RemS64

Hi Guys, I have been lurking here for a few years, Reading some very good posts on how to. etc. Now I am stumped.

A little history first. I have owned this 86, since Sep. 85 It was the 1st 86 sold in New Orleans. I drove it as my daily driver several years. I laid it up in 1995, It has been sitting in the corner of my warehouse ever since. It only has 30 k mi on it.

The other day I decided I was going to try to get going again. Not that easy. I Drained the old fuel from tank, maybe 2 gallons. I put a couple of gallons of fresh gas in. Then hooked up a jumper battery, cause the old battery was dead. turned the key several times. to flush out fuel rails. could hear fuel pump run. good sign. I thought. several attempts at starting nothing at first. then she starts up, but dies when key released. Now that is all it will do. it will run a second or two after key is released. If I hold the key in start it will try to continue running. I don't want to do that long as it isn't good for starter.

Here are my thoughts and what I have done.

1st, I think it is only running on CSV. (9th injector)

I have 45 psi on fuel rail and it holds 41 after an hour.

I made a homemade noid light. getting pulses to injectors.

Checked codes with SES light Only code 12.

I disconnected MAF to try to put it in limp mode. NADA

Only thing I can think of is that I have 8 clogged injectors. But I would think that is unlikely. some of them should squirt fuel and it would at least try to run, even if badly.

I am at a loss here now, any suggestions would be appreciated. I am willing to try anything at this point.

Thanks

Ron

jake corvette

Perhaps it is a dirty ignition switch? Sounds like everything is operational during crank but when the ignition key is returned to the run position it stops?

Not sure about Corvette's but on some other cars, the ignition, injectors and fuel pump all operate during crank and then operate on a different circuit when the ignition key is returned to the run position. The "run" circuit is usually part of the safety system which shuts everything down in the event of a vehicle crash. The "run" circuit is usually controlled by the ECM which energizes a relay that feeds the injectors, fuel pump and ignition. We called it the Auto Shut Down (ASD) relay - dunno what Chevy calls it.

Does the radio, wipers and heater blower operate when in the run position?

Sorry of such limited help but I'm wintering in Florida but my car and shop manual are both in upper Michigan.

RemS64

Hi Jake,

Thanks for your response. I actually thought about that this afternoon after I wrote my post.

All the functions work in the car when key on. I have a SES light on when key on so I am sure the ECM is getting power. It does run for a couple seconds when I release key from start. That is how I came up with idea it's only running off fuel delivered by Cold Start Valve.

Again thanks for reply.

Ron

seamoose

Just dragged my tail in from a 12 hr shift no time to go out to the shop for the manual right now plus its snowing like heck . When I did my 86 barn vetts injector system I found they have like a start injector stuck in the intake or a cold start injector that gives fuel for start up then the rest kick in to join the party after start while the cold start stops .I forget exactly the sequence .But you might be getting fuel from that then not feeding the rest . I think it sat under the rail mid manifold drivers side and wasn't part of the rail fuel feed had a line from the back of the rail feeding it I think .I'm sure someone will jump in on this before I wake .If not Ill take my fsm to work see if I can help .I spent a month screwing around then did the all injectors fuel rail and top gaskets and everything was gunked up from sitting with fuel in it . I''m just too tired to think it out how it all gets actuated as you start it .Anyway you might check on how fuel is delivered to this compared to the ones on the rail maybe its not getting to the run injectors but is feeding that odd one causing it to start not run ??? just a thought from what my understanding of the sys !!!!I think If noid is flashing the ign sys is engaged and signaling injector coils to open with that kind of pressure if you have fire on the plugs you should be banging .Could pull a plug or two see if fuel is loading up a cyl or not I read on here a guy lifted the fuel rail and tested by having a injector pulled out of the manifold but I couldn't see how it he would be able to do that with out pulling everything apart when I was working on mine I think the runners are in the way of bolts that had to come out to lift the rail .

Cliff Harris

The fuel pump should run for 2 seconds when you turn on the ignition but don't start the engine. Does that happen?

