I'm trying to get my 86 to start and have been leaning towards the injectors as a possible culprit. I have a multimeter and checked the resistance of the injectors and all were between 16 and 16.4 ohms. I was wondering if there was any purpose or reasoning for testing the resistance or voltage of the injector connectors. If so, what information would that give me? I don't currently have a noid light to test the injector pulse, but I read somewhere that you can check it with a mutimeter by grounding to the battery and attempting to start the car. It said that if you set the multimeter to voltage it should jump back and forth from 0 to 12 volts as you crank the engine? Not sure if this is bs or if I was reading the wrong thing. Another question I had was about listening to the ticking of the injectors with a stethoscope - will this method still work if the engine is just cranking and not running?

Any input is greatly appreciated.

Background on the car: stock 86 automatic, has been sitting for years..started looking at it last summer and fuel pressure, timing, spark were all good, new fuel pump/fuel filter. Didn't get it started last year by the end of the summer so everything put on halt until now.

Here's a link to the thread from last summer with more info:
http://forums.corvetteforum.com/c4-t...turn-over.html

 

bad gas

 

You can pull the plug off of an injector and pulse it manually with 12 Volts, do not pulse for more then a second or two at a time or the injector's coil could overheat. I have had the injector's internal pintles stick closed due to dried fuel after a long, multi-year vehicle storage. When you briefly tap an injector with voltage, you should hear it click. With them having passed your ohm check, if they do not click, their pintles are stuck. If stuck, here are some ideas that I have used and usually have worked them loose. Tapping on them aggresively with the plastic handle of a medium sized screw driver can shake the pintle loose. Pulling the fuse on the fuel pump sometimes helps to release pressure that helps because the fuel pressure is working against the pintle helping to prevent it from lifting when pulsed. Leaving the new, wet fuel soak in the rails for a few days sometimes helps. Heating and cooling and injector with a heat gun (hair dryer) can help. If it comes to having to remove the injectors, I have tapped them upside down on a steel surface and released stuck pintles. No one proceedure has always worked, but after rotating the different proceedures, I have succeeded most of the time. Good luck

 

The car has new gas in it, old gas was flushed out. Could stuck pintles prevent the car from starting?

 

Yes

It's been a year and still no noid light.

 

Yes it is possible but it is rare to see all 8 injector's pintles stuck closed but has happened. Usually an engine will almost start or fully start but only be running on a few cyls. An engine stethascope really comes in handy when placed on each injector and listening for the clicking. If you are not getting even one cyl to fire during your attempts to start the engine, I question if it is caused by all 8 injectors stuck, but still possible. A voltmeter placed in the AC range on the two pins of the injector plug will also indicate if your injectors are getting pulsed or not.

 

hah you got me, I ordered one today so hopefully it will be here by this weekend

 

noid light came in today, tested all connectors and all pulsated (blinked) when cranking the engine so I guess the injectors are all getting power?

 

The ECM is trying to fire injectors and from your previous thread, you have good fuel pressure and spark.
Have you tried a compression test ?
Are you 1000% sure your timing is good and wires are in correct order ?

 

rechecked fuel pressure, spark plugs, and timing - all were good. I didn't do a compression test, but shouldn't the car still at least start for a little if the compression's off? I'm starting to think maybe clogged fuel injectors or something? I'm going to start looking into ordering new ones.

 

My test for determining whether the no-start condition is ignition or fuel is to spray some starting fluid into the throttle body. If there is any spark at all it will fire. If it's dead, probably ignition. It's possible this won't tell you anything but it's a cheap and quick test that's always worked for me.

 

..... DYNOCAR suggested it above but I had swapped an LT1 into a C3 that wouldn't start , had power to the injectors , spark , etc. so I had an assistant crank it over while I tapped on the bottom of each injector with a wooden paint stirring stick hit by a small hammer and it started ... ran a little rough at first but cleaned itself up pretty quickly ...

 

I bought some old injectors a while back, and installed them on a run-stand engine. it ran on a couple cylinders, then one by one, each one started working. I didn't tap on them either.

wow, the C3 didn't start, so you put an LT-1 in it?

 

I tried that, but the engine still didn't start. When removing the spark plugs to check for spark they were all bone dry. Shouldn't they be wet with fuel at the tips from cranking the engine so much? Does anyone know a good place I can get new injectors from?

 

When you say it didn't start, do you mean it didn't fire or pop at all? Did you open the throttle blades and spray the starting fluid into the openings? It is possible you have both ignition and fuel problems at the same time. This would tend to make things confusing when trouble shooting.

 

It didn't pop at all - same as when I try to start it without starter fluid. When I sprayed it I did open up the throttle and spray it deep into the opening

 

How are you checking the timing? Do you have the bypass connector open?

 

I checked the timing by rotating the distributor but I also used a timing light to confirm

 

:bump:

anyone have any ideas? would it be better to buy new injectors or have mine cleaned?

 

You can send your injectors to FIC injectors, the owner is on the forum and is an advertiser. Do you have any stored error codes? Pull a plug wire and bring a grounded wire close to the plug wire boot while someone cranks, you should have a snappy at least 1/2" spark. Weak spark will prevent an engine start. If you sprayed starter fluid into the MAF that would eliminate a clogged air filter preventing air from getting into the intake if you left the MAF open. Fuel pressure should be 35-42 psi and it should hold up for 1/2 hr after ign is off. If not, you could have leaky injector/s and too rich condition to start. Can you smell raw fuel out the exhaust while cranking? If so, you may be too rich to start. Unplug the MAF and try a start. Measure compression, that is another condition for starting and continuing to run for engines!