Hey gang, so yesterday I drove 120 miles, ran great, no issues.

Today it started fine and made it down the road two miles and just cut out and died. No noises, hesitation or other symptoms, just died.

Cranks fine but will not start.

When I turn the key to "on" I can hear the pump prime but when I crank I get no pressure on the line (have a mechanical fuel pressure gauge installed).

I sprayed plenty of ether thru the T/B and it doesn't even attempt to fire. I'm guessing no spark at all.

Jumpered the ALDL and I get the three flashes of code 12, long pause and code 12 again. Is the second set of code 12 an actual trouble code or just the ecm repeating the diagnostic mode code?

Can I test the fuel pump by applying power to terminal G in the ALDL plug? It's a '91, I now there are some differences on this but I will not have access to my FSM for about a week so I can't confirm this.

Any help will be much appreciated, TIA

 

my 1988 & 1991 Camaros both did this same thing. get a shop manual and locate the fuel pump fuse in the fuse box (its 20 amp0 and make sure it's ok. On the driver side firewall behind the brake booster are 3 relays, one for the A/C, one for the engine cooling fan and one for the fuel pump. Your car uses the 1988 to "96 oval weather pack relays. The fuel pump relay has four wires, two small & two large. The small wire colors are green with white stripe and black with white stripe. The large wire colors are orange and the last is tan w white stripe. unplug the correct relay and carefulley look at the underside if the grey plug where the wires enter and you'll see small 'A B C D markings. The large orange wire is the feed wire from the fuse and should be in the '" E " terminal. An ohm meter should read 12V there at all times. Make a jumper wire and connect it from the " E " terminal to the " A" terminal. The A terminal has the large tan w white stripe wire, This wire goes to the pump. Using your jumper like this, by passes the relay and puts 12v directly to the pump. Remove the gas cap, put your ear to the filler and you should hear the pump whine. If silent, then your pump is bad. If working, then the relay is bad, but that design relay seldom fails. I hope this helps you.

 

Code 12 always shows as it is the ECM's way of telling you the engine is not running.code 12 means the ECM is seeing no reference signal from the distributor and is what it is supposed to do. When you check codes, the ECM will flash code 12 3 times and then the ECM flashes any stored and current trouble codes and then it starts over by flashing code 12 again.

 

If your getting no fuel pressure at the rail AND no spark it sounds like a VATS problem. I believe the system kills the spark and the fuel.
If you are getting spark then it could be only your fuel pump. If the pump makes noise when you turn the key on it is getting power, but not necessarily working...
Pull a plug and find out for sure whether you have spark or not.

 

VATS has nothing to do with the spark (code 46 shuts off the fuel injectors only, ignition is completely independent whether the ECM controls it or not, which is why we have to set base timing as the ECM won't take over the controls until the engine hits about 400 RPM). OP has an ignition problem, probably a fried module inside the distributor. Again, "No spark, no squirt." It's not firing when he uses starter fluid, so obviously he has no spark.

 

I've had plenty of engines with spark that wouldnt run on starting flud... SOmetimes spark was weak, sometimes there were other problems. There's only one way to diagnose an engine and thats to actually CHECK things, not make assumptions. You know what you do when you assume things, right?

 

Dude, read his first post. If he was having a VATS problem, he would have a code 46, not just 12. 9 times out of 10, a no start without VATS trouble, and not running with ether, means a dead ignition module or wiring. Which is why I said to check the module (or actually replace it). I know people who keep spares in their glove boxes because one can never tell when they are going to fail, almost like fuel pumps.

 

I forgot a couple of things: Code 12 doesn't just mean that the system is okay. If the engine were running, you wouldn't get trouble codes BECAUSE the "symptom" for code 12 doesn't exist at the time. Code 12 means that no RPM signal is reaching the ECM. Which usually means either a broken wire or bad ignition module, since the module is the go-between for the pickup coil and the ECM.

Pull a plug and check for spark. If you have no spark, take the module out of the distributor and take it to AutoZone or somewhere that will test it, and have it tested. More than likely, it's fried. Also check to make sure that the pickup coil leads are tight on the module.

My own car has experienced this, and I got the pleasure of working on an 86 Cutlass Ciera with the 2.5 that was towed into the shop with a dead module. Getting to that thing was a royal PITA, all crammed down under the intake at the back of the engine where there was NO room for a hand to get in there and plug it in .

