Cranking way too slow experts question 4.0

OH-K lets make this 200% perfectly transparent gentlemen.

Battery voltage, 12.7 before cranking at the battery and at the starter.

Voltage while cranking, with a new fully charged battery and new starter, did the same crap the 1 year old battery and 1 year old starter did, to be PRECISE, it had 9 volts at the battery and 9 volts at the starter while cranking for 1-2 seconds. By the end of the 1st second, the starter was still fully engaged and busting its ass under full load trying to turn the forking engine, and it did not turn after the first second, between the first and 2nd, second.

We tried it twice, The engine has something forking jamed up inside.

What are the possible things, and likely things that can cause it to do this IN THE DAMN ENGINE?????

denverd1 said:

This. Was getting good voltage now 10?

Also have the person check the wires and terminals on the starter itself for good connectivity and no corrosion. Although new starter should've fixed that issue.

Still question the helpers skill

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Except that the problem was not repeatable. A fully seized bearing would not fix itself a minute later, and crank and start. This one did in the earlier testing minutes earlier. One minute it started the next it acted like it was hydrolocked.

I have had fully seized bearings and been able to crank my 4.0

This one dead heads and refuses to turn after 1/6th of turn and dead heads.

This not a slow crank/no start. It is turns about 45 degrees, and locks up with the starter fully engaged and busting its balls trying to turn the engine. The belt, never made any noise, when t started, ran and when it slow cranked etc....

trippled said:

Not true at all. Seen many locked up ac compressors that cause slow crank/no start without making a sound.

Removing the belt would be my first thing to do and one of the easiest thing to do.

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With a new battery mine drops from 12.75 volts to 12.3 volts while cranking.

Renix ECU according to 5-90 will not function with less 10 volts.

I had one last year that would not start with 11 volts cranking voltage at the battery, as the CPS did not generate enough voltage due to the RPM being too low. And it has a Renix CPS that generates .60 volts AC while cranking.

Even the Renix manual says it must reach 275 (or was 225?) rpm cranking to get them to wake up and start.

I have neev seen one start with 10 volts cranking voltage.

old_man said:

A voltage drop during cranking is normal. 9 volts is a bit more than normal but within tolerance. If the drop is measured at the battery, then it can't be cables. It could be that the starter is pulling more than typical current or the battery does not have as low an impedance as most. The best way to tell is to get a clamp on meter and measure the cranking current and compare it against another XJ.

I would be surprised if the motor itself is dragging things down. If it had that much resistance, you would see some performance difference.

I converted over to large gauge welding cable for my battery cables and the starter spins way faster. The starter will spin when there isn't enough juice in the battery to run the ECU.

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Basic electrical engineering/physics-science 101,

If the ground is bad it does not conduct well. If it does not conduct well, the battery will not be able to dump 1000+ amps out of the battery into the starter and drop from 12.7 volts to 9 volts at the battery and at the starter, as those massive numbers of electrons have no way to make the round trip from the starter back to the battery ground with a bad ground connection.

I was told the earlier cranking before it got to when the engine would not make a full rotation even with new stuff...., was smoking the battery posts/clamps, as in getting super forking hot from too much current draw.

The lady that owns the jeep said she pulled over and stopped because she heard a loud scary noise, like she ran over something or something broke. That was the only time a noise of any kind was reported. They found nothing on the road or on the rig that looked broken.

BIG1RED9 said:

You shared that it was running is it 100% a starting issue or when it ran it did so like crap and made other engine noises?

If once started it runs fine then that points to items related to the starter circuit.

Not suggesting it is the issue, but when I just changed my starter for slower than typical turnover rpm I found the stud on the starter and the cable to be coated with rust. Although I changed out the starter, it is possible that by itself would have solved the problem. Engine grounds clean and tight?

It was running like crapola then I join the suggestions of pulling plugs - looking at them for clues, try to turn it over by hand and finally pop the valve cover.

Good luck.

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If the engine spins back easily, then forward again and locks up hard against something, my first bet would be a rod let go. Without knowing anything to it's prior condition or running or whatever. Anything you do at this point is exploratory.

I still say take the belt off and recheck. Don't care if it ever made noise or not.

