help with injector volume bench test
August 21st, 2014, 9:46 AM
#1
help with injector volume bench test
I have CSFI setup. (central sequential fuel injection). i'm trying to bench test 1 injector.
after intake manifold job, cleaning (avoided injectors), one "delicate" injector no longer working. (maybe some carb cleaner let some gum clog it, though i avoided that)
injector ohms good just like rest, i assume i need to clean it out, there are youtube videos on that.
I'm trying to clean injectors and test (spray, possibly volume)
my benchtest failed on a known good injector: so i can't expect to see if the bad one is working either
(I connect 1.5V or 3V bat to injector, shop air to fuel tube that is in injector body, should spray some gas/cleaner out of injector with V applied)
I can't find specs on what voltage to supply to injector terminals (or how many amps will be needed). I also can't find diagram saying which pin is positive per injector (not symmetrical - has odd shared ground mixup and wire colors aren't to be trusted)
(however, i had a leaky fuel regulator so the psi supplied was only say 15psi - i'm trying that again (i need to reinstall the regulator, it wont go in the way it came off, must screen & grommet out) to get seated right)
anyone ever bench tested injectors (in body or out of) successfully ?
after intake manifold job, cleaning (avoided injectors), one "delicate" injector no longer working. (maybe some carb cleaner let some gum clog it, though i avoided that)
injector ohms good just like rest, i assume i need to clean it out, there are youtube videos on that.
I'm trying to clean injectors and test (spray, possibly volume)
my benchtest failed on a known good injector: so i can't expect to see if the bad one is working either
(I connect 1.5V or 3V bat to injector, shop air to fuel tube that is in injector body, should spray some gas/cleaner out of injector with V applied)
I can't find specs on what voltage to supply to injector terminals (or how many amps will be needed). I also can't find diagram saying which pin is positive per injector (not symmetrical - has odd shared ground mixup and wire colors aren't to be trusted)
(however, i had a leaky fuel regulator so the psi supplied was only say 15psi - i'm trying that again (i need to reinstall the regulator, it wont go in the way it came off, must screen & grommet out) to get seated right)
anyone ever bench tested injectors (in body or out of) successfully ?
August 21st, 2014, 9:51 AM
#2
OH FORGOT. i'm testing injector in the body because i'm afraid the dainty plastic body will break
injector (as usual) is stuck in their - GM left no way for me to pry it out or push it out w/o risking damage to body or tube that i can see - just 1/8" smooth cyl that is definitely not enough to work out an old injector
anybody know "the trick" for removing old injectors from this dainty plastic body w/o breaking body and (hopefully) not damaging injector ?
also be nice to know if pcm supplies ac or dc volts
-------------------------------
i find GM has really done truck ownerns a favor here (see SUMMARY)
I found 12V DC 300mA or 9V AC 300mA work injector (i'd like more accurate info on amps, volage, and pulse modulation!). ac makes an audible buzz, 12v hardly a click. injectors ohm the same before / after hookup and testing. i wouldn't leave them on longer than for testing they do warm up.
--------------------- I found 2 tricks. AFTER i decided to order a $250 kit (after unit was expendable) (dumping any money into the unit, even $50, does not make sense)
found trick for removing these injectors. my bad eyes, 1/8" wrong, didn't see seal. pry cap off. like many there is a seal to take out (bad eyes i thought it was plastic), spray with penetrant and use a (not sharp) hook to get seal out: then there's 1/4" to grab easy. but with these inj even use penetrant both ends and either use straight pick to push out (theres a small hole) OR after rocking it loose, pull on tube hard and slow (maybe even leave seal in just pull). (note technically need a seal kit, old seals expand "no good")
BUT I STILL NEED trick ? ! need to remove tubes ? they are clogged not injector (usually). far as i see they come pre-installed new and if removed there's no sure way to know if they will hold at 60+psi for extended period. (ie, factory may force on and apply correct heat for plastic to "form it on"). if tube did "pop off" on the road: it might dump 60psi fuel into a cylinder, hydrolock the engine - AND LITERALLY CRACK THE BLOCK (might throw rode through block) - and maybe cause a death / accident. but maybe not since it's on other side of injector. but what about that old fuel regulator? it can dump fuel when it's rtv 75psi "pressure membrane" disintegrates (confirmed happened to some people): it's cloth embedded with rtv it's not rock solid - they disintegrate. youtube shows how to clear the tube.
SUMMARY: new regulator $50, new seals $40, injectors $50 + $xx? shop supplies: $150+. a new kit is $250 - spending any money fixing an old unit likely will be wasted when it breaks again down the road, and the new kit will get better gas mileage hands down! some car models inj are $400 EACH: but GM has really done truck ownerns a favor here.
SUMMARY: I rebuilt the regulator (other article) and got all injectors working for a cost of $shop supplies: but new one is on the way. I think I put the new one
Putting any money into the old spider is a waste of time and money: it will cost on fuel (allot $ these days) and might cause engine failures later or more repairs GM has really done truck ownerns a favor here using a cheap setup (body, 6 inj, regulator, seals, all in kit!) that one can drop in (very little work) for less than the cost some car makers charge for a single injector. (also, new kit is even easier to repair if it does ever need it, also think: if you decide you know $40 will fix it - the fragile old inj system might get another problem while you uninstall/reinstall it)
But it's not $40. Your fuel regulator (100k, 150k) is bad trust me. It's over $100 ($130 w/seals) just to get started for 1 injector to repair old spider. Not worth it.
injector (as usual) is stuck in their - GM left no way for me to pry it out or push it out w/o risking damage to body or tube that i can see - just 1/8" smooth cyl that is definitely not enough to work out an old injector
anybody know "the trick" for removing old injectors from this dainty plastic body w/o breaking body and (hopefully) not damaging injector ?
also be nice to know if pcm supplies ac or dc volts
-------------------------------
i find GM has really done truck ownerns a favor here (see SUMMARY)
I found 12V DC 300mA or 9V AC 300mA work injector (i'd like more accurate info on amps, volage, and pulse modulation!). ac makes an audible buzz, 12v hardly a click. injectors ohm the same before / after hookup and testing. i wouldn't leave them on longer than for testing they do warm up.
