s10sbc350

I have been messing with this motor for over the last month, and have replaced the ecm, icm, and have ohm'd out the injectors, and checked fuel pressure and fuel filter which was all good, and it doesnt have a vats system on it.
The only thing i can think of would be the injectors fuses, the memcal, or the ignition possibly but i dont know if those are all plausible so here is what it's doing.
When i turn the key on the pump turns on and it gets fuel, but it wont start at all unless i put a little starting fluid through the throttle body of plenum then it runs for a second or less and shuts rite off. Also the spark plugs are good but either way theyd have to be for it to start for a second or two, so please help me. Tunedperformance has been helpin me the entire time so thanx for sticking with me and helping.

s10sbc350

Also itt has a push button start aswell if it matters to any of this, so then when i turn ignition to on the pump kicks on, oh and i have disconnected a line after filter near them otor and it was getting plenty of fuel flow.

OrangeBird

iTrader: (1)

I have not seen your original thread , but , have you tried a "noid light" on the injectors ? Since your suspecting injector electrical signals the first thing you want to do is to determine if there actually IS in fact a signal to spray being suplied to the injectors . Say for instance your noid light don't light when it should during the test . Well , there are only two possibilitys , the +12V positive power as being fed through the ign switch and fuse , or the negative side which is the side being "pulsed" to give the spray signal . The + side remains constant and the - side is switched against - ground to produce the circuit required . If you noid light don't light check for one side of the injector plug to have +12V with the key on . If it does , your computer or wiring between the computer is highly suspect . PS , your computer needs at least it's own 12V+ power and - grounds properly connected to function properly itself .

And if your noid light DOES pulse properly when doing the test , now ya gotta suspect maybe gummed up injectors or maybe even the fuel itself as being too stale to run ....

s10sbc350

Yes i have used a noid light before during testing, and it didnt light up or do anything, so then tunedperformance has been telling me to get a proper volt ometer since mine is crap, but i will i guess tommoro hopefully if i truly need to buy another one. But basicaly whats the possible problem parts?

OrangeBird

iTrader: (1)

Since Tunedperformance knows his stuff I'm sure he has already asked you about the ground wires attached to the back of the cylender heads ? These grounds are essential for the computer/injectors to work and are often overlooked during engine replacement .

The list of suspect components will vary depending on wether you've lost the +12v to the injectors or the - that the computer is supposed to pulse .

If no +12

Bad fuses in the fusebox , the ignition switch , the wiring harness , or possibly a fusable link

If no switched - ground side

Bad fuse mounted to front fender . This is the Computer's main fuse , if bad , it will keep the computer from making the proper negative going pulse , wiring harness , Computer , Vats .

there may be other suspects , but i'll bet one of the above mentioned will solve your problem . Now you need a means of checking wether the +12V is there or not , a meter as Tuned Perf has said would be ideal for this and many other future measurements you may need to make should the need arise . A test light , properly used , will tell you if the +12V is there or not , and go from there till ya get the meter . Course , the meter will allow you the check the injector's resistance also and would be the preferred tool of choice here ....

s10sbc350

I have checked their resistance with my multimeter and they were all 17ohms. It has no vats, i checked the ground and all three wires on the bolt, and if you could post a link to the corrcect meter i need to buy to figure out if its a +12 volt issue or -12volt issue, and find the cheapest one at a autozone or oreilys if you could that'd be really awsome and more helpfull sice i dont have much cash on me, thanx

s10sbc350

Also is a (test o light) circuit tester for ac/dc the same as a test light, or will it at least work since it has a light on one side, and a pos/neg cable n the other? Just asking since i have one laying around, and my meter has a 9volt setting but is it not what i need to test it for 12volt in injector harness

OrangeBird

iTrader: (1)

The auto parts supply stores sell 12V automotive test lights that look like a screwdriver but with a sharp point instead of a screwdriver blade , a clear body with a little 12V lightbulb inside , and a length of wire coming out of it with an alligator clip on the end of the wire . Is that what you've got ? Anything called "AC/DC" is usually for household wiring and will be of no use here . Houses are 110/220 volts and our cars are 12 volts = vastly different testers required .

