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85 K5 Starting Problems

  #1  
Old 11-16-2009, 11:37 PM
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Default 85 K5 Starting Problems

I have a 1985 K5 5.7L, 'carbed' that died on me driving the other day. It turns over and over, wants to start but to no avail. I replaced the battery and plugs because it needed it. Replaced the fuel filter and checked for fuel...no prob there. I checked for spark at the plugs but it seemed real light. I read on one of the earlier posts that it could be the coil. Any advice would be appreciated.

Rob
 

Last edited by Horns K5; 11-16-2009 at 11:50 PM. Reason: More Information
  #2  
Old 11-17-2009, 06:07 AM
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Have you tried starter fluid?

Have you checked for spark?
 
  #3  
Old 11-17-2009, 09:32 AM
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Yes I tried stater fluid but it didn't work. Also I checked for spark but it was really light and I am not sure what kind of spark...shouldn't it be a nice blue stong spark?
 
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Old 11-17-2009, 09:46 AM
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Yes, it should be nice blue/white spark. You can pick up a new HEI coil for not too much $$. Test it first though.


From hotrodders.com

On the coil, Remove and invert the cap, Measure between the tach and BATT terminals , using a DVOM, Set to OHMS scale, RX1 and calibrated to 000. It should read less than an ohm, but more than 000, If not it's bad.

Next measure the secondary, set your DVOM scale to RX10k or higher..put the probes between the BATT and the carbon pickup for the COIL..it should read between 6000 and 30,000 OHMS..Outside of that range toss the coil and get a new one.

Check the Carbon pickup and spring follower, it may not be reaching the rotor pickup..or be worn or snapped past runout.

If that won't bring it to life, check the Magnetic pickup, by measuring the resistance across it. (you'll have to lookup the spec's for that year HEI..GM made a year divider on the pickups, and from a certain year Down were one resistance and a different resistance for that year and up..) If it is bad, you'll have to pull the distributer, and disassemble it to replace it.
For further information, google "GM HEI Coil Testing" or something to that effect.
 
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Old 11-17-2009, 03:32 PM
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EGR only ever works going down the road at cruising speed , it will not keep it from starting.... My best guess would be the spark module in the dizzy. About 20 bucks......
 
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Old 11-17-2009, 03:36 PM
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You can test the pickup coil as well. Autozone has some pretty decent test information on their website.
 
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Old 11-17-2009, 08:40 PM
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I tested the coil and had 40 Ohms (not within the .02 to 1!) Went ahead and replaced that and the cap and rotor. Plenty of spark now! However it wasn't the only problem. Checked the fuel pressure in the line from the pump...plenty there as I said before. However, I noticed quite a bit of fuel on the top the motor.???? It leaking out from the fuel filter nut going into the carb. Removed it, which I was going to anyway, to replace the filter. Low and behold it had been stipped out. Absolutely no threads left. Autozone can order an oversized replacement that will tap it at a bigger size going into the carb for about $5. Much cheaper than finding a rebuilt carb!
The question I have is how much fuel and what kind of spray should I get out of the venturi(s). Before I removed the fuel filter nut, had a buddy press on the accelerator and was getting a small stream coming out. Shouldn't it be more of a good spray? Should I get a rebuild kit for it anyway?
 

Last edited by Horns K5; 11-17-2009 at 08:43 PM. Reason: More info
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Old 11-17-2009, 09:01 PM
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The accelerator pump will push a fairly decent stream. It is difficult to explain what is enough...

I'd pull the carb off and go through it all with a fine toothed comb. Check the well plugs on the bottom to make sure that they are not leaking. I had to remove the lead well plugs from the primary jet wells on the Q-jet in my '74, tap them out, then install screws into the tapped holes. My carb was leaking out of the well plugs so bad that it would drain the fuel bowl in an hour.
 
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Old 11-17-2009, 09:20 PM
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I plan on taking the carb off and doing an assessment. I was wondering if that much of a leak would be the issue with it still not starting. I seem to have fixed the spark prob, which is great! However, it still turns and turns without starting. When I sprayed starter fluid in the carb it almost started but I didn't want to keep doing that...and I found the leak. It is a pretty substantial leak. Thanks for the help.

After pulling the carb how would I check for leaks like that. Once I get the fuel filter nut prob resolved...should I set up something to put gas in from that side...like a turkey baster or something?? Weird question I know but...

BTW I have a Rochester Quadrajet E4ME
 

Last edited by Horns K5; 11-17-2009 at 09:31 PM. Reason: more info
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Old 11-17-2009, 09:29 PM
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You may have an over rich condition that is keeping the engine from firing. Have you tried holding the throttle wide open while you turn the engine over?

With my K5, I pump the throttle 3-4 times before I turn the engine over when it is cold. It'll pop off every time when cold with just that. When it is warm, I hold the throttle to the floor and turn it over and it starts after a second or two of cranking.

Carb'd vehicles can be picky and rarely are two vehicles the same. Once you get the carb done up right, you can get to know what your truck likes.
 

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