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Bad Fuel Pressure Regulator
#1
96' 1.6L 16-valve 2-door 2WD 5 speed, 205k miles. Fuel pressure in range throughout all tests at 38psi. The pressure never fluctuates, not with 23 or 20 inches vac or even if vac hose unplugged from FPR and plenum port blocked. Constant pressure not good. Just trying to get confirmation that FPR certainly seems bad. Fuel Filter new as well.

Thanks for any advice.

Leak down test was good, held 8" for over 2+ minutes. Vacuum at plenum good and constant. No issues with cranking hard at all.

To know what has transpired I'll give detail, but only read if you desire.

Started stumbling horribly out of the blue. CEL popped on and, on occasion blinking. DTC was misfire on Cyl 3. Cylinder 3 wire tube had hole burnt clear through side of it about 1'' from plug. Put full set wires, cap and rotor NO CHANGE.

Bought set NGK stock plugs and put ONLY #3 in NO CHANGE.
Put rest of plugs in and VIOLA ran smooth as silk. All gapped .28

Next day started stumbling ONLY at first 1/4 of acceleration in each gear but smooth on WOT. 2 days later went to crap again, CEL blinking and this time DTC was multiple misfires. Stumbles at idle but no stall and also throughout entire acceleration range.

All 4 cyl's range 70 to 80 psi on compression test.

My thoughts were Coil (Distributor) or FPR.

Now, with FPR not impacting fuel pressure no matter the vacuum applied, I think that is it. Both are on order.
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#2
welcome !!!!
your fpr jammed and bad, dead, as mackerel,, this failure will make fuel injection super inaccurate.
.028" gap im sure
70 to 80 psi on compression test. is 1/2 normal at sea level if not done WOT, compression can be very low. did you block open throttle cranking?
if yes.(im surprised it runs at all) my law mower does 100 and the model "A' ford does 75.

the cam belt slipped CAUSES low compression, i can get 125psi top of pikes peak, or highest mountain on earth.(with road, not k2)
normal is 170 to 180 psi

the fuel pressure is highest at keyon (no start) and WOT
and mid range at idle

my Ugly drawing
[Image: reg-graph-mpi-g.jpg]


nice work, finding the killers of happy engine.
very nice.

FPR stuck closed (valve part)

or diaphram cranked, might leak full too at vacuum nipple

FPR like this causes over injection , except full throttle.

every word fun to read
thanks for sharing
http://www.fixkick.com
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#3
Thanks for the response. I am no mechanic, but you guessed that I am sure..hahah.

On compression test I only bumped starter on each cylinder until compression stroke and then read it. Sorry for my ignorance, should I try to run it and see what highest compression build is? When truck is running great is has tons of power, so I bet I just didn't do it right. Since you mention run it at WOT I am certain I goofed here. What did you mean by "block open throttle?

Sorry to sound so ignorant, but glad to know FPR is the culprit on the fuel testing done.
thanks again.
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#4
(01-31-2016, 09:56 AM)jlyon Wrote: Thanks for the response. I am no mechanic, but you guessed that I am sure..hahah.

On compression test I only bumped starter on each cylinder until compression stroke and then read it. Sorry for my ignorance, should I try to run it and see what highest compression build is? When truck is running great is has tons of power, so I bet I just didn't do it right. Since you mention run it at WOT I am certain I goofed here. What did you mean by "block open throttle?

Sorry to sound so ignorant, but glad to know FPR is the culprit on the fuel testing done.
thanks again.

WOW, dangerous to give a man a tool if he doesn't know how to use. Didn't know how to compression test, but do now. Read up on it. Those readings stated were just first puff, all other plugs in and throttle plate not open.

I will certainly be redoing that!!!!!!

Thanks again.
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#5
(01-31-2016, 11:16 AM)jlyon Wrote:
(01-31-2016, 09:56 AM)jlyon Wrote: Thanks for the response. I am no mechanic, but you guessed that I am sure..hahah.

On compression test I only bumped starter on each cylinder until compression stroke and then read it. Sorry for my ignorance, should I try to run it and see what highest compression build is? When truck is running great is has tons of power, so I bet I just didn't do it right. Since you mention run it at WOT I am certain I goofed here. What did you mean by "block open throttle?

Sorry to sound so ignorant, but glad to know FPR is the culprit on the fuel testing done.
thanks again.

WOW, dangerous to give a man a tool if he doesn't know how to use. Didn't know how to compression test, but do now. Read up on it. Those readings stated were just first puff, all other plugs in and throttle plate not open.

I will certainly be redoing that!!!!!!

Thanks again.

yes 2 things, stave it of air
the tv is closed.100%
compression is best done warm or hot, so the IAC is close, no air there
and if doing so hotwiring the starter, the ISC is closed, no zero air,
just crank with foot in bit in to the trottle suck in some air
under hood doing it remote starter jumper( a tool)
i block open the throttle, key in pockets. so jam a screw driver in the throttle on TB crank, holding open throttle a bit.

im sure now your compression is ok.
it will do 170+ easy
or power would be way low. about 1/2


hey you went straight to a dead FPR, NICE WORK, and a real pain to drive a car with one dead.
waste fuel and hot CAT AND carbon packing up egr.
nice work@@
http://www.fixkick.com
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#6
(01-31-2016, 12:26 PM)fixkick Wrote:
(01-31-2016, 11:16 AM)jlyon Wrote:
(01-31-2016, 09:56 AM)jlyon Wrote: Thanks for the response. I am no mechanic, but you guessed that I am sure..hahah.

