Cadillac Owners Forum banner

1 - 9 of 9 Posts

·
Registered
1999 Eldorado
Joined
·
19 Posts
Discussion Starter #1
greetings ... tried to push my 99 eldo to the limit with low gas... it ran out of gas and fried my fuel pump. I had my mechanic replace it with an ebay part, sending unit and fuel pump, all in one. The problem with the car is that it surges a bit at idle, and if you hold the throttle steady in a certain range of movement, the vehicle will buck (hesitate, as if there's a problem with vacuum/fuel/gas/spark).

note: one of the things I did while the car was down was remove the MAF meter and clean it with CRC electrical cleaner. Upon reinstalling it, I noticed a hairline crack on the outside of the electrical connector portion of the plug (square area). I'm wondering if this will cause my issue. There's no check engine light on, however, and the vehicle has gone through a full cycle.

my mechanic doesn't think it's the fuel pump, as it either delivers fuel or it doesn't. i'm thinking there's a fuel pressure regulator in play here. the frustrating thing it no check engine light, so i'm unable to narrow it down. I had a similar issue with a Dodge Ram cummins diesel truck, it turned out to be the throttle position sensor, easy fix, is that a possibility here?

another thought (stay with me lol) ... the vehicle did have a traction control issue, the vehicle would buck like this from a standstill, only. I turned the TC off.

and finally, to make it a complete puzzle... it didn't buck like this before the pump and unit were changed, however,the ignition was left on while out of gas, coasting down a looong hill on the freeway, so that pump was thoroughly fried, and i may have sucked quite a bit of debris into the fuel filter from the bottom of the gas tank. it used to idle without surging and only buck when approaching a certain range on the throttle, now it's idling rough too.

i'd like to avoid throwing fuel injector cleaner or replacing the fuel filter (if you guys don't think it's a high percentage play)that used to work on cars from the 70's and 80's. how would you play this situation?

thank you kindly, in advance.. :)
 

·
Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
·
19,245 Posts

·
Super Moderator
White Diamond '03 DHS (with DTS floor shift)
Joined
·
86,778 Posts
Re: 99 Eldo ETC hesitation, need advice, thanks

If the MAF sensor is cracked, you can't rule it out, even though it SHOULD set a DTC.

Doesn't sound like the fuel pump, but check the fuel pressure to rule it out.

Fuel filter is not likely, but can't be ruled out considering it is 16 years old. If fuel pressure drops when your symptoms occur, the filter may be your problem.

How old are the plugs & wires?

Coils are another possibility. You could borrow a known good one from another GM car and swap them one at a time to see if that cures it.
 

·
Registered
Too many...
Joined
·
878 Posts
Re: 99 Eldo ETC hesitation, need advice, thanks

I had a significantly breached PCV line and connector (vacuum leak) and had very similar performance issues, but no codes! I would start with repairing the leak. My feeling is the same as your mechanic, fuel is pumping or it is not.
 

·
Registered
2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
Joined
·
26,323 Posts
Fuel pumps are absolutely not a "works or doesn't work" item. If they're not providing sufficient pressure, the engine won't run right, or at all.
 

·
Registered
Too many...
Joined
·
878 Posts
Fuel pumps are absolutely not a "works or doesn't work" item. If they're not providing sufficient pressure, the engine won't run right, or at all.
You are right, nothing is absolute. In the case of dynamic, non-positive displacement fuel pumps, such a scenario is extraordinarily unlikely. DC motors are very simple, with a steady signal there are not enough factors involved to cause it to intermittently speed up and slow down unless of course something elsewhere intermittently opening and closing the circuit. Vac leaks, faulty FPR... no sense wasting time on the fuel pump again until the easy stuff is tended to.
 

·
Registered
2001 Seville STS, 1990 Seville (RIP), 1972 Sedan Deville
Joined
·
26,323 Posts
There is no shortage of threads here of these cars with low fuel pressure caused by a faulty pump.

Takes less than 5 minutes to check pressure with a loaned tool... Simple enough thing to check to rule out, as posted.
 
1 - 9 of 9 Posts
Top