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#2446736 - 02/05/18 08:07 AM Another GM Post! A Blown Fuse Blew My Engine Up
LTDan Offline


Registered: 01/20/03
Posts: 12802
Loc: Gloucester,VA STOP MOVING HERE
So I use all of my classic cars as regular commuters. Since my old Mopars generally only need a minimum of care and feeding to keep them roadworthy, this is a non-Mopar post.

My 1987 Grand National, which is a nice, original, #s matching car with about 140K miles on it that was on the regular DD rotation roster up until a few weeks ago when I replaced the ignition module and coil. After I replaced them, it wouldn't start. Now let it be known that I have no experience working on Turbo Buicks. At first I thought it was the fuel pump because I didn't hear it cycle on when I turned the key but I found it had no spark. After going through some troubleshooting, which included testing and priming the fuel pump and lots of cranking the engine I finally found the culprit was a blown fuse that controls the engine ECM. Im not sure how it blew, maybe I left the key on when I replaced the module and coil?

So I replaced the fuse.

Then I knew I had spark when I turned the key.

This time I heard the fuel pump come on.

Ive been shot at and know the sound of close quarters gunfire pretty well. I thought that's what happened. The explosion just about blew the muffler clear off the pipes and the flames out the exhaust was pretty damn impressive. Thankfully the Mopars in the garage were not hurt in the explosion.

My guess at this point is all the gas that had been shot into the cylinders caused the violence when they tried to compress all that fuel sitting on top of the pistons at once. So now I have spark but no engine. It cranks haphazardly and unevenly so Im thinking the backfire either broke the timing chain or the engine skipped time, or possibly (not likely?) blew a valve or bent a pushrod.

If I get time this week, I'll pull the front cover and see what it looks like but like I mentioned, it has 140K on it, which is borrowed time for a Buick 231. Oil pressure was pretty low when it idled so it may be a good excuse for a rebuild, but with a pregnant wife, it may have to wait unless I can get a Buick Turbo V6 on the baby registry.

Anyone else ever have a 25 cent fuse turn into a $3000 repair?

Happy Monday!

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#2446741 - 02/05/18 08:35 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
EV2DEMON Offline
master

Registered: 01/19/03
Posts: 6508
Loc: Indiana
If the fuse that blew actually controlled the ECU, the injectors would not have been firing, so there would not have been fuel pooled in the cylinders.

Sounds like timing is somehow way out.

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#2446743 - 02/05/18 08:36 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
ScottSmith_Harms Offline
Mr Wizzard

Registered: 01/20/03
Posts: 42184
Loc: Spokane Washington

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#2446761 - 02/05/18 09:15 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: ScottSmith_Harms]
Rhinodart Offline
Rhinotruck

Registered: 01/20/03
Posts: 36946
Loc: Round Lake Beach, Illinoisy
Probably gas in the mufflers. I was working on a friends 64 300 after he changed the timing chain and put it all back together and it wouldn't start. After he cranked it a few dozen times I figured it out that he had put the distributor in 180 degrees off. I put it right and he cranked again producing a large backfire that blew the chrome exhaust tips off and they hit the house across the street! eek The mufflers bulged out to twice their size too! laugh2 After taking the next few minutes to regain our hearing, the car fired up just fine... pity
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#2446805 - 02/05/18 10:13 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
300by500 Offline
master

Registered: 12/19/05
Posts: 2847
Loc: Bowling Green KY / Nashville, ...
Not a 25 cent fuse, but back in the 1980s I owned an international S-Series Truck with a 6.9 diesel in it. A glow plug controller malfunctioned and kept the glow plugs on after the truck had been started. The tip of one of the glow plugs melted off, jammed into the piston, and cracked it in half - engine blown.

Years later I had another international with a 7.3 diesel. I was going down the road about 50 mph when the rear tires simply stopped turning because the engine had completely locked up. It turned out to be broken welds on the windage tray. The windage tray somehow got sucked up into the crank, and that was that - it locked up the tires on that 22K GVW truck instantly!

I drove those stupid things for over 20 years. I’ve always referred to them not-so-fondly as InterTRASHionals! 😡 LOL

Hopefully you can get your GN back on the road soon!
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#2446809 - 02/05/18 10:18 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
I_bleed_MOPAR Offline
master

Registered: 01/20/03
Posts: 7946
Loc: Dacula, GA
Tough way to start the week, Dan. frown I would pull #1 plug to get it on TDC and the dist. cap to check before I pulled the front cover but that's just me. wink
Good luck with it. up



Tim
_________________________
'71 Charger McCandless-built 383/727
'00 Durango 5.9 w/ 5 spd. conversion
'17 Challenger SXT (wifes car wink )

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#2446931 - 02/05/18 01:31 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: I_bleed_MOPAR]
EV2DEMON Offline
master

Registered: 01/19/03
Posts: 6508
Loc: Indiana
Originally Posted By I_bleed_MOPAR
I would pull #1 plug to get it on TDC and the dist. cap to check before I pulled the front cover but that's just me. wink


Not familiar with the Turbo 231 I take it? They use distributorless ignition. I'm thinking maybe a few crossed plug wires?

