knock sensor wire to ecm? (L-body)

[jmgtp]

Does anyone happen to know (or have a manual that would indicate) which wire into the ecm is the knock sensor wire (1990 beretta 3.1)? (color, harness, pin# ??) I think that the KS may possibly be the problem with my 3.1s total lack of power. I've tried everything else, including fuel filter, put old spark plugs back in, new spark plug wires, various sensors (including tps), 3 different ICMs and coils amongst other things. I havent bothered replacing the coolant temp sensor as I am fairly sure it is accurate (the digital dash uses the same sensor for coolant temp that the ecm uses, it in fact gets its info from the ecm, and temp seems right on so the sensor must be good). Unfortunately freescan does not work with 1990 computer code and I can't seem to get my hands on a 91 memcal. So I can only suspect that KS is pulling a lot of spark, perhaps from a short to ground and that is why I want to try running a new wire to it. I've had the car for about 3 months, it ran right for a week and then all went to hell when I changed the spark plugs, what could have possibly gone wrong I don't know (yup all the wires go to the correct coil/plug matchings) and the car has perfect fuel pressure and all fuel injectors ohm at 12.2. I'm done spending money trying to fix it, if the KS theory doesnt work I'm just going to cut my losses and junk it. It is undriveable with so little power and is only taking space in the garage and my parents want it out because I'm already hoggin the other bay with the grand prix (which isnt about to spend the winter outside).

[v6h.o.]

it should be the same as a Jbody ECM and IF so then it is:

ECM Green Connector(32pin) PIN F9, (circuit 496) DARK BLUE coloured wire.

[jmgtp]

Thanks for the info.

I bypassed the KS and ran the wire from the ecm harness and to ground (with a 10k resistor inline) and the car runs just the same). Now, I'm really at a loss. I really dont understand why the car runs ok (but no where near normal) for about a minute and then after that it loses all power whatsoever.

[bszopi]

Open loop versus closed loop... because I've forgotten the list of what you have changed, have you checked the O2 sensor?

[jmgtp]

Open loop versus closed loop... because I've forgotten the list of what you have changed, have you checked the O2 sensor?

I've considered that as well. The reason I dont think it is that is because i dont think the engine could be hitting closed loop that quickly from a dead cold start, the decrease in performace occurs within 2 minutes max. Secondly, even right when i start it the car it is missing tons of power. Lastly, even at WOT it has no power (actually seemingly less power) and as far as I know the ecm doesnt even look at the o2 reading during WOT conditions. I've checked the TPS it reads a range from something close to 0v closed throttle to 4.5v at full throttle. I replaced the map sensor with a known good one from my dohc. KS doesnt seem to be the problem. Tried 3 different ICMs all with their own coil packs. CPS must be good, the tachometer works fine as does the temp gauge so the CTS must be good (the engine and dash share the same sensor for coolant temp - digital dash). New spark plug wires, fuel filter, spark plugs, all routed correctly. Engine makes a putt putt at idle (but that could be from the leak in the exhaust just before the muffler), seems to rev smoothly in neutral, in gear it bucks and lacks all power. At first it will be smoother in gear and rev up to 5k without a problem (although it is underpowered) but within a minute or two it has dead spots throughout the powerband and will not rev high, and will maintain speed only if a tiny bit of throttle is used. BTW, fuel pressure checks out perfectly and all injectors have ohmed out at 12.2-12.3 (k? ohms).

i'm so frustrated with it at this point. i can't even get my hands on a 91-93 3.1 5 speed chip so I can use freescan to get an idea of whats going on as 1990 is uncompatible with freescan.