4.3gi no start new ICM. how to set base timing?

[GHBAY]

4,3gi throttle body injection

been having a number of issues. i believe i have it pinned down to ignition at this point. after replacing injectors, fuel regulator, plugs cap and rotor, i was able to get it running very rough with backfire at intake. was acting like timing was squirrelly. could barely keep it going for 30 seconds or so before it would die out. VERY rough slow burping idle

replaced ICM hoping that was the issue but now i can no longer get it to fire at all, just cranks with no joy.

i have spark. i have good compression. rotor is pointed at cylinder 1.

been reading a number of threads on the internet about needing to set base timing, but getting confused as to needing shunt at module vs paperclip at the diagnostic plug. in any event, both scenarios seem to require an engine at idle to perform those steps. ive found a few threads with good information on here that offer links to other threads & more detailed instructions, but those links all seem to come up dead or pointing to unrelated threads.

any/all help is welcome. ive been throwing parts at this for a while now and local marine mechanic has been unable to solve- their last suggestion in the fall was that it was my injectors which have now been replaced and led to the current ignition diagnosis.

 

[alldodge]

The Gi should have a MEFI 3 ECM and Delco EST distributor

You mentioned ICM, are you referring to the Distributor ICM?

While the rotor would point toward number one cylinder, but it should be on the compression stroke and the timing mark on balancer would line up.

Where did you get the injectors? I hope not off Amazon or Ebay

 

[GHBAY]

Yes- the ignition control module that sits under the distributor.

Marks are lined up tdc on engine and rotor is pointed at 1

Yes- after a ton of research I got standard tj17 injectors that properly cross reference and have the correct pressure rating. The 'marine' equivalents were over $400/each and would have taken months. I do not think injectors are (or ever were for that matter) the issue. These new injectors are firing well and I have good pressure both low and high.

 

[alldodge]

Many list injectors as rebuilt and for the most part, electrical injectors can not be rebuilt, they can be cleaned up to look great. The injectors are standard GM type, but we can let this one go for now

Was running rough and now it won't even start after replacing the ICM. Have you tried putting to old one back in to see if it will restart?

Check grounds and engine connectors for corrosion

Check for spark and also the rotor. If the rotor/cap was not in correct position when cranking the first time after iCM replacement, rotor could be damaged by cap

To set timing the motor must be running and then a paper clip is inserted in DLC connector to place in base timing mode

 

[dubs283]

If you're sure the distributor is installed correctly you could try rotating it one way or the other to see of it will fire/run

If that doesn't work you'll need to verify tdc #1 compression with #1 spark plug removed

Firing order 1-6-5-4-3-2

 

[GHBAY]

Yeah, this is driving me nuts.

Didn't do much today- was too rainy and needed to let the battery charge back up.

Never had the distributor out- just changed cap and rotor. Cant figure out what I am missing. I have verified I have spark, but even the new plugs are getting fouled from not firing so I'm assuming it has to be timing at this point. Going to put the old module back in tomorrow and try again. Will also double check grounds.

Firing order is correct. I think I have tdc on 1. Can't get anyone to look at it for weeks, so I'm on my own trying different **** to try and figure this out. I'm no mechanic, but I like to think I am pretty handy with stuff generally, but this has my head spinning.

If anyone has a link to the electrical/ignition/fuel manual, please let me know. Can't find a copy anywhere and feel like at this point I need to read the thing cover to cover to try and find what detail/basic understanding I am lacking. Thanks

 

[dubs283]

HOW TO: Find #1 TDC on the compression stroke.

First thing you need to do is remove all the spark plugs. This makes the engine easier to turn, and if using a remote start button keeps the engine from kicking back when you are trying to make very small movements. The Merc OEM service manual suggests you put your finger over #1 spark plug...

forums.iboats.com

 

[alldodge]

With new plugs fowling, put the old injectors back in

 

[GHBAY]

Plugs were fouled from the old injectors. It's not the injectors.

 

[GHBAY]

Plugs were fouled from the old injectors and it not firing. It's not the injectors.

 

[GHBAY]

Well, my starting issue turned into a much bigger issue now...

Was cranking last night trying to start, heard a loud bang, and stopped cranking. Decided to walk away for the night. Went back today, and had water with oil mess on starboard side of the bilge. A fair amount. Also appears to be slightly watery in oil dipstick.

Pulled the plugs, water in cylinders 2 &4. Got the water out. Checked compression. ZERO compression in cyl 4. All others fine.

Been going in circles reading various potential causes. Boat hasn't been running. Compression was fine in cyl 4 after no start issue began, now it's gone and I got water in cylinders. Did have it on muffs so assume that's how water got into system, but not sure how got into cylinders.

Looks like I have a bigger issue now and not really sure where to start.