As best as I recall she said it started with a loud sudden scary noise while she was driving. Then or later (not sure when), after she restarted it or before she parked it, it suddenly ran like crap, backfired a time or two.

That was when she called for help.

Then IIRC, it was started 2 times, while I was listening on the phone and it sounded perfectly normal running at idle, like a new jeep.

Then the slow cranking issue started. The rest is already posted.

BIG1RED9 said:

You shared that it was running is it 100% a starting issue or when it ran it did so like crap and made other engine noises?

If once started it runs fine then that points to items related to the starter circuit.

Not suggesting it is the issue, but when I just changed my starter for slower than typical turnover rpm I found the stud on the starter and the cable to be coated with rust. Although I changed out the starter, it is possible that by itself would have solved the problem. Engine grounds clean and tight?

It was running like crapola then I join the suggestions of pulling plugs - looking at them for clues, try to turn it over by hand and finally pop the valve cover.

Good luck.

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trippled said:

If the engine spins back easily, then forward again and locks up hard against something, my first bet would be a rod let go.

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Is there no way for a top side part failure to do this?

Pretty sure I have heard of a valve keeper failing after a spring broke and the valve dropping on top of the piston once before in 4.0 chats.

It was running just fine when she turned it off, before the current issue started. But it had made the loud noise (unknown what it was) with a back fire or two before I heard her start it and run it for 2 minutes with no issues, before this cranking problem started.

Made me think something came loose and rattled around until it jammed something.

Timing chain? As in something broke and lodged in the timing chain at the gear tooth?

Oil pump on the Cam shaft seized?

May be time to see if something is lodged between the flex plate and the bell housing?

But a lot of this sounds like reaching.

She checked the oil again tonight, still at the same level, looks like clean new oil (which it is) with no contamination no water.

I could see this as being either a thrown rod or a bound up accessory (such as AC compressor).

It is easy enough to pull the belt.

If not the belt then it is probably time to pull the engine.

The odds of it being just the top end are pretty slim. If it works out that way someone should be buying a lottery ticket.

Update, the large power cable + to the starter is pulling current with the ignition switch off. It drained the battery over night. She had no power at all today, until she disconnected the main + cable going to the starter solenoid.

Hope is that it is typical Durajunk starter failures, but the verdict is still on hold.....

Anyone in Colorado Springs want to help a social worker/lady that works with homeless PTSD military vets on the streets that is not made of money? The Jeep is parked at a church.... 97 Grand Cherokee 4.0

Needs help pulling the starter and taking it and the battery to the stores they came from, and the right socket/ratchet to see if the crank turns OK or not?

I am over 1500 miles away....

From the Colorado thread:

Ecomike said:

Some friends of friends, mechanics got her running for now.

Thanks!!!

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Can we gather this means the starter was bad?

I am not drawing any conclusions yet. It sounds like they did not replace any thing. But that remains to be seen. They did not R&R the battery or starter with replacements (I was told).

I was not able to get a direct run down from the guys that did the work, I was tied up (Granddaughter's 4th BD and BBQ), and the second hand translation was too garbled after the fact, to be of any use
as to what all they actually did or did not do. That said, the engine itself seemed to be fine. She was driving it again. arty:

The oil filter threads were stripped/cross threaded and it had already leaked on the new starter. :gag: They got the oil filter back on right/square and told her to buy a new one right away and change it.

And they "super charged the battery with a portable field rig", and did not, I am told, did not replace the starter or battery.

Maybe the Cloaked JeepRimlins went back into stealth mode. If it throws an engine gut part in a few days???? or not, Who knows.

We all know these rigs like to play hit and run tag games.

I can not trust the rest of what I was told second hand, to mean anything useful for now. She mentioned something about their saying the distributor... being too tight, but she was not sure she had the right part name (ugh).

She may get a paper run down on what they did. If she does I will try to get a copy. We are all curious what they did. One of the guys owned a repair shop but was a Ford person, and said I saved him hours of work with my feedback and run down before they started.

They did test the engine for rotation at the crank shaft, at my request first. It passed! It is 98 Grand Cherokee.

for now, It Lives!!! If I get any more solid feedback I will post the end game story!!!

I also want to know if it is really fixed, and if so what the problem was.

