDchanic

Oldsmobile distributor rotors rotate counterclockwise, so turning the distributor clockwise makes the spark occur earlier (advances it) and turning it counterclockwise makes it occur later (retards it). If your initial setting was 8° and you turned it clockwise, then you advanced it.

You should set your advance to about 34°BTDC at about 3,500 RPM, and ignore the settings at idle, especially if you are using an HEI distributor on a car that was originally a points car, as the HEI distributor has less mechanical advance than a points distributor does, so the idle specifications for a points distributor no longer apply.

So long as you can start the engine, the idle timing doesn't matter.

If you want to get fancy, you can replace the advance springs on the HEI to change your curve a bit, but that is not essential at this stage.

- Eric

frankr442

When you say the balancer didn't spin, did you mean between the balancer and the crank, or between the balancer hub and the outer ring? There's usually a mark stamped into the hub which should line up with the groove on the outer ring.