Urgent No crank after top end rebuild - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
Reply
 
LinkBack Thread Tools
post #1 of 20 (permalink) Old 08-04-2018, 02:22 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
No crank after top end rebuild

1995 LT1 Z28 automatic.

I had the coolant leak at the back of the heads. Upon tearing down, it looked to be the steam pipe seals. I replaced those and put everything back together. Negative battery terminal was unhooked the whole time. It's been about 3 months. Car started and ran just before the tear down. It just overheated.

I got everything put back together, and now it won't crank. Security light is on, but does not flash. Just stays on. I'm pretty sure it would flash and then go off after the car started before. Even with a jump, it won't crank at all. So it's not battery. Is this normal for the security light?

In the Hayne's manual, it says something about doing a certain procedure before disconnecting the battery to disable the anti-theft in the radio. This thing doesn't have a factory radio, so I thought nothing of it. Is it possible I set off something in the security to disable the starter by not disabling it before unhooking the battery? I don't think it's a vats problem as it started before and usually the security light will flash with VATS. Or is it normal for the security light to just stay on?

Black Bullit is offline  
Sponsored Links
Advertisement
 
post #2 of 20 (permalink) Old 08-04-2018, 08:25 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
I'll find out tomorrow afternoon if it is indeed the VATS. I think the lock cylinder went bad, but after the VATS had gotten the okay from the key. So the car would still start and run, but the light was on. The previous owner tried to bypass the VATS to make the light go off, but it didn't work. When I had the battery unhooked for so long, it reset. So it was no longer in that mode that would allow it to run. The light must have been on the whole time, but I just didn't pay any attention. Especially since I've only driven the car around the back of the house, one time.

The way I figured out this out was that I was gonna do a bypass real quick just to eliminate that possibility. When I pulled the under-dash cover, I found his work. It was shoddy. Then I unplugged it at the little black electrical plug and tested his setup and it came in at 887 ohm. The pellet in the key comes in at 3730 ohms. He had three resisters running parallel instead of in series. One at 4400, and two at 2200. Some how, that came out to 887.

I've put together a bypass that gives the exact same reading as the key and I'll plug it in tomorrow and see what happens.


Last edited by Black Bullit; 08-05-2018 at 06:35 AM.
Black Bullit is offline  
post #3 of 20 (permalink) Old 08-05-2018, 07:59 AM
Global Moderator
 
cocobolo95's Avatar
 
Join Date: Sep 2008
Location: Fruitland Park,Florida
Posts: 12,706
 
You've figured out how to bypass the bad key lock cylinder by using resistors wired into connector under column. That works in 95% of vats problems.



If security light still doesn't go out after resistor bypass, then you will have more work to do. Vats does 2 things; (1) it disables starter by not applying ground to theft deterrent relay (TDR) and (2) it keeps theft deterrent module from sending 50 hertz fuel enable signal to pcm. Without the fuel enable signal, pcm will not open fuel injectors.


Here's a link to 95 service manual. It has wiring diagrams to help you if you need to bypass other 5% of vats problems My Files


Also, here.s a link to Shoebox site. He explains vats system. shbox.com


Bypassing the tdr involves cutting the small yellow/black wire going to tdr. Splice in some wire and attach other end to a good ground. Starter will now work. That is if other starter system components are good.


Then you will need a 50 hertz bypass module. Get one @ www.bakerelectronix.com


The module will have to be (1) power wire hooked to a key on power source. (2) ground wire to good ground. (3) signal wire runs to pcm. Cut the dark blue wire at pcm connector A cavity 25. Connector A is the red one. Connect signal wire to side of cut wire going to pcm.


Your car will now start & run. But security light will remain on.


Another way to get around vats would be to have vats programmed out of pcm. But you would still have to do the tdr bypass.

Last edited by cocobolo95; 08-05-2018 at 08:10 AM.
cocobolo95 is offline  
Sponsored Links
Advertisement
 
post #4 of 20 (permalink) Old 08-05-2018, 03:02 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
This problem has to wait. I've now confirmed my problem, and it is what I originally thought. I'm kinda glad this thing didn't start yesterday. I decided to check the oil and it looked to be WAY too full. So I decided to drain it out, and put in new oil ( I suspected more animal urine than expected to raise it that high ).

When I started loosening the plug, what started dripping out was clear. So I drained about 3 quarts of clear, clean, water. I had sprayed through all the coolant hoses with the garden hose to flush out all the old coolant. Apparently, a good bit got into the oil pan. Meaning the oil and coolant passages are meeting somewhere when they shouldn't meet at all. Since oil and water don't mix, all the water was on the bottom and the oil on top. It also hadn't blended so the oil didn't look milky on the dipstick.

