what's a fuel filter going bad go like?

[wdkingery]

i noticed when i started the vehicle this mornin it was alittle sluggish; normally it's very consistant with power levels and throttle response, but i dismissed it. then, as i was late to my exams this morning, i was runnin the vehicle harder than i ever have since i started on WMO, and after about 20 minutes of 70mph, it started to lose power, then come back, lose power, then come back.. did this 4 good times.. i thought it was done for! but i continued on; after i got off the highway it didn't do it again.  reminded me of having air in the lines after a fuel filter change.. it was like the throttle just stopped working.

So i'm guessin i have a fuel filter that's beginning to fill up.

i installed a 95 chevy turbo diesel electric lift pump, and that is still functioning correctly, so i don't think it was a viscosity issue.

auto zone wants $28 for the filter, it's clean cross town, and i don't have time today.. i have 3 exams, 1 paper due and a 20 minute presentation on "indian genocide" to do today..


it's ok as of now, but i have a feelin high flow needs (70mph) will bring it back

[Baron VonZeppelin]

Usually what i see is idle gets lower, lil more black smoke, and some less power overall. But you might have already bypassed that stage, and be in the next stage.

Filter is first suspect.

85-87 Bosch are $20 at AutohausAZ.
Comparable brands are less than that at RockAuto.

With what you're doing - best thing would be to go to Mk1 spin on filters.
Advance has them for about $8 Purolater.
RockAuto will have some for probably cheaper.
Find best deal and buy 5-6 at a time, and keep 1 spare in car at all times.

I've been priced as high as $40 locally for Mk2 filters before.
Tried Prothe $10 Mk2 filters once, was not a good experience.
One went bad in a week.

[wdkingery]

Usually what i see is idle gets lower, lil more black smoke, and some less power

I was noticing this in the past few weeks

[JBG3]

If you are running WMO, you should throw a restriction gauge in the fuel line, then there would be no question if its clogging or not. 

[745 turbogreasel]

Reduced upper RPM power, then it may start to pull air  in downstream of the filter.

[ORCoaster]

wdk-  maybe since you are running "ahem, non-standard fuel" you should invest in a MK1 flange and just prefilter the fuel with an oil filter.  Then take out the real fine ones with the regular fuel filter.  Might be cheaper to change the first filter every three times to the one for the diesel.

[fatmobile]

 Great responses all I can add is clear fuel lines will show lots of air when the filter cloggs,.. and I believe it makes white smoke.
  I agree on the restriction gauge. You really need a vacuum gauge. It would have warned you way before you noticed a problem. You are probably pulling 15"hg by now.
 Ebay is the cheapest place to get them. Get one with a long sweep so the number are far enough apart,.. especially between 0 and 5 which is where you will want to run.

 

[wdkingery]

how will a vacuum gauge work, considering i have a lift pump? i think that little pump will build up PSI .

any recommendations on what kind of vehicle runs a spin on filter? obviously diesel mk1's are more rare then obama's transcripts in Virginia

[ORCoaster]

Put the gauge on the pump side of the filter(s)  I wouldn't do with a standard vac gauge.  I would try a boost/vac gauge.  then when you are good with a new filter you will see the normal operation pressure after all the filters and as the system ages you will see a reduction in pressure and possibly a vacuum from then on.  It would alert you to a problem that the filter is plugging up and you need to service it.  And not with a plunger either.  Swap it out.  I always pack a spare filter.  1 minute to replace instead of hiking to the store and paying what ever just to get fuel to flow again.  

Most auto places have a spin on flange do job available for off engine filters.  Many oil coolers use them. 

[wdkingery]

http://www.dultmeier.com/products/0.2623.2629.4606/8346

what about that jobber?

[ORCoaster]

Looks about right.  Might go with a reducer in the in and out ports to better match the fuel line sizes but other than that I say it would do the job.  So Job that Jobber. 

And for the record, that word has not been common for 20 years now. 

[Baron VonZeppelin]

People parting out Mk1's usually sell the filter mounts fairly cheap.

A few days ago i saw one of those remote oil filter set-ups with dual filter provision - that would be trick prefilter set-up. It was new for about $20.
Can't remember if it was on one of the NC craigslists , or if it was on NCdubs.org website.

The prothe boost/vac gauge is one of his few decent/good items.
About 8, 10 or 12 bucks. iirc

[belchfire]

I always keep a spare filter, pair of nitryl gloves and a plastic bag for the old filter on hand. The electric pump is great for priming so you don't wear down the battery cranking the engine or risking contamination trying to fill the new one from the old one. I've noticed that top speed and acceleration decreases when the filter starts to go bad. At highway speeds there's enough suction from the charge pump to keep things going but as soon as you slow down, the idle isn't there. Also starting will be harder. A couple of times the failure was immediate. I'd notice a slight drop in performance and within a mile or two complete failure. Once had to bypass the filter and run it straight just to get home. I was changing them almost twice a week in the early days of SVO experimentation so I know how expensive it can be. NAPA was charging $14 for the MK1 filters.

[wdkingery]

This filter must have been bad for a while.. Made a big difference. Converted to spin on as well. Thanks everybody

[fatmobile]

I always keep a spare filter, pair of nitryl gloves and a plastic bag for the old filter on hand. The electric pump is great for priming so you don't wear down the battery cranking the engine or risking contamination trying to fill the new one from the old one. I've noticed that top speed and acceleration decreases when the filter starts to go bad. At highway speeds there's enough suction from the charge pump to keep things going but as soon as you slow down, the idle isn't there. Also starting will be harder. A couple of times the failure was immediate. I'd notice a slight drop in performance and within a mile or two complete failure. Once had to bypass the filter and run it straight just to get home. I was changing them almost twice a week in the early days of SVO experimentation so I know how expensive it can be. NAPA was charging $14 for the MK1 filters.

NAPA gold filter sale on now.
 They are only about $6.
 This is when I stock up.