On compression test I only bumped starter on each cylinder until compression stroke and then read it. Sorry for my ignorance, should I try to run it and see what highest compression build is? When truck is running great is has tons of power, so I bet I just didn't do it right. Since you mention run it at WOT I am certain I goofed here. What did you mean by "block open throttle?

Sorry to sound so ignorant, but glad to know FPR is the culprit on the fuel testing done.
thanks again.

WOW, dangerous to give a man a tool if he doesn't know how to use. Didn't know how to compression test, but do now. Read up on it. Those readings stated were just first puff, all other plugs in and throttle plate not open.

I will certainly be redoing that!!!!!!

Thanks again.

yes 2 things, stave it of air
the tv is closed.100%
compression is best done warm or hot, so the IAC is close, no air there
and if doing so hotwiring the starter, the ISC is closed, no zero air,
just crank with foot in bit in to the trottle suck in some air
under hood doing it remote starter jumper( a tool)
i block open the throttle, key in pockets. so jam a screw driver in the throttle on TB crank, holding open throttle a bit.

im sure now your compression is ok.
it will do 170+ easy
or power would be way low. about 1/2


hey you went straight to a dead FPR, NICE WORK, and a real pain to drive a car with one dead.
waste fuel and hot CAT AND carbon packing up egr.
nice work@@


Well, the FPR didn't fix it. Sure it was dead, but the truck is still stumbling on its face. Started out great after FPR for about 10 miles or so. Outstanding power no stumbling. Then pulled up to stop sign and got rough idle. Took off and now stumbling again about about 60% of the time. Rest of the time runs smooth. Obviously I am getting spark as it runs so good at times. I am still only getting DTC for multiple misfires, so I guess it is time to move on to injectors??? Your thoughts?
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#7
p0300, random misfire,
or 301,302,303,304 mixed and wild>
no other dtc codes?
egr sticking open as you come to stop is real comon. and low rpm and stumbling.
key off
cold,
cycle egr main. push finger in , it, clunk it closes,. fully, repeat , thunk thunk, hum sounds good...

then remove top hose, of egr at TB ported vac port, at end of hose VSV >>>>>>port at vsv end of hose insert a golf tee.
egr is now dead. as a door nail., and hand closed, per above.
start engine
idles ok hot rpm 800? steady, regulated?
drive, run ok now,,, bingo egr bad. (more tests)
ir still bad , injection issues
chevron injector cleaner (the best. is Benzene, the best is that)
ok now? im not a snake oil guy but , removing injectors is pain.

i need to know all times its stumbles. (and if bogging or misfiriing, bogging is weak power, misfire is violent
hesitations
bogs
hard violent misfires
when? on hills only.?
and all DTC codes, need them all.
good luck
http://www.fixkick.com
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#8
(02-03-2016, 03:39 AM)fixkick Wrote: p0300, random misfire,
or 301,302,303,304 mixed and wild>
no other dtc codes?
egr sticking open as you come to stop is real comon. and low rpm and stumbling.
key off
cold,
cycle egr main. push finger in , it, clunk it closes,. fully, repeat , thunk thunk, hum sounds good...

then remove top hose, of egr at TB ported vac port, at end of hose VSV >>>>>>port at vsv end of hose insert a golf tee.
egr is now dead. as a door nail., and hand closed, per above.
start engine
idles ok hot rpm 800? steady, regulated?
drive, run ok now,,, bingo egr bad. (more tests)
ir still bad , injection issues
chevron injector cleaner (the best. is Benzene, the best is that)
ok now? im not a snake oil guy but , removing injectors is pain.

i need to know all times its stumbles. (and if bogging or misfiriing, bogging is weak power, misfire is violent
hesitations
bogs
hard violent misfires
when? on hills only.?
and all DTC codes, need them all.
good luck


Well, before I read your post I went back to the very beginning and started again. Only DTC is Multiple misfires and none pending. When checking that brand new set of wires, #1 wire boot split all the way down side and causing the current issue.(SEE ATTACHED PHOTO) Ordered replacement set and we'll go at it again. Thanks for the other information and if the wires don't fix once and for all I will update and begin with your latest suggestions. Thanks so very much!!!
   
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#9
ooooohhhhh ugly that,, the lightening got out...
bosch has nice mag wires, that last better.
thanks for sharing such a very graphic photo. of this... "action"
http://www.fixkick.com
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#10
(02-03-2016, 08:34 AM)fixkick Wrote: ooooohhhhh ugly that,, the lightening got out...
bosch has nice mag wires, that last better.
thanks for sharing such a very graphic photo. of this... "action"

Looks like, finally, all is well. Put old #1 wire on awaiting replacement set. Runs perfect. Long journey but great lessons learned. Thanks to any and all for this great website and forum. Sanity has returned!!!
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