draco

See https://www.thirdgen.org/forums/v6/6...questions.html for prior information.

Finally got out today and checked for injector pulse, I used a 194 bulb in the harness to see if it would even glow, I get nothing. I've done the same on a 2002 Malibu 3400 and (knowing they were good) the bulb glowed. I hope the same trick works on the Camaro 3.1l. I assume this means no injector pulse. I also drained all of the fuel in the tank and I'm in the process of installing a new pump and strainer just because I'm in there. Where do I go next to pinpoint the no injector pulse. Also if it matters, I have the VATS bypassed with the proper resistors, car ran fine bypassed for months.

In short :

New - plugs, wires, cap, rotor button, distributor, pick-up, ignition module, TPS, IAC, upper intake gaskets, coil pack, coolant temp sensor, o2 sensor, catalytic converter. EGR is blocked off at pedestal and at intake.

Car rolls but will not fire, occasionally hits and stumbles, bulb showed no injector pulse. WILL RUN ON STARTING FLUID.

ringo234

I'm not sure if it's the same on a V6 but I had no injectors pulse on my 350. The problem was the ignition control module. Dyno Don told me it controls the injectors. the module is located inside the distributor on a 350, again not sure about a V6 but it may be the same.

91rs-t-tops

your right on the v6 it is in the cap like a 350 i went through two new ignition control modules before i got one that worked. i would check the ecm if you know that the icm is good

draco

ICM is new with the distributor, whats the easiest way to test for ecm output?

Base91

iTrader: (1)

You don't mention if you tested the injectors.

draco

Haven't tested for resistance yet, just pulse. Would one faulty injector cause the entire line to fail?

RBob

iTrader: (1)

Yes, there is only one injector driver in the ECM ('90 - '92 MPFI & TPI). If the factory injectors are still installed don't even bother with a resistance check, just replace them.

RBob.

Base91

iTrader: (1)

Southbay on this board has a set for a good price. Replace the fuel pressure regulator diaphragm while you're in there too. If it's original it'll be 'done'. Save taking the top off again.

draco

had a hard time locating the correct injectors on southbay's site, can someone link me?

91rs-t-tops

hey since we are talking injectors im replacing mine because i have a feeling that they are bleeding off. I did check them about 6 months ago and i cant remember but they was like 11.5 or close to 12 ohms 2 seemed a little low at the time i dont remember the actual numbers but. With them being the original set and had set with bad gas in the system for eight years. I cleaned them out and let them soak for some time. well the 3.1 runs great when plugs are not fouled. when the car sits for a day or two i have to change a couple plugs and mainly the same 2 or 3 so it makes me wonder about injectors. i ran a kill switch to the fuel to the pump to let the car die from loss of fuel pressure and then crank it some to kinda clear it out, if i do that before parking it for the night it will never miss as lick the next day. i feel as if the pressure behind the week injectors is alowing them to bleed off fuel and foul my plugs... dose that make since or am i going way off track. like some feedback here

91rs-t-tops

i got a full set for 107.11 on ebay My buddy orded his for his fox body stang from the same people and yes they are remans but they are 6 hole injectors and the ones my buddy got worked GREAT!

Maverick H1L

iTrader: (8)

Going to point out the obvious here:
1. Is the SES light on when you turn the key on?
2. Have you tested for a code 46?
3. Do you have POWER at the pink wires on the fuel injectors?

Just because the engine will run on starting fluid doesn't mean that the ECM is working or that VATS hasn't disabled the fuel injection. Or that the fuel injectors are getting power. For some reason, I've found that, even with a VATS error, the engine will still occasionally cough while cranking but won't do anything more than that.

Also, hook the "test light" up to a POWER source (as in the alternator BAT terminal or other 12V source) and the other lead to the blue and green wires at the injector connectors. You haven't yet proven that the ECM is indeed sending the fuel injector pulses or not...

draco

1. SES light comes on and goes out as per test procedure. Does not flash or remain on.
2. There are no stored DTCs. SES light is functioning normally with the code 12 handshake.
3. Have yet to remove upper intake to check harness there, however I have 12v at the pink coil wire if they are connected.