For now we wait. :cheers:

Anak said:

From the Colorado thread:



Can we gather this means the starter was bad?

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Sounds like she is dealing with quite the cluster. How does someone install an oil filter cross threaded? That takes some effort. You have to know you are screwing up while doing that. Dang.

It sounds strange to me that an oil leak would cause the starter to drain the battery, largely because I have a 12V Cummins that maintains a pretty consistent oil bath for the starter. It seems to be an effective rust prevention system. But perhaps I should count myself lucky that it hasn't had other effects.

At any rate, good to hear that she is up and running again, and that she got some professional assistance that could see what others were not seeing. Keep us updated if there is more to be learned.

Just for info if one brush isn't making proper contact the starter will draw excess amps, overheat and turn over slower. Oil can mess with brush contact, as can muddy water getting into the starter, then when the water evaporates it leaves something resembling clay. Oil mixes with the carbon dust from the brushes and leaves a similar substance.

I mudded my XJ on my hunting lease, starter issues were common. I've also had a leaky oil filter adaptor which gives much the same results. Cleaning out the starter is something I did multiple times a year. Cleaning them out also affects longevity, some of the stuff that finds its way into a starter is abrasive.

The wire from a brush, if kinked can catch on the brush holder as the brush wears down, keeping the brush from making good contact, With similar results to mud and oil being on the brushes.

A few years back I was legally blind (cataracts from Rx Drugs that saved my life....but ... traded one problem for another) and I could barely move the joints in my fingers, or stand or walk. A family friend was helping me keep up with stuff, but now he is 1/2 blind in one eye and can't see out the other close up, and he has the shakes. Any time he tries to thread something now one can be sure it is cross threaded if he did not drop and lose the bolt first. He was a mechanic.... This getting old shit sucks.

I had an 81 starter on my diesel bite the dust at least partly from oil leaking on it for a while.

Anak said:

Sounds like she is dealing with quite the cluster. How does someone install an oil filter cross threaded? That takes some effort. You have to know you are screwing up while doing that. Dang.

It sounds strange to me that an oil leak would cause the starter to drain the battery, largely because I have a 12V Cummins that maintains a pretty consistent oil bath for the starter. It seems to be an effective rust prevention system. But perhaps I should count myself lucky that it hasn't had other effects.

At any rate, good to hear that she is up and running again, and that she got some professional assistance that could see what others were not seeing. Keep us updated if there is more to be learned.

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Great feed back. We did not expect oil on the brand starter to be an issue. But 3-4 seconds of cranking must have been enough for it to get soaked according the new mechanics that got it running a day ago. Also your comment about the brushes fits 100% . More and more it seems one must ask for a bench test on a new part before leaving the stores these days.

Oil is a poor electrical conductor and can bake into an insulating varnish over time.

8Mud said:

Just for info if one brush isn't making proper contact the starter will draw excess amps, overheat and turn over slower. Oil can mess with brush contact, as can muddy water getting into the starter, then when the water evaporates it leaves something resembling clay. Oil mixes with the carbon dust from the brushes and leaves a similar substance.

I mudded my XJ on my hunting lease, starter issues were common. I've also had a leaky oil filter adaptor which gives much the same results. Cleaning out the starter is something I did multiple times a year. Cleaning them out also affects longevity, some of the stuff that finds its way into a starter is abrasive.

The wire from a brush, if kinked can catch on the brush holder as the brush wears down, keeping the brush from making good contact, With similar results to mud and oil being on the brushes.

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Anak said:

How does someone install an oil filter cross threaded?

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I'd suspect it's the wrong filter. It's not uncommon to see someone force the wrong one on, in particular Renix versus HO filters are metric versus sae threads. You also have to pay attention as some Renix owners have swapped the oil filter adapter to use the newer filter.

Indeed!!!

I have also had one with bad threads right out of the box.

lawsoncl said:

I'd suspect it's the wrong filter. It's not uncommon to see someone force the wrong one on, in particular Renix versus HO filters are metric versus sae threads. You also have to pay attention as some Renix owners have swapped the oil filter adapter to use the newer filter.

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Ecomike said:

Indeed!!!

I have also had one with bad threads right out of the box.

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Yep, I have too. It was a Motorcraft filter, not one of the crappy brands. Go figure.