Coil signal?

Chevy Forum Chevy Classifieds Photo Gallery Chevrolet News Search Contact CF Sponsors
Member List Forum FAQ Chevy Timeslips Chevy Recalls TSBs Calendars Register Login

Coil signal?

Printable Version

Chevrolet >> General Chevrolet Forums >> General Tech >> Coil signal?

Page: [1]

Message

<< Older Topic Newer Topic >>

Coil signal? - 2/14/2008 12:18:02 PM

drmoeder

Posts: 6
Joined: 3/12/2007
Status: offline

I've got an 88 k1500 that just shut off while I was driving almost like it was out of gas but it wasn't. I pulled the air filter and looked in the throttle body while someone else cranked it. Fuel was being injected just fine, so I put a timing light on the main wire to the distributor. No current. So I replaced the coil. Still nothing. I inspected the connectors going to the coil and checked for voltage on each of the 4 wires. They were all hot. Now what I don't know is what the 4 wires should be doing because their states don't change at all when it's being cranked. I thought maybe 1 or 2 should go low or even pulse to activate the coil. I have a wiring diagram for the truck and that doesn't really help. 2 of the wires are pink and the other 2 are white. Can anybody shed some light? Otherwise, I'm looking at just replacing the computer to see if that fixes it.

Post #: 1

RE: Coil signal? - 2/15/2008 8:07:39 AM

rutler101

Posts: 38
Joined: 1/30/2008
Status: offline

Your problem is most likely the ESC module in the distributor. At least one of the white wires if not both should pulsate high low voltage. This module is about 35$ from napa. Give it a shot this sounds like your problem.

_____________________________

go chevy big block i dont need that cute little 350!

(in reply to drmoeder)

Post #: 2

RE: Coil signal? - 2/15/2008 10:47:38 AM

dewey

Posts: 69
Joined: 12/17/2007
Status: offline

quote:

ORIGINAL: drmoeder

I've got an 88 k1500 that just shut off while I was driving almost like it was out of gas but it wasn't. I pulled the air filter and looked in the throttle body while someone else cranked it. Fuel was being injected just fine, so I put a timing light on the main wire to the distributor. No current. So I replaced the coil. Still nothing. I inspected the connectors going to the coil and checked for voltage on each of the 4 wires. They were all hot. Now what I don't know is what the 4 wires should be doing because their states don't change at all when it's being cranked. I thought maybe 1 or 2 should go low or even pulse to activate the coil. I have a wiring diagram for the truck and that doesn't really help. 2 of the wires are pink and the other 2 are white. Can anybody shed some light? Otherwise, I'm looking at just replacing the computer to see if that fixes it.

Were there any codes? If you used the timing lite on the coil wire, you have to be sure the coil wire is ok?

I'm not sure how you checked for a pulse reading? If your dmm has a tach setting--dwell setting---dutycycle setting, any of these will give a reading, if there is a pulse. If your just looking at voltage, I don't think that will work unless the meter has a min/max feature. If the meter averages the pulse reading then the voltage would be half compared to the B+ circuit, but the reading wouldn't pulse.

I looked up the ignition module in a parts book, it shows two connectors. The two wire connector, the wires are pink and white. The pink wire is B+ and the white wire is a tach signal. The wires at the coil may be the same.

I agree with the other person, if there is no pulse, check the ignition module or pick-up coil.

(in reply to drmoeder)

Post #: 3

RE: Coil signal? - 2/17/2008 10:40:11 AM

drmoeder

Posts: 6
Joined: 3/12/2007
Status: offline

I used a logic probe that has a pulse reading. I will try replacing the ESC. thanks for your help.

(in reply to drmoeder)

Post #: 4

RE: Coil signal? - 2/22/2008 2:33:29 PM

drmoeder

Posts: 6
Joined: 3/12/2007
Status: offline

That fixed it! Thanks a lot for your help!