91 Z28 no spark
#1
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
91 Z28 no spark
alright, so I’ve been battling this no spark issue for quite awhile now. It all started when I went to pull into the gas station and the car just cut off. Went to go start the car again and it just cranked and cranked, every other crank it would back fire just a small amount. Long story short I got it towed home and it sat for a while before I started to mess with it. I’ve changed the cap and rotor, new ignition control module and new coil. I decided to test the pick up coil today and it only fluctuated between 0 and .5 volts. I read online that it should fluctuate between .3 and 1.8 volts. Everything else has tested out okay. I’m stumped, even with that low of a reading on the pick up coil would it still be a good part or is my pick up coil the problem? Tired of throwing parts at the car and not getting anywhere. Thanks in advance guys.
#3
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Okay, I just tested both sets of pink wires. The top set of wires with the key on read 23. The bottom set read nothing while cranking and with key on.
I probed the end that would connect to the ICM and got nothing. The top set I tested with it being unplugged from the coil.
I probed the end that would connect to the ICM and got nothing. The top set I tested with it being unplugged from the coil.
#5
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
So is it the coil or the wiring to the ICM? I’ve already tried two different coils and got nothing from it.
#7
Sponsor
iTrader: (92)
Re: 91 Z28 no spark
If you do have to repair the jumper you can find parts on eBay.
https://m.ebay.com/sch/i.html?_from=...=tbi+coil+wire
https://m.ebay.com/sch/i.html?_from=...=tbi+coil+wire
Trending Topics
#8
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
I tested diagram one key on and cranking and got no reading at all. I’ll double check it again tomorrow and if no luck I guess I’ll replace the connector and see if that does the trick.
#10
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Been busy with work so I haven’t got the chance to look into it. When I do, (hopefully I’ll get time today) I’ll post my results. Appreciate all of your help.
#11
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Okay, I know it’s been a while but I finally found some time to mess with it again. I hooked everything back up and got it the way it should be. I just tested diagram one KOEO and I’ve got 11.3 volts coming from the coil to the ICM now. Battery is pretty drained from sitting so I’m gonna charge it up and see if I can get anything out of it.. I’ll update ya soon.
Update: Still no start!
decided to check the resistance on the pick up coil while I was at it and that tested out at about 732 from what I read that’s a good reading. I’m lost.
Update: Still no start!
decided to check the resistance on the pick up coil while I was at it and that tested out at about 732 from what I read that’s a good reading. I’m lost.
Last edited by VictorGBKirk; 04-01-2018 at 02:59 PM.
#13
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
so I just pulled a plug and grounded it out and whatya know, I’ve got a weak orange spark. So at least we’re getting somewhere. The wires on the pickup coil look like they’ve definitely seen better days. I moved them around quite a bit when I checked the resistance on them. Could a bad pickup coil lead to weak spark or no?
#15
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Yep, I pulled all of the plugs and they were pretty fouled with carbon deposits so I’m gonna pick up some new ones tomorrow and see if that helps the cause any. I appreciate all of your help though.
#16
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
So, today I went back thru and hooked everything up, hooked the battery up to my Jeep to jump it and it’s getting fuel and spark now but when it turns over after igniting a spark it just stops turning over all together, and if I keep holding the key it’ll crank again, fire 2 or 3 times and then stop and repeat the process... it’s being jumped while doing this also. It’s got a new starter on it btw too. Any ideas? Could it possibly be that the timing is off? Timing chain maybe?
#18
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Will do, going to pick up a distributor wrench when I head back to town today.
#20
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
Nope, distributor hasn’t been removed since I’ve owned the car which has been about 4 years now. Kinda getting ready to send it off to my buddy’s shop bc I’m tired of messing with it.
#21
Sponsor
iTrader: (92)
Re: 91 Z28 no spark
Compression test and double check battery ground and positive connections. I hope you get it figured out without to much aggravation.
#23
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
#24
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
yeah, I guess I’ll just give it a complete rundown. Might be overlooking something simple. Appreciate all of your help thru the process.
#25
#26
Junior Member
Thread Starter
Join Date: Aug 2013
Location: Northwest Indiana
Posts: 39
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 Z28
Engine: 305
Transmission: 700R4
Axle/Gears: 3.23
Re: 91 Z28 no spark
So I finally said whatever and adjusted the timing and it ran as smooth as it should. On my way back home with it, I put my foot into it and whaddya know. Started backfiring and couldn’t hold an idle. It runs fine on start up sometimes and then other times it’ll run like complete crap. Any ideas to this now?
Thread
Thread Starter
Forum
Replies
Last Post
breathment
Tech / General Engine
24
01-23-2020 03:43 PM
dandealer
Tech / General Engine
13
10-14-2005 05:58 PM
zedder 1 9 9 0
Tech / General Engine
1
07-09-2001 11:28 PM