justaguy92320

First time post, bare with me. 1988 v-6 2.8l with an intermittant code 42. Now I can't get it to run at all. Have read all the code 42 threads and followed every procedure I could find. The car has a new distributer with new pick up coil and ignition module. New ignition coil and new (bought and tried yesterday) ECM. I have check all wiring. checked all grounds but still it will not run. The only schematic I have is in the Hanes manual and it isnt that great. From what I see, it appears that I am not getting any reference to the ECM. also when I crank my tach isnt showing any rpm. My schematic shows that the negative for the coil primary comes from the tach or the ignition module. which one??? How do I get the ignition module to send the pulse train to the ECM. Anybody have any thoughts or ideas???? THANKS

justaguy92320

WoW ...... Nobody with any ideas????? or did I do something wrong???

D's89IROCZ

I would get a test light , recheck the contanuity on the wires involved . I am thinking bad wire , but it's just a guess at this point.

justaguy92320

I have a test light as well as multimeters and other test equipment. the wiring all checks out good. I am not getting any spark though. I have 12 volts going to the positive of the ignition coil primary, but I am not getting the negative. I believe the ignition module is supposed to provide the negative to the primary and that actually creates the spark. Is that right??? Does anybody know or have a schematic of the internal operations of the ignition module???

magadith

I hope someone has a clue on how to fix your car, because I kind of have the same problem, but my car starts. I can't figure out why I have a code 42 when everything is working fine.

justaguy92320

I could get it to run before by disconnecting the battery and leaving it set for awhile then I could start it and it seemed to run fine but then all of a sudden it just dies and sets the 42 and its hard as hell to get going again. There has to be more going on in the ignition module because the rule is "no reference to the ECM, NO RUN!". The module isnt sending the pulse from the pick up coil to the ECM and it isnt giving the common to the coil. since the ECM isnt seeing the pulse train from the reference it wont trigger the injectors. I have talked to several people and they told me that this was a problem that plagued GM and it is very difficult to find the cause, hence not that many replies.

sqzbox

Have you checked the connector in the wire loom on the firewall? Someone may have set the initial timing and forgot to re-connect it.

Crazy 84 Z28

My camaro would throw code 42 every once in a while but my car started and ran fine. The reason code 42 came up was that I cranked for a long time. That could be cause that code 42 appears off and on.

justaguy92320

yeah I have tried to start it with the bypass wire both plugged and unplugged. I just cant understand why I cant get the spark.... ....my guess it that the ignition module wont give the coil a negative unless the ecm sends it the signal. but im not sure

SpitotRs305

is this an aftermarket accel coil or the stock unit?

justaguy92320

its not an accel its just stock

Bigwavedave

I had this for a while (start with code). I would restart and it would clear. I tried replacing the distributor (Autozone - I did not know better at the time)and no change.
Then the car started dying and not restarting.

Found out the security (VATS) was bad (causing no start and dying on the road). It did not fix the code.

Finally got a new distributor from the dealer - no more code problems.

I recommend checking the VATS for the no start and distributor for the code problem.

justaguy92320

my camaro doesnt have the vats

RodsRideSS

Check for 5v on 'B' wire when the engine starts...or see if there's voltage with the key on. This is the ECM 'BYPASS' wire,...should be 0v with the key on...as soon as the engine starts the ECM applies 5v to this wire to take the timing control from the module, to the ECM. Thats why we need to unplug this to set the timing.
more later!

justaguy92320

cant get it started to check for 5 volts....has 0 volts with key on.....not getting any spark from the coil......cant start it if i dont have any spark...this is a new coil that i put on 2 weeks ago and it would start and idle fine. then just quit. I took the coil back off yesterday and checked it with my meter. I didnt like what i was reading so I took it to autozone and they said it was if...but im not convinced. there should be two SEPERATE windings in the coil... the primary and the secondary and they should not be shorted..... well if I put 12 volts on the primary and do no put the negative on the primary I do not complete the circuit and should not be "inducing" any power to the secondary but when I do the above mentioned I read 12 volts on the secondary. If I then ground the negative side of the primary I should then "induce" power to the secondary thus get a good spark....BUT IM NOT.....this is the craziest problem I have ever had with any car I have owned.....what the hell am I missing........if I check the resistance between the primary and secondary im getting 9.50 K ohms... this seems too low to me...any ideas....anybody have a better way to check it or to make it get a spark????? THANKS FOR ALL THE HELP AND IDEAS!!!!!!!!

RodsRideSS

Right....I'm off track! ...sorry

RodsRideSS

I have pics of module and info but haven't figured out how to upload....But go back the the module and make sure the two wires are connected from the magnet to the module...without it you get nothing! You are right...the module receives the magnetic pulse from the reluctor and manet...as the field collapes, a spark is generated at the coil by some fancy electronics in the module.
i'll work on those pics!

justaguy92320

PROBLEM SOLVED!!!!! I found that the pick up coil wires were pinched between the distributor and the cap. This caused high resistance which in time caused the pick up coil to heat up and open. I replaced it and it fired right up. I havent incurred and of the previous problems any more (code 42) so i believe the new computer helped with that part. It is running great......THANKS TO ALL for the help that was given!