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Tech Area => General Buick Tech => Topic started by: phagen28 on June 29 2020, 09:54:49 PM

Title: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 29 2020, 09:54:49 PM



I tried as I might to search this problem but didnt find anything. This year when I brought car out after the winter,it started then stalled. scan master displayed only dashes---------.I did do some searching online and someone said unhook the orange wire at the battery, remove the ECU and the chip to check connections. did that, put it back together and at 1st it was the same, i left it alone (discouraged) came back to it and turned key on and Scanmaster said 2.1 and it started. Seemed like maybe a connection was dirty and it was corrected. Now today I started the car to go for a little ride and got only up the rd and it stalled like I shut it off with the key.Now when I turn the key on it is back to just dashes from the Scanmaster, but now sometime it goes to display 2.1 then changes to dashes and still wont start.It just cranks over. I am not really sure where to go with this,now any help would be appreciated.
thanks
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Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Steve Wood on June 29 2020, 11:38:18 PM
the first thing I would do is disconnect the ScanMaster and see if the car would then start and run okay.

If it does not then start and run, I would check to see if the check engine light is on when the key is turned to run (still leaving the SM disconnected)
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 30 2020, 12:17:27 PM
I unhooked the ScanMaster and didnt start. with key in the on position and ScanMaster still disconnected, the check engine light is on and steady but no start.I have checked all fuses in the fuse box under the dash and all were good. battery is also fully charged. this has a Turbo Tweak chip, is it possible that a chip just goes bad? or the ECU that its in?
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Steve Wood on June 30 2020, 01:32:02 PM
It is possible, very unlikely in my experience-though.  Usually, one gets some kind of error code or flickering of the check engine light.

Okay, time to go to basics..

Does it have the proper fuel pressure?
Does it have spark?
If it has spark, spray some cleaner in the throttlebody (remove the hose to the tb, open the throttle and spray some cleaner into the plenum)-try cranking it.  Does it try to run?
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 30 2020, 02:59:05 PM
NO fuel pressure. I will replace the fuel filter, when i removed the schrader valve to put on my fuel pressure gauge there was no pressure behind it and nothing came out. I am confused though as to the relationship between the lack of fuel and the scanmaster not giving any reading at all. then like i said previously it would read 2.1 and start.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 03:02:50 PM
Check your SM connections. No fuel pressure could be a variety of things. Steve has all the checks on his site.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 03:05:28 PM
Twist the key to the run position...you should here the pump prime.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 03:07:48 PM
Fuel pump/Injector circuit


http://www.vortexbuicks-etc.com/fuel_pump.htm (http://www.vortexbuicks-etc.com/fuel_pump.htm)
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 30 2020, 03:49:16 PM
followed instruction to test and with key on no noise from pump. applied power to gray wire that is below alt to manually get power to the back of the car and when i touch it to 12v it causes the hot wire relay (  this has a hot wire kit and 340 pump installed about 3yrs ago) to click but thats it.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 04:34:12 PM
Okay, slide down to where it says pump is not running...and do what Steve says at number 2.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Steve Wood on June 30 2020, 05:09:01 PM
Scanmaster may be a different problem..
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 30 2020, 05:35:23 PM
ok so I tried it jumping off the gray test lead and had no noise from the pump. i unplugged everything with regard to the hotwire kit and plugged the factory plugs back together at the tank still no pumping,reconnected hotwire kit then i went to the hotwire relay with test light and had power at the heavy power wire and power coming out of the small red wire that goes to the pump with the key in the on pos and the test light went off after about 2 sec.this was again in normal operation with the key and not any jumper from the gray lead. so i'm pretty sure from what i know thru the testing i've done, I'd say that my couple year old pump might have gone bad. do you agree or is there something else i should check?
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 09:12:49 PM
If you followed Steves directions and come up empty, I'd drop the tank. You may find a melted wire back there. If not my guess would be the pump is fukd. I use to change the pump in mine every spring, whether it needed it or not. I was beyond anal with fueling with these cars.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Scoobum on June 30 2020, 09:13:52 PM
Hard wire your SM on the rear of the ALDL. I had all kinds of issues with the SM acting stupid till I did. If it still acts up contact Bob.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on June 30 2020, 09:35:48 PM
thanks for the help guys. i ordered a new pump and will have it in a couple days then i can put in in. in the meantime i'll hard wire the SM. i will reprt back as to how i make out with the pump and not starting.
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Steve Wood on June 30 2020, 10:03:09 PM
Good deal!
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: daveismissing on July 01 2020, 04:49:57 PM
Check the connectors on the ECM, pull them off carefully , any corrosion?
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on July 11 2020, 11:17:48 AM
Ok I got the pump, dropped the tank and put in the new pump. started right up and runs fine. thanks for your help! I always know where to look...here!
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: Steve Wood on July 11 2020, 12:32:10 PM
Glad it's going. Now, what happened with the SM?
Title: Re: 87 GN won't start. Scanmaster not giving any reading
Post by: phagen28 on July 11 2020, 09:09:26 PM
I'm not sure Steve. When it started the SM worked as it always did.I did hard wire the SM directly to the back of it and a good ground. My intent is to run it some and then check it for any newly stored codes. I will be back after I do that. Thanks again!