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Discussion Starter #1
Hello All!
Well here I am bought a 94 Camaro with 200,000 mi. Said had bad transmission (It Did) said ran good but wouldn't start when I looked at it. i bought it took it home tried to start it and started right up. Found out it had a blown head gasket water coming out the exhaust. Ok I figured with that many miles i would rebuild the transmission and engine. (So I did)
OK so I rebuilt the engine had the transmission rebuilt put it all back together tried to start it no luck. i found that a ground was not hooked up from motor to frame installed that no luck. Checked the plug connector to the Distributor cleaned it out then it started had a miss. It ran for about 5-10 minutes then die. Would start with a lot of gas but ran rough still had a miss. Found a fuel injector was leaking bad, fixed that now will turn over but won't start. Im looking at optispark being bad but don't want to waste time finding thats not it. Any help would be appreciated. Sorry so long winded.
 

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You need to start with the basics. Get a spark tester, the kind that puts a load on the ignition system. Check for spark on a couple of the spark plug wires. If no spark there, pull coil wire from opti & check for spark there. If no spark continue with testing.

If you have an obd 1 scan tool, check for codes as ignition codes dtc 16, 36, 41 & 42 don't light the check engine light.

You can use your multimeter set to dc volts to check for low & high resolution signal at connector on passenger side of intake manifold. Low resolution wire is the red/black one. To check place red probe of meter on bare spot of wire. Black probe of meter to battery negative terminal.

Have assistant crank engine. Voltage should toggle between 1 and 4 volts. If it does not, there is no low res signal, engine will not start.

High res wire is purple/white wire. Check the same way.
 

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Get a fuel pressure gauge and check key on fuel pressure. Should be around 43 psi. Connect a noid light or 2 lead test light to one of the fuel injector connectors. Have assistant crank engine. If injectors are firing light will blink on & off. If no, you have no injector pulse and are getting no fuel into cylinders.

Several things can cause injectors not to open. Dtc's 16, 41, & 42 all cause injectors not to open. If security light is stating on, injectors won't open.
 

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ok guess I need to buy a scanner any suggestion on a good one?
What was done on the rebuild? Who put all the accessories back on?

You used the original optispark? Did you dump a lot of coolant on it removing the water pump?
 

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The best & least expensive obd 1 scan option is right here.

Buy the $55 shipped obd 1 12 pin cable found in the parts for sale section.

Then go to 4th gen section sticky threads and open the free obd 1 scan program thread. Download "scan9495" it will turn any pc based computer into a powerful scan tool.

It scans for regular codes, ABS & SIR codes. It does running sensor scans and will log data to a file for later playback. It also tests engine and auto trans actuators. All this for free. And member GaryDoug wrote program and he can help with any issues you have with scan9495.
 

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Discussion Starter #7
I had the machine work done i put it all back together. I wanted to know what went in and that all measurements were correct. Did not spill coolant on the optispark. But car got hot before I got it so I'm guessing that it might had a that time. Im thinking with 200,000 miles probably wouldn't hurt to replace it
 

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The scan program called "scan9495 is found in 4th gen section sticky threads. Thread is called " obd 1 scan program for free".

Open the thread click on the link "my files" it will take you to the program.

Then go to parts for sale section and open the thread "obd1 to usb cables" buy the 12 pin obd 1 cable.
 

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Sounds like bad option/coil/or ICM crapping out when it warms up. Start with the basics and test them 1 at a time when hot after it dies. You can check them with a multi meter, but you have to wait for it to die first because if it starts cold and you check it cold, it will all look to be OK.
 

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Discussion Starter #11
Ok decided to change the Distributor or Optispark and the coil put it together still won't start. going to track down ground wires again. check for codes. Painted motor going to check ground there thought maybe not getting a good ground there from the paint.
 

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Don't be hasty, if you installed any other opti besides a GM,Delphi, or Msd, you have a real good chance that your new opti is defective right out of the box.