ECM diagnosis is still in process, I'm leaning towards bad injectors or no ground in ecm as I get no injector pulse on #1 cyl (the easiest to reach while assembled). I do not believe VATS has solely disabled the injector pulse, when I bypassed VATS with the resistor method the fault was a worn key/switch. When the key/switch failed I had no crank at the starter, no fuel pump AND no injector pulse. The car has ran for some time prior with the VATS bypass, I have no security light on. I believe this issue is not VATS related.

For this test does the key need to be on, or cranking, or should the injector harness plugs always have ground? The two wires that run to each injector should be one +12v and one -ground, and if this is the case then when cranking my 194 bulb test should have shown injector activity, correct?




I feel like I'm in a bad episode of HOUSE, where's my damned dry erase board? hahahaha

Maverick H1L

iTrader: (8)

You have to be cranking the engine to get an injector pulse. The ECM grounds the fuel injectors in sequence to get them to function IF it is seeing reference pulses from the ignition module AND the ground circuits are functioning along with the drivers inside the ECM.

To check for either power or ECM switched ground, all you need to do is to disconnect the injector harness by the thermostat housing and probe the engine harness side. Any test light should light with the ignition on and the light connected between a solid ground and the injector power wires, and should flash while the engine is being cranked if the light is connected between POWER and the injector ground wires (blue and green) in the injector harness IF the system is functioning AND the VATS module is providing the 30Hz signal to the ECM to enable the fuel injection (if not, code 46 appears). While you have the injector harness disconnected from the engine harness, probe the injector harness (NOT the engine harness side!) between the pink wires and the blue and green ones. There should be NO LESS than 4 ohms resistance, and 6 or more indicates an open (also faulty) injector.

I have a 1227730 ECM I can't seem to get rid of if you're looking for one...

Base91

iTrader: (1)

Not saying you shouldn't test things and get to know the systems better but you're concentrating on the less likely possibilities. The most likely problem is the injectors so go straight to the heart of the matter and at least check the resistance which may eliminate them as the source of the problem. But they most likely need to be replaced.

draco

key off, test light from positive terminal of alternator to injector harness from #1 injector, lights up on both wires? That shows that both wires to injector #1 harness are grounded all the time, even with the key off?

I don't quite understand which wire you are describing when you say...

"While you have the injector harness disconnected from the engine harness, probe the injector harness (NOT the engine harness side!) between the pink wires and the blue and green ones. There should be NO LESS than 4 ohms resistance, and 6 or more indicates an open (also faulty) injector."

Where is the connector for the injection harness located? I'm with the car now so I should be able to test as you message me.

Maverick H1L

iTrader: (8)

Yeah, so he can spend $200 on injectors and NOT FIX THE PROBLEM .

The injector harness is the harness that is connected to the injectors AND the CTS. The connector that connects it to the engine harness is behind or to the right of the thermostat housing, is about 2" long, and rectangular. There are 6 wires in it, 2 pink (one with a black stripe), a green, a blue, a yellow, and a black. The yellow and black are ignored because they are for the CTS. Anyways, when separated, the connector splits into a part about an inch long with female terminals in it on the engine harness side (has the orange seal) and a 1.5" long hollow connector with male terminals on the injector side.

First, the harness connector may be attached to the fuel line and needs to be slid out of its clip. Second, there may be a locking tab on it that needs to be pulled out before the latch can be separated.

Once you separate the harness connector, probe the injector side first between the pink and the blue and green wires with a meter set to measure resistance. There shouldn't be any measurement between both pink wires and also between the blue and green wires. You should get 4 ohms between each pink and a blue or green wire. 0 ohms means a shorted injector and 6 or more means an open injector. You may get less than 4 ohms but ONLY if the 3 injectors on that side of the engine have a resistance of more than 12 ohms. Each injector should have a resistance of NO LESS THAN 11.4 ohms.

