Lurching & Loss of Power After Fuel Pump Change & 12V Mod
03-27-10, 03:40 PM
#1
Lurching & Loss of Power After Fuel Pump Change & 12V Mod
I have a 92 SC400 that had a whining fuel pump. Replaced it with a TRE 255 LPH pump listed for this car & also did the 12V mod at the same time. Pump runs much quieter now but...
1) Can only get to ~40 mph before it starts to loose power. If I floor it it will sort of lurch like it's intermitently getting fuel (I guess). I can barely hear the fuel pump but it sounds like it may also be oscillating. Even have same problem in 2nd gear.
2) If I shift into neutral I can get the tach up to high RPM's & hold it steady. Didn't think this would happen if there was a fuel flow issue.
3) Pump runs even when key turned to Accessory & car not started. This is a minor issue relative to #1.
Now I'm thinking to put the old pump back in just to confirm it doesn't cause the same problems, even though it was noisy. Sort of trouble shooting.
So does anyone have ideas what could be going on?
1) Can only get to ~40 mph before it starts to loose power. If I floor it it will sort of lurch like it's intermitently getting fuel (I guess). I can barely hear the fuel pump but it sounds like it may also be oscillating. Even have same problem in 2nd gear.
2) If I shift into neutral I can get the tach up to high RPM's & hold it steady. Didn't think this would happen if there was a fuel flow issue.
3) Pump runs even when key turned to Accessory & car not started. This is a minor issue relative to #1.
Now I'm thinking to put the old pump back in just to confirm it doesn't cause the same problems, even though it was noisy. Sort of trouble shooting.
So does anyone have ideas what could be going on?
03-28-10, 12:06 PM
#2
I kept the new pump in & I undid the 12V Mod wiring & put it back to original wiring. Now it runs like a champ. No more lurching & power loss when I punch it. So I plan to leave it w/o the 12V mod. But...now another problem just occurred. The Tach & Speedometer don't work. Other instruments work & no CEL. They were working fine before reversing the 12V mod. I this just coincidence??? I'll put the mod wiring back in place just to check if the gages work again, but I wouldn't expect they'd be related if it weren't for the timing of it. I'll do some searching on the tach & speedometer problem, but if anyone has some pointers on what to check, I'd appreciate it.
03-28-10, 01:03 PM
#3
This is getting me puzzled. No more lurching/loss of power regardless of w/ or w/o 12V mod. So that's good news. Tach & speedometer didn't work with either wiring setup. I still expect these aren't related problems. The tach started to work midway into the test drive, but speedometer still dead.
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