Bob88GTA

iTrader: (2)

Hmmmm? I'm going with shorted injectors being the wires are a little toasty...

Anthony0128

I'll test it out today, and yeah they're kinda fried not too much but switching them out wouldn't hurt

Anthony0128

If the wires going to the injectors are no longer good would it be causing this problem, the injectors fire but cut off after a short amount of time. This is obviously a fuel problem, can I test the wires ? And if they are shorting out would that cause the computer to shut them off ?

Bob88GTA

iTrader: (2)

Anthony, it could be possible to do that. OHM the wires and move them around. Hard to say. The could be internally shorted(the injectors)

Anthony0128

How many ohms should I be reading out of the wires & where could I get some new ones ? Mine are pretty burnt I'll take a picture when I get home & they're burnt to the point where you can see the wire inside it burnt through the plastic. I'll test them out but if the injectors are turning on doesn't that mean they're good? I'll still replace them don't want nasty wires.

Bob88GTA

iTrader: (2)

2.5 OHMS, like Tuned Performance said. Unplug each one and test the injector. As for the wire, you can poke the insulation on each side of the burn mark and wiggle the wire to see if it shorts on the meter

redneckjoe

i think some pictures would really help at this point.

i've seen the injector wires get pinched under the metal air filter spacer, and have seen the wires burnt before, causing issues. you can buy new pigtails if needed.
http://www.autozone.com/fuel-deliver...-ohv/79638_0_0

Anthony0128

I'll get some pictures on here soon and is there a difference in pig tails? Since the wires are a different color

Bob88GTA

iTrader: (2)

^^^^^What he said1

redneckjoe

IF,...you need to change them, cut and splice 1 wire at a time or take a pic with your phone. just match up to your current wiring. it's pretty simple. it only goes on the injector one way IIRC?

Bob88GTA

iTrader: (2)

Anthony....Is your tack wire hooked up? Does it bounce when trying to start?
There is should be a tach signal wire that goes to the tach on the HEI. This is the only wire that tells the injectors to fire. If there is no tach signal, the computer thinks the engine is not turning over and will not fire the injectors.

Tuned Performance

iTrader: (92)

It's not the purple/white wire from the icm ?

Bob88GTA

iTrader: (2)

Another thing to ponder
Injectors are "hot" with key "on". ECM controls the ground for the injectors, causing them to spray fuel. ECM controls ground based on signal from distributor that distributor is turning. You won't have ground to the injectors without cranking the engine, or supplying a cranking signal as if the distributor was turning.
ECM knows the engine is being cranked. It should be supplying pulsed ground to the fuel injectors while cranking. Since you have power to the injectors, pulsed ground should make them spray fuel. Since you have no fuel spray, apparently there's a problem between the ECM and the injector when started..

Bob88GTA

iTrader: (2)

see circled wires

Bob88GTA

iTrader: (2)

Tuned, yes.

Anthony0128

Sorry for the late reply, but what is the "HEI" ? and what should I be reading on the tach ? And honestly I'll try out anything just give me some time to kinda comprehend all this wiring lol. And what exactly do you want me to test ? I had a shower come in and I couldn't go out to work on the car today but tomorrow for sure I will.

redneckjoe

HEI is your distributor.

this video might be helpful?

RBob

iTrader: (1)

TBI injectors are 1.2 ohms. Low impedance port injectors are in the 2.2 - 2.5 ohm range, doesn't apply here.

RBob.

Anthony0128

I was reading over a few things and Bob lead me to test out the ground at the module which sends the signal to the computer. I'm going to test it out and see what happens, I remember when putting on my distributor the mechanic sort of bent a prong in the icm but we bent it back and I figured it'd be alright maybe it's not getting a good signal

RBob

iTrader: (1)

Sitting eating lunch and a thought came to mind, maybe the EGR valve is leaking exhaust into the intake. That will definitely cause the engine to stall at lower speeds.

RBob.

