Timing advance

[Rshort4747]

I have a 98 vortex 5.7, had the engine swapped and because the timing was off got a code P1345. Distributor was a tooth off. Got timing at -2 degrees. The problem is I don’t think my timing advance is working and here’s why. It starts fine, runs fine except when you start up a grade and the engine starts to accelerate for more power I’ll get a miss unless I manually accelerate so it down shifts. Which makes me think it’s the timing that’s not advancing. I been reading different post and there’s been mention of a knock sensor might cause this. If a knock sensor is bad, won’t it throw a code? P.s. the old engine did the same thing but not as bad.

 

[Schurkey]

"Missing" does not mean the timing isn't advancing. In fact, under load the timing might retard.

Sounds to me like you're describing failed insulation on the secondary circuit, or a weak ignition coil. How old are the spark plugs, plug wires, distributor cap 'n' rotor? Caps seem to be a high-failure item for these engines.

Will the ignition coil consistently/reliably fire a spark tester calibrated for HEI ignitions?
.https://www.amazon.com/dp/B003WZXAWK/?coliid=I3S98D7T1J0RLJ&colid=2VLYZKC3HBBDO&psc=1&ref_=lv_ov_lig_dp_it

xc_hide_links_from_guests_guests_error_hide_media

 

[Rshort4747]

"Missing" does not mean the timing isn't advancing. In fact, under load the timing might retard.

Sounds to me like you're describing failed insulation on the secondary circuit, or a weak ignition coil. How old are the spark plugs, plug wires, distributor cap 'n' rotor? Caps seem to be a high-failure item for these engines.

Will the ignition coil consistently/reliably fire a spark tester calibrated for HEI ignitions?
.https://www.amazon.com/dp/B003WZXAWK/?coliid=I3S98D7T1J0RLJ&colid=2VLYZKC3HBBDO&psc=1&ref_=lv_ov_lig_dp_it

xc_hide_links_from_guests_guests_error_hide_media

Maybe a miss really don’t describe it correctly. It’s kinda like a hiccup or small backfire would best describe it. But like I said, give it some gas when it does it and no problem. Of course it’s only doing it in overdrive. Will not do it in lower gears because the engine RPM is higher.

 

[Schurkey]

Connect a scan tool, look at the data stream. See what the fuel trims, O2 sensor, MAP sensor, etc. are doing during the "hiccup".

 

[RichLo]

^ What Schurkey said.

I got one of these OBDlink MX+ and connected it to a spare iPad that I had via bluetooth. You can connect them to anything cell phones, laptops, etc.

xc_hide_links_from_guests_guests_error_hide_media

 

[Pinger]

I have a 98 vortex 5.7, had the engine swapped and because the timing was off got a code P1345. Distributor was a tooth off. Got timing at -2 degrees.

So, if the distributor and thus the cam position sensor is out by +- 2 degrees then P1345 shows. Then does the absence of that code indicate the distributor/cam position sensor is within the permitted +- 2 degrees range?

 

[Schurkey]

I don't think so. I think the synchronization has to be farther off to get the code to set.