305 Issues, need your help

[Jeff86inMS]

Hey Guys!  Looking for some advice.  I have a 1986 Custom Deluxe C-10, 305 CID stock motor.  I've had the truck about a year, and it has started acting up, so I have started replacing things.  Started with a tune up, since I had no idea when the previous owner did it last, wires, plugs, cap, rotor, all new filters (fuel, oil, air), changed the oil.  I thought the tune up would fix my issues, but it's getting worse.  When I crank it the engine runs and cranks fine, but when I get it out on the road and try to accelerate, it doesn't.  It seems to just want to "squat", if that makes sense.  I have had the carb adjusted a couple of times prior to the tune up, when my choke thermostat went bad.  Would the carb need to be readjusted with the new tune up components installed?  The carb is pretty nasty and have thought about replacing that too, so my next question is what should I go with, any reccommendations?  Any suggestions on how to fix my problem would be greatly appreciated.  I don't want to get in the cycle of just throwing new stuff on it in hoes on the next "new" part fixes the problem.  That gets costly.  If it was the fuel pump, would it even start?  This is my daily driver, so I need to get this baby back on the road.  Thanks for any diagnosis/advice you can offer.  Yesterday afternoon I tried replacing the fuel filter, got it back on the road, same issue.  I can actually press the pedal all the way to the floor and it barely wants to accelerate.   HELP!!!!

Thanks again,
Jeff

[rich weyand]

What's the timing set at?

[Jeff86inMS]

Rich - I'm not sure.  I'm afraid I'm not the mechanic I would like to be, gaining experience everyday.  I'm not sure what the timing is.  I haven't changed any of that from what it was before prior to installing all of the tune up components.  Would the timing typically have to be reset after those components are installed?  I'm embarrassed to be so ignorant on these matters, but my limited knowledge is what it is.  I guess I'll nurse it down to the shop to see if that's what needs to be done.  I can probably borrow or rent a timing light but would have to learn how to use it.  Thanks for the input, that gives me something to check into.

[nlauffer]

Something quick and easy you can check with out tools.  Grab ahold of the distributor, preferably right below the cap, and try to turn it.  If it moves, the timing could be off.  You can also look at the distributor where it enters the engine through the intake.  There should be a bolt and hold down tab.

Another option is check all the spark plug wires.  If you replaced these and it is getting worse, it could be that a couple are out of sequence.

These are easy and require no tools to check.  The farther you go, you may need to take it to a shop or someone that is knowledgeable.  This could be many things, timing is a very good possibility.  Maybe related to engine internals, though. Like a broken valve spring or any number of other.

How about the vacuum line running to the distributor.  Did it come lose or is it leaking?

[Jeff86inMS]

Good suggestions.  I'll check those things as well.  I did check the wires with the Haynes manual twice to be sure I did not have them crossed.  I'll check the distributor to be sure it's not loose and check the vacuum line as well.  One thing I will say I noticed.....all of the vacuum lines need to be changed/replaced.  They are all in terrible shape.  Noticed that when I had the air cleaner housing off.  At least all the rubber needs changing, there are some hard plastic lines as well, though they appear okay.  I'll check those things and post the results when I get home.

[thirsty]

When I crank it the engine runs and cranks fine, but when I get it out on the road and try to accelerate, it doesn't.  It seems to just want to "squat"

vacuum advance maybe?

[bd]

Does it 'squat' when the engine is cold as well as warm?

• Replace the rotted vacuum hoses.
  
  
• As previously recommended, verify the timing.
  
  
• Procure a suitable pressure/vacuum gauge (pictured) to measure fuel pump suction (>20" Hg, cranking/running), pressure (5-7 PSI, cranking/running), and volume (>1 quart in 30 seconds of cranking/running).  Have shop rags and a suitably rated fire extinguisher handy, know how to use it, and work cautiously!
  