Anthony0128

How can I go about to check it ? And would it cause this problem I'm having?

RBob

iTrader: (1)

One way is to unbolt the valve and check if the pintle is seating closed. Maybe even temporarily block off the EGR ports and see how it runs.

Start up then sputter and die, yes. On a properly running engine opening the EGR valve at idle is an instant stall.

RBob.

Anthony0128

I'll remove it and see if it's dirty I'll give it a nice cleaning

Faolan

Egr is a good idea RBob, I never would've guessed that. Has it helped to clean it?

Bob88GTA

iTrader: (2)

"If the wires going to the injectors are no longer good would it be causing this problem, the injectors fire but cut off after a short amount of time. This is obviously a fuel problem, can I test the wires ? And if they are shorting out would that cause the computer to shut them off ?"

"Start up then sputter and die, yes. On a properly running engine opening the EGR valve at idle is an instant stall."

RBob.

EGR issue wouldn't cause the injectors to turn off though, would it??

redneckjoe

man, go buy a noid light at harbor freight or somewhere.

if your worried about the EGR, cut a piece of sheetmetal the size of the gasket and bolt it where the gasket goes.

sounds to me like that "bent" module might be your problem? but you'll never know anything til you get a noid light. JS

Bob88GTA

iTrader: (2)

^^^^^^^YUP!

RBob

iTrader: (1)

No, but what came first, the chicken or the egg.

RBob.

Anthony0128

Cleaned the EGR and it did nothing. It wasn't clogged much but gave it a nice cleaning. Hooked up a computer to check for anything radical and the car seems to be fine. Mechanic decided to call out the ecm so I'm purchasing another one. Could killing the battery and then re-charging it putting it on the car more than once mess up the ecm over time? Just a question I had. And well just waiting on the ecm. I don't see why it would go bad but every thing else is there to keep her running except the start and stall.

redneckjoe

did your mechanic use a noid light to check injector signals?

Bob Harris

On the battery,no.

Anthony0128

Yes he did and and everything checked out fine with them I got some diagnostics off of chevythunder and it all led to checking out the ecm

Anthony0128

New ecm and still no start. I'm all out of ideas. Not even the mechanics can figure it out.

Faolan

Where are you from? (Sorry if I missed it) if you're around Johnston county North carolina me and a few others could look at it. I'm curious to find out what it is to!

Anthony0128

I'm way down south down here in Texas. I'm so disappointed I really want it running and it's just being a pita

Faolan

Idk if this would make a difference but what does it do if you shift it into reverse or drive and start it ?

Anthony0128

Well it don't even stay running long enough to put it into any other gear. Today when the ecm was plugged it would just crank and crank and crank. Of course spray from starting fluid and it'll run I've taken out the ecm of the equation my mechanic has done stuff coming from him but not even be can figure it out. I appreciate everyones help a whole lot it's been great reading everyone's inputs. I hate to rack everyone's brains but thats just how problems go. Once again fuel pressure is there spark compression, but there's something wrong with the fuel and I just can't seem to find out what it is

Faolan

List everything you've done to the fuel system please

Anthony0128

Replaced: Fuel tank, fuel pump, sending unit, fuel filter, fuel pump relay, fuel pressure reg & I actaully bought a new tbi unit off a member, I told my mechanic to take off the one it had since it was stripped and I just decided to get another one. He said he changed it but there was no change to the car but I saw the part on the driver seat. Anyway i have been reading a lot and I stumbled upon an old thread where a guy literally changed almost everything and in the end a pinched fuel line was causing a start and stall problem. So today I'm going to go look and see if I find any crimps or pinches along the lines. I tested fuel pressure at prime but not when cranking so I'll make sure to do that too maybe try to keep it running with starting fluid and see if the pressure drops or stays when increasing the throttle

Street Lethal

iTrader: (16)

