Noisy IAC, No start; fuel, IAC, or?

[nimrod.sixty9]

GF's 99 Yukon has been developing a no start issue. Not sure if it's low on fuel (gauge issue, another thread) or if there is an actual issue. It does have a code for one of the CATs and idle's a bit off.

One time I actually showed up with a gas can and it fired right up, another time (after she went to work and took my Hoe) it simply just fired up. Took it to get gas just in case. Did fine a few days until today, once again it did not start. She did state, going by her word, that it seemed that the starter engage and disengage was delayed. Not sure if related or even a fair explanation. But what I did notice the other times I was around and it did not start, was an incredibly noisy IAC. Now this I could imagine to be related. It does stop before cranking, but there is a very noticeable spin click click spin (on and off key cycle).

Ideas? Input?


Videos:
Start and shudder start;
https://www.youtube.com/watch?v=eRNbugWLztQ&feature=youtu.be

IAC noise, no start, and putter; with fuel pressure;
https://www.youtube.com/watch?v=W7XKROSdw68&feature=youtu.be

 

[nimrod.sixty9]

It may be worse than I thought. Motor comes to an abrupt halt, shudder and shunts when cranking. Sometimes complete stops then continues cranking. Then runs...
Even had a shunt/shudder after what I think to actually be a running motor. Almost seems like a total lockup. Very crazy acting.
Thoughts?

 

[nimrod.sixty9]

https://www.youtube.com/watch?v=eRNbugWLztQ&feature=youtu.be

 

[rockenthebowtie]

Sounds like a bad starter.. ignition switch... Also might want to start with checking the battery connections make sure those are nice and tight

 

[nimrod.sixty9]

Sounds like a bad starter.. ignition switch... Also might want to start with checking the battery connections make sure those are nice and tight

One terminal was a hair loose, but didnt help. Starter is the suposed gold edition with lifetime warranty (about a year old now). How could I diag?

 

[rockenthebowtie]

One quick way is when it starts acting up see if you can smake it with a hammer as someone is turning the key over in the start position.. and since it was replaced about a year ago make sure thr connections at the starter are also nice and tight

 

[nimrod.sixty9]

One quick way is when it starts acting up see if you can smake it with a hammer as someone is turning the key over in the start position.. and since it was replaced about a year ago make sure thr connections at the starter are also nice and tight

Hammer trick is if its binded. Dont think it will work cause it is intermittent. Im going to check the lines as you said, if tight then Im gonna return and get new.

 

[SunlitComet]

it looks as if you have a electrical power issues.

 

[nimrod.sixty9]

it looks as if you have a electrical power issues.

Do you mean within the starter or elsewhere?

Truck has been working fine since my last post; cept for the last three or so days. What I dont understand is that its already turned over enough times to actually run. Instead it may putter, spark here and there, or simply keep jumping with the starter.

As about 20 minutes ago, it fires right up. I dont even get two rotations. Just as I normally would.

Could the starter be causing all this?

 

[nimrod.sixty9]

Wombats taste like chicken.

 

[SunlitComet]

power supply to starter. from battery under load.

 

[nimrod.sixty9]

Look at this TSB. This really makes me think this is it.

Date: April, 2000
TECHNICAL Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338 (Replace Crankshaft Position Sensor)

Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT Models
1996-2000 Chevrolet and GMC C/K, M/L, G, P Models
1996-2000 Oldsmobile Bravada
with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine
(VINs W, X, M, R, J RPOs L35, LF6, L30, L31, L29)

Condition:
Some customers may comment on one or more of the following conditions:

^ Backfire during crank/start
^ "Kickback" during crank/start
^ "No" start
^ "Slow" or "hard" start/crank
^ "Grinding" or unusual noises during crank/start
^ Cracked or broken engine block at the starter boss
^ Broken starter drive housing
^ Broken starter ring gear on flywheel
^ Any combination of the above

Cause:
A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures
which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.

Correction:
Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining
components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).

Notice:
When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated





inoperative conditions of the starter or flywheel.

Important:
Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal.

Parts Information
Parts are currently available from GMSPO. Warranty Information:











For vehicles repaired under warranty, use the table.

 

[SunlitComet]

monitor your rpm thru a scanner and compare it to the tachometer. do they match or does the pcm rpm seem really erratic?

 

[nimrod.sixty9]

monitor your rpm thru a scanner and compare it to the tachometer. do they match or does the pcm rpm seem really erratic?

Unfortunately I cant even get it to run now.

 

[nimrod.sixty9]

Well went to inspect the CPS and instead of coming out, the half in the motor stayed. Now how in the hell do I get the rest out?!

 

[SunlitComet]

use the force luke.

 

[nimrod.sixty9]

use the force luke.

Not really sure what to do atm. Thinking maybe taking a sized bit and weakening the plastic. Maybe pick at it with needle nose pliers. Damnit, wish someone would have mentioned this thing could break in half, I was just going to inspect it and now stuck. FML

 

[SunlitComet]

actually you are the first time i have seen that happen as it did.

 

[nimrod.sixty9]

That explains it.
Well, I was able to get out the remaining part of the CPS and installed the new one... Same result. It would turn and turn and no fire, just a blump here and there with the occasional kickback. It would at least start once and awhile but it got worse and worse up until it stopped running (just before I broke the CPS).

For ***** and giggles I changed the coil between this and my Tahoe... Same result, except, if I ever find the ******* who designed this crap, I will beat him till he is ******** himself.

So what now?

 

[99Vortec]

I had a weird no-start issue once and this tutorial helped me to find a coil wire that was grounding out on a bracket.

http://easyautodiagnostics.com/gm_misfire_diagnostic/ignition_misfire_tests_1.php

Noisy IAC is strange though.

Before starting ignition testing, I like to verify that fuel pressure is within range. (Either through the Schrader valve pressure test, or by using some starting fluid directly into the throttle body to see if things change.)

Good Luck though ******.sixty9