  
• If your engine has a smog pump, using the same gauge as above, remove a check valve (pictured) from either air injection manifold, attach the gauge to the air injection rail, and measure exhaust backpressure to evaluate for a collapsed or, otherwise, plugged exhaust system.  Excessive exhaust restriction will measure over ~1.5 PSI @ 3,000 RPM.
  
  
• Lift the distributor cap.  With the ignition switched OFF, slowly bar the motor over clockwise by hand until the timing marks on the balancer are aligned to 0° (TDC).  If you rotate the engine too far, don't back up; just note where the timing mark is pointing on the timing scale.  Now, while watching the rotor, slowly bar the engine over counterclockwise until the rotor just barely begins to move.  Look at the timing mark and estimate how far it moved relative to where it began.  The separation represents the amount of stretch (wear) in the timing chain, with zero being no wear.
  

Post the results.

[Jeff86inMS]

nlauffer - I checked the distributor, not loose as suspected.  Also rechecked wires, seems they are good as far as being on the right plug.  Checked vacuum line to distro, still attached, can't really get a good view of the condition but as I said, all the vacuum lines are trash, probable need to go ahead and replace all of them one by one as "BD" suggested.

BD - Great suggestions.  Though I'm not in a $ position to go buy a lot of tools, it seems that I need to start picking up some of these things and learning how to use them.  I'm sure I could save myself a lot of money in the long run by being able to diagnose these things myself.  I'll search these items out and report back.  As I posted before, all of the vacuum lines are trashed, based on the condition of most, I cannot imagine them not being the original hoses and look very well deteriorated.  I'm changing those as we speak.  Thanks again guys, super appreciative!

[nlauffer]

What parts stores are in your area?  Some I have heard rent tools.  You have to put a deposit down, but get it back when you return it clean and unharmed. This might allow you to do some of the checks without spending much money.

[Irish_Alley]

the rental tools come with a warranty so you can break them if you want lol. but what carb do you have?

[Jeff86inMS]

Irish_Alley - I think it's the original Q-Jet, but have not really researched it.  I have had to have it adjusted a couple of times and it has been suggested in the past that I replace it with something along the lines of an Edelbrock or Holley.

I did make it to the shop yesterday,  Local garage I have used in the past is about 4 miles down the road.  I have some hills between the house and the local garage that gave me some concern, didn't know if the truck would even have enough power to make it up the hills in it's current condition.  It took me about 2 miles just to get up to 45 mph, but up made it to the shop.  Hopefully they will know something today.  I'll post any results.

[Boone83K10]

sounds like a clogged exhaust system, specifically the catalytic converter. Cars start and run fine but have absolutely no power when you try to accelerate. This is all premised on you still having the cats...

if not, I would look towards the carb. I could range from just a clogged fuel inlet filter all the way to you just need a new one. replace the vacuum lines, it's cheap and gets away from trying to chase down a vacuum leak which is so annoying.

[Jeff86inMS]

Thanks Boone!  Yes, I still have the converter on the exhaust system.  Would the converter make any noise if it was clogged (rattle or something)?  Haven't heard anything.  As I said previously, the vacuum lines are trash and I agree with you, they all need to be changed out.  What about the "shaped" rigid plastic lines?  Are they available in a catalog somewhere?  Have had a couple of those break at the rubber fittings and had enough slack to reconnect them.  Do they make a "Vacuum Line kit" for a 305 that has all the sizes/lengths or do you just buy them separately?  I'll check around.

I changed all of the filters including the fuel filter at the carb inlet as well.

[greasemonkey54]

I would check the ESC module. You unplug the connector from the dist. and jump 2 wires together but I cant remember the colors off hand. I would need to look. If it runs better you permanently run those wires together or replace the dist with an older style HEI

[454Man]

I would check the ESC module. You unplug the connector from the dist. and jump 2 wires together but I cant remember the colors off hand. I would need to look. If it runs better you permanently run those wires together or replace the dist with an older style HEI

   black and green

What's under the hood??? If you have to ask maybe we shouldn't race...