This thread has me scratching my head. You say your mechanic really knows what he is doing, but I have a few questions. How did your mechanic set Initial timing with the engine only running off of starter fluid? You mean to tell me he sprayed, then cranked, then sprayed and cranked his way to 0* BTDC with the EST disconnected? Did he really set base timing, or is he full of it? Did you reconnect the EST at least? Also, you're stating you're getting spark, just not fuel. However in the very first few posts I am reading how the engine will start, but die shortly after, yet now I am reading it won't start at all. Well which is it? If it starts then stalls, then either you are losing fuel pressure (when you test for fuel keep the pressure gauge on the schrader valve for longer than a minute or two after shut down and see if pressure remains), or the injectors are causing driver overheating and shutting off on you...

Anthony0128

To be very honest with you I have no clue as to how he set the timing. I didn't ask he had just said he set it and when I told him about the est wire & the whole process of disconnecting it and what not he said he knew so I then believed he did time it correctly & stating what you said I will now start questioning even more, and your saying the car had to at least be running maybe roughly but running in order to time it correct?

Anthony0128

And why would the injectors cause the driver to overheat ? If they were to be doing that

redneckjoe

i hate to admit it, but i accidentaly pinched a fuel line while changing a fuel pump on a third gen once. it was TPI though. it ran but was down on power. it was fairly obvious to see when i crawled back under there and had a "DUHHO!", moment.

Street Lethal

iTrader: (16)

Certain injectors are notorious for that, Multecs are a good example. Bottom line is you are getting spark as per your explanation. Air is a given. No SES codes, ECM was confirmed, so fuel is the only thing left. You need to confirm 0* BTDC too. If you are telling the truth that the engine will start will starter fluid all day long then the timing is at least close, so worry about base timing later. Get a fuel pressure tester gauge, crank the engine with it hooked up, doesn't need to start, and monitor pressure. After a few minutes it should remain the same, if it drops fast then you have a leak in the system and losing fuel pressure. If pressure remains solid, then borrow a set of injectors from someone and replace what you have, then test. It cannot be anything else other than that based on what you are saying. If it starts, then dies immediately after, it's in your fuel system, and if the fuel pressure is there and remains, then the injectors are the only thing next on the list to check. Not sure if you took the advice from the others, but a noid light is also your friend and helps simplify the process regarding a skewed signal...

Anthony0128

I'm going to do exactly that ! Might take me some time but I'll get it done! And yes it runs on starting fluid and my mechanic might not be the man for the job and since I'm only 18 he looks at me like a kid wanting a car and once I start telling him check this check that he just stares at in awe. I'm young but I know so much about this one car and well hopefully everything youre telling me to check pays off I'll get back to you and everyone else asap thanks a lot I appreciate it.

Anthony0128

AND SHE'S UP AND RUNNING !!! THANK YOU ALL SO MUCH FOR ALL THE HEADACHES AND INPUT !! I FINALLY GOT HER RUNNING. So the problem was the ecm but after a new ecm it continued. Well we hooked up a battery booster at least that's what I call it and she turned one faster than ever. The mechanic had not set the timing well he had but like one of you all said how could he without it running well he messed with the dizzy a bit hit the spot and she stayed running. Well we unplugged the jumper and the car died ! He then told me your alternator is out, just replaced it car runs now and just need to set my timing and shes ready to go ! I'm grateful to have this site to help me out and for everyone here who was stumped by this. Thanks all !

Tuned Performance

iTrader: (92)

Congrats!
Reminds me of this thread where injector pulse was only when the battery was low .
https://www.thirdgen.org/forums/tbi/...o-350-tbi.html

henryd3

iTrader: (128)

Hey, great to hear! Knew if you kept at it you were bound to get it going.
I'm sure it was an annoying way to find out lots more about your car and how it works
but lessons like that seem to be remembered longer!
Have fun with your car!

Bob88GTA

iTrader: (2)

Super news. Damn, now enjoy it!!!!!!!!! Have a beer!

Faolan

Nice work! Now go have some fun with the car