starting problem after sitting years

[carnold]

Recently purchased 90 ZR1 sitting for 6 years w/o starting. Changed all fluids, filters and plugs. Pumps working ,good gas and pressure at injector rails. Fuses fine.Plugs firing but no fuel in cylinder when I pulled a plug. Turns over good just will not fire on any cylinder. Drained gas had shellac smell but no gum in filter or tank. Can't imagine all injectors clogged so I wouldn't get atleast one cylinder to fire. Is there a security issue? Any suggestions on what to do next?

[tccrab]

Originally Posted by carnold

Recently purchased 90 ZR1 sitting for 6 years w/o starting. Changed all fluids, filters and plugs. Pumps working ,good gas and pressure at injector rails. Fuses fine.Plugs firing but no fuel in cylinder when I pulled a plug. Turns over good just will not fire on any cylinder. Drained gas had shellac smell but no gum in filter or tank. Can't imagine all injectors clogged so I wouldn't get atleast one cylinder to fire. Is there a security issue? Any suggestions on what to do next?

Congratulations on your purchase and welcome to the Brotherhood of the Beast!

First thing that comes to mind is VATS.
If the VATS is triggered, it will kill the fuel system and the ignition.
When you insert the key and turn it to start, the Security light (on the bottom left of the Tach) should flash a few times then go out.
If the light stays on, then try a different key.
Try locking/unlocking the drivers side door a few times with the key.

Another thing that comes to mind, did the PO (previous owner) install an aftermarket alarm with an ignition cut off?
These are notorious for causing problems.

The ECM has a fusable link with a fuse holder. It's possible that the fuse is bad or has been removed as a security measure.
It's located on a wire that comes directly from the positive side of the battery. It's a little tricky to see in there or even get your hand back there, but reach in very carefully along side the battery and feel for a small wire (10 or 12 gauge) that comes directly from the battery connector. There should be enough room on the wire to pull it out far enough to inspect the fuse. Make sure the key if off when you're messing about with this, even better if you've disconnected the negative battery cable. A spark or a short can fubar your ECM.

Good luck!
TomC
'90ZR1 #792

[carnold]

Thanks. Nothing aftermarket car only has 1100 miles will try your thoughts. Since the plugs are firing is there something that is stopping the electrical to the injectors?

[Corvette95]

Yes, all injectors are probably bad.

[carnold]

Assumed was the problem but was hopeing for an easier fix.

[tccrab]

Originally Posted by carnold

Assumed was the problem but was hopeing for an easier fix.

I agree that it's without a doubt something to do with the fuel injectors, however..........
I have a hard time believing that ALL the primaries have failed completely.

What usually happens with the '90-92 Multec fuel injectors is that ethanol in the gasoline eats through an internal seal and shorts out the coils.
You can measure the resistance of the fuel injector coils quite easily without taking the plenum off, All you need is a DVM (digital volt meter)with fairly long leads.
Remove the negative battery cable.
Open passenger door and remove the INJ fuse, it's a yellow 20A, top row about halfway across.
Remove the "A" connector on the ECM, it's the Yellow one closest to the outside drivers side.
Using your DVM, measure between the correct pin on the ECM and the right hand side of the INJ fuse connector. Just stick your black probe from the DVM into the INJ fuse hole that is closest to the firewall, make sure it's got good contact.
My probes were too big to fit into the pin holes yellow connector on the ECM, so I cut a 2 or 3 inch piece of solid core wire to stick into the pin hole, then I could clip the Red lead of my DVM to it.
The actual ohms read from the ECM connector will vary depending on temperature and wire resistance. If you were to have measured at the fuel injector itself, the Ohms at room temperature should be 13+/-1 ohm.
What you are looking for is a variance between injectors, it'll be obvious if you've got a bad one or one out of spec.
No ohms at all would indicate a bad connection or a shorted coil in the injector.
Low or high ohms indicate coil failure in the injector itself.
Below is the appropriate page from the Helms manual that shows the primary fuel injector circuit.
The dotted box at the bottom represents the ECM. The first circuit on the bottom left hand side is Cylnder 2, just to the left of the is a small Y7. This means that pin "7" on the "Y"ellow connector reads the coil on cylinder 2 fuel injector. A few of the pin numbers are on the yellow plug, they are numbered from the upper left hand side and theres 4 rows of 6 pins each. So, 7 would be second row down, first pin. Put the postive lead of your volt meter into pin 7 and the negative lead of the volt meter on the right hand side of the fuse plug for the INJ fuse.

Good luck!

TomC
'90ZR1 #792

[carnold]

TC thanks for information. Assuming coils are shorted what is the remedy?

[tccrab]

The only viable option is replacement.

I highly recommend that you do not waste your money by having yours "Refurbished", it's a total waste of time and money.
I would also not recommend buying factory replacements, by all accounts GM has not seen fit to update the design and the ethanol problem will come back to bite you again.

RC Engineering make a replacement set specifically for the ZR1, however they are a little pricey. $64 each last time I checked. You'll need 16. Do the math.

Accel makes a compatible Fuel Injector, see my posts here:
http://www.zr1netregistry.com/forum/...ead.php?t=2206

So far they seem to be working just fine. The price was right too. They can be bought from Atlantic Racing for about $500 plus shipping for all 16.
You'll need special "O" rings from Marc Haibeck for the primary fuel injectors:
http://www.zr1specialist.com
630-458-8427

Keep us posted on updates about your car. I'm really interested as what could cause all the fuel injectors to not fire at all.

I'm hoping you don't have ECM problems, it appears that they're not easy to find these days. I got lucky and bought what must have been the last one on stock from GM a couple of weeks ago. I had no idea they were down to the last one or two.

TomC
'90ZR1 #792

[TommyL]

Fuel Pump or Filter?

[Tyler Townsley]

Spark : Easiest way to check spark is to get 8 plugs pull the wires and plug in the plugs lay them on the plenum and crank the car, if you have good spark on all plugs then move to fuel.

Fuel: Easiest way to check fuel is to check the rail pressure with a guage, it should be 45+ while cranking. If you have rail pressure then check injectors by pulling the plenum, pull the fuel rail with injectors attached up enough to see if there is a fuel spray when the motor is cranked, and also use a noid light if there is no spray to see if they are getting signal.

I would also pull the pumps from the gas tank to check them. I have known of cars with less than 1000 mile that were stored ended up having to replace the pump assembly because it was rusted.

Tyler