The cold start injector only fires while the engine is cranking. If you think it is masking your problem you can disconnect it, either at the injector itself (between the runners on the driver's side) or disconnect the cold start thermo switch (located on the front of the intake manifold -- it has the same kind of connector as the injectors).

Disconnecting the MAF will NOT put the ECM in limp mode. It just uses the TPS to estimate air flow and goes on with life. That will set an error code, though.

The ECM turns on the fuel pump relay when it sees DRPs (Distributor Reference Pulses). It also uses the DRPs to synchronize the firing of the injectors to the rotation of the engine. If the noid light is flashing then all this is happening.

If the fuel pump relay fails, the oil pressure switch will bypass the relay and turn on the fuel pump. This can take several seconds of cranking to get enough oil pressure to close the switch (4 PSI).

For seamoose: you can lift the fuel rails very easily on an LT1 to test for leaky injectors. A LOT more difficult on an L98.

joe paco

you will eventually have to verify a strong spark -even tho' the engine fires. it has to fire under normal cylinder pressures. remove dist cap and verify no moisture, dust, etc.

if it has been sitting since 1995 it is possible that the fuel left in the rail and injectors has lost the "gas," or has changed chemically -or even clogged the injectors. not likely in my opinion, but the fuel is no doubt worthless.

to see if they are opening, you can put 12v to an injector while grounding the other side and watch the fuel gage. they should all fire/open and the gage will react.

disconnect the TPS to see what reaction you get.

can't imagine why the spark plugs would be bad, but....eventually, all the simple things have to be verified until it starts.

seamoose

what I couldn't say was explained very well by Cliff H.

RemS64

OK gentlemen,

She's running, Problem was that even though I had drained the old gas and put fresh gas in. It took way longer to purge the old stuff out of the lines and rails than I would have thought.

I started bleeding off the fuel pressure gauge into a water bottle, it was milky and about maybe 5% water. When I saw this, I did that about 25 or 30 times, she started but ran real bad. I kept doing it till it leveled out, when engine temp got up to about normal she is doing fine. Just took a while to get all that crap out. Lesson learned.

My theory on running with key in start is that, when CSV is just dumping that bad fuel into the intake, there was enough vapor to make it fire off for a couple of seconds.

Next up, Valve cover gaskets, they are leaking like crazy.

I sincerely thank you for all your input. I really appreciated it.

Ron


PS now when I drain Fuel Pressure Gauge into bottle it is clear gas.

playsdixie

hey Jake....hope when you said u.p. you're a YOOPER!!!!!!! not too many of us here.....Paul

seamoose

Hey great deal ! Just a heads up , my 86 sat 5 -6 years w/ 45000 and when I first got it running it didn't leak a drop after i began to run it trying to find lack of power issues and have the drive train checked out I guess for a week or so about 100mi everything started to leak .Intake gasket /china walls / valve covers . I also found my fuel tank to injectors loaded with crap. Ended up going down to the heads and renewing gaskets all the way back up with injectors /rail kit / egr . The amount of varnish and little chips in the fuel system was allful. injectors sticking ,I don't know if the enviroment up here may be different and part of the cause but it was indoors . I also just stuck a new fuel pump last week in just cause I know what had been running thru the old one .I also read that the old pumps may not handle the gas we use now . I plan on pulling it back out on my day off as I didn't get the right wiring with it and don't like what I did to get it back together and back into the shop before last nights snow .It does run quite well now but I have more in it than it will ever be worth . Good Luck

RemS64

I am sure I will have more leaks pop up too. I am going to do the valve covers next, then just try to keep up with them if/when they occur.

I bought a new fuel pump, sock and fuel filter before I even started this project, But when I turned the key 1st time and pump ran. I decided to just try to start it. The new stuff will be installed before I take it out the warehouse. That will be quite a while yet I believe.

I must say I am enjoying working on it. I also have a 58 that sat for 15 years It was much easier to get going than this one was after a a layup.

Thanks for the Luck,

Ron

seamoose

Wow !!! just happen to have a 58 sitting .
life must have been keeping you real busy !!!
Now maybe it will allow you time to have fun !!!!Enjoy dude