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 more 2.6 timing help (i'm a bit rusty)
#764809
11/12/06 10:05 PM
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Joined: Sep 2000
Posts: 4,277
OP
Roll Me Over
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Well, as some of you know, my summer/fall was pretty much occupied with wedding/honeymoon planning which has left our trucks neglected. Now as things settle down, I'm trying to get back into things, but my skills are a bit rusty. Where I last left our '89 Trooper RS was in the middle of a head gasket swap. I managed to locate all the dismantled parts and get the head back together, but now I'm having some problems getting it running and could sure use some advice. Whats happening is, as soon as I start it, it acts like its going to run, but then just about the time I let go of the key, it fades and dies. There is no violent shaking or backfiring, it initially sounds smooth, but then just fades away. I've been thinking its a timing issue and have spent the better part of today pulling the dizzy, rechecking all my marks and trying again. but so far, i've been unable to find my mistake (and I must have reset the configuration at least 5 times today). So, heres the details... both the camshaft and crankshaft marks lined up at their indicators (see pict). this should indicate TDC compression on #4. So I inserted the dizzy with the marks at the end of the shaft lined up... which points the rotor at #4 (roughly horizontal, pointing back at the firewall). ![[Linked Image]](http://www.isuzu4x.com/albums/album69/IMG_0666.jpg) I've checked and doubled the dizzy so many times now, I'm more or less confident I'm not missing a tooth there. As for my base timing, the marks line up and I've spun it several times over, so I don't think i'm off there either. What gives? if I rotate the dizzy counter-clockwise as far as it goes, it seems to idle just a hair longer, but still won't run on its own. I'm still thinking timing issue but not seeing where my mistake is. any help would be great. Thanks -Rob
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 Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764810
11/12/06 10:23 PM
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Joined: Dec 2004
Posts: 287
Mudrunner
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Sounds more like a fuel pressure problem or something electrical.... Your timing skills ain't all that rusty, seems spot on to me. <img src="/forums/images/graemlins/kewl.gif" alt="" />
B.Y.E. ~ Back Yard Engineering 
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764811
11/12/06 10:27 PM
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Joined: Aug 2002
Posts: 3,007
Roll Me Over
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If you think you've got the timing correct, then I'd probably look at the alternator. If the alternator isn't charging, then the engine will only run for a few seconds, give or take. It won't be long though. What it is, is that there's a diode inside the alternator that trips a relay to run the fuel pump. The fuel pump runs off of battery power only during cranking and then switches over to alternator power after starting. It's a safety feature so that if the engine over stalls, like in a wreck, the fuel pump won't keep pumping fuel and possibly making things worse. My .02 Richard <img src="/forums/images/graemlins/patriot.gif" alt="" />
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: Richard Saylor]
#764812
11/13/06 12:55 AM
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Joined: Sep 2000
Posts: 4,277
OP
Roll Me Over
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Thanks guys. I decided to do a little more testing based on your response.
I'm confident I have fuel pressure. I jumpered across the fuel relay and can definely hear the pump come on. I tried starting it off this configuration (constant 12v power to pump straight from the battery) and there was no change in behavior. It started and promptly died.
I also decided to rule out the alternator. I jumpered across the engine relay to defeat the alternator low voltage indicator. Once again, no change in behavior... it would not stay running.
Any other suggestions? i still think its somehow timing related as I can vary its running time slightly by fine tuning the distributor. but i've tried advancing/retarding a tooth as well as changing out 180* to make sure I'm not crazy, and those configurations result in no start at all.
-Rob
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764813
11/13/06 03:14 AM
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Anonymous
Unregistered
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the mass air sensor is hooked up ?
