No spark to plugs.

I Rebuilt a motor 1985 2.6L, and have got to the point of no spark at the plugs and weak yellow spark to the distributor off the main coil wire while grounded to the block and cranking. Have installed a new cap and rotor and will try a new coil today. I don't think its coil or distributor issues i had two of each known to work that I tried and still the same problem, but I'm making 100% sure as i go through the process of eliminating issues, and have tried a different battery, cap, rotor, and will try a new coil today. Any other suggestions?
Could this have something to do with adding a electric fuel pump and the oil pressure shut off switch? I don't think so based on having power to the coil going into the distributor but just weak. Any help would be appreciated before I have to get a mechanic.

It is possible your not getting sufficient voltage to the coil depending on how you connected the fuel pump. Remember that the electrics in Gen 1 trucks are pretty rudimentary and it doesn't take much for them to start glitching. Did you hook up the pump directly to the ignition circuit? Maybe you need to install a relay triggered off the coil and have a fused connection straight off the battery to the pump.

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Originally Posted by geezer101

It is possible your not getting sufficient voltage to the coil depending on how you connected the fuel pump. Remember that the electrics in Gen 1 trucks are pretty rudimentary and it doesn't take much for them to start glitching. Did you hook up the pump directly to the ignition circuit? Maybe you need to install a relay triggered off the coil and have a fused connection straight off the battery to the pump.

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I installed a relay and have a fused wire off the battery to the relay and a wire off the relay to the pump which I will install a fuse when I get this thing going. Sitting here typing this out I thought of disconnecting some oil pressure gauge wies coming off the coil, related to shutting the pump down in the event of a accident and try starting it after bypassing the new oil pressure switch, this is getting very exasperating.
I also have a new coil resistor to try tomorrow, and if that doesn’t work I’m going to have to get some help.

You've done all the right things to protect and maintain voltage to the fuel pump (except that primary fuse to the pump). The gauges "shouldn't" draw enough power to nerf the coil but like I said, the wiring in Gen 1's from factory isn't super awesome. Maybe there is an oil pressure switch fault that's glitching the coil/ignition circuit... hope you find this gremlin soon.

If everything else checks out. Do you have a tach? Just the other day we had a car with no start but all the ign was checking out fine. The cheap aftermarket tach had shorted out inside and was bypassing the coil

It has a tach, I diconnected the wiring for the oil pressure emergency shutoff, and hot wired the pump, which only puts out three lbs. pressure it’s working can see the gas going in the carb. The next check is to be sure I’m getting fuel to the cylinders, it was suggested by a guy at home here to put a teaspoon of gas down each cylinder. Will try that, after I first check to see if I’m getting fuel to the plugs.
I just hope I don’t end up pulling the dam head and timing chain cover again to check timing.

Electrical is sorted out, it appears a wire off the coil to the choke was the culprit, as soon as I removed it the electrical fell into place and I had good spark to the plugs. Will have to hook it up elsewhere. Tried firing up yesterday. Its backfiring into the intake manifold. So I tore it down to double check check the timing and it looks ok to me. The marked links on the chain are 20 links apart, and my cam mark and crank marks are still 20 links apart. So to a layman like me that appears to be correct. The crank and cam marks are basically at 3 o'clock when number 1 is at top dead center, and 20 links apart..
Even still I'm getting a pro to check the timing this morning. Assuming its ok, could a bad valve job and head rebuild cause the backfiring? Or is it possibly a Carb issue. Which is a Weber. When i started this project my plan was to rebuild the engine and get it running with the known to work Mikuni carb to simplify the issues. Then do the carb transfer to the weber after I had the motor running. But I jumped to the weber while rebuilding, and I'm wishing I stuck to plan A.

the carb is not the issue - check the distributor - it may be stuck advanced.

+1 on that. A bad carb will either cause detonation from being way too leaner mix or diesel from being rich (or possibly a bad fuel cut solenoid)

My apologies for all the questions. Not hard to tell my first rebuild. Yesterday on the advice of my buddy the mechanic I retimed the motor the marked links back to the mark on the cam and crank sprockets and marks at 3 O'clock, number 1 TDC.. I noticed before disassembling and retiming the chain tensioner was retracted and applying no pressure on the chain creating slack. When i retimed it before I popped the chain tensioner to expand it and put pressure on my chain. However when installing the head and cam bolt I'm sure the chain tensioner retracted and stayed in the closed position causing slack. Tightening the crank bolt and cam bolt caused minimal slack 1/2 a link or so. If the tensioner stays out chain is nice and snug. But I noticed after installing the silent shaft bars and torquing the silent shaft sprocket yesterday the chain tensioner retracted again and stayed closed no longer putting pressure on the chain and I had the above slack in the chain again. This is whats been happening and must be my timing issue. I am using a New timing chain also.
Am I missing something here?
With the chain cover on and retorquing the cam and crank bolts I know that pressure is causing my chain tensioner to retract and stay closed, no longer applying pressure on the chain. obvious after doing it yesterday with the chain cover off. That chain tensioner has to have the spring loaded tension on the chain at all times doesn't it? With no tension on the timing chain from the spring in the tensioner, would that explain timing issue? Is that spring not supposed to have enough tension to keep that chain tightened, until the oil pressure takes over? Hopefully you can help out on this.


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istheir some locking pin or something I’m missing to lock the spring load on the tensioner to prevent it retracting?

Yes the spring and plunger is getting stuck in the bore.
Yes the spring should hold tension tell the oil hits it.

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Originally Posted by camoit

Yes the spring and plunger is getting stuck in the bore.
Yes the spring should hold tension tell the oil hits it.

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So i guess the one that came in the rebuild kit is junk. And I need another. Carid stepping up with a new oil pump, timing kit, head and oil pan gasket. Talk about learning the hard way.

Well here we go new oil pump, new full timing kit showed up, to replace faulty timing chain tensioner in the original kit. I've had two major issues getting this rebuild on track. first I also installed a weber carb with a electric fuel pump which i wired to the coil causing me juice to the plugs issues, took me a bit to figure it out, have removed the wire to the choke from the coil and its all good, just need to find a power source for the choke now.
The other major issue has been a timing chain tensioner sticking in the retracted position removing all tension from the chain when the least bit of pressure was put on it like when tightening the cam or crank bolt. So I'd put it all together and unknowingly put enough pressure on the timing chain tightening up a cam, crank, silent shaft bearing bolt to cause the chain tensioner to retract and stick open causing enough constant slack to throw the timing out. When cranking the motor over the oil pressure on the chain tightener was not enough to pop it loose to allow the spring to work, by then it probably would have been to late anyways and the timing would have been out. I hope to find out in the next two days if this "project" is going to have a successful conclusion.

Waiting on a camshaft spring pin.

Yeah. It’s running, tried posting video says invalid file!