96 Tahoe, starting problem

[m610]

I've never seen these symptoms before.

1. The engine cranks
2. It seems to fire, once, on one cylinder
3. Cranking stops
4. The engine stops, but sometimes it seems to turn a little more, slowly, due to compression in a cylinder I expect.

I'm new to this type of vehicle and it seems like cranking is disabled once the engine fires/ECU thinks the engine has started. I have to release the key and turn it again to resume cranking.

The truck ran fine yesterday, no hints of engine trouble. It has a full tank of gas. Etc.

This has to be electronic, some sensor. Any idea where I should start looking?

Mike

 

[MO Viet Vet]

What happens if you attach jumper cables and use another vehicle for starting? You may have a failing starter or loose cables or dirty cables.

 

[lesterl]

What do your lights/ guages do? Suspect starter, cabling, or battery....

 

[Ice98]

Mine had intermittent trouble starting, spent the worst two hours of my life in the parking lot of discount tire after buying several new tires, trying several sets of jumpers and a couple different vehicles, ended up being that the side-mount battery posts are just utter ****, after weeks of trying new screws from the autoparts store and online I finally said f-it to the whole situation and bought a pair of marine terminals, bolted the cables to those, and attached them to the batteries top-mount posts (thankfully, mine has both side and top)

This solved any cranking issues, also solved an alternator whine through the speakers and a lack of power when using accessories (I have a 1kw amp installed)

 

[m610]

Thanks, all.

It cranked strong on the battery, but I hooked up a charger/starter anyway and it cranked a little stronger, but the problem still persists. As soon as it sounds/feels like the engine fires everything stops. In fact, it even sounds/feels like the motor bucks or something, then stops. Difficult to describe.

The connections on the starter feel solid, and the starter is bolted up tight.

It looks like a tow and time at a shop is in my near future.

 

[Ice98]

Is your fuel pump consistently pushing fuel?
if you give it a little gas as you start it can you get it to run?
Have you checked the spark plugs and wires to make sure you are actually getting spark to all the cylinders?

 

[MO Viet Vet]

If you go from cranking to no crank when you experience this problem then I suspect a starter problem to be found at the shop. Connections loose or dirty?

 

[m610]

It looks like it is a starter problem. Symptoms gradually got worse every time I went out to crank the car and finally it was pretty obvious. The starter could not turn the motor once it encountered resistance due to compression. It was also getting loose, which would explain the rare (never before last week) but now more frequent grind, usually just before the started stopped turning the motor. Electrical connections looks OK, tight, solid, although there could be some corrosion I can't see just looking at the started and pulling on the wires.

Odd how the two things happened at about the same time.

I'll have a new started in the Tahoe by the weekend.

 

[MO Viet Vet]

Double check ALL of the teeth of the flex plate.

 

[lesterl]

Good point Ron......

 

[m610]

I've got a starter and will put it in int eh morning.

Meanwhile, fuel has started leaking from somewhere near the filler tube, and the tank is full.

 

[MO Viet Vet]

How did the flex plate teeth all look? Do a search for threads about the fuel leak. Lots of them.

 

[m610]

I am assuming that by your asking that it is easily damaged. (I had to Google to find out what a flex plate is. )

I haven't looked yet. I'll find a friend to help with that, after I figure out how to do it, which I assume will be -- remove a cover, remove spark plugs, put a wrench on the front crank...

More diversions, clever little truck. The fuel leak turned out to be a half gallon of water in the fender. I had looked everywhere for a source of the leak but all I could find was wetness at the plastic plug just behind the left rear wheel. I could smell gas but the smell was not strong enough for a 24"x24" puddle, so I loosened the plug and when I was just it was just water I pulled the plug and drained it into a pan, flushed out the dirt and algae, and will let it dry before spraying it with CRC 3-36 (instead of WD-40) then letting that dry to display the remaining water before plugging it again. I checked the other fender and it is dry inside. Now I just need to find out how the water gets in there. I suspect the fancy aftermarket fuel flap thingy.

Also, I need to track down this smell of gas.

I've owned this Tahoe for about 6 months. I guess we are finally getting to know each other better.

 

[MO Viet Vet]

The smell of gas could be from the full tank you say you have and seepage or leakage at the sending unit seal at top of tank or hoses that are leaking. A tank less full will back this up and make dropping it less dangerous.

The flex plate is what the gear on the starter engages to spin the engine. The time to inspect was when the starter was off and remove cover to have easier sight access. It is time consuming but you can take a large flat blade screwdriver and walk the teeth around by prying at the edge of bell housing and move the flex plate. Easier if plugs removed and then can attach socket at the center front of harmonic balancer and spin there. There is also a tool that spans the teeth and allows the movement of the flex plate by engaging and then pulling. Look for chipped or cracked teeth on the flex plate. While you have that cover off make sure you get a flashlight and look up to center of flex plate where the attaching bolts are and look for any cracks. They can be hard to see or easy if the crack is dirty and looks like veins spreading out from the bolts. If there is cracks or teeth damage the flexplate needs replaced.

 

[lesterl]

Again with Ron.... Also, if you have rear air, perhaps your condenser has a plugged up drain? Perhaps something in the rear door is leaking and allowing water to flow into that fender......

 

[m610]

The new starter took care of the problem.

Strange. I have never had a starter that just gradually lost its power. I guess being so close to the exhaust had something to do with that.

Thanks all, for the help.

 

[MO Viet Vet]

So the teeth on the flex plate are fine? You keep avoiding the answer. eace:

 

[m610]

I tried. I was working under the Tahoe, on my back, and even with jack stands I didn't have much room to get to things. I tried using a hefty screw driver to turn the engine but things were too cramped. Then I figured if there was a problem with the flex plate I wasn't going to be able to fix it there, or do the work myself, so I put the starter back in and so far there are no indications of problems.

I assume you are thinking of chipped or broken teeth. Is there anything else involved here?

 

[MO Viet Vet]

Chipped or broken teeth and even cracks radiating out from where it bolts to the crank. The cracks typically happen over time/age or if you hydraulic a cylinder and the teeth problem can also happen with a hydraulic or misalignment or starter drive problems.

 

[lesterl]

Well glad you got that figured out, hope the flexplate is good, if it is cracked in the center it could leave you stranded somewhere, but I havent seen many crack (doesnt mean much), but good luck.....