1993 Chevy Camaro timing jump

Tiny
RORY123
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  • 1993 CHEVROLET CAMARO
Electrical problem
1993 Chevy Camaro 6 cyl Two Wheel Drive Automatic

Hi, I love your site and I was hoping some one could help me im no expert but I know a little bit I have a 93 camaro 3.4 with the dis ignition system and the car starts and runs great for ten minutes then it seems like the timing jumps and the car wont idle back fires and deisals but then if I shut it off and let it sit for five minutes it runs fine ive been over every thing I could think of iac, tps, ecm, knock mod. Lt4upgrade, coil packs, ignition mod, plugs & wires, fuel pump, vacum and new map sensor, crank and cam positioning sensors, and I have recently replace the head gasket and went over all valves and wires in engine control harrness what can this be please help.
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Thursday, October 23rd, 2008 AT 6:08 PM

4 Replies

Tiny
MASTERTECHTIM
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I dont think timing is jumping, (not very common). Any codes? Ignition module is where I would be leaning but you already replaced it. Did it change at all when you replaced module? Did you actually check fuel pressure? Do you have access to a scan tool to watch data? Let us know
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Friday, October 24th, 2008 AT 8:14 AM
Tiny
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Thank you for responding tim,
The car hasn't changed at even though all the repairs. I know the timing cant jump that far because it would destroy my valve train and probley would not allow the car to start any more its just seemes like something is making it advance beyond a point that the car can run at. And yes the fuel pressure stayed at a constant 40 psi even when the car started to act up and when I replaced the ignition module the car still did the same thing so I swapped out the coil packs from a grand am gt 3800 motor which I new were good and still no change in the symptoms.
I don't own a code reader but my friend loaned me his every thing came up normal but the manifold tempiture was -38 turned out to be a bad ground which I replace and cleared the ses codes and still got the problem with a normal temp reading
I have all the data from the reading I will post shortly thank you for your time.
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Saturday, October 25th, 2008 AT 10:05 PM
Tiny
RORY123
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Engine run time 760 sec.
Idle air mtr pos 114 steps
learned idle pos 22 steps
rear oxy sense ready
left & right block learn value 100
throtle sensor.92 vlts
a/c wot logic false
spark advance 23.8
knock retard 14
battery volts 13.9
left oxy sens 418 mvolts
right oxy sense 334 mvolts
ac pressure 84 psi
air to fuel mix 14-7
map sensor volts 1.37 volts
manifold temp -38 deg. (Fixed)
blk lrn cell 4
barometric press 4.66 volts
8% throtle angel
rpm 1724 (car wont run below 1000 until warmed up)
desired rpm 875
knock sensor 0
injector pulse 4.0 ms
right intergrator value 120
left intergrator value 126
fuel pump 13.7 volts
loop statues closed

error codes
left oxy sense fault
24x error
86 a/d error (running without knock module replaced with lt4 version less sensitve and code no longer gets thrown)

thanks
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Saturday, October 25th, 2008 AT 10:23 PM
Tiny
MASTERTECHTIM
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That 24x error is leading me towards the crankshaft position sensor which is quite possibly why you feel like the timing is advanced. They had a real problem with the crank sensors advancing the timing so far that the starter motors were breaking. Try that
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Sunday, October 26th, 2008 AT 7:10 AM

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