back with new problem on 90 camaro 3.1 v-6

[cocobolo95]

Am currently cleaning my fuel injectors. Soaking the bottom part of injectors in my special blend injector cleaner. Will soak for a week. The first soaking changed the clear fluid to a orange brown color so they must have been pretty gunked up. The 2nd soaking, the fluid has a light orange/brown tint to it, so injectors are still dirty.

Will change fluid 1 more time and soak 2 more days. Then I'll put them in the ultrasonic cleaning machine for a final cleaning. Will power up the injectors during the final cleaning using an ac power source. That way injector will open & close 60 times a second. This will help break up any last bits of varnish built up. Will back flush while in last cleaning cycle.

[RobertISaar]

as long as your AC supply doesn't exceed about 15 or 16 volts peak, you should be fine(or is just current limited to about an amp). above that and you start risking damage to the injector coils.

I think ideally, you would want to drive them with a square wave to build/hold the magnetic field fast, seems like it would be more likely to break free anything that might be holding onto the pintle.

[cocobolo95]

Voltage runs just under 12 volts when hooked to injector. If I would have had a square wave source at hand, I would have used it. But I used what I had.

Hit one injector with the ultrasonic machine, while powering up the injector and back flushing with a mity vac brake bleeder. The discolored stuff just poured out of injector. I'm hoping to get some more life out of the 25 year old parts.

But still 95% that clean injectors won't solve my original problem. But hope is still there. I'm betting on the 5%.

[billygraves]

In this era the injectors shorted out internally. Methanol, Ethanol and MTBE eroded the internal injector wiring coating. Have seen where the splice for the injectors within the harness had a highly corroded splice. The splice connects the two injector drive wires together. Try to temp 2 wire a jumper from the car injector harness to the ECM injector driver.
If it has a distributor, the base will corrode and do some very odd things. Remove it and insure it's clean. Test the strength of the magnet and if the pick-up coil connector is slimy or corroded ar sticky, replace it. Regrease the module with silicone grease. Install a new dist o-ring or oil will leak.

[cocobolo95]

Car has brand new distributor. Checked it out and everything in dist is top notch. Old dist had cracked magnet.

Thing about the dist in relation to injectors. If I pull dist out and turn by hand, the injectors will fire for as long as I turn dist shaft. Same with ignition coil wire off and engine cranked. Injectors will fire for as long as engine cranks.

It's only when engine actually runs that it goes for about 4 seconds and dies. I can do this all day long also. Start-run-die.

I will try rewiring the injector wires to ecm and power supply and see if that makes a difference. This is if cleaning injectors makes no difference. I've ohm ed the injectors and all is well there. Will check again to see if resistance changes after injectors have been pulsing for a while.

Keep the ideas coming.

[billygraves]

You say "All is ok there" with the resistance of the injectors. What was the ohm reading at what temp was this done?
All is OK with the distributor? What does this mean? Does the magnet on the shaft have a strong pull when the poles line up? What does the block look like, was it cleaned? It has a bearing on the Reference out to the ECM signal if the base or grd is corroded. Ask a shop in the rust belt.

You can try this: I use niod lites for the injectors because this will fill up the cylinders very fast. I place a ST-125 spark tester on the secondary coil wire to take the spark load instead of having the spark go to unknown cyl inside the cap
Using a Weller 550 soldering gun, get it close the the dist pick-up coil and pull the trigger on the soldering gun. This pulses the pick-up coil at 60 hz. You can calculate your 6 cyl RPM it well simulate. It is easier to test electrical items this way rather than run down the road til it fails. Wiggle wiring, connectors or spary H2O on wires to test for failures.

[cocobolo95]

I have the 90 Camaro factory service manual to get my specs from. It was about 80 degrees when I tested the injectors. They all ohmed within factory specs. I tested the pickup coil for dist using ac volts on multimeter. Turned dist shaft, voltage was within specs even with shaft turning slowly.

When I say I disabled ignition system, what I did was swap coil wire for a longer one and use my st-125 on the coil wire. This way it was a long way from the gas being sprayed when my fuel rail was out of engine being tested. There are no ignition problems as my engine will run as long as gas is being sprayed into throttle body. This is when engine is put back together for testing. I can open the throttle and rev the engine to 4000 rpm, as long as amount of gas sprayed matches engine speed.

While my assistant is spraying gas into tb, I have wiggled & pulled on wires to see if engine would run without spraying gas. But every time the gas spay quits, so does my engine.

And I've read the data from sensors & actuators while engine was being run with gas. The only readings that were off, besides fuel trims, were the injector pulse widths which stayed around 1.2 - 1.3 no matter how fast engine was turning. So the problem seems to be the ecm not commanding the fuel injection pulse width long enough to run engine.

My normal pulse width at idle runs 1.7- 1.9 with increasing pulse width as throttle opens up.

[cocobolo95]

Finally had some real progress today. Decided to test the 30 hertz fuel enable signal again. Last time I tested it was good. This time signal started out at 30 hertz then went crazy. Anywhere from 20 to over 100 hertz. Think I've found the smoking gun.

I am going to order a 30 hertz bypass module from baker electronix. For those with problems with newer models, they make a 50 hertz module also.

[JP86SS]

Do you mean the VATS signal?
It can be anything from 33-66 Hz IIRC.

You can change the min and max parameter in some of the bins.

[cocobolo95]

It's always been right around 30 hz but I"m getting a signal now that is unstable and going way higher hz. Changing the bin file would be a good idea, but I'm not set up to burn chips. That's why the 30hz bypass module. I could buy a new tdm, but they start at about $240. Too much.

An used one would make me find which of the 15 key resistances it's programed to. And being as old as the one in my car, I have serious doubts about how long it would last.

If I did burn a chip, I'd just eliminate security altogether. Don't believe thieves are hanging out waiting to steal my 25 yr old 3.1 v-6 bomb.