If you DO have an automotive voltage tester , take the alligator clip and clip it onto the engine somewhere to get a good ground . Check the light by touching the sharp pointy end to the positive battery terminal , the light should light .

Now , with Key on in the running position and the alligator clip of the testlight still grounded , unplug an injector and touch the pointy end to first one , then the other , to the socket of the wiring harness . One side of the harness should light the light and one side shouldn't . If neither side has +12V , it's the positive going side of the system you need to focus on . If one side does light the light , then you've lost the negative going side . These tests will literally take seconds to do , and will isolate which side of the system has lost continuity .

s10sbc350

Ok ill be buying a test light tommoro then, and since it will work fine im not going to spend the money on a volt meter for now.

s10sbc350

ok so here is a link to a test light that will work for what i need rite?
http://www.oreillyauto.com/site/c/de...0221&ppt=C0371

Also this is the meter i currently have so will it not test the injector plugs for what i need?
http://www.oreillyauto.com/site/c/de...1001&ppt=C0103

Ok and last link lol, so is this exactly what i need to check the volts at inj plugs, or will me meter in the link above already do this.
http://www.oreillyauto.com/site/c/de...1001&ppt=C0103

TTOP350

iTrader: (8)

I gotta ask, is there fuel in the tank????

s10sbc350

UMMM ya! Haha I can hear it slushing around when i shake the back, and i added a few gallons not to long ago. Besides the noid light never lit up so it definetly has an issue lol

OrangeBird

iTrader: (1)

Yes , the test light in the link is exactly what I was referring to , and is in fact the one I use often for quick troubleshooting tests .

Either of those 2 meters would be fine , provided they function properly . A lot of the cheap electronics will be either DOA , or worse , they will function somewhat but not give accurate readings . Since you are sure you have no noid light action it's clear that you have lost one portion or other of the circuit . As per my post above , determine if it's the constant +12V side you've lost or the pulsed - 12 volt side that your missing . This cuts the circuit roughly in half , and will determine your next steps to get it running . Remember , a circuit needs a power source , something to do the work , and a return path for the electricity to make the circuit complete . In a lot of circuits it's the + 12 volt side that will be switched , but there are also a lot of circuits where the - 12 volt side is switched . In this case , the "main" switch for the injector's +12 volt side is the ignition switch , and the "operating" switching element in the - 12 volt side is the computer . The ign. switch gives the injector it's always present (when the key is in the run position) positive 12 volts , and the computer pulses the path to ground at the appropriate time to spray the injector .

s10sbc350

ok i understand what your saying mostly, but how do you check for -12 volts on the harness, and +12 volts, p.s i have the yelow meter in that second link if you could just tell me which settgs to put it on, as i tried it set on 9v test, and it did nothing

tomlyons

you have to go old school

DENN_SHAH

iTrader: (1)

as long as it works right, the test meter you have should work ok.
forget about the 9 volt setting, its only purpose is to test the little 9 volt radio batteries. the 1.5 volt setting is for things like AAA, AA, C & D size batteries.
the setting you need to use is the the 20 volt scale in the DCV area.
that test light should be fine.
along with the DVOM, you really need a test light too.

once you find out if you have power or not to the injectors, that will decide where you need to go next.


when repairing cars, certain tools are needed.
quality tools are not cheap.
i probably have more invested in 2 of my test lights than most people spent on their test meters.
i know its not easy when your young, but when taken care of good quality tools can last a life time. my newest test light is over 10 years old.

s10sbc350

Ok thanx ill still go buy the test light tommoro since it's just $3 and ill go try my meter and see what happens.

s10sbc350

Ok this kinda makes no since so here is what i got on the first to injectors on different sides of the motor.
driver side injector plug. one port read about (.15)-(.08) and the other port in plug said(.04) to (.03)
passenger plug one port read .26 and the other port in plug was saying around .35
So those readings make no sense, but they wouldnt read anything untill id tuch the probe while it was grounded on the block so please someone clear up this confusion, thanx

s10sbc350

Alright I just checked the injectors plugs and the light didnt do anything ,and it works because i checked it on the battery and it lit. So what should i look at now?

