74 w200 wiring/starting/running

[KenP]

hi guys -- some help appreciated if possible - My 74 with 360 (ca 90k) & 727 trans ran OK then died a while ago. Replaced the distributor internals -reluctor etc. Then decided the worn (ca .010 play) distributor shaft called for replacement. I've done the usual elimination & replacements and checks including new control module etc - finally decided to go back to points system as in 1971. This truck now has new plugs,wires,coil, cap etc. with the new (rebuilt) points dist. Timing set for # 1 TDC for rotor location & firing order - all correct. Still no start & run - it tries to catch briefly then zip - same problem as before all my efforts to fix.

Cranking on the rebuilt starter is a bit strange with initial fast cranking then slow down to near stop when it then catches - it always did this when it ran normally a year ago. I suspected some kind of ring gear problem. The starter while cranking shows a voltage measured at the battery which only drops a volt or so - the manual says anything above 9 volts while cranking is fine. I've tried jumping to the coil + bypassing the ballast resistor since with the ign key in run position the voltage at the lower ballast posts is over two volts lower than battery - it should be 12v I think. To the chase - what could cause the lower voltage at the ballast resister? (both red wires come from the 6-way splice) I've spent much time with the wiring diagrams & have traced everything so I believe I have the correct wiring hooked up. Short of tearing everything out & re-wiring from scratch, what is your advice? Could it still be the starter, although it cranks & doesn't show too much voltage drop? Any suggestions are very much appreciated. Thanks and all the best,

-- ken

[KRB64]

So, have you verified that you're getting fuel and the plugs are firing? What about the timing?

[KenP]

thanks --

thanks KRB64 -- yes I'd checked all the spark issues - timing I'll re-check - and it has been a while since I'd checked the mechanical fuel pump output. Carb can flood so I've assumed fuel pressure was OK. Other vehicles when I've had a fuel pump go out - it still fires and runs for some seconds on ether spray into the carb. This just fires - say one or two times spark - then dies. Also, do you have any idea on the cranking characteristics I mentioned? It cranks fast initially, then slows to near stop - then (used to) fires up and runs normally. I put a complete rebuilt starter & solenoid - & relay in a few years ago. Still does the same thing - although I thought the starting seemed at least a bit better. Do you recommend an electric fuel pump? - block off the mechanical? is there a plate available? - maybe go through the pump at first, but probably shouldn't be a permanent solution - since I've read that a ruptured mechanical diaphram would then allow fuel directly into the crankcase - not such a good idea, eh? Thanks again, & I'll look forward to any further thoughts you have on this. All the best,

-- ken

[KRB64]

Also, do you have any idea on the cranking characteristics I mentioned? It cranks fast initially, then slows to near stop - then (used to) fires up and runs normally.
-- ken

That description is what made me think timing but if it would start and run before while doing that then that can't be it.

I'm not a big fan of electric pumps, They have to be just right to work just right (correct pressure, correct placement from tank & carb etc).

I'll need to ponder your situation some more...

[712edf]

How much play is in the timing chain?

Bucky

[Ron in Indiana]

How much play is in the timing chain?

Bucky

I was wondering the same thing. As for the starter, are your cables in good shape? No quickie clamp on ends ? Bad connections rob a lot of juice.

[greg rider]

Sounds like a compression leak down also,,spins easy for a while then slows and fires normally,,sounds like it needs to build compression up.

[KRB64]

Good thing to check anyway. Let us know.