6.9 Hard Starting
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Joined: Dec 2006
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6.9 Hard Starting
My '86 6.9 is getting increasingly more difficult to start. At first it was only a problem when the truck sat overnight but now it takes a minimum of 3 cranking attempts before it will fire even when warm. After doing a lot of reading on this site I decided to install a new return line kit. I did that yesterday but the starting has not improved. (BTW - The return lines that I replaced did not have fuel in them when I removed them.)
What I've noticed is that the engine sounds like it is cranking faster when it is about to fire which is usually on the 3rd or 4th attempt. I don't have a tach to verify this but it is possible that the engine isn't spinning any faster but simply has a different sound because the motor is now getting fuel.
What should I try next?
Thanks.
Tim
What I've noticed is that the engine sounds like it is cranking faster when it is about to fire which is usually on the 3rd or 4th attempt. I don't have a tach to verify this but it is possible that the engine isn't spinning any faster but simply has a different sound because the motor is now getting fuel.
What should I try next?
Thanks.
Tim
Last edited by genovet; Sep 2, 2007 at 09:24 PM.
Posting Guru
Joined: Oct 2005
Posts: 1,030
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From: Powell River B.C.
Under the assumtion that you may still have an air intrusion problem, check fuel filter, water seperator, pick up pump, etc for possible other leaks, sucking air in. A clear hose on the return line out of the filter head return line will let you see if you have an air problem. Then just a matter of finding it.
How old is your starter?? Mine started to get slower and slower-harder to start due to the starter motor brushes eventually wear out and do not have enough spring tension left for good electric contact with the armature. Once this happens, it just doesn't turn over fast enough to start no matter how good your fuel system is!
How old is your starter?? Mine started to get slower and slower-harder to start due to the starter motor brushes eventually wear out and do not have enough spring tension left for good electric contact with the armature. Once this happens, it just doesn't turn over fast enough to start no matter how good your fuel system is!
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
Is the OEM water separator still connected in line...located on the firewall by the booster. They have a tendancy to allow air into the system..... jam a 3/8 bolt up the drain hose to seal it. Remove to drain water separator as required.. then re install.
There are numerous air intrusion points on the engine...... visit...
http://www.intellidog.com/dieselmann/idi.htm check into the clear hose installation to find air leak point.
Are there any wet spots on the return lines or the filter header.....
It certainly sound like you are re priming the system for every start.......
There are numerous air intrusion points on the engine...... visit...
http://www.intellidog.com/dieselmann/idi.htm check into the clear hose installation to find air leak point.
Are there any wet spots on the return lines or the filter header.....
It certainly sound like you are re priming the system for every start.......
Posting Guru
Joined: Aug 2006
Posts: 2,175
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From: Kent WA
<TABLE><TBODY><TR><TD vAlign=top width="100%">If it isn't the GPs, air in the lines, or the starter itself then another thing to check is the rest of the starting circuit (batteries, cables).
My turbo-ed truck was getting to where it needed about a 1/3 to 1/2 second shot of ether to fire up the first time I would try to start it from dead cold most of the time.
The clamp on the positive battery cable for the PS battery was in bad shape, so I replaced the whole cable with a good spare I had laying around. In the process I cleaned all the battery terminals and re-tightened the clamps and then put a good charge on the batteries.
The high resistance of the poor connections were keeping the starter from cranking it over fast enough to start up. Extended/repeated cranking also drew the batteries down and with the poor connections it wasn't charging all the way back up.
After the cleaning/replacing/charging session - which took me all of about an hour - she's fired right up every time since.
</TD><!-- KEN: 1-13-2007: show 300x250 ad-block to non-Club FTE users in the 1st post of every page --><!-- / Ken, end of hack --></TR></TBODY></TABLE>
My turbo-ed truck was getting to where it needed about a 1/3 to 1/2 second shot of ether to fire up the first time I would try to start it from dead cold most of the time.
The clamp on the positive battery cable for the PS battery was in bad shape, so I replaced the whole cable with a good spare I had laying around. In the process I cleaned all the battery terminals and re-tightened the clamps and then put a good charge on the batteries.
The high resistance of the poor connections were keeping the starter from cranking it over fast enough to start up. Extended/repeated cranking also drew the batteries down and with the poor connections it wasn't charging all the way back up.
After the cleaning/replacing/charging session - which took me all of about an hour - she's fired right up every time since.
</TD><!-- KEN: 1-13-2007: show 300x250 ad-block to non-Club FTE users in the 1st post of every page --><!-- / Ken, end of hack --></TR></TBODY></TABLE>
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