Speedtoys

Car has been getting 'sicker' on fuel delivery as of late.

A sliiiight hesitation you feel under all conditions, mostly NOT at idle, but when more severe fuel delivery hesitation happens..idle is also affected and can kill it.

Its not a spark miss..its a slight loss of power you feel..and in sharktuner, if it lasts longer than a quick bit..you see momentary really lean AF numbers..which leads me to fuel.

Died side of road leaving Sears Point..did a highway fuel pump swap (had all I needed) after also swapping relays and making sure the FP fuse was in the socket nice and tight. So..the FP is out of the equation.

The fuse does feel loose. There is carbon arcing on the legs of the fuse. I bent the legs to tighten it up. The fuse before tightening it, was warm..not hot, just an observation.

When I pull the fuse when the car runs OK..the way the car dies like that..is just like when it dies on its own..sounds/acts the same. Just when it does on it's own, what makes the FP run could come & go enough to not quite kill it sometimes.

However, on the way to the hotel from side O road repair, it still "died" three times, but picked up again before coming to a complete engine halt as we were going fast enough to still turn the engine with the tranny in gear.

So..the next thing that I think keeps the fuel pump running, is..crank position sensor?

But if that was flaky, the tach would also hop around on me too, right?


What else could be causing this? Where ta go next?

jcorenman

Jeff,

If the fuse looks toasted, then it still might be the problem. You can (and should) replace the fuse, replacing the female terminals in the panel is harder but may be needed also.

But what about the fuel pump relay? Have you swapped that? (Same type as the horn relay).

You can also try jumping the FP relay. Make up a test-switch with a couple of lengths of 14 ga wire, a toggle switch and a couple of 1/4" male spade terminals, to bypass the FP relay. Very handy for testing fuel pumps.

When it died on the road, did it restart by itself? Or did you have to turn ignition off and back on?

And yes, a flaky CPS would show up on the tack, but then the tack goes to zero when the engine dies in any case.

A lean reading on the wideband can also be ignition, the wbo2 sensor is measuring oxygen. Lots of oxygen means not enough fuel, or no no spark to burn up the oxygen.

But I am still thinking that the problem is most likely getting power to the fuel pump.

Speedtoys

1) Will have a new fuse in there in the AM, with the spades thickened a little with solder.
2) Jumping the FP relay JUST hit me in the shower..will do that at the track in the AM as well. (The contacts to be linked are 30 and 87)
3) Yes, horn relay is in there, no change.
4) When it dies driving..if the pump is told to work again before you lose the speed required to turn the engine with the tranny, fires back up just fine.
5) Tach never jumps..or..it hasnt been a huge "waving arm of WTF" catching my attention in the middle of the dash.
6) Yes, Ive been on the fence WRT fuel and fire as well, but..most all signs point to fuel. Its never flooded for anything LIKE that, which a loss of spark but continuing to inject fuel would seem to do in the more chronic deaths of the car.

FWIW..I did get a 3Bar GM MAP sensor hooked up and logging to the sharktuner nicely today.


Mark Anderson won his class as well. By..a large margin. In a very old and tired ***-dragger 911.

Landseer

Do you have an LH to swap-in?

Observation, cat in Coreman avatar has more manly eyes than Sean Penn in yours, especially considering the pink window fixture clothes the guy has on. Creepy. Probably from some iconic movie shot, but I can't place it.

Speedtoys

Ya LH is on the mind too.

May have to roadside short relay this AM...bout to find out how lucky I can get for 12 miles before I have track support.

Lizard928

Jumper FP,
Swap LH,
As Jim has noted though, it's possible to be the inj not being told to fire, or the ign system not firing.

Put an LED on the FP bypass, and see if it turns off.
You can do this with the injectors too....

But just also make sure the battery terminals are tight.... If the additional red wires are loose, you will have this same problems.

jcorenman

Good short-term "fix", but now you really need to get into the CE panel and replace those contacts. Making the spades thicker beats up the socket contacts.

Yes, 87 and 30. Check the numbers on the relay, you do not want to get that wrong.

OK, good info. It could still be the fuse or relay contacts, or the drive-signal for the relay, which comes from the LH. The jumper will bypass all that, but Landseer's thought is good-- might be time for a rebuilt LH.

If the tach doesn't drop then I think you are correct, that rules out CPS as the source of the problem.

Cool! So get this problem fixed and then check the fueling with ST and then get back to the dyno!

And great picture of Mark, Thanks!!

Cheers,

Speedtoys

Cruise around the paddock "feels" that with the jumper, the UhhhhUhHhhhHhhhh odd hesitation is gone.

Will...report if that changes, and late tonight after the drive home.

Landseer

Last thought that might help is FP ground.
I think on 86.5 and up its located in spare tire well.
(earlier S cars / behind the rt quarter interior panel)

Speedtoys

Gah...new problem..now resolved.

Started it to do something..would barely run.

TO THE SHARKTUNER..

18:1 AF ratio..were starving..

New pump
Jumped relay

Called Jim..ok..got a meter.

No power at pump.

Started at the battery post..all looked good, felt right. PUSHED down on the terminals..

bzzzz

Pump is back.

*shrug*


And pulled 370rwhp on the dyno soon after on cali 91octane gas.

Speedtoys

Jim/etc:

Got into the smaller red wires from the battery, and one set was pretty green.

Cleaned them up, back together..and it appears all is well for now.

IcemanG17

Jeff
I had a slowly dying fuel pump issue on sharky......it would raise its internal resistance once it warmed up...but it worked for a little bit when cold...

However you have a new pump....so it can't be that....still quite odd.....I think it goes to the odd electrical gremlin....or bad grounds-connections in your case....

Speedtoys

Ya..."moving" the cable connection Sunday got power BACK TO the pump again, but by the drive to work this AM with the relay jumper on..the pump couldnt react quickly to throttle punches.

Cleaned that connector up and out..its cool now..it seems, for now.

Even put the 70mm pulley on the SC, and with that quicker fuel request..its fine.

Cant wait for the cooler weather.

KLVA

Fast Times at Ridgemont High.....gnarly, dude.......