If the car had started, it would have pumped water through the motor and blended and gotten sludge all inside the motor. Looks like my coolant leak wasn't just the steam pipe seals. I'm gonna have to remove the heads. *sigh*

Black Bullit is offline  
post #5 of 20 (permalink) Old 10-13-2018, 04:53 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
Okay, so I got the heads off, confirmed it was a blown head gasket. Put everything back together. Still won't crank. I assumed it was hydrolocked the last time since the cylinders were full of water ( because of flush and blown gaskets ). There doesn't appear to be water in the oil so I don't think coolant has filled the cylinders and I don't hear the starter clicking or making any noise ( as it would if it were hydrolocked ).

I've heard of people jumping the starter with a screwdriver to get it to crank. But I have no idea how to do that. I know it involves touching both leads with the screwdriver. Are there any pics showing which two leads to arc across? Or would it not matter if it's the TDR module? Would grounding the tdr be the easiest way to check? As in if it cranks, I know it's that?

I connected the correct resistance wire under the dash, but the security light stays on. If I put the key in, turn it to the run position and wait, the light goes off ( still won't crank ). Pull the key out, security light stays on ( only light on the dash ). Does that sound like it's still a VATS problem? Seems weird that the light would go off at all, and it still not work. If it were bad, it should stay on, I would think.

Where is the TDR located so I can check that first?

Black Bullit is offline  
post #6 of 20 (permalink) Old 10-13-2018, 07:48 PM
Global Moderator
 
cocobolo95's Avatar
 
Join Date: Sep 2008
Location: Fruitland Park,Florida
Posts: 12,706
 
If you apply battery voltage to where the large purple wire hooks to starter solenoid, starter should crank over. Key does not need to be on. If starter does not crank engine over with battery power hooked to where largel purple wire is, try turning engine over with a socket on the crank pulley bolt.

Use a breaker bar on ratchet to help you turn engine over. If you can't turn engine over by hand you have an engine problem. If engine turns over by hand, then either starter, battery, or battery cables are your problem.

Test applying battery power to where large purple wire eliminates all the other components of starter system.

Tdr is tucked way up in the dash. It's attached to passenger air bag bracket. You will know it by the 4 wires it has. 2 large yellow wires, 1 large purple wire, 1 small yellow/black wire.

The small yellow/black wire is the wire that tdm grounds to enable starter operation. But I would try to get starter to turn engine over by hooking wire from positive battery terminal to where the large purple wire is on starter solenoid.

The purple wire should be around 12 or 10 gauge wire. It is a large wire for normal wiring but much smaller than battery cables
I still suggest you downloading the 95 service manual at provided link. You need to study starting wiring diagram. If you scroll through the pages of the starter & charging diagrams, you'll find they tell you where, components, connectors, splices, & grounds are in system.

Last edited by cocobolo95; 10-13-2018 at 07:58 PM.
cocobolo95 is offline  
post #7 of 20 (permalink) Old 10-13-2018, 11:44 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
I turned the engine over with a ratchet when I was adjusting the valves, so I know the engine will rotate. Keep in mind, it started on the first chug before I tore it down. It had a blown head gasket, but it would start on the first chug. So that isn't the issue.

I'm just trying to figure out if the VATS went bad while the car sat for a couple of months with the battery unhooked, or if the starter went bad. The VATS is funny because I did the bypass and it worked a few months ago. If it wasn't for the security light actin weird... It goes off if I leave the key in the on position long enough, but still doesn't crank. But then when I remove the key, it stays on. Everything I know about VATS is that when it's bad, the light stays on. Always. And then when it goes off, it should work. So it's acting peculiar. It shouldn't need time to re-learn the new resistors I put in because that's not how this system works.

Since the starter is so hard to get to, testing it by running a wire to it won't be easy. So my next step should be to find the TDR and bypass it by grounding the wire. If that lets it crank, I can hook up my injector testers to see if they're getting pulse. If it cranks then, but no pules is getting to the injectors, I'll know the VATS went kaput.

I've used a bakerelectronix box before on a 1992 Buick Park Avenue that lost it's VATS. I was actually able to remove the pass-key module and put the baker box in it's place. I found the hot, ground, signal, and DTR activation wire and hooked everything up. I hooked the ground wire to the baker box and the DTR ( thus activating it ), and the hot and signal wires hooked up to the baker box. It worked perfectly. I didn't have to mess with the DTR at all. Now if only I can find all those wires ( and the pass key module ) on this Camaro, I'll be in business.

Black Bullit is offline  
post #8 of 20 (permalink) Old 10-14-2018, 08:02 AM
Global Moderator
 
cocobolo95's Avatar
 
Join Date: Sep 2008
Location: Fruitland Park,Florida
Posts: 12,706
 
I never had to get to either the TDR or TDM while I owned my 95 trans am. But on page 8A-30-2 of the 95 service manual gives component locations. The TDR is mounted to right side of SIR bracket behind instrument panel.

