Ricoch3T

Been fiddling with this no start problem for a little bit now. Heres what I've got
89 Vette
Has fuel pressure (about 43psi)
Has spark
Has voltage (battery)
Engine will crank
While cranking the security light blinks.
Thing doesn't seem to be firing the injectors. I had a set out of my 94 camaro that I swapped in (they were in working condition), still nothing.
I was thinking vats related but I've seen soo many people on here say it won't crank if its vats related but I have no idea what else it could be.

and btw the car WILL run if sprayed with starting fluid or something similar.

schrade

Not a vats gig. That will kill the starter power.

Air - filter ok?
Fuel, - does the exhaust smell like gas after a start attempt? Wet spark plugs?
Spark - spark/no spark, timing?

widebodyzr-1

check this out:

http://forums.corvetteforum.com/show...n%27t+start%21

in the end, after excruciating troubleshooting, replacement injectors did the trick.

edl

AGENT 86

ECM needs to see a reference pulse from dist., before it will fire the injectors.
This could be a good place to start.
http://members.shaw.ca/corvette86/En...ButWontRun.pdf

jfb

Starter fluid proves that the injectors are not working. Put a noid light (available from parts stores) or a low power 12v lamp like a 194 side marker lamp across an injector plug while cranking and see if it pulses. Check both injector fuses with an ohmeter. If you have spark, then you have reference pulses and the injectors should also be pulsed during cranking. You may have a defective ECM.

AGENT 86

Having spark does not guarantee the ECM is seeing a reference pulse.

Ricoch3T

Sounds good, I'll dig up some kind of test light and try that out. I've got everything except fuel in the cylinder.
I wouldn't think the injectors are bad, they are used but were working when I took them out. I'll check the resistances while I'm at it.

Also thanks for the troubleshooting page agent, I'll run through that and double check some stuff if I have to.

rick lambert

Could be bad fuses, the ECM receives its pulse signals from the pickup coil. I'd take a look at it too.

Ricoch3T

Alright heres what I've found today...

Checked ohms on all injectors:
all 13 +- 1 ohm
Checked both banks for light during cranking and received a blinking light when cranking
Also checked each side of the injector harness to ground and received a light.
Checked fuses all checked fine. Forgot to ohm the terminal block tho, but nothing has blown so I wouldn't think any have shorted to ground.

I forgot to mention earlier when this first happened the first thing I replaced was the ignition module so that is new also.

I did notice when looking at the fuses that the inj2 fuse area looked burned up. Checked the voltage there and it was getting 12v, and when I put the fuse in (key on) I can hear something cycle. (fuel pump maybe)

Rick, is the pickup coil attached to the ignition module in the distributor? I was down in there again and didn't noticed anything out of place. How do I check to see if the ecm is receiving signals from that?

Thanks for the help guys!

PurtyLilC4

is this a manual or automatic car?

WW7

Put my money on the ECM. I worked on a car last week that had the same symptoms. When we cranked it the nod light would light , as soon as we used starting fluid it would run and the nod light would stop working. Pulled a ECM off a car on the lot and put it in, started right up and worked fine..ECM...WW

Ricoch3T

It a manual...

It maybe the ecm. If I have access to one from another vette, how easy is it to swap? I hadn't looked under the dash to see where or how tight it is to get it out.

65Z01

The ECM is easy to access:
-drop the PS hush panel
-remove two screws that hold the ECM to the lower ledge
-drop the ECM
-remove the two large connectors and the CalPac
-put the CalPac into the "new" ECM
-plug in the new ECM and see if she starts up before installing under dash

To see if the ECM can fire the injectors you could hook the test light between the Blk/Pnk wire of an injector and ground. The light should normally be On and then flash off when the ECM fires the injectors, as the ECM pulls the Blk/Pnk wire to ground over that firing interval.

rick lambert

Hmmmm, not the pickup coil if you're seeing a pulse at the injectors using a low voltage light (usually we use a noid light). Your injector ohms sound fine, but you really need to check them both hot and cold, kinda hard if you can't keep it running to bring it up to temp. Soooo, forgot the year, but I think I'd run a wire from the battery (positive side) to the ALDL, lower pin, left side, this will enable the fuel pump to run continously, by passing the circuit. You definetly have a fuel delivery problem...proved that by getting it to run on starting fluid.

That's what I'd do first!

BTW, the pickup coil is in the bottom of the distributor, even a crappy Haynes shows how to OHM test it, do you have a factory service manual...year specific?

Ricoch3T

I don't have a factory service manual, I was hoping I didn't have to buy one b/c its my moms car. If I have to I guess I can buy one, or maybe borrow one from someone.

Her friend has a vette that he is working on right now (paint and restoring) so I may just swap out the ecm quick and see if that cures it. That way I'll know what to buy. If not I'll continue on with the checks as suggested..


Thanks for the help!!

Ricoch3T

Well the easy swap didn't work. Still just turns over.

Quick question, I thought when the computer was pulsing the injectors they would fire? What goes into making those things work?

schrade

Air is good - right? Filter probably ok

Substitute fuel makes it fire - fuel problem?

Spark - probably ok, since it fires with substitute fuel.

schrade

I don't think it necessarily means the injectors are NOT working.

It could mean the connector to at least one of the injectors has a short, or isn't connected.
It could mean there's a vacuum leak.
It could mean the injector screens are plugged.
It could mean they are not compatible injectors.
It could mean the connectors are crossed.
It could mean a few other things too...

All it proves is what CAN work - air, and spark.

Ricoch3T

The injectors should be compatible but then again I'm not positive. They are injectors off of my Lt-1 motor that were working when I swapped them out for bigger ones.
Thing thats funny about how it happened, it didn't sit very often. At most a week or two. But she had just driven it to the store and everything was fine. When she left it didn't start. Someone picked her up and they went back to pick it up later on and it fired right up and she drove it home. That was the last time it fired.

When I got to working on it, I verified everything. Got it to fire with starting fluid and figured 1 or more of the injectors were bad (originals) and swapped out for my set.

jfb

One thing you know with certainty, no fuel is being sprayed out of the injectors even though current pulses from the ECM are occurring. Are all the other injectors plugged in when you do your injector test with your light bulb? They should be so that you know the ECM can source enough current to operate the injector coils. Get a test strip for determining if there is water in your gas tank and test the gas in the fuel rail, water is not fuel!