vipergtx500

My car is acting very strang, the tachometer periodically works, most of the time it doesnt. My car has alot of trouble starting and usually doesnt. And when it does start, it will stall after a few minutes, but usually it will misfire a few times and then turn off. The SES light is on and its throwing codes P1641 and P1642. I brought it to my mechanic and he checked all the relays and grounds, and replaced the ignition module and crank position sensor and nothing changed. I am running out of options and my mechanic thinks I need the get my PCM reflashed. Anyone heard anything like this before?

djjab57

iTrader: (17)

P1642 Vehicle Speed Output Circuit
P1641 Malfunction Indicator Lamp (MIL) Control Circuit

vipergtx500

but what do these codes have to do with how the car is acting, and i looked up the codes and it said
P1641 Primary Fooling fan
P1642 Secondary Cooling fan
Where are you getting your code descriptions from?

shbox

Apparently from the wrong place.

The codes are from the PCM seeing something electrically wrong with your fan circuits (you didn't recently do some work, like putting in a fan switch, did you?). With your other problems, it might be a PCM issue, but PCM problems are pretty rare. It could even be an opti issue.
Maybe you need a mechanic that is more familiar with diagnosing your type of car.

vipergtx500

the only work i did recently was swap the starter, but it was fine after that, and i doubt that the fans are the issue because the temp of the car has been fine, and this nonsense of events occurred on a very cold day and it never overheated. The opti was replaced by the previous owner a couple months ago right before I bought it, so i kinda ruled that out. I am trying to get a pcm unit to swap in and see if thats the issue. I only have one from a 95 A4 and i know it won't work right but does anyone think by swapping that one in for a min i could tell if it is actually a bad pcm or not?

robsquikz28

iTrader: (246)

i got those codes before but that was after i installed a fan switch....because i was bypassing the pcm for fan operation but after i removed the switch codes went away too.....

djjab57

iTrader: (17)

http://autorepair.about.com/od/obdco..._1996_year.htm

vipergtx500

ok, maybe that makes more sense than the fan sensor, I ran the codes again today and got:
P0336 - Crankshaft position sensor
P0372 - Timing Reference High Resolution Signal 'A' Too Few Pulses
...along with P1641 and P1642 as mentioned before. It is strange because my mechanic replaced the crankshaft position sensor, so im starting to think that its not the sensor itself but either the pcm or the wiring from the sensor to the pcm. Also, I have no idea what P0372 means, sounds like its refering to the opti, which was just recently replaced on my car by the previous owner before i bought it a month ago. None of this makes much sense to me. After I brought it home from the mechanic, my dad drove my mom to work 40 miles away and it was fine, but when i started it later that day, all the problems were still there, so he got lucky but its odd that it could work fine for 40 miles and the problem be any major mechanical component. I'm still leaning toward electrical.

j0n

iTrader: (5)

Omar... It sounds like the same problem I had with my T/A back when it first took a crap on me. A couple hundred miles after I replaced the opti it randomly started running rough as hell(sounded like it was on 2 cylinders) and then eventually wouldn't run at all. When I eventually removed the opti cap i noticed that the screws holding the rotor on had backed themselves out. I think we need to pull everything up to that point and check to see that the rotor is still attached. Give me a call anytime from now till 645am or tomorrow sometime after 2PM(im working till 6am tonight).

shbox

Too generic (and plain wrong in this case). There is a link to f-body specific DTCs in my sig.


vipergtx500: make sure you clear the trouble codes (remove PCM BAT fuse for 30 seconds) and are not looking at old, stored ones.

vipergtx500

thanx jon, ill give you a call before i start work today. Spaz's garage seems like the ideal place for this, since its cold as hell.

vipergtx500

i just replaced the coil, just to make sure it wasnt that before i took on the big opti swap, and i tried starting the car but it sputtered and then a little smoke came out of the intake, i tried again, it started but died immeadiately, so i tried again and gave it a little gas when it did start, and more white smoke came out of the intake, this time i had the K&N intake off so it came out of the MAF, i don't think i blew anything, the car was barely started when the white smoke came out the first time, and it never did this before, could it be the fuel built up in the cylinders from trying to start it and it ignited all at once? i need some kinda of answer, im going to drain the oil tomorrow and check for coolant in the oil to make sure i didn't blow a head gasket, but i seriously doubt it, it wasnt on enough to blow anything but why did this happen only after i installed the new coil?
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vipergtx500

anybody know what this white smoke is?

shbox

If your engine coughs, it is normal to see some vapor come out of it. It's atomized air+fuel.

vipergtx500

checked the opti, everything seemed to be ok, no moisture, no backed out screws. the wiring harness from the opti to the main harness was chipped at the opti end, so i went to the junkyard and replaced that, figuring it was probably that, put the car back together and now it doesn't even turn over. The other thing i noticed was that when i turn the key to on, instead of the normal "ding ding ding" my car goes "di di di di di di ding ding ding" and the interior lights flicker. Im thinking the battery might be weak from trying to start it so many times, or there is as lose connection or short somewhere. Im going to try and jump it tomorrow to rule out the battery. Anyone have any ideas?

shbox

Yeah, sounds like your battery is now dead.

vipergtx500

I jumped the car, the battery is fine, still doesn't turn over. Any suggestions/methods on how to check to see what's not getting spark?

Green3spd

iTrader: (7)

This is from a site I use very often...

P1641-Fuel Pump Primary Circuit Failure
p1642-Fuel Pump Monitor Circuit High Input

vipergtx500

I hear the fuel pump come on everytime so I assumed it wasn't that. The lights still flicker when i open the door, and the battery is fine, that's what's preventing me from just buying a new opti, cause that has nothing to do with the opti

Green3spd

iTrader: (7)

Just because you hear the pump doesnt mean it is working at full potential... Id look into it...