So you should still check your low & high resolution pulses. An oscilloscope is the tool of choice for this. You can get a pc based scope for $70. But if that's a budget breaker, you can check low & high res pulses with a voltmeter.

For this check an old analog voltmeter works much better than a digital one. What your going to do is hook red lead to low or high res signal wire. Make a bare spot on wire to put probe. Black wire to negitive terminal of battery.

Have assistant crank engine. Voltage will toggle very quickly between 0 and 4 volts. On analog meter needle will swing between 0 & 4 volts.
 

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Ok so my son comes over and I had him turn it over to check if any spark at the plug. I had Fire there. So I checked to she if the injector and any fire. Well then it started I have not finished putting this all together yet so going to do that today and see what happens. Then start it and let it run I want to get coolant it first.
 

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UPDATE: Ok I got it all put back together it starts not as easy as it should then after it starts it has a miss like one plug wire off. Drove it down the street and back defiantly has a miss. Bad thing with these cars its a pain to tell if all plug wires are firing even though they are new.Also going to check injectors even though they are new, probably need to check codes
 

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Discussion Starter #15
ok checked fuel pressure has about 35 at idle goes to 40 when reed up. Motor sounds good has a mis when running and hard to start
 

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Discussion Starter #16
OK I changed the fuel pump assembaly. fuel pressure is at 40-41 when you turn key on. I started it up starts easier still has a stumble.
 

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Have you checked your rocker arms to see if any are too tight. A too tight rocker can cause a miss also. Easiest way to check rocker arms is the red neck method.

Run car until warm, remove valve cover from one side. With engine running, loosen rocker nut until rocker makes clattering noise. Tighten rocker nut until clatter stops. Tighten nut 1/8 to 1/4 turn more.

Move to next rocker arm. When all done on one side of engine, do the 2nd side.

Have you checked, double checked, then checked again, that all plug wires are on the correct cylinders. Have you sprayed down plug wires with water, run at night to look for spark leakage. Car should be up in the air for this test so you can view from bottom also.

You also might want to invest in the $70 pc based oscilloscope sold on ebay, amazon, etc. It is the only 100% reliable way of testing for opti low & high resolution signals. Scope will show the signal waveform and you can make sure it is proper shape, frequency & voltage.

You can check opti low & high res signals with a multimeter, but that just shows that a signal is present. Not that signal is proper shape,frequency, or voltage.

Besides the large ground strap, have you checked the gazillion other grounds in engine compartment for engine & pcm.

Have you removed the opti wiring pigtail. Visually inspected it for bad wires, burnt connector pins, melted wires and pins, corroded pins. Did you check all 4 wires for continuity & 0 ohms resistance on each wire.

Did you check all your fuel injectors for proper spray pattern and no leakage. I remember you saying you have new injectors. Are they really new, or are they rebuilt injectors.

Rebuilt are old injectors that have been cleaned, have new inlet filters & o-rings. But the injectors are old and could have one or more that aren't good.
 

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Discussion Starter #18
I noticed in one of the threads that I read that an exhaust leak could give wrong signals to the O2 sensor? Apparently the car got real hot before I got it so i'm thinking the water temp sensor could be bad also. Is it ok to pull one injector loose at a time to see if engine changes the way it runs? This weekend I will check it out some more. Thanks for the help
 

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I've never tried pulling one injector connector off at a time, but I imagine it would give you an idea of how big a rpm drop each disconnected injector would cause. If you disconnect one and rpm doesn't drop, that injector wasn't spraying, or is clogged partially.

You can do a similar test by unplugging spark plug wires, one at a time, and checking rpm drop. A cylinder with bad plug, wire, etc, the rpm would stay the same when you unplug the wire.
 

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UPDATE: Ok I got it all put back together it starts not as easy as it should then after it starts it has a miss like one plug wire off. Drove it down the street and back defiantly has a miss. Bad thing with these cars its a pain to tell if all plug wires are firing even though they are new.Also going to check injectors even though they are new, probably need to check codes
Look at night for any flashes of light from arcing near the headers.
Mist the area with water with a spray bottle.
 
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