New Owner - Help with a DNS issue

[Arctic91]

First off, let me say what a great resource this registry is. As a first time vette owner who couldn't resist putting a Z in the garage, I spent quite a bit of time lurking on the forum both before and since I made the purchase and only felt comfortable pulling the trigger because of the support and knowledge that resides here.

I'll try to post some pics of the car later, if I can figure out how to reduce the file size, but here are some of the basics: '91 #1231, white on tan, both tops, good glass, bone stock and no-touch on the paint work. A little detective work and you can figure out what I paid, the mileage and overall condition (hint: row 318), if you're so inclined. I feel I got the car for a very fair price and had a blast driving out to CO. There's slight bolster wear on the driver's side, but it's not bad at all; one small spot in the carpet. As best as I can tell, I'm the 3rd owner and the two previous obviously took very good care of her.

Now to the bad news...

Unfortunately, I've got a DNS situation (hoped to avoid that) and was looking for a little help. Here are the details: she fired right up when I took delivery and had no problems between PA and KS, but after making a stop for fuel and caffeine, she just wouldn't start. All indications were normal, but she did nothing when I turned the key. Classic DNS. Of course it happened on a Sun and NOTHING was open, so I called the wife to let her know what was up and run through the options. Just before calling to get a tow to the local chevy dealer I tried one last time out of desperation and... she fired right up again like nothing had happened.

Got her home without further incident and two days later, same thing, only she was cold this time. Since then, I've only got her to start twice (it's been about 2 mos!!). Given my hectic schedule, limited knowledge of the electrical system and lack of service manuals, I've tried all the so-called "easy" and cheap troubleshooting steps: clutch is being pushed to the floor (no obstructions like floormats), pushed started her once (eliminated VATS as the problem, although that was my first suspect), cleaned the keys, removed the battery and had it checked out (checked out OK at the store and the cables seem to be good, no obvious corrosion), swapped out the starter relay (hoped it would be that easy - no joy), and while looking for the purple wire under the ECM noticed that it had been probed before - big tear in the insulation but no corrosion yet.

So, I'm thinking that this was a relatively recent issue for a previous owner as well. None of the typical work-arounds like jumpering the clutch safety switch or installing an add'l relay installed (aka tccrab's solution bringing 12v directly from the batt to the starter solenoid) seem to have been performed.

The last "easy" check before considering a costly starter replacement or adding an add'l relay (and all the jeers that seem to come with that option, although I'm seriously contemplating it since the integrity of the purple wire has already been compromised) is to try "tapping" the starter with a rod. I remember seeing a thread about that and can probably dig it up again, but there wasn't much detail on the technique. I've looked all over for a glimpse of the starter, but for the life of me I can't figure out where to insert the rod and don't want to start banging around under the plenum unless I'm pretty sure of what I'm doing. Is anyone familiar with how to do that without causing add'l damage?

Any other thoughts out there?


Thanks,
Scott

[GrayZ]

check out this thread, it should anwser your question, another quick thought, push the key in slower, as sometimes we push the key in so fast it does not give the starting god, enough time to read the chip on the key. and welcome to the zoo.




http://www.zr1netregistry.com/ZR1_tr...ting.htm#Start

[bradslt5]

starter price not too bad about 120 @ napa it a rebuild but it seems ok

[-=Jeff=-]

my 90 had the DNS issue twice, once in the garage (cold motor) 5 min later started, second time, I drove it about 8 miles, let it sit for 45min, would not start. the Starter enable relay clicked, no Solenoid click.

I added an additional relay after the clutch switch. the OEM switch path now controls the new relay and the new relay supplies 12v directly to the starter. I honestly don't think the starter is bad because my 89 vette (with 91 dash) has the SAME path for the Solenoid and does the SAME thing. btu the Starter in my 89 is BRAND NEW. I need to do the Relay fix to my 89 as well. so in my case I don't think I need a starter

[gbrtng]

Measure the solenoid current which should be in the 10 amp range. If it's a lot more than that, some turns in the coil are shorted and the thing can't develop enough force to pull the piston in. This problem gets worse at high temperatures which may explain why it works cold and not hot. I think that's the 10 ga purple wire but better to look at the wiring diagram before you start.

[-=Jeff=-]

Originally Posted by gbrtng

Measure the solenoid current which should be in the 10 amp range. If it's a lot more than that, some turns in the coil are shorted and the thing can't develop enough force to pull the piston in. This problem gets worse at high temperatures which may explain why it works cold and not hot. I think that's the 10 ga purple wire but better to look at the wiring diagram before you start.

Hmm mine also did it cold, as well as hot

[tccrab]

Scott:

Welcome to the Brotherhood!
Can't wait to see some pictures.
Don't worry about sizing them, just set up a free account with http://www.photobucket.com and upload them there. Then just copy and paste the URL tags to a new post on the forum.

Sorry to hear about your DNS, sounds like a classic case.
I still to this day regret having to hack the wiring of "Girlfriend", but I didn't have any other option. I couldn't find any one particular fault that would explain the DNS. I spent weeks digging under the hood and under the dash tracing wires and testing everything with my multi-meter.

Before you do my starter relay mod make sure to check EVERYTHING.
It could be something as simple as the clutch safety switch or the igntion switch.

Good luck!!!

[Arctic91]

I appreciate all the "welcome"s and help...

Just to give an update, I tried everything without luck then broke down and took it to a local shop. Figured it was either the starter or a voodoo curse from the previous owner. The shop diagnosed it as a bad starter and are doing the swap while I'm out of town.

Makes me feel a little better that it wasn't something that I overlooked, but the $$$ makes me realize how badly I need to get the manuals and break out the tools myself next time (that plenum can be intimidating).

I know that I still owe some photos and will get them on when I get the car back, but wanted to say thanks again for all the support!!

[tccrab]

Here's hoping that it cures the problem.

How much was the quote for replacing the starter?
And the important question....
Has the service technician replacing the starter ever laid hands on a LT5 before?



Tom

[Arctic91]

Tom,

Looked like there is no recommended shops for "Zs" in the area, so my next best option was Corvette Connection (one of two Vette specialty shops in Denver). I was told that the mechanic was familiar with the LT5... to be safe, I sent them the following links in a *tactful* email:

http://www.zr1netregistry.com/plenum.htm (plenum removal)
http://www.bcvettes.org/ (step-by-step under how-to)
http://www.zr1netregistry.com/ZR1_issues.htm#10 (adding add'l drainage)

I'm keeping my fingers crossed... we should find out in a week or so.

Another good reason to get a manual and do it myself.

Scott