Thread: A Gearhead question...

"fourdoorchevelle" wrote:

"pack93z" wrote:

"fourdoorchevelle" wrote:

yeah , mostly on the older computerized cars (pre-96), now the programs are so much smarter.

Hmmm since it is a 93 that may be the case hey.. so alternate way of checking the computer out other than the reader?

i would go through the manual , it's gonna give you factory specific steps for diagnostics. look under trouble shooting.

make sure its like a chiltons or a haynes manual , if not a factory repair manual . im not talking about the manul that tells you how to check you oil. ummm "repair manual " i guess would be the way to put it , they were like $20 (when i was buying them)

Stopped tonight and bought a new Chilton book, an updated one.. reading it now.

Thanks for the advice... it is very much appreciated..

Question
My 1985 Chevy C10 P/U will not start, no spark. It has a 305 V8 Vin code H, automatic, 2WD.
It has just over 61,000 actual miles.
It has had this intermittent problem for several years. Sometimes it will start, sometimes it won't. When it won't start, there is no spark at any of the spark plugs. I have voltage at the B+ terminal and ground at the coil. I've changed the entire distributor.
Had it towed for repair, but after getting it to the shop, it started OK and they couldn't find anything wrong.
I've followed the troubleshooting tree in the typical repair manuals.
There is a 4 wire harness coming from the distributor going into a wire loom.
Can't find any information about these wires.
Any ideas?
Thanks!

Answer
Hi Terry, I'm not sure if this truck has one but there is a spark control unit that is mounted to the firewall. This unit controls spark advance and can fail causing the no spark problem your having. It can be intermittent also. I was thinking that you should replace the complete dist but you've done that. Then I thought of this spark control. Yes 1985 was a while ago for me to remember, these cars and truck change too much every year.

Thanks Singer.. I will see if that is here in the book.. better get to reading..

Maybe of some use

http://answers.yahoo.com/question/index?qid=20080127234936AAyrsZ1

"singersp" wrote:

Question
My 1985 Chevy C10 P/U will not start, no spark. It has a 305 V8 Vin code H, automatic, 2WD.
It has just over 61,000 actual miles.
It has had this intermittent problem for several years. Sometimes it will start, sometimes it won't. When it won't start, there is no spark at any of the spark plugs. I have voltage at the B+ terminal and ground at the coil. I've changed the entire distributor.
Had it towed for repair, but after getting it to the shop, it started OK and they couldn't find anything wrong.
I've followed the troubleshooting tree in the typical repair manuals.
There is a 4 wire harness coming from the distributor going into a wire loom.
Can't find any information about these wires.
Any ideas?
Thanks!

Answer
Hi Terry, I'm not sure if this truck has one but there is a spark control unit that is mounted to the firewall. This unit controls spark advance and can fail causing the no spark problem your having. It can be intermittent also. I was thinking that you should replace the complete dist but you've done that. Then I thought of this spark control. Yes 1985 was a while ago for me to remember, these cars and truck change too much every year.

yeah i mentioned this earlier by disconnecting the timing advance wire, which is a way to check it , but things vary from year to year...


well after tabing out i did find an Ignition Engine Computer and a Engine Control Computer

i have very limited expeiriance with item like these , espicially gm , because alot of their computers require that they be reprogramed or "flashed"

let me know what the chiltons diag brought you to

"pack93z" wrote:

I am trying to time a 93 Chevrolet 350 EFI... can anyone walk through the proper way to time it without a timing light..

We have the firing order correct..

1 8 4 3 6 5 7 2

We have the timing mark TDC on the compression stroke and the disto cap rotated to one... however we have to advance the cap about a quarter turn to get any fire.. however it runs rough..

Any knowledgeable help would be appreciated... thanks in advance.

Your a packer fan, can't you just take one from one of the other 8-9 cars sitting in the front yard?

"singersp" wrote:

Maybe of some use

http://answers.yahoo.com/question/index?qid=20080127234936AAyrsZ1

Might be worth a shot as I remember getting weak voltage to a vehicle before & it was mentioned in the link. Check & clean the battery & ground connections at the starter.

Thought I would share this here... has updated service bulletins as well..



Free Online Service Manuals:

http://www.oplin.org/databases/proxy2/proxy.php?qurl=http%3a%2f%2farrc.epnet.com%2fautoa sp%2fframerq.asp

enter 123456789 for the library card number, submit the library indicated, scroll fown to AUTO REPAIR REFERNCE CENTER, pick year and make

This is good for most vehicles.

Pick the Cinny Public Libary...

Quick update... traced all the wiring through the truck after recieving a low voltage at the module, cleaned all connections of all the sensors and even at the computer... put it all back together and she fired up.. not sure where the issue was but as of about 9pm last night I am getting a code 43 which is the knock sensor, so going to trace that one down, clear it with either a new sensor or what not and should be done..

To sum it up.. only thing I can think of was a bad connection someplace with low voltage issue and it cleared it..

Thanks again.

"pack93z" wrote:

Quick update... traced all the wiring through the truck after recieving a low voltage at the module, cleaned all connections of all the sensors and even at the computer... put it all back together and she fired up.. not sure where the issue was but as of about 9pm last night I am getting a code 43 which is the knock sensor, so going to trace that one down, clear it with either a new sensor or what not and should be done..

To sum it up.. only thing I can think of was a bad connection someplace with low voltage issue and it cleared it..

Thanks again.

"singersp" wrote:

Maybe of some use

http://answers.yahoo.com/question/index?qid=20080127234936AAyrsZ1


Might be worth a shot as I remember getting weak voltage to a vehicle before & it was mentioned in the link. Check & clean the battery & ground connections at the starter.

I also found something out about the knock sensor when looking before. let me see if I can find it again.