1987 Chevy 305 nightmare

[nosurrnder]

Hi guys, I'm new here but I won't bore ya'll with a lengthy introduction. I have an 87 chevy with a 305 engine that recently jumped time. I replaced timing chain and gears, timed it (0 TDC compression stroke) rotor is at 5 o clcock position pointing at #1 plug. I know its timed right because I have done it before and had it running like a sewing machine but now its running terrible. Popping back thru the intake and exhaust periodically, wont idle unless i advance the heck outta my timing has knock that comes and goes until i advance the timing. Vacuum gauge says late ignition timing while est wire is unplugged and late valve timing or intake leak with wire plugged in. I've done a compression check 145 cylinder 1, 145 cylinder 2, 155 cylinder 3, 140 cylinder 4, 145 cylinder 5, 150 cylinder 6, 150 cylinder 7, 155 cylinder 8 and have had my valve covers off and watched my rocker arms and they all moved the same. I replaced the dizzy cap, rotor, knock sensor, ignition module and ESC module. The thing that has me puzzled is why it runs better with est wire unplugged. Any help with this problem will be greatly appreciated as I am literally dead in the water

[zieg85]

Welcome from NW Indiana.  Firing order correct? 18436572?  I've made that mistake more than I care to admit over the years...

[nosurrnder]

Howdy from Arkansas. I've checked and double even triple checked the firing order and it is correct. I forgot to mention I changed the plugs but not the plug wires because the wires are fairly new.

[Nightowl]

My guess would be you have timing 180 degrees off. I know you said you dont think so but it is quick to check

[VileZambonie]

Recheck your distributor installation. Ensure no vacuum hoses off, good fuel pressure.

[nosurrnder]

If my timing were 180 off it wouldn't run but it runs just runs horrible and all my vac lines are connected and leak free and my fuel pressure is at a constant 10-11 psi. I'm replacing my dizzy tomorrow and if thats not the problem I'm thinking maybe its in my wiring.

[Streetrod00]

An old trick from the JD two-cylinder world - set to required non-vac advance for #1 (6btdc) and retard the distributor.  With ign on, advance slowly until spark appears.  Tighten dist.  If No spark, prolly retarded on the cap by one spot.  I've set up this way for years - old school but always works.  Good luck...

[roundhouse]

Ive had to do this before

I get an old dizzy cap and use a dremel to cut a large hole in the top
As large as you can without removing the plug wires
Install it So I can see exactly where the rotor is pointing





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[NCali]

sounds like you are 1 tooth off on the dist gearsince it gets better when you advance it

[frotosride]

If the engine was backfiring there is a very high chance that you cracked the porcelain and the spark is jumping through the crack. I had this problem 3 times before I found out that my brand new knock sensor was bad and so was the second one. I went through 3 sets of plugs and finally bought the acdelco from GM dealer. No problems since.

[Irish_Alley]

is it running the same now as it was when you thought it jumped a tooth?

[78BIG-TEN]

What kind of timing components did you use,ie stock,double roller?