Open to suggestions

 

[GHBAY]

Pulled off valve cover starboard side. The small plastic baffle on the inside that connects to the breather hose to air filter was broken off. Don't know if it was as I was pulling it off (dont think so) or if it was somehow broken before.

Don't really know what I am looking at/for, but nothing appeared out of place, broken or stuck. Signs of milky oil under valve cover.

Trying to decide if I should pull off the intake manifold and inspect at this point, or some other step. I have the workshop manual and am decent following directions, but in a bit over my head at this point and can't afford to drop it off at a shop for what is sure to be a shockingly high diagnosis and repair bill.

With everything I am reading, I can't find a good explanation for what would cause me to get both the water in the oil and loss of compression on one cylinder/ all just from cranking without it starting more than a few seconds.

Had good compression and no water in oil while previously troubleshooting the no start.

 

[Dillusion808]

Whens the last time you check the exhaust manifolds and elbows.

 

[GHBAY]

Adding some notes here for myself to consolidate some of what I have read and get it all written down for myself. Also hoping it prompts any suggestions / expertise from anyone here.

Setting aside the cause of the original no start issue and possible timing problems...

If what I am reading online from multiple sources is accurate and i understand it all:

- sounds like over cranking and no start could introduce water to the cylinders as water builds up and doesn't get pushed out exhaust
/ valve could be stuck which could give me no compression in that cylinder

- IF intake manifold had its own issues, water and oil could mix and that is what circulated and got into cylinders/dipstick

- crack in intake could be where oil/water mix dripped out into bilge overnight.

(Oil in water/no compression is a new occurrence in last 24hrs) no start very short rough start has been ongoing issue for a while with confirmed good compression and good oil/no water along the way)

So, if all of that is correct, remove/inspect/replace intake manifol d?

Compression could be blown head gasket, but what are the chances only one cylinder with no compression as opposed to two adjacent cylinders?
If head gasket, could it get blown from cranking if the motor wasn't actually running?

And finally, if intake manifold is the root cause of valve sticking, no compression, oil/water, could it also have been my original root cause of the no start situation?

 

[GHBAY]

Whens the last time you check the exhaust manifolds and elbows.

Have not. Boat hasn't been in water or running for a while. I will add that to the list of things. Anything in particular I should look for?

 

[alldodge]

If what I am reading online from multiple sources is accurate and i understand it all:

- sounds like over cranking and no start could introduce water to the cylinders as water builds up and doesn't get pushed out exhaust
/ valve could be stuck which could give me no compression in that cylinder

No, no kind of cranking will induce water in the cylinders

- IF intake manifold had its own issues, water and oil could mix and that is what circulated and got into cylinders/dipstick

No

- crack in intake could be where oil/water mix dripped out into bilge overnight.

Kind of, sort of
Intake crack can induce water into oil, but will not be slow

My opinion
You need a Mechanic to look it over, the process of DIY is a bit beyond the current understanding right now

 

[GHBAY]

"No, no kind of cranking will induce water in the cylinders"
interesting. ive just beenreading numerous examples of this scenario online: will find what i read and cross post here

 

[GHBAY]

here is one explanation- not sure of validity or specific application to my motor.

and yes, would be good to get a volvo mechanic on it, but im in a remote area, cost would be astronomical, and time and budget isnt in the cards. im comfortable learning and have some time to investigate for now.

......................
"
Most of these boats were left in the driveway all year, and needless to say had dead batteries, wet iginition systems etc.
It was very common to find water in the cylinders when they called me to help get the mess sorted out.
The water came from extended cranking when trying to start an engine with a dead ignition system.
Raw water pump dumps into exhaust manifold/heat exchanger and there's no hot exhaust to blow the water back down the pipe.
Instead, it flows by gravity into the cylinders."

 

[dubs283]

At cranking speed the raw water pump does not create enough draw for water supplied through muffs to first get to it let alone pump through the entire cooling system and enter the exhaust portion of the manifold. Even if you force fed the cooling system with city water pressure there's little to no chance of water entering the cylinders via gravity through the exhaust unless something is damaged in the cooling/exhaust system

You first need to find the cause of zero compression at #4 cylinder. Stuck, burnt, broken or bent valve(s), hole in piston, completely blown head gasket, severely worn rings or broken rod are the only things that come to mind for zero compression.

Water can enter the cylinder via damaged exhaust manifold, riser or gaskets, through the intake fuel/air passages, cracked head or a severely damaged head gasket but that is a very rare and specific cause

Has this engine ever run well for you?

 

[Dillusion808]

Have not. Boat hasn't been in water or running for a while. I will add that to the list of things. Anything in particular I should look for?

Cracks, rust.

I locked up #6 because of leaking manifold. Tried to stretch them one more season and that was a bad idea.

Luckily got it un-stuck and running just fine.