PLEASE HELP! 1999 Yukon crank no start

[Fless]

Post up the Passlock codes you have.

 

[JP907ATB]

Well i feel pretty ****** about myself, i researched testing these ignition systems with the spark tester and found no spark to all plugs. Tested ignition coil and had spark. So i put new cap and rotor on plug wires and plugs and she lit right off!! I feel so dumb because i just pulled a plug out the wire on it and touch the manifold while cranking and had spark there so i thought the entire time i was getting spark i wasn’t, apparently that is not an accurate spark check, but it the way i have been doing it for years lol. Anyways still have 40
Codes in the pcm but the truck is running like a top!! Thanks for your responses to everyone that had input!

 

[drakon543]

these 5.7 are notorious for getting moisture in the dizzy cap. wish i had noticed the post yesterday i would have helped ya pretty quick. the electrode paths in these caps are quite close together and some moisture can cause them to ark out between them. the amount of moisture you can get can also just burn the center rotor button clean off.

 

[Joseph Garcia]

Well i feel pretty ****** about myself, i researched testing these ignition systems with the spark tester and found no spark to all plugs. Tested ignition coil and had spark. So i put new cap and rotor on plug wires and plugs and she lit right off!! I feel so dumb because i just pulled a plug out the wire on it and touch the manifold while cranking and had spark there so i thought the entire time i was getting spark i wasn’t, apparently that is not an accurate spark check, but it the way i have been doing it for years lol. Anyways still have 40
Codes in the pcm but the truck is running like a top!! Thanks for your responses to everyone that had input!

Thank you for posting the solution to your issue. Much appreciated.

 

[510man]

I have this Vortec 5.7L in a '99 Suburban (purchased new) and the 5.0L version in a '02 Mercruiser boat. Truck has been reliable with no cap/rotor moisture issues. The boat, which is rarely used, corrodes the cap resulting in significant misfire and difficulty starting. I have several caps now so I install a clean one every spring as preventive maintenance. Runs like a dream. I share only to agree with other posters that moisture in these caps can be an issue. Glad you got it fixed.

 

[Oobuck12]

Hello i am working on a friends 99’ Yukon. A few days ago it was running rough and stalling, changed the fuel filter and air filter and was running like a top. A few days later truck died after going through carwash, and am currently in a crank no start situation. I have scanned codes there are no global obd2 codes, but there are 40 codes coming up in the pcm under gmc oem enhanced. I have verified fuel pressure via manual gauge on shrader valve on fuel lines top of motor. 60psi prime and 62psi while cranking. I pulsed the injectors and saw in even 9-10psi drop on each injector. I beleive this isn’t a fuel issue because i can’t get the truck to fire at all even with a shot of either in the intake. I have tried changing the mass air flow sensor, crankshaft sensor and camshaft sensor with no change. I have pulled wiring harnesses apart and cleaned them and applied dieeltric grease to them. I cleaned up all the grounds i could find and used copper anti seize on them. And still crank and no start and 40 pcm codes that will not clear. I’m starting to wonder if the ecm/pcm shit the bed?? Other then that i am running out of ideas.
The codes are:
P0101 mass air flow sensor performance
P0106 manifold absolute pressure sensor performance
P0107 map sensor circuit low voltage
P0108 map sensor circuit high voltage
P0121 throttle position sensor circuit insufficient activity
P0125 engine coolant temp insufficient for closed loop fuel control
P0131 heated o2 sensor circuit low voltage bank 1 sensor 1
PO132 heated o2 sensor circuit high voltage bank 1 sensor 1
P0133 heated o2 sensor slow response bank 1 sensor 1
P0134 HO2S circuit insufficient activity bank 1 sensor 1
P0135 HO2S heater performance bank1 sensor 1
P0137 HO2S circuit low voltage bank 1 sensor 2
P0138 HO2S circuit high voltage bank 1 sensor 2
P0140 HO2S circuit insufficient activity bank 1 sensor 2
P0141 HO2S heater performance bank 1 sensor 2
P0151 HO2S circuit low voltage bank 2 sensor 1
P0152 HO2S circuit high voltage bank 2 sensor 1
P0153 HO2S slow response bank 2 sensor 1
P0154 HO2S corcuit insufficient activity bank 2 sensor 1
P0155 HO2S heater performance bank 2 sensor 1
P0157 HO2S circuit low voltage bank 2 sensor 2
P0158 HO2S circuit high voltage bank 2 sensor 2
P0160 HO2S circuit insufficient activity bank 2 sensor 2
P0161 HO2S heater performance bank 2 sensor 2
P0171 fuel trim system lean bank 1
P0172 fuel trim system rich bank 1
P0174 fuel trim system lean bank 2
P0175 fuel trim system rich bank 2
P0300 engine misfire detected
P0325 pcm knock sensor circuit
PO327 knock sensor low voltage
P0336 CKP sensor a circuit performance
P0337 CKP sensor circuit low duty cycle
P0338 CKP sensor circuit high duty cycle
P0339 CKP sensor circuit intermittent
P0340 camshaft position sensor circuit
P0341 CMP sensor performance
P0401 EGR flow insufficient
P0404 EGR open position performance
P0405 EGR position sensor circuit low voltage
There is also a pass lock code that comes up twice it shows the same code as current and as in the history
C0472 steering hand wheel speed sensor circuit

I am pretty stumped here and leaning towards a new ecm/pcm. I find it hard to beleive all of these sensors could fail at once. If anyone has any input i would greatly appreciate it.

My 99 Yukon SLT left me stranded several times. Fuel pump failure, crank forever but no fuel. Worn out distributor shaft gear. There's a important ground connection under the drivers position on the frame but don't remember exactly it's location.
Good luck!

 

[jayden0529]

Well i feel pretty ****** about myself, i researched testing these ignition systems with the spark tester and found no spark to all plugs. Tested ignition coil and had spark. So i put new cap and rotor on plug wires and plugs and she lit right off!! I feel so dumb because i just pulled a plug out the wire on it and touch the manifold while cranking and had spark there so i thought the entire time i was getting spark i wasn’t, apparently that is not an accurate spark check, but it the way i have been doing it for years lol. Anyways still have 40
Codes in the pcm but the truck is running like a top!! Thanks for your responses to everyone that had input!

im having same issue in my 99 silverado 4.8 ls 40 pcm codes exact ones an crank no start no spark but mines is bistrbless what do i do

 

[strutaeng]

im having same issue in my 99 silverado 4.8 ls 40 pcm codes exact ones an crank no start no spark but mines is bistrbless what do i do

Start a new thread please...in the right section.