Fueling & Injection - how do the pumps fail?

Hi,

Searched threads but didn't see anything like this.. my car (2000 TA manual with 130k miles & a few mods) has been fine, I've owned it several years, but then recently it has started sometimes giving all the symptoms that in a carb car, I would say were "fuel starvation". BUT it does not do it all the time, and never when I first start it, only after it's been running a while (more than 30 mins usually). The symptoms can come and go again during the same journey. So it isn't something like the filter (which I changed 6 months back anyway). Once it happens, it stays like that for quite a while, many minutes, perhaps an hour in a long journey.

It doesn't give any error codes, always starts, and behaves totally normally under about 1/3 throttle. Once you go above that, if the problem is present, it starts to feel really 'flat' & won't accellerate. But it doesn't seem to misfire.

The only thing I could imagine would be that the pump might be failing somehow(?) or in some way I'm getting low fuel pressure (haven't measured it, sorry..).

The thing that gets me is that it's intermittent?

Ideas? (I ordered a racetronics pump anyway, after 130k it seems fair..).

Thanks, D.

"(haven't measured it, sorry..). "

Maybe, start there???

It's possible for the pump to become very weak but still operate. Do a pressure check, and check the current draw from the pump.

Well I made a start by cutting a hole in the rear area so I can change the pump now anyway.. :)

I'll get a pressure gauge next and check that as well, it seems to maintain pressure when off anyway, using the highly technical method of popping the schrader valve and seeing how far over the engine bay it squirts... :)

kr D.

Oh yeah... will one of these do for measuring the pressure (whilst moving, got to put it somewhere I can see.. )?

http://www.summitracing.com/parts/HYP-4004/

Reason I ask is that it says it's LT only(?) but surely it's just a schrader connector? I'd rather get one that isn't fluid filled.

kr D.

TPIS sold me a pressure gauge w/ an extra-long hose, so it could be run outside the hood and taped to the windshield for reading while driving. Ghetto, but functional. $45 or so.

^^^^ Now that's funny!

Ok, ordered a TPiS one, we shall see...

-D

Changed the pump for Racetronics today - instant difference! The internal fuel filters also looked like shite:

http://www.vf750.co.uk/imagedump/filters.jpg

(I deliberately ripped out the ring of the external one to make it easier to get off, the other splits were already there...).

The presssure gauge will turn up here in the sandpit in a few days, but I could tell the difference as soon as it fired up. BTW and for infromation, racetronics fitting information, kit parts etc. were all very good.

kr D.