Now, for the engine harness side.
1. With the key on, probe the pink wires with either a voltmeter or a test light to GROUND. There should be battery power (or close to it) on both. Do the same for the green and blue ones, but there should NOT be any power here. Anyways, there are 2 fuses in the dash for each bank of injectors, but you will need to find out why the fuse blew first or it could blow again.
2. With the test light connected to battery power, crank the engine and probe the green and blue wires while cranking. The test light should flash. If it is on steady, disconnect the ECM and find out if the light goes out. If not, there is a short to power in the harness. If the light goes out when the ECM is disconnected OR if the light never flashes while cranking, the ECM is crap, and you will need to double check the injector resistance to make sure you don't fry another.

:edit: And keep in mind I have personally seen a pink wire fade to blue...

draco

Roger that! Time and chemicals do crazy stuff. Will perform those tests tomorrow when there is sun light.

I did however check both INJ 1 and 2 fuses and they are OK, also the fuse that it mounted to the passenger front fender support is good as well.

Stewie

FYI - The easiest way to check the ICM is to take it to your local auto parts store (Advance, Auto Zone, etc.) and have it tested for free. Probably not your problem, but since you asked. I and a lot of other owners carry an extra one with us because an ICM can go bad any time and it's only a 10-15 minute job to replace.

Base91

iTrader: (1)

He doesn't have to spend that much (mine were $125) and if the injectors are bad then new injectors WILL FIX THE PROBLEM. Point is he hasn't checked them and it's easier and quicker to check them than all the other diagnostics being mentioned.

Classicroute66

Just got my injectors wed from Southbay. I was very impressed by the design and price.......6 injectors shipped to my door, $120.75.

Here is their number......
Shop: 516.442.4707

Make sure when you call that you tell them you're a member here, you'll get a discount. Normally they are $125.00 before shipping.

draco

Thanks for the info on injectors guys, I'm with the car now, about to start testing wires. I'll post shortly

91rs-t-tops

what have you found

draco

See attached image.

I have no reading between the blue and green wires, as well as the pink wires.

My pink and pink/black wires are impossible to tell apart, but probing in the X pattern you see in the image gave me these readings.

With key on, I get battery voltage (about 11.1v right now, low battery) across both pink wires on the engine harness side, and no volts on the blue and green wires.

I don't have a second person handy right now so I cannot get the cranking test across the blue and green wires. Will do that asap.

But with what I can see so far, the injectors and harness are in ok shape, looking like an ECM problem.


UPDATE: 6:00pm

Tested injector resistances, by cylinder #:
#1-12.4ohm
#2-12.2ohm
#3-4.5ohm
#4-11.2ohm
#5-12.3ohm
#6-8.6ohm

I see #3 and #6 are way bad, #4 looks weak. So I know I need a set of injectors. Just need to verify the condition of the ECM. Also is there an injector upgrade I could perform without any modifications?

Base91

iTrader: (1)

You definitely need new injectors. Southbay on this board has a good deal on them. Also, replace the fuel pressure regulator diaphragm while you're at so you don't have to pull the top off again. I wouldn't even bother testing the other stuff until you have the new parts in place and see how things go.

draco

I'm really hoping that the ECM wasnt damaged by the bad injectors though. Who carries a decent FPR diaphragm?

Base91

iTrader: (1)

I got mine from Autozone.

draco

Finally tested for injector pulse, from the positive post of the alternator to the blue and green wires gives me no pulse on the test light. Looks like ECM is shot too, Maverick H1L, price me one to 26104?

draco

If I have no pulse at the ECM side of the fuel injection harness, is there a chance that VATS could shut down injector pulse and still allow cranking? I have my VATS bypassed with the resistor trick, and my security light turns off like normal. I'm buying new injectors, FPR, and a good ecm tomorrow and I want to be driving this car damnit! lol

Maverick H1L

iTrader: (8)

Pull the codes from the ECM. If you get a code 46, you have a VATS injector disable signal error. Which means the ECM isn't going to fire the injectors.

draco

negative on the code 46. FPR and Injectors are in route. Maverick H1L, I'm installing the fpr and injectors first, and if no start still I'll be sending out for your ecm.

draco

It's ALIVE!

