Cadillac Owners Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
5,496 Posts
Discussion Starter #1
Hello Boosted V's!

Just had a strange thing happen. Car died while idling in line at a fast food drive through (I know). Pushed it into a parking spot with help of some good employees, and a little research revealed the 20A fuse on the fuel pump booster in the trunk was blown.

Replaced it and drove home (3 miles). Checked when I got home and the fuse and wire were quite warm - warmer than I expected. I limped her home and stayed out of boost best I could. My understanding is that booster shouldn't even be working unless under boost.

Can someone do me a favor? Drive your car - and then feel that wire for me? I know it is a bit of a hassle to pop the side trim of the trunk off...but I'd really appreciate it!

WW
 

·
Registered
Joined
·
5,496 Posts
Discussion Starter #5
Heavy -

Since the power lead to the pump is cut to install the booster, and the power basically runs through the booster - if the fuse is bad - then no fuel pump. Checked and doubled checked again tonight.

Will do some more checking tomorrow. Denniscars had a few ideas (thanks Dennis!) and I think he has my mind on the right track.

WW
 

·
Registered
Joined
·
2,874 Posts
wildwhl said:
Heavy -

Since the power lead to the pump is cut to install the booster, and the power basically runs through the booster - if the fuse is bad - then no fuel pump. Checked and doubled checked again tonight.

Will do some more checking tomorrow. Denniscars had a few ideas (thanks Dennis!) and I think he has my mind on the right track.

WW
Im guessing that you checked the wiringto make sure its not grounded anywhere. Myself and another member ran that wire in the car, not under it. No problems.

Also, check the fuse connection. If its the least bit loose, it will fry.
 

·
Registered
Joined
·
5,496 Posts
Discussion Starter #8
lasstss-

Just finished checking the wire underneath the car, and then rerunning it inside the car. I'll drive her later and see what's up. There were no nicks or shorts anywhere in the wire that I could see.

Heavy - sorry - wasn't arguing with you, just saying the same thing differently ;)

The strange thing is I've had 7,000+ trouble free miles...and the 20A fuse that blew looks very strange. It is barely blown, almost like it just semi melted - or in otherwords - marginal overload.

I have a handful of spares. I'll drive it and see if it continues. I even idled the car with the boost switch disconnected - same condition - so whatever is up is happening within the module.

Thanks for the help guys.

WW
 

·
Registered
05 maggied CTS-V, 2017 NSX Whoo Hoo!
Joined
·
8,810 Posts
I think the 20A is underated for the "bursts" that the fuel pump draws.

I would bump up to a 25A.

The wiring that you run from the booster to the switch is very low current stuff.

It is just to sense the switch closing. Even if it was "grounded" it shouldn't draw much juice.

If it looked like the fuse blew apart, then UH OH!

In your case, just stress melting.


Make up your mind to either stay at WOT or not!:histeric:
 

·
Registered
04 ctsV platinum,maggied,rt cats,headers,corsa,stealth tune
Joined
·
4,750 Posts
I have looked at mine,nothing out of the ordinary here.Wire wasn't hot and doesn't look like it's been hot,booster was warm to touch though.Pretty hot in there period.Good time to tape a couple spare fuses in there.
 

·
Registered
'05 CTS-VM 51 track days in Maggied V & 82 in Atom 2 in Volt
Joined
·
1,690 Posts
heavymetals said:
I would bump up to a 25A.
I don't prescribe to uping the fuse if the wire is getting hot. That only means that the wire is too small and will still get hot and hotter with a bigger fuse. But only one man's opinion.
 

·
Registered
Joined
·
5,496 Posts
Discussion Starter #12
Dennis -

I have to agree with you. Fusible links are sized a certain way for a reason. Heavy may not be wrong, but I need to find the reason that this is occuring all of a sudden. Going for a bit of a drive right now (passengerless) to see if I can recreate the situation.

WW
 

·
Registered
05 maggied CTS-V, 2017 NSX Whoo Hoo!
Joined
·
8,810 Posts
Well, a 5 amp bump shouldn't set the drapes on fire, but if it blew, then you either have a bad booster or pump.:crying:

From the failure described, it sounded like the fuse failed from repeated pump boost requirements. Stressed looking , melting seperation, not the "vaporized" major amp pull blow the junction apart failure.:eek:

Also, check the splice/tap from the booster into the +12 and the exit to the pump +.
 

·
Registered
Joined
·
5,496 Posts
Discussion Starter #15
Just wanted to give everyone an update.