The TDM is just right of radio, attached to air bag bracket. I had to find the TDM in my 90 f-body. I had to tear out whole dash to get at it. But study the passkey wiring diagram starting on page 8A-133-0. That way you'll know the number of wires TDM has & their colors. There's lots of small electronic boxes stuffed in the dash area.
cocobolo95 is offline  
post #9 of 20 (permalink) Old 10-18-2018, 07:54 AM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
Oh no! I went to bakerelectronix to order a module and it says they closed up shop as of May of this year...

Are there any other sources for a bypass module to make that 50Hz signal?

Black Bullit is offline  
post #10 of 20 (permalink) Old 10-18-2018, 12:07 PM
Global Moderator
 
cocobolo95's Avatar
 
Join Date: Sep 2008
Location: Fruitland Park,Florida
Posts: 12,706
 
Do a search on Ebay of vats bypass module, or passkey bypass module. There's a seller making an inexpensive 50 & 30 hertz bypass module on there.


If worse comes to worse, you can find schematic diagrams to make a timing module. You would have to buy the proper resistors & capacitors to get the 50 hertz signal. Of course a small bread board circuit maker to put the 555 IC & other components on.
cocobolo95 is offline  
post #11 of 20 (permalink) Old 10-18-2018, 09:38 PM
Regular Member
 
shoebox's Avatar
 
Join Date: Aug 2006
Location: Little Rock, AR
Posts: 6,369
 
shoebox is offline  
post #12 of 20 (permalink) Old 10-23-2018, 04:13 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
Quote:
Originally Posted by cocobolo95 View Post
I never had to get to either the TDR or TDM while I owned my 95 trans am. But on page 8A-30-2 of the 95 service manual gives component locations. The TDR is mounted to right side of SIR bracket behind instrument panel.

The TDM is just right of radio, attached to air bag bracket. I had to find the TDM in my 90 f-body. I had to tear out whole dash to get at it. But study the passkey wiring diagram starting on page 8A-133-0. That way you'll know the number of wires TDM has & their colors. There's lots of small electronic boxes stuffed in the dash area.
Just scrolled back up and saw this. The page you mentioned appears to be missing from the PDF I downloaded. It goes from 8-1 which mentions 8A, but then the next page says "BLANK", then it goes straight to 8B...

Black Bullit is offline  
post #13 of 20 (permalink) Old 10-23-2018, 05:23 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
Okay, so I studied up on the diagnostics part of the PASS-key system. The way mine's acting, it's like it has the wrong resistance.

It seemed to be in "fail enable" mode when I got it. He had a shoddy 3-resistors in parallel setup. After having the battery unhooked, it got out of fail enable mode, and wouldn't start with his resistor setup. I matched the key and it still wouldn't start.

My guess is that he got a new key made while it was in fail enable mode, and didn't worry about the pellet since he'd already "bypassed" it.

How do I determine what resistance it needs to start? Just wire up 15 different strings of resistors and try them all? And no, I don't have access to a VATS/PASS Interrogator. Do any national chain parts houses rent those out?

Black Bullit is offline  
post #14 of 20 (permalink) Old 10-24-2018, 06:20 AM
Global Moderator
 
cocobolo95's Avatar
 
Join Date: Sep 2008
Location: Fruitland Park,Florida
Posts: 12,706
 
Yes, you will have to try all 15 resistor values until you hit upon the correct one. When I changed the TDM in my 90, using a used TDM, I started at the lowest resistance and worked my way towards the highest resistance. Did this to I found the correct value.

And I pretty much guarantee that which ever resistance end you start testing at, weather low or high, your resistance needed will be at the other end of the resistance values.

The vats/passkey interrogator is not a tool that's readily available to the public. Only ways to get one would be to find a GM dealer going out of business and buy there. Or maybe find one on Ebay.

Keep looking in the manual chapter 8A is in a different part of the manual scan. The scan is 3 separate manuals combined into 1 pdf file. Section 8A follows after section 6E. I recommend going to same site you got manual at. Then download the pdfil tools. With them you can break manual up into as many parts as you want.

Last edited by cocobolo95; 10-24-2018 at 06:26 AM.
cocobolo95 is offline  
post #15 of 20 (permalink) Old 11-10-2018, 05:55 PM Thread Starter
Regular Member
 
Join Date: Mar 2015
Location: Georgetown KY
Posts: 87
 
Okay, so I got it started today. I strung together all 15 resistors.. Started with number 1, and it ended up being number 4.

Now it idles at 2200 rpm. Any ideas why that might be? Any sensor or something that I might have left unplugged that would cause that? It idled just under 1000 before the tear down, even with the blown head gasket.

Black Bullit is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome