Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Pontiac > Trans Sport
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools Search this Thread
Old 04-11-2016, 01:02 PM   #1
Jeffrv
AF Regular
 
Jeffrv's Avatar
 
Join Date: Jun 2006
Location: North Bay
Posts: 178
Thanks: 0
Thanked 13 Times in 12 Posts
weird ignition problem 95 TS

My 1995 TS with 3.8 just quit driving down the road, would not restart. had to be towed home.
Fuel pressure just meets specs at 41 PSI engine off ( Gm says 41 to 47), but has been that way for some time. Put Actron scan tool on, got a code 361, EST not toggling. GM has no code 361, but based on past experience, this has usually pointed to a defective ignition module, and I thought that was that. While testing, scan tool kept losing communications and having to be reset. Finally I unplugged power source of tool, and engine immediately quit and would not restart. Resetting scan tool would allow engine to restart, albeit very rough. Doing a wiggle test of engine wiring harness makes no change. Crank sensor was replaced, about 12 years ago, so it not the trouble prone OEM; cam sensor about 10 years ago by a garage who was unsuccessful in solving a driveability issue.
Issue here is why would scan tool affect engine operation has anyone else had similar experiences?
Jeff
Jeffrv is offline   Reply With Quote
Old 04-11-2016, 02:18 PM   #2
brcidd
AF Enthusiast
 
brcidd's Avatar
 
Join Date: Jul 2005
Location: troy, Ohio
Posts: 2,226
Thanks: 2
Thanked 151 Times in 149 Posts
Re: weird ignition problem 95 TS

I've seen my scan tool not allow an engine to even crank- unplug it and it cranks and starts- saw it on a '97 U-van and just saw it last week on 2004 Lesabre...have seen it cause instrument clusters to go wild on Chryslers and Jeeps- speedometers flutter, gas guage goofy- unplug scan tool and all is fine.

So it has to do with data line and communications- doesn't always happen. I remember wasting 2 or 3 hours dubugging why a Pontiac Transport would not crank- when finally, I unplug scan tool and it starts right up...WTF....You never forget to unplug the tool first, now.....
__________________
Automotive A/C Engineer with:
'99 IH 4700 Toy Hauler
(2) '95 GEO Prizms both maroon
'99 GMC Yukon
'95 Chev 3500, 454 Dually Crew Cab- 145k miles-
Wife's Camel trailer puller.
'94 Astro- 370k miles
'94 Firebird Formula- 5.7L 180k miles- gone-
'92 Chevy Lumina Van 3.8L 264k
'86 GMC S-15 - 2.8L 154k
'87 Buick Park Ave . 187k
'86 Buick Park Ave 3.8L 199k miles- gone
'77 Chevy Vega- 2.5L 175k miles gone but not forgotten
'68 Camaro 396 4 spd RS/SS -72k miles-
brcidd is offline   Reply With Quote
Old 04-13-2016, 01:42 PM   #3
Jeffrv
AF Regular
Thread starter
 
Jeffrv's Avatar
 
Join Date: Jun 2006
Location: North Bay
Posts: 178
Thanks: 0
Thanked 13 Times in 12 Posts
Re: weird ignition problem 95 TS

Update:
Van back running now. I did replace ignition module, would not start, but at least didn't throw that code again. Googled car wont run without scan tool, got a few hits, none from GM cars. However, the recurring theme was OBD II ( and this van has that oddball OBD II packaged in OBD I guise) and loss of ground link in PCM circuit. Apparently the scan tool will allow a poor ground connection, enough to just get engine started, but once scan tool removed, engine will quit. Checked all fuses, power connections, and disconnected and reconnected battery. Lo and behold, the ground wire located under the ignition module was frayed through- repaired it all well again.
Jeff
Jeffrv is offline   Reply With Quote
Old 04-14-2016, 10:52 AM   #4
sergeimoskva
AF Newbie
 
Join Date: Sep 2014
Location: Moscow
Posts: 42
Thanks: 0
Thanked 12 Times in 11 Posts
Re: weird ignition problem 95 TS

Hello !
Watch the wire from ignition module to PCM
sergeimoskva is offline   Reply With Quote
Old 04-16-2016, 02:50 PM   #5
LMP
AF Enthusiast
 
LMP's Avatar
 
Join Date: Jun 2004
Location: Chicoutimi Quebec
Posts: 3,279
Thanks: 7
Thanked 59 Times in 59 Posts
Re: weird ignition problem 95 TS

Well the wire bundle going to PCM plug C111 has an history of wires breaking close to the plug.
Ahhh..I see you are aware of that........
__________________
'93 Ponty Transport 3.8; 2011 SUzuki SX4 AWD (wife's) ; 2015 Sorento 2.4 AWD 1928 Graham Paige Model 629
I don't believe in miracles.
LMP is online now   Reply With Quote
Old 04-16-2016, 04:21 PM   #6
sergeimoskva
AF Newbie
 
Join Date: Sep 2014
Location: Moscow
Posts: 42
Thanks: 0
Thanked 12 Times in 11 Posts
Re: weird ignition problem 95 TS

Hi !
I meant the, it is one of the the reasons of malfunction
sergeimoskva is offline   Reply With Quote
Old 04-18-2016, 10:16 PM   #7
Jeffrv
AF Regular
Thread starter
 
Jeffrv's Avatar
 
Join Date: Jun 2006
Location: North Bay
Posts: 178
Thanks: 0
Thanked 13 Times in 12 Posts
Re: weird ignition problem 95 TS

In this case, it was a defective wire on the ground stud under the ignition module. Yes aware of the engine wire bundle issues, which is why I did the wiggle test on the engine harness, paying particular attention to the area around the engine side of the bulkhead connector. Not the problem this time.
Jeff
Jeffrv is offline   Reply With Quote
Old 04-25-2016, 09:45 AM   #8
LMP
AF Enthusiast
 
LMP's Avatar
 
Join Date: Jun 2004
Location: Chicoutimi Quebec
Posts: 3,279
Thanks: 7
Thanked 59 Times in 59 Posts
Re: weird ignition problem 95 TS

Quote:
Originally Posted by Jeffrv View Post
...defective wire on the ground stud under the ignition module....
Thanks for the update....will record that for eventual issues...
Wiring problems at this age ..I would not qualify as "normal"....but , let's say, explanable. After recent issues (solved) with the wire bundle from passenger door to body, some more have come recently. I cannot lock doors (unlock OK) from the driver side now, just from passenger's. A little soldering will take care , when I have time...
__________________
'93 Ponty Transport 3.8; 2011 SUzuki SX4 AWD (wife's) ; 2015 Sorento 2.4 AWD 1928 Graham Paige Model 629
I don't believe in miracles.
LMP is online now   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Bookmarks
Go Back   Automotive Forums .com Car Chat > Pontiac > Trans Sport

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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



All times are GMT -5. The time now is 10:46 AM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts