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Gary
Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 15707
Experience:  15 years GM master tech
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Actually 2004 Envoy. Had code for crank/cam sensor problem

Customer Question

Actually 2004 Envoy. Had code for crank/cam sensor problem and wouldn't start. Changed both and then exchanged ignition switch with known good one. Now no start but no codes. Sprayed ether into intake.....no start either. Have to also disconnect battery since minor short kills it in couple of days.....probably not part of starting problem. Chk engine lite has been on for couple of years
JA: Does the vehicle stall at low speeds? Does it sputter?
Customer: It did for about hundred miles but sometimes was ok.....just finally quit
JA: What is the make/model of your car?
Customer: 2004 Envoy....4.2 engine
JA: Are you fixing your Envoy yourself? What have you tried so far?
Customer: Yes, fixing myself. Replaced crank and cam sensors and ignition switch
JA: Anything else you want the mechanic to know before I connect you?
Customer: Engine cranks but no start and no codes now. Chk engine lite has been on for couple years
Submitted: 1 month ago.
Category: Chevy
Expert:  Gary replied 1 month ago.

Welcome! My name is ***** ***** I will do my best to assist you with this problem.Ask me about added features such as phone contact anytime if you wish !

Expert:  Gary replied 1 month ago.

can you tell me the code numbers that where set before ?

Customer: replied 1 month ago.
I don't remember.....just cam/crank disagreement
Customer: replied 1 month ago.
Ether sprayed into intake didn't help either . Also changed ignition switch
Expert:  Gary replied 1 month ago.

any access to a compression gauge ?

Customer: replied 1 month ago.
Engine spins normal.....but yes, I can chk. Real pain to get to plugs. Doubt if I have spark since ether didn't help
Expert:  Gary replied 1 month ago.

if it will not run with added fuel to it then we are missing spark or compression is low alot of times with crank to cam codes set means the timing chain is loose and or had jumped

do a compression test on all 6 cylinders only if you have spark

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Customer: replied 1 month ago.
I'll chk for spark tomorrow.....tough since it has individual coil drivers. I'll first chk for input to coil drivers. I thought perhaps you had seen similar problem and had obvious answer. Car has only 150k miles so doubtful if mechanical problem.
Expert:  Gary replied 1 month ago.

i have seen many with the cam to crank codes set and it is due to the timing chain being too loose or has jumped

so to eliminate that if all 6 cylinders have over 125 PSI then the compression is good

if the compression is good and there is spark try a new set of plugs if they are wet and or old

dont forget to rate us here

you can always get me back for FREE for any follow up any time with this question even after you rate me here at Justanswer

if you have any questions please ask as i do not get credit for my work until you rate me here at Justanswer

Expert:  Gary replied 1 month ago.

how are you making out ?

dont forget to rate us here

you can always get me back for FREE for any follow up any time with this question even after you rate me here at Justanswer

if you have any questions please ask as i do not get credit for my work until you rate me here at Justanswer

Customer: replied 1 month ago.
Didn't do much today..... just checked tach to see if crank sensor is picking up rpm while cranking......it is not. Also checked old crank sensor.......around 745 ohms..... should be good? Also unplugged map sensor, maf sensor and cam sensor to see if codes showed up. Only p0107 for map came up. I have a good running trailblazer so I will unplug same sensors on it to compare codes with this Envoy. I may have a wiring problem or bad ground somewhere?
Expert:  Gary replied 1 month ago.

it should be

with the key ON does one terminal show 12 volts and another show a good ground at the crank sensor ?

Customer: replied 1 month ago.
I was going to unplug crank sensor tomorrow on both trailblazer and Envoy to compare.....and I'll chk plug per your suggestion. Lots of things to remove to get to plugs but I'll probably replace them at same time. 150k miles and I doubt they have been changed..... ran too good to think about it......and it's not my vehicle. But it actually sounded like one cylinder fired earlier tonite.....strange
Expert:  Gary replied 1 month ago.

let me know