my 95 TA won't crank. it cranked and i drove it to work this morning and it wouldn't crank when i left. i checked everything that i could think of and it all points to the opti, but it is just a month old.

i have a 12 volts with the key on at terminals A and D on the ICM, but no pulsing volts at terminal B on the ICM.

i have no continuity on terminal D on the Opti wiring harness, but i have ground on terminall C and 6 volts on terminal A and B.

also the grounds on the computer are good.

there is supposed the be continuity on terminal D on the opti harness, but what would cause it not to have it? i took the DVOM and probed the wire with one lead and grounded the other and it didn't beep so there is no connection.

i thought it might be my MSD6al so i un wired it and am using the factory wiring and still nothing.

HELP car is in hte work parking lot!!!

list anything esle i can test tomorrow when i go to work on it.

car ran awesome this morning on the way to work, never missed a beat.

 

no one has an idea of what it could be? i am fixing to go start working on it again.

 

Why did you automatically look at the opti? Does the car turn over just not start or does it not crank at all?

 

SES light on? Scan for codes? Can you hear the fuel pump prime?

 

no ses light. fuel pressure is 42 on the a pillar guage.
the reason i pointed at the opti is because it has no pulse at the ICM, and the last time it did this same thing it was the opti.

any other info jsut ask, this is pissing me off.

just got the car running good and was beginning to enjoy it and now this has it stuck at work in the parking lot.

were do hte wires from the opti that go down the intake run? i know they end at the PCM, but were are they b4 then? i hate having to trace wires win the factory wiring loom.

 

first post says it won't crank?????

you mean it won't crank?
or it cranks and won't start?

 

Are you using the AC scale to check for the 1v-4v pulses? Your email to me says you just changed the opti today? The opti harness plugs into a test connector on the side of the intake and the wires go directly to the PCM.
You say no SES, but did you check for trouble codes? DTC 16 (low res pulse)does not light the SES.

 

yes shoebox i was on the AC scale, when u turn the key on it goes to 1.5v and stays there while spinning hte motor over. i am not pulled the codes yet because i didn't have my laptop with me. but there is no ses light.

the car spins over but won't fire up.

if it did have a code for low res pulse from the distributor, what esle could it be since it is brand new?

the car was sitting there running and it died like u turned the key off.

on the 5v on A and B on the opti harness is that with the key on or off?

 

Take off your belt and try to start it. Could be your ac compressor or somthing is locked up.

 

Words like "crank" and "turns over" mean different things to different people. Generally better to avoid using those words, and to be very specific about what the engine does when you turn the key to "start".

A fault in the harness connectors.... either of the ones Shoebox mentions... can prevent the low res pulse from reaching the PCM. That would set DTC 16 and the PCM would shut down the injectors and fuel pump = no start.

 

From my website:
I don't know all the proper values on the opti harness. You could always check the continuity of the opti-PCM wiring with it unplugged from end to end.

 

update.

i went and worked on it again today. i pulled the computer and checked for power getting to the PCM from the opti. It has 12v on the right wire, it has a low resolution pulse on the right wire, but no high resolution pulse, and no ICM pulse out of hte computer.

What does the computer use hte high res pulse for? the low res pulse pulses from .6v-1.6v is that right? it also does have the low res reference at the computer.

y won't my car crank????

 

high res is for fuel sync(sequential injection) mainly, but it will run and start without it(in batch fire mode)

 

Not exactly... the low res pulse is used to set the injector timing, and the ignition timing. The high res pulse is there to allow the PCM to measure exactly where the crank/cam is when the shutter wheel is between the low res pulse windows.

Most systems simply interpolate between the cam reference pulses, but the Opti provides increased spark timing accuracy (less spark scatter) by having the 720-degree pulse markings on two crank revs.

The system will work without the high res pulse, and simply defaults to interpolating the space between the high res pulses. It does not default to batch fire. The system will not work without the low res pulses.... that's when the PCM shuts down the fuel system.

If the PCM can't find the pulses, you should get code(s) (DTC 16, DTC 36) for whichever pulse is missing

You indicated you had the low res pulse pattern. Is that varying between 0-5V?

 

So the the Low Res DTC 16 is opti harness problem?