First - kudos to Bryan at MagnaCharger once again who offered to ship a new fuel booster unit out right away if I felt it necessary. I held off.

Glad I did - because the blown fuse must have been a fluke. My guess is that the fuse took some abuse upon one of the few times the fuel system has had to be recharged (maggie off and on a time or two, and another project that requried disconnecting the fuel line a few times). I suspect the fuse partially burnt through at some point and then just so happened to finally finish while I was at idle. Could have just as easily happened at speed I suppose.

Anyway, after two weeks and no issues - I pulled the fuse to see how she looked. Perfect.

So, to test a theory, I replaced it with a 15 amp fuse this morning. Took a VERY spirited run up and through Virginia City, down 6 mile canyon and into Dayton. Let me just say it is about 45 miles total - 33 of which are 15 and 25 mph turns, and I averaged 42.7 mph according to the trip computer :D Yes, I was speeding - but never exceeded 65 mph...just hung the corners at speed to enjoy what the V is all about. I might also add that I did most of the trip in 4th gear - from down low at 30 mph and up - the Maggie was beautiful and plenty of low end torque where you needed it. I did my best to "ride the pace" as we used to call it on motorcycles - or basically never use your brakes. Just go as fast on the straights as you know the corners can handle. It was :thumbsup:

Anyway, once there I pulled the fuse. Looked brand new - no issues. So, to further test my theory - 10 amp fuse goes in for the return trip.

Return trip was less spirited - but no issues. Got home and checked it out - again, looked brand new.

So, one last thing to do. Disconnected the fuel line under the hood. Let some pressure drain. Gave it about 10 minutes. Left the 10 amp fuse in place. Upon "recharging" the fuel system - sure enough - 10 amp fuse popped! So...there you go. Put a 20 amp fuse in and replayed the same scenario - but had a friend turn the key for the recharge while I watched the fuse in the dark to see if I noticed any glow. The 20A fuse got a touch warm, but nothing serious.

My conclusion? Under normal circumstances the 20A fuse is correct, as supplied by MagnaCharger. For some reason though, and this doesn't make sense because the booster isn't working during this time, current goes up when recharging the system with fuel.

Also, MY final ruling is that the Wildwhl lowering technique doesn't degrade handling at 9/10's (I don't ever drive 10/10's because I'm not good enough). There is a slight bit of increased body roll in the front during hard left/right transitions - but I'm sure once the Hotchkis sway bars are available, that will be gone. YMMV.

Just my .02 for the weekend.
 

·
Registered
Joined
·
573 Posts
wildwhl,

i had the samething happen to me twice.. that little small fuse that is in the rubber seal.. it has a little plug that goes on top of it also..
Lund caddy dealer, put a 30amp fuse in it,, for some reason, it kept blowing the smaller fuse.. we checked evrything.. the booster was fine it kicked in right when it was suppose too. But if i was you, even when you get the new booster, i would put 1 size bigger fuze in it, since then no problems.. what made me chnage my mind on this, the last time it happened, it was 5:15pm in the afternoon rush hour in Phoenix, on the 202 loop... talk about an nightmare,, took 2 1/2 hours for a wrecker to show, roadside service could come out, but they were busy working on an Escalade, it would be 3 hour to wait on them... so i waited on the side of the road for 2 freaking hours, 115 degree heat with a car that was only 3 months old.. magiee had been on there for only 3 weeks... if i knew that was the only problem, bam easy fix.. NOW YOU SEE WHY I BOUGHT A FUEL PRESSURE GAUGE...and of course 3 extra gauges, boost, oil temp ect...


I WILL NEVER LET THAT HAPPEN AGAIN.. TRUST ME.

later blitzer
 

·
Registered
2017 Camaro ZL1; 2011 CTS-V sedan; 2004 Lightning
Joined
·
12,007 Posts
A little birdie told me that this booster pump has a failure mode of "always on." I didn't pursue the conversation, but it's possible that it's "intermittently always on," not "always always on." In which case, it could be pumping away for inappropriate periods of time, even when you aren't at boost. I'd ask Brian about that... if you have a pump that decides to leave itself on for too long, that could be the reason your fuse blew. And it may happen again.
 

·
Registered
Joined
·
573 Posts
My fuel pressure guage jumps constantly.. LAWFIVE, when you drove my car did you get a chance to see the bottom guage dance like it did? it jumps left and right constantly, then when i do get into oost mode the gauge increases pressure suddenly like it should, but it still never stablelizes, it still jumps around.. that is what scares me i never have a constant fuel pressure even at boost.

later blitzer
 
1 - 19 of 19 Posts
Top