Installed the new injectors and FPR, drained the tank and added about 2 gallons of high test fuel. Crank, nothing, Crank, stumble, Crank, Fire. Runs well, I can definetly feel a difference in the new injectors. Much better throttle response. However, it's idling a little high. I never let it get to operating temp to see if it would fall but I know it needs to go through Idle relearn still. Will get that done tonight.

more importantly, thanks to everyone for all of the help. Your information and knowledge has been invaluable to me. The thirdgen forum is hands down the best place to get info on our cars. When I make it to thirdgenfest, I'm bringing cookies! haha

Maverick H1L, looks like I'm not going to need that ecm after all, thanks!

Base91

iTrader: (1)

Congrats! Injectors and fpr before spending a ton of time and money on other stuff. Should be a rule!

draco

one more question. My tach is reading way off, like 1000rpm over, ecm and dash cluster are stock, it was fine before the car layed down. ideas?

draco

well never mind.....Drove the car from my dad's (about 1 mile) to my house, it ran fine although the tach was reading high, and it seemed to lack a little power. It sat for about an hour or so, then drove back to my dads. At the foot of my dads driveway (steep hill) it lost power, spit and sputtered, would not pull itself up the hill. Stalled on two attempts, no SEL. Started it up, slow to start, drove around the block, spit, sputtered, stalled again. Sat a minute, started up (hard to start) drove back around the block and towed the SOB up the hill. At the top of the hill, the car started up, seemed to have more power. Drove it 15ft to parking spot and revved it out. The more I revved it the less it wanted to take fuel until it started to spit and sputter again. It was at operating temp from the time I first got to my dads house.

Man, I am so angry. Where do I look now?

scury13

I am fighting a similar beast, fix one proble only to have another with something that was not bad before. Anyway, as hard is it is to believe after testing good before your fuel pump may now be crapping out. My sons ran just like yours when it was failing. Sounds like you fixed your spark issue and injectors but now its not getting good fuel. Do a fuel pressure check again while its running like crap and see if its good or bad.

draco

will do, thanks. I'm also going to put a vaccuum gauge on it to look for any leaks. It's just odd that it waited until it warmed up before it started to act out on me, I know the timing is off a hair, would that affect how it ran after it warms up?

scury13

I myself am dealing with a poor idle, stalling condition when car is hot. Little different then yours though, mine fires right up after a stall out and never lacks power or stumbles while driving. Anyway, I would not think it would be your timing as it should run rough, miss right from start up if it was off. I dont recall if you said you had but someone had suggested checking the ICM. These can cause stalling, no start and hesitation problems when bad and get hot as well as ignition coil. there are ways to test them, as opposed to tossing new parts in. let me know what you find.

draco

Complete dizzy is new with icm, pick up, cap and rotor. Car started up and ran fine this morning, tach is still off, (idle shows 2000rpm), and once it hits operating temp (i think it's trying to hit closed loop) it goes to hell.

scury13

Hmmm, sounds a lot like mine. I plan on checking my intake gasket, might not have got it on well after i replaced my injectors. I would assume it would run bad regardless if that was the issue but I may be wrong. Mine seems to go to a surging idlel after it gets pretty hot under the hood and some stalling. I have changed a lot of stuff with no luck, no bigie because we are restoring anyway but would love to find the problem. We may be on our own at this point as the suggestions seem to have died off. I will continue to update as I try other things. Closed loop issue may point to sensors giving bad readings. Be it from bad sensors or an actual issue causing the sensor to give an out of range reading. Sorry I cant give you much more help.

RBob

iTrader: (1)

There is a tach fix sticky thread on the electronics board here.

RBob.

draco

Rbob, i would understand I would need a tach fix if it were an issue before, or if I had changed over to a v8 cluster, but it is still factory. I have installed a new coil pack, could that have affected the tach output?

Scury13, if there were a problem with your intake manifold gaskets, upper or lower, you would have running issues from the get-go, But using some carb cleaner and spraying around the intake while running would answer your question quickly.