crankshaft sensor etc
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764814
11/13/06 04:25 AM
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Joined: Sep 2003
Posts: 1,214
Body Damage is Cool
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Well, as some of you know, my summer/fall was pretty much occupied with wedding/honeymoon planning which has left our trucks neglected. Now as things settle down, I'm trying to get back into things, but my skills are a bit rusty. Where I last left our '89 Trooper RS was in the middle of a head gasket swap. I managed to locate all the dismantled parts and get the head back together, but now I'm having some problems getting it running and could sure use some advice. Whats happening is, as soon as I start it, it acts like its going to run, but then just about the time I let go of the key, it fades and dies. There is no violent shaking or backfiring, it initially sounds smooth, but then just fades away. I've been thinking its a timing issue and have spent the better part of today pulling the dizzy, rechecking all my marks and trying again. but so far, i've been unable to find my mistake (and I must have reset the configuration at least 5 times today). So, heres the details... both the camshaft and crankshaft marks lined up at their indicators (see pict). this should indicate TDC compression on #4. So I inserted the dizzy with the marks at the end of the shaft lined up... which points the rotor at #4 (roughly horizontal, pointing back at the firewall). I've checked and doubled the dizzy so many times now, I'm more or less confident I'm not missing a tooth there. As for my base timing, the marks line up and I've spun it several times over, so I don't think i'm off there either. What gives? if I rotate the dizzy counter-clockwise as far as it goes, it seems to idle just a hair longer, but still won't run on its own. I'm still thinking timing issue but not seeing where my mistake is. any help would be great. Thanks -Rob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Re: more 2.6 timing help (i'm a bit rusty)
[Re: JLEMOND]
#764815
11/14/06 02:05 AM
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Joined: Sep 2000
Posts: 4,277
OP
Roll Me Over
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Jerry -
This afternoon, I did what you said. peering through the #4 spark plug hole, I rotated the crank until the piston reached its maximum height. Looking that the timing marks, everything was lined up, exactly like previously pictured, when the piston stopped its uptravel. About a half a (camshaft) tooth more, and the piston starts its downtravel (crank mark is several degrees clockwise of 0 by this point). Does this sound right? I'm not exactly sure where I'm supposed to be taking the reading, as the piston seems to stay at its maximum height for a few degrees (at least as far as I can tell looking through the hole.
based on this, I would still say base timing still checks out. but I still have an uneasy feeling this is what's wrong. like you said, the symptoms seem to point being off here.
what would you recommend? pulling off the dampner and taking another stab at the base timing dispite this?
-Rob
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764816
11/14/06 04:08 AM
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Joined: Sep 2003
Posts: 1,214
Body Damage is Cool
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HEY ROB, THAT IS WHAT I WOULD DO ,PULL THE DAMPNER AND LINE UP THE LOWER GEAR WHERE IT IS SUPPOSSED TO BE, THE KEYWAY IS TDC SET AT 12. OCLOCK , ALLSO ON THE GEAR ITSELF IS A NOTCH THAT YOU CAN LINE UP WITH A SLASH MARK ON THE FRT SEAL RETAINER , IF THESE LINE UP, THE MOST THE CAM PULLEY SHOULD BE OFF IS ABOUT 1/4 TO 1/2 TOOTH, AND THIS IS USUALLY CAUSED BY THE HEAD OR THE BLOCK BEING SURFACED AT SOMETIME OR THE WRONG HEAD GASKET THICKNESS, THIS AMOUNT WILL NOT CAUSE ANY PROB, NOW WITH THESE MARKS LINED UP SLIDE THE DAMPNER ON AND SEE IF THE 0 MARK ON THE LOWER CVR LINES UP WITH THE SECOND MARK ON THE PULLEY EDGE (THE SECOND ONE THAT COMES UP AS YOU ROTATE IT CLOCKWISE , I HAVE SEEN THESE THINGS OFF BY AS MUCH AS 3-4 TEETH, DONT HOLD THE PULLEY WITH A BELT WHEN YOU TIGHTEN THE BOLT THAT CAN CAUSE IT TO SLIP ON AN OLDER DAMPNER, PUT THE TRANS IN 4TH GEAR AND STAND ON THE BRAKE AND YOU CAN TIGHTEN THE BOLT TO WHATEVER YOU NEED TO, DONT TRY TO USE 5TH TO MUCH SLACK IN THE GEARS TO TAKE UP, JERRY
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arghh! the problem still avades me
[Re: JLEMOND]
#764817
11/15/06 01:43 AM
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Joined: Sep 2000
Posts: 4,277
OP
Roll Me Over
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Jerry - I stripped it back down to where I could get a look at the keyway without the dampner in the way. What I saw is pretty disappointing... keyway dead on at 12 o'clock, lined up with the mark on the seal retainer, and matched up with the camshaft mark exactly. I didn't redo the belt because I couldn't see what I would change. everything is in order. here's a pict (same setup as previous pictured, haven't changed a thing but removed all the dress). ![[Linked Image]](http://www.isuzu4x.com/albums/album69/IMG_0681.jpg) ...so, what in the world is going on here??? symptoms act like a timing issue, but the more I dig/redo, the more I become confident the timing is spot on. suggestions? -Rob (big thanks for all the troubleshooting advise thus far)
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Re: more 2.6 timing help (i'm a bit rusty)
[Re: RobG]
#764818
11/15/06 06:43 PM
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Joined: Apr 2003
Posts: 1,994
Body Damage is Cool
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A shot in the dark,is your coil getting power when the key is at the run position?
DO Isuzu's have seperate wires going to the coil circuit?One for cranking and then it switches over to a "run" circuit to power the coil after it's started?
How about: Is the oil pressure switch hooked up?It may bypass the switch for cranking,then when key is turned to run,it's reading oil pressure and shutting motor down.
Just trying to help.
Bansil
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