I haven't adjusted the timing since doing a straight up timing chain install. I understand this is likely the culprit, but if I get it timed and the carb adjusted and it still does this what is the likely cause? 1 tooth off?

To expound on the issue I start up my pickup and have to keep it revved up, and as soon as I let off the gas it idles down and dies. When I am keeping the power to it, it runs great, just as soon as I let off the throttle almost instantly it dies.

 

If it was me I would connect the vacuum advance to full manifold vacuum and see if it runs better or worse. If it's better then it wants the timing advanced more, if it gets worse then the timing could be advanced too far. (probably not the case though since you can keep it running off idle, which is when the vacuum advance starts to kick in)

 

Good to know will give it a shot. Just was a bit surprising because she was running like a dream prior to this chain install.

 

You couldn't have knocked a vacuum hose off or damaged one by any chance?

 

I checked everything like that several times, at least 3 times. All my vaccumn lines are plugged, I'm not getting air anywhere checked it with starting fluid, had no idle changes there. The first thing I am going to check is that my timing is correct, second would be to adjust the carb. Its really hard though to do any adjustments when I have to keep the idle rpms about 2000 or so to get it to stay running. It runs great there, just almost as soon as I let off the gas it bogs down and dies unless I hit the gas again. I have no fuel leaks, or mis routed wires there. Its just damn weird that a timing chain could alter the fuel situation so much. I guess I don't know whats going on until I get that done and I will report back.

 

Your timing could be anywhere, especially if this was the original timing chain on the truck.

Make sure to set the timing, to at least 8*. Maybe more to keep it running without the vac advance.

 

Could be the ignition timing, yes. But, you said it ran great prior to the chain install, so the ign timing was not off then, and I assume you didn't change the ign timing so why would it be off now? Definitely worth checking, tho.

What brand timing set did you get? I'd say it is likely that your valve timing is off. Be careful tuning the carb and ign timing, because you might just be tuning terribly timed valve events.

Even if the dots are lined up, and it's not off a tooth, it could still be off. Even name brand sets, mostly the cheap ones tho, can be marked incorrectly.

 

Cloyes True Street Double Roller 9-1122 I believe. If my valve timing is off what exactly does that mean teardown and back into it? Damn I really really hoped I wouldn't ever have to change a timing chain again in my life.

 

If you got even reasonably close to dot-to-dot, you shouldn't be that far off that it'd cause the engine not to idle.

That said, you can verify by pulling the pass side valve cover and verifying valve events.

 

Dude are you an idiot? You changed your timing chain and are crying that your truck runs poorly and stalls, but you haven't set your ignition timing or adjusted your carb after the new chain? Wow, just wow. If you spent half as much time after working on your truck as you do complaining and daydreaming you would have everything right and working well. It took me more time to write this post than it takes to set your timing.

 

Easy, cadunkle. I don't see why the ign timing would be off anyway. Yes, he should definitely check it, but all he did was install a new chain, and it ran great before, so he's probably thinking, and I am too, that it is likely not the ign timing... Which is why he's here.

 

Like I said before, the ignition timing is going to be off a minimum of 4*, which isn't enough to make or break a motor, but the slack in the timing chain could have an effect as well.

 

^ This, is exactly why you set your ignition timing after changing a timing chain.

 

Yes, the timing is going to be off. The cam was retarded 4* when the chain was new. By the time it was changed, I'd bet the cam was retarded closer to 10*.
Now, factor in the crank spinning at 2 times the speed of cam, and the 10* gets turned into 20* of ignition timing. That's enough to really make an engine run poorly..... Heck, even the 8* (4* X2) change in timing that occurs just by setting the cam back to 0* would be enough to make an engine run much differently.

Cadunkle was a bit harsh with that one post, but it was otherwise accurate. I don't agree with the tactics, but he was on the right track.....

 

Geeze bro calm down a bit here. Good thing about these forums is that you are not required to respond, if your time is worth so much you are free to not post. In addition, in my first post I noted that the timing and carb are going to need adjusted, but I was just thinking about other possible options in case those two don't fix it up.