--------------------- I found 2 tricks. AFTER i decided to order a $250 kit (after unit was expendable) (dumping any money into the unit, even $50, does not make sense)
found trick for removing these injectors. my bad eyes, 1/8" wrong, didn't see seal. pry cap off. like many there is a seal to take out (bad eyes i thought it was plastic), spray with penetrant and use a (not sharp) hook to get seal out: then there's 1/4" to grab easy. but with these inj even use penetrant both ends and either use straight pick to push out (theres a small hole) OR after rocking it loose, pull on tube hard and slow (maybe even leave seal in just pull). (note technically need a seal kit, old seals expand "no good")
BUT I STILL NEED trick ? ! need to remove tubes ? they are clogged not injector (usually). far as i see they come pre-installed new and if removed there's no sure way to know if they will hold at 60+psi for extended period. (ie, factory may force on and apply correct heat for plastic to "form it on"). if tube did "pop off" on the road: it might dump 60psi fuel into a cylinder, hydrolock the engine - AND LITERALLY CRACK THE BLOCK (might throw rode through block) - and maybe cause a death / accident. but maybe not since it's on other side of injector. but what about that old fuel regulator? it can dump fuel when it's rtv 75psi "pressure membrane" disintegrates (confirmed happened to some people): it's cloth embedded with rtv it's not rock solid - they disintegrate. youtube shows how to clear the tube.
SUMMARY: new regulator $50, new seals $40, injectors $50 + $xx? shop supplies: $150+. a new kit is $250 - spending any money fixing an old unit likely will be wasted when it breaks again down the road, and the new kit will get better gas mileage hands down! some car models inj are $400 EACH: but GM has really done truck ownerns a favor here.
SUMMARY: I rebuilt the regulator (other article) and got all injectors working for a cost of $shop supplies: but new one is on the way. I think I put the new one
Putting any money into the old spider is a waste of time and money: it will cost on fuel (allot $ these days) and might cause engine failures later or more repairs GM has really done truck ownerns a favor here using a cheap setup (body, 6 inj, regulator, seals, all in kit!) that one can drop in (very little work) for less than the cost some car makers charge for a single injector. (also, new kit is even easier to repair if it does ever need it, also think: if you decide you know $40 will fix it - the fragile old inj system might get another problem while you uninstall/reinstall it)
But it's not $40. Your fuel regulator (100k, 150k) is bad trust me. It's over $100 ($130 w/seals) just to get started for 1 injector to repair old spider. Not worth it.
Last edited by silverado 1500 2001; August 24th, 2014 at 9:27 AM.
August 23rd, 2014, 9:54 PM
#3
update. rethink.
i had 1 inj not working (usu. the tube clogged inj is ok). ok clean the tube? poppet at end look different color after cleaning all poppet tube ends. after removing tube (see above if this is "wise"). i cleaned just tube part (inj was good, spider tube is what "clogs")
but i couldn't get the tube to blow for nothing
finally i use rust penetrant and a wire down tube to gently "tap" (not scratch) ball, and tapped other side (note: like ball point pen, do not crush it!) with 120 psi, tapping, rust penetrant it cleared and sprayed
LESSON: w/o flow this poppet tube can get rust. i'm afraid once that happens it's likely to happen again (once rust has set in...) so again, even though i have a fully operational unit, more for learning/experience purposes. i'm not going to gain anything putting it back in. i let it set a month rust will be back and i'll have 1 cyl w/weak or clogged inj again
SUMMARY: maybe varnish clogs them. but they RUST (after clogging?) once rust sets in, it pits and is never really gone and waiting to dominate again. poppet needs replacement not cleaning (comes w/injector not separate), and as discussed above: $250 kit is the much better alternative and easier.
i had 1 inj not working (usu. the tube clogged inj is ok). ok clean the tube? poppet at end look different color after cleaning all poppet tube ends. after removing tube (see above if this is "wise"). i cleaned just tube part (inj was good, spider tube is what "clogs")
but i couldn't get the tube to blow for nothing
finally i use rust penetrant and a wire down tube to gently "tap" (not scratch) ball, and tapped other side (note: like ball point pen, do not crush it!) with 120 psi, tapping, rust penetrant it cleared and sprayed
LESSON: w/o flow this poppet tube can get rust. i'm afraid once that happens it's likely to happen again (once rust has set in...) so again, even though i have a fully operational unit, more for learning/experience purposes. i'm not going to gain anything putting it back in. i let it set a month rust will be back and i'll have 1 cyl w/weak or clogged inj again
SUMMARY: maybe varnish clogs them. but they RUST (after clogging?) once rust sets in, it pits and is never really gone and waiting to dominate again. poppet needs replacement not cleaning (comes w/injector not separate), and as discussed above: $250 kit is the much better alternative and easier.
Last edited by silverado 1500 2001; August 24th, 2014 at 9:22 AM.
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