Also is this the correct ignition part that might be causing the issue or is it another part in the ignition system, thanx

DENN_SHAH

iTrader: (1)

with the key on engine off and no power to either terminal at the injector means there is a problem with the power supply side of the system.
first check the injector fuses.
there is more than 1 fuse box, one under the dash on the drivers side, & the one you need to check on the passenger side.
there are 2 injector fuses, 1 for each bank of injectors. key on engine off, at least 1 side of the fuses should have power if the fuses are blown.
if the fuses are blown, then you have a short between the fuses & injectors. with a blown fuse, it could be a wiring problem or one or more of the injectors could be shorted.

both sides should have power if the fuses are good. no power at all to the fuses means there is a power supply problem to the fuse box and you will need to find where the problem is.

without knowing what year your car is, this link may have the diagram you need,
http://92b4crs.tripod.com/86wiring/86wiringindex.html

if 90 or newer, you may need a different diagram for the power supply to the FI fuse box.

OrangeBird

iTrader: (1)

Go to the fusebox under the driver's side dashboard . You will find in the fusebox two fuses marked "inj 1" and inj 2"

Ground the alligator clip and with the key on probe both sides of both fuses and see if the light lights on both sides of each fuse . If yes , you've likely got a wiring or connector problem (the "body connector" perhaps ?) or possibly the ignition switch itself . If no , replace whichever fuse only lights the test light on one side and try to start it . If it blows the same fuse twice , there is a short to ground in either the harness or an injector .

OrangeBird

iTrader: (1)

Denn and I were both typing at the same time , and both of us have come up with the same advice .

s10sbc350

Ok but i have a 1987 iroc-z tpi 350 in my 1989 s10 that used to have a 2.5litre, so its still got the stock s10 fuse box, not the iroc-z one, and there is no inj fuse in the pannel, but what ground on the front fender are you talking about like where does it come from, and im going to trace the injector harness untill i locate the inj fuses but if one was blown wouldnt the opposite fuses side still light the test light, because im thinking its a ignition switch issue, how do i check it while im there

OrangeBird

iTrader: (1)

I see no way that the wiring harness/computer for a 2.5 L four banger is gonna run a 350 TPI ! Has this "conversion" ever ran ? Is the harness and computer from the 350 TPI donor car still available ?

I was under the assumption that we were talkin a Camaro or Firebird here , and not a cross platform swap .

At this point , I believe you need an automotive electric systems expert , cause this really ain't "learn as you go" territory .

Best of Luck .......

s10sbc350

Ya it was running great three weeks ago, and im pretty sure it has the iroc-z wiring harness swap obviously, because just a s10 harness wont run a iroc-z motor they arent the same. And it isnt going to be that hard i think its either the ignition switch, or the injectors fuses and im like 80% sure its not the fuses snce ne side would still be good since it was driving then it died all the sudden after acting up for like 10 seconds

s10sbc350

Yes the computer is already installed and so is everything else you would find on your iroc-z except, the aldl, and the fuse box but almost everything else is there from the camaro, so its the same diagnstic procedures youd be doing if its was a camaro.

TTOP350

iTrader: (8)

He has a few threads started that tell what he has going on. Its kinda tuff to figure it all out if you haven't read them.. His name kinda drops a hint also.

