H16 Code question Needing help please
Thread Starter
Racer
Joined: Sep 2012
Posts: 259
Likes: 6
H16 Code question Needing help please
I have a 1995 base automatic with 195,000 miles. It doesn't smoke any and doesn't burn any oil. I doesn't make any strange engine noises and the transmission shifts very well. Is there anything else that will cause the H16 code other than a bad opti spark ? I have that code plus H43, H74, H83, H90 then module 9 shows: H72, H75 and H76. I have experienced one time my car didn't want to start immediately plus a couple of times it really stalled out under hard Excelleration. Thank you
Flatulent Dwarf
Joined: Nov 2009
Posts: 729
Likes: 84
From: Poverty Holler NC
Generally when you get the H 16 code, you’re screwed. My experience with “codes” when the opti starts going out is it dials up everything and craps the bed while it’s failing. Go ahead and get a new water pump while you’re in there because I can guarantee you if you go back with the old pump it’ll bust a seal inside of three weeks & soak the optispark. Take a hard look at your belt tensioner too.
later,Tiny
later,Tiny
Thread Starter
Racer
Joined: Sep 2012
Posts: 259
Likes: 6
Generally when you get the H 16 code, you’re screwed. My experience with “codes” when the opti starts going out is it dials up everything and craps the bed while it’s failing. Go ahead and get a new water pump while you’re in there because I can guarantee you if you go back with the old pump it’ll bust a seal inside of three weeks & soak the optispark. Take a hard look at your belt tensioner too.
later,Tiny
later,Tiny
Thread Starter
Racer
Joined: Sep 2012
Posts: 259
Likes: 6
There are two timing inputs to the ECM. Hi-Res (360 pulses per crankshaft revolution) and Low-Res (4 pulses per crankshaft resolution). The ECM compares the two signals, and if one is not frecieved, but the other is, Code 16 (Low-Res) or Code 36 (Hi-Res) sets. Understand that either of these codes depends on the other signal being present, which can only occur with the engine running. Code 16 will _always_ be a History16 because the engine is not running when you check it.
According to the FSM, Code 16 sets when low-res pulses are not detected but hi-res are. The reference signals toggle between 0 and 5 Volts.The cited possibilities for Code 16 are: "An open, a short to voltage, a short to ground, or a defective sensor inside the distributor can prevent the voltage from pulsing at the ECM." So other than a defective sensor, wiring and connections (certainly the connectors themselves) are the primary suspects for an intermittent Code 16.
There is an inline connector under the RH injector cover, above the #2 and #4 injectors. Ensure that these terminals are clean and tight to each other, and the wire itself isn't broken at the crimp. Same for the same harness where it connects to the opti itself.
Be sure the terminals mentioned above are clean and tight, clear the code(s), and if it acts up again, and Code 16 is back, it is the opti. There is no other cause for a Code 16 other than loss of the lo-res pulses while the engine is running. Wiring and connections are prime suspects in "intermittent", and only a few wires and terminals are pertinent to low-res pulses. If they check out, it can only be the sensor ("opti") itself.
I. When it began running really bad (I didn't make it back to the house, it quit for good and never fired again) I observed that the Service Engine Soon light was on. The only code was H16. I installed a Petris. Not inexpensive, but it receives many accolades on here and the F-car forums. I haven't driven it much, but I notice that it now fires instantaneously, where before it would crank at least a couple of seconds before firing.
Best of luck with it. Check the wiring and connectors. Clear the codes. If Code 16 comes back, put in a Petris.
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