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#2446967 - 02/05/18 02:53 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: EV2DEMON]
I_bleed_MOPAR Offline
master

Registered: 01/20/03
Posts: 7946
Loc: Dacula, GA
Originally Posted By EV2DEMON
Originally Posted By I_bleed_MOPAR
I would pull #1 plug to get it on TDC and the dist. cap to check before I pulled the front cover but that's just me. wink


Not familiar with the Turbo 231 I take it? They use distributorless ignition. I'm thinking maybe a few crossed plug wires?


Oooopppssss.... blush


Tim
_________________________
'71 Charger McCandless-built 383/727
'00 Durango 5.9 w/ 5 spd. conversion
'17 Challenger SXT (wifes car wink )

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#2446994 - 02/05/18 03:48 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
a12rag Offline
top fuel

Registered: 04/23/07
Posts: 2137
Loc: Calgary, Alberta Canada
Fuses don't "blow" . . .they operate or "open" . . .blown fuse is mis-applied fuse that is in a circuit producing fault currents BEYOND the capacity of the fuse to SAFELY interrupt . . . .

Sorry to hear of the maladies . . . . think of it as an opportunity to "get to know" your Buick . . .????

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#2446996 - 02/05/18 03:52 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
AARCONV Offline


Registered: 03/06/03
Posts: 4958
Loc: NEW JERSEY
Im going with crossed wires or you didnt connect the body ground in the back of the coil/module bracket
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#2446997 - 02/05/18 03:52 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: a12rag]
Pacnorthcuda Offline
I Live Here

Registered: 11/19/07
Posts: 19273
Loc: Kirkland, Washington
Originally Posted By a12rag
Fuses don't "blow" . . .they operate or "open" . . .blown fuse is mis-applied fuse that is in a circuit producing fault currents BEYOND the capacity of the fuse to SAFELY interrupt . . . .

Sorry to hear of the maladies . . . . think of it as an opportunity to "get to know" your Buick . . .????


Really? So fuses don't "blow". Who knew?

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#2447004 - 02/05/18 04:07 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: Pacnorthcuda]
buildanother Offline
I Live Here

Registered: 08/30/05
Posts: 11265
Loc: chicagoland,usa
Well, they sure do "pop" when they are entering "open" phase of life.....

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#2447010 - 02/05/18 04:18 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
Pacnorthcuda Offline
I Live Here

Registered: 11/19/07
Posts: 19273
Loc: Kirkland, Washington
I came home late last night and my wife opened a fuse!

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#2447048 - 02/05/18 05:22 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: Pacnorthcuda]
feets Offline
Senior Management

Registered: 01/20/03
Posts: 27242
Loc: Irving, TX
Originally Posted By Pacnorthcuda
I came home late last night and my wife opened a fuse!



At least she didn't blow anything.

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#2447082 - 02/05/18 06:48 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: Pacnorthcuda]
Morty426 Offline
master

Registered: 03/12/08
Posts: 8670
Loc: Sacramento CA
Originally Posted By Pacnorthcuda
I came home late last night and my wife opened a fuse!


What kind of beer name is "Fuse"?

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#2447092 - 02/05/18 07:10 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
maximum entropy Offline
master

Registered: 02/08/07
Posts: 5080
Loc: organ
Originally Posted By LTDan
So now I have spark but no engine.

i'm sorry, but that's really funny...
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#2447095 - 02/05/18 07:19 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
Sinitro Offline
master

Registered: 01/20/03
Posts: 4998
Loc: So Cal
Was it the correct value fuse??

Just my $0.02.. wink

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#2447289 - 02/06/18 05:42 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: Sinitro]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 1994
Loc: Haslet, Texas
Ok...let's holster our fuses... grin
LTDan, I have a co-worker who is an owner of a GN Buick also and is an avid member of Turbobuick.com, he says if your not a member already you should check it out, lots of help there up
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1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2447746 - 02/06/18 08:39 PM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
LTDan Offline


Registered: 01/20/03
Posts: 12802
Loc: Gloucester,VA STOP MOVING HERE
I lurk on Turbobuick.com but I haven't registered yet. Luckily theres a shop about an hour from me that specializes in Turbo Buicks so I have them for a local expert and I will probably have them rebuild the engine if I need to go that route.

The wires are definitely not crossed and I rotated the engine by hand from TDC and it seemed to be off a bit so I'm leaning more toward it skipping time. I'm going to try and get to it this weekend. Anyone think I might have busted a valve or bent a rod?

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#2447911 - 02/07/18 07:35 AM Re: Another GM Post! A Blown Fuse Blew My Engine Up [Re: LTDan]
I_bleed_MOPAR Offline
master

Registered: 01/20/03
Posts: 7946
Loc: Dacula, GA
Possible if you had enough fuel in the cylinders. Pulling the valve covers and checking rockers will tell if you have a bent valve. Compression test will show a bent rod.
Here's hoping the backfire simply made it jump timing and nothing else is hurt. luck

A$$-uming a turbo Buick is somewhat easy to work on. I missed on my other suggestion. blush

Tim
_________________________
'71 Charger McCandless-built 383/727
'00 Durango 5.9 w/ 5 spd. conversion
'17 Challenger SXT (wifes car wink )

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