I've been tryn 2 get him 2 buy a factory service manual for weeks now. This way he'll know how to check things without wasting time here with people guessing.

s10sbc350

I already bought a manual off ebay and recieved a **** magazine instead of the manual, so im not spending another $25 on one for awhile

Tuned Performance

iTrader: (92)

Since you have verified that there is no power on the pink/blk wires of each injector bank with the key on. And can't find the injector fuses at the fuse box or a accessory aco fuse box. And verified several circuits have power with the key turned on at the fuse box. The only think left to do is keep trying to find the injector fuses or rewire the injectors to a switched power off the ignition switch and fuse both leads.

TTOP350

iTrader: (8)

Tuned, Do you have a inj harness/ power/ground diagram pic handy? Im inside now and manuals are in file cabnet in garage.

OP, what kinda **** mag? Is it useful ?? lol

s10sbc350

This is probably going to sound stupid but to get power to injectors can i run some wire spliced into injector wires to my battery and put a relay in the circuit and try that or is this completly crazy, lol because im about to go splice into injector harness and run some wiring.
Also I dont remember what was on the mag i let my freind have it

Tuned Performance

iTrader: (92)

[IMG]http://i43.photobucket.com/albums/e390/brianlvs/86-165v8tpi-
5_zps91b37487.jpg[/IMG]


The schematic doesn't show the wire color for the power side of the injector's but it is pink/blk.

TTOP350

iTrader: (8)

http://imageshack.us/photo/my-images/197/tpiguide.jpg/

s10sbc350

So is that a go for wiring up the injectors power wire side to my battery to give them the 12volts since they have everything working to open them they just need the power supply, let me know if it will work, or kill me lol

TTOP350

iTrader: (8)

Y not look for the 12volt power supply to the injs? If you backfeed it to the batt and there is a short or unhooked wire grounded out, you could have a lil fire.

s10sbc350

Trust me i have looked throught the huge miny wire supply store thats located under my dash and they all connect up to ecm or branch off into the dash to never be found agin.
But seriously lol so will wiring like 8gauge wire from each injectors power wire to my battery work or how can i do this, please help because i need to know what to buy tommoro.

Tuned Performance

iTrader: (92)

http://www.ebay.com/itm/Raised-4-Fus...36d58b&vxp=mtr

get one of these hook the buss to the ignition switched power and 2 fuses one to each injector bank pink/black wires instal two 3 amp fuses and be done .

Tuned Performance

iTrader: (92)

The harness becomes a fusible link

TTOP350

iTrader: (8)

Tuned Performance

iTrader: (92)

s10sbc350

Lol

s10sbc350

Ok so here is the complicated stuff. So im 100% confused by this post as i dont get it, the fuse block in link only holds like 4 and you said 2 for each bank so thats 16? Also the switched ignition power, basicaly just hook up a remote wire to my ignition fuse so they wont stay powered on? And lastly whre will the 2 three amp fuses be installed at?

Tuned Performance

iTrader: (92)

Just because the fuse holder can use four fuses you just need two

s10sbc350

Ok i know that you dont have to use them all, i meant there arent enough holes for 16fuses like you said id need 2 for each injector. Did you mean 1 for each injectors side of 4? Also is the switched ignition power basicaly just a remote wire spliced into the injectors and going to my fuse boxes ignition fuse hole? Oh and can i buy a fuse block at my autozone or o'rielys, walmart etc? thanx

Tuned Performance

iTrader: (92)

One to each bank, look at the schematic

s10sbc350

I dont get the schematic its showing like 32 injectors and man i really dont get it, it's not making since. Just tell me if this will work 1 wire going to 1 injectors power wire side spliced in the wire then going to my battery + with a fuse somwhere near the battery. Then doing it with all the other 7 injectors? Then if thats fine so far what would be left to do for this to work?

TTOP350

iTrader: (8)

Click on the picture to enlarge it then read it. A stock tpi only has 8 injs.

s10sbc350

I know it has 8injectors but that not the confusing part lol either way will the way i posted in post#46 work or not?

Tuned Performance

iTrader: (92)

hook the power to a switched ignition source

s10sbc350

??? I need to know what to buy and what to do tommoro so please help me figure it out where i understand it.