Just recalled, I installed a new IAC, maybe the adjustment is off? Doesn't it shut off for closed loop?

scury13

Ok, I was thinking that was the case., I also tried carb trick and nothing changed. If you changed the IAC and had the battery disconnected for any period of time you would need to do the idle relearn. Here is a link from RBob on the procedure.
https://www.thirdgen.org/forums/v6...dle-learn.html (Correct Idle Learn??)

draco

I'm familiar with Idle relearn, and I've also driven the car above 40mph which should have forced the IAC closed. But I recall the manual states there is an initial adjustment for the IAC and I don't think I set it before I put it in, Will correct that tonight.

draco

Fuel pressure holds good through the temperature range. Vaccuum varied from 14hg to 18hg depending on how it was idling. I noticed that at the EXACT moment the cooling fans kick on is when the idle and power go to crap. Inspected the underhood, and caught a glimpse of spark. Turned off all the lights and found #1, #3, #4, #6, and the coil wires (all new) were bleeding spark at the base and along the wires. I'm going to warranty them out at advance tomorrow and we'll see if that changes the situation.

scury13

Cool, keep us updated.

draco

Replaced plug wires, still bleeding spark. Turns out the metal boot covers at the base of the wire let spark pass through them. I pulled them off and I'm no longer bleeding spark. However the situation has not improved. Car will start faster now, until it gets hot underhood, and then I get a no start condition. I'm going to let it get hot today, then shut it off and start testing for fuel and spark. I really need to track down a timing light also.

I've also developed a fear, I'm worried that my issues might be with the timing set. 210k and never been checked. I've been told by several people that it is a possibility that the timing chain has developed slack. Thoughts?

scury13

Not sure about the chain, timing could be part of the issue. I rebuilt my distributor on Saturday. I found that my pick up coil was cracked and rusted. Replaced all parts in the dizzy and did an idle relearn again. So far it has been idling much better and no stalling. I am not sold that its fixed yet as temps have been fairly cool here. By Thursday though we are going to be back around 90, so I will keep my fingers crossed. I will say I suspect that the Idle relearn for our cars is needed each time a problem that would cause poor running is fixed, otherwise the ECM will not have the correct settings causing poor idle even after the problem part is repaired. Just a suspicion and maybe incorrect but worth a try after you fixed the spark problem. The no start condition after its hot sounds electrical. I know you hit most of the parts associated with spark but they may be worth checking again.

strrtwinkle

I am hopefully posting this to get info to some of the similar problems as draco is...
I have a 1991 3.1L Firebird which had a stalling and now not cranking problem..
so the list of things been checked and done..
fuel pump and all things in tank, fuel filter, ECM replaced, plugs (not wires recently), fuel injectors had fire but no squirt, having ICM tested in morning, might be planning on replacing MAP sensor, and IAC as they look bad.
now on another note I have 2 pictures listed below I need to know what they are as the one under the throttle body the pink/black wire is almost in half and the other unknown what it is in the canister for the air filter..

http://i43.tinypic.com/33mtlyg.jpg

http://i42.tinypic.com/2d5446.jpg

and I also need to know what and where a power control module and a Hall-Effect Sensor is located.

thanks in advance for all and any help everyone can give me.

draco

~~~~~~~~~~~~~~~~Notes for TLDR: New - plugs, wires, cap, rotor button, distributor, pick-up, ignition module, TPS, IAC, upper intake gaskets, coil pack, coolant temp sensor, o2 sensor, catalytic converter and Injectors. EGR is blocked off at pedestal and at intake. No DTC's or SES light on. Car intermittently will not start, was running today. When running it sounds fine, tach reading is off (too high)~~~~~~~~~~~~

New news, Car started today. Nothing has changed since last post.

Car will intermittently be difficult to start, but when it starts it seems to run great, however my tach is reading between 1750-2500 at cold start idle, and a constant 1750 when warm. I know for a fact (trained ear) it's not revving that high. Bringing the motor to what sounds like 2000rpm makes the tach read 4500rpm. Im leaning towards an issue with the wiring pigtail at the distributor. I say this because my father went through today with a spark tester, moved all of the plug wires around, and then suddenly the car wants to start. When I say move around, I want to be clear that he DID NOT change the firing order of the wires.