85 6.9 IDI trouble turning over

[ArdWrknTrk]

It says "starter relay page 41"

(I think... I'm on my phone and half blind)

[ArdWrknTrk]

Well, that's a pretty big draw just to hold it closed.

I know my PMGR says 40 to pull & 13 to hold.

[old55pete]

Yes, the 6.9/7.3 have a gear reduction starter from the factory. The cable should be an double 00 ga or 2 ot
The hot cable runs acrost from battery to battery in front of the radiator on the top of the support, HOT, not ground.

The grounds run to ether side to studs at the lower corners of the timing gear cover. Right batt to stud on right side, left to left stud.

The relay on the fender is just that, a relay. It also should have a 6GA from the batt to the bat side of the relay that powers the cab, lights and the rest of the acceries. Then one that goes to the selonid on the starter.

It sounds like there is not enough power is getting to the starter to spin it over fast enough. Keep in mind that that engine has a 25:1 compression ratio.

Did you change the voltage regulator when you changed the alt? If not both may well be fried again. It sounds like a multi meter is going to be in your near future. Use a multimeter to check the batt voltage on the right battery and write it down, then the left battery and write it down. Get it started and run it at 2000 rpm and run the same test. You should get from 13.6 to 14.2 at each battery. If not put the hot lead from the miltimeter on the large stud on the back of the alt and the ground lead in the ground on the batt, it has a 6 ga cable coming off of it. If it reads the same as the first battery test, check the grounds at the block and clean them up. let me know what you get. some pictures of the batterys and cables would be helpfull too.

[myrl883]

Are you sure that this is an electrical problem? From your first post, it sounds like you could have an air problem... What condition are the injector bleed off lines in? This is by far the most common hard start problem on an IDI.

[ArdWrknTrk]

ArdWrknTrk wrote

***Caveat, I am not an IDI guy, so more knowledgeable folks may have better answers***

See?  

[6.9-250]

Once the engine is warm, will it start again?  I know for a fact mine will not start unless the glow plugs are working.  You do not need the glow plugs once the engine is warm though.  The glow plug light may be cycling but the plugs could be burnt out.  They are easy to test (there are several methods) but I like checking the resistance.  You will need a DVOM for this.  $20 should get you a decent one.  The glow plugs are common to burn out as the factory relays sticks/fails and holds them on until they burn out (ask me how I know, lol).  Cold engine will need glow plugs for about 10 seconds.

If the truck is warm and it starts with a boost, shouldn't be bad to figure the issue out.  Note - I believe they want you to boost from the passenger battery - should be a sticker under the hood or in your manual to confirm.  

If it doesn't start when warm, even with a boost, it could be air intrusion somewhere. The water separator is common and the return lines.  A worn injection pump could give you trouble as well.  

If you have any further symptoms to report, let me know.

[old55pete]

He was saying in an earlyer post that he put new battries in it and the first time it would spin over fast, each time after that it would spin over slower and slower. That is why I and Jim and Gary were steering him to ward the electrical system and possable the starter.

[6.9-250]

It sounded like with a boost and with the new batteries, it started right up.  If so, fixing the charging system should resolve the issue (keeping the batteries at full capacity).  I have the stock alternator with 2 batteries on mine and it is serving me well.  I don't drive it much, so every 3-4 months I disconnect the negative cable from one battery and use a smart charger to charge both batteries separately.  I also never recommend boosting unless absolutely necessary.  I believe it does hurt the capacity.  If it is necessary, fully charge the battery back up using a trickle charger as soon as possible (I use 1 or 2 amps - nice and slow). Driving around will not recharge it sufficiently.  I have a quite a few vehicles and thus batteries and this charger works awesome = "Noco genius 1 - Restore your battery - Detects sulfation and acid stratification and restores lost performance for stronger engine starts and extended battery life.  Enjoy precision charging - An integrated thermal sensor detects the ambient temperature and alters the charge to eliminate over-charging in hot climates and under-charging in cold climates."

Labored cranking isn't good for sure.  But if it cranks over fast but is not starting right away, of course it will slow down.  This is when I would be looking into why its not starting right away, possibly fuel supply or glow plugs.

[ArdWrknTrk]

"Driving around will not recharge it sufficiently."

This is an unfortunate fact with 1G alternators -especially low revving engines like the IDI-

And thanks for your charger recommendation.  

I have a giant Schumacher 200A 'cart' that is better used for electrolysis, because it is not auto-anything except the timer, and a 30 year old Sears charger that doesn't see any use now that I 'upgraded' to a 3G charging system.