 

Thanks for the help guys.

As far as the VATS.....it's a non issue on my car. I had a custom chip burned seven years ago with the VATS disabled (long story). Plus as mentioned above (if I remember right) it only disables the injectors. In my case the fuel pump does not engage while cranking.

No spark for sure. Took the module to NAPA and the guy said he tested it three times and it checked out OK (assuming he knew how to test it, won't be the first time I had an electrical part tested and pass and still end up being the problem). But for now let's ASSume it's ok.

All connections at coil and dizzy nice and tight, got 12v with ign "on" and good ground at coil terminals, bypassed the fuel pump relay and can get pump to run continuously

Other related symptom; Tach does not move at all while cranking

Yep, used to own a 4 cyl. Cavalier, had the pleasure of replacing that %&#@**%$# twice

Any other thoughts would be greatly appreciated

 

VATS disables both the starter and the fuel injectors on non-modified cars, that's why it's there. Since you have a chip burned, you don't need to worry about it except if it won't crank.

Don't just make sure the connectors on the module are tight, check to make sure the wires are solid as well. I ended up replacing the 2-wire connector on mine because the pink wire literally fell apart on me, and between that and my fried AC/Delco module, my car wasn't leaving school...

If you don't have a tach signal also, it's either the module (most likely) or a problem with the ignition coil.

I'll tell you my experiences with NAPA... My dad's Cavalier had a thermostat gasket on the 2.2 fail RIGHT AFTER installation (and that doesn't count the countless times the shop he went to used NAPA parts that failed after about a year and a half including radiators and hoses). They gave me the wrong water pump gasket. Guys in my class got the wrong parts. They sent me the wrong brake shoes for a job on a Plymouth I was doing (no parking brake struts attached to the shoes like they're supposed to be). So, in hindsight, I wouldn't trust them as far as I could throw them. I don't even trust the testers at AutoZone (I knew my ignition module was failing but they said it passed anyways AND they told me they couldn't test either one of my 730 ECMs, but I not only saw the test harness but the instructions to use it on their test bench when they were looking for the test harness for my ignition module a week before).

I think that with all you have done so far, you could probably spring for the module. It won't hurt to have a new one in there AND to clean up the base of the dizzy while it's out. It will help with heat transfer. Those round things in the bottom of the dizzy are vents. More than likely, they are clogged with grease and grime. Clean them and improve the air flow in there while the module is out.

Also, you may want to look into a new oil pressure sending unit. If the fuel pump doesn't run while cranking for a bit (and oil pressure shows on either the gauge or the idiot light goes out), it's dead. The switch closes at 15 PSI oil pressure. Or it should.

 

you may have lost the pick up coil. Use an ohmmeter to test it(green and white wires to the back of ign module) it should test between 800-1000 ohms. If not you will need to replace it. This means disassembly of the distributor. If the coil tests okay, check wiring to the ECM. A short to ground in the tan/blk EST bypass wire can cause a no spark. An open in the ppl/wht wire can cause no injector pulse and no tach signal.

Visually inspect the dist carefully for signs of damage to the pole peice and timing core. Make sure the distributor shaft actually turns when you crank the motor. You may have lost the dist gear or, god forbid, the timing chain.

In 20 years as a GM engine performance specialist, Ive never heard of code 12 meaning anything but that the system is in diagnostic mode.

 

Look it up... It literally means "ECM not receiving reference pulse from module". Yes, it's a system OK signal (no code 12 is another problem), but it's also a trouble code.

 

Code 41 is "no crank referrence signal to ECM". Code 12 has no trouble code description because its not a trouble code.

EDIT: This information in incorrect. Haverick IHL had it right. Just haven't seen it for so long, Id forgotten. Code 12 does mean "no referrence pulses to the ECM", as well as being an indication that the system is functioning normally in diagnostic mode. Also, code 41 is "cylinder mismatch or incorrect memcal". How I got that mixed up, I don't know.

 

Thanks guys, I'll check on the above suggestions over the next couple of days and report back.

 

Well, yeah

Weather finally got better a couple of days ago and I decided to see if rotor was even turning...NOPE!

Then I stuck my finger thru the oil filler hole on the valve cover so I could feel the rocker arms while someone cranked the ignition...nothing moving at all

Never thought of the timing chain being the problem, when the engine died it never made any noise at all. I had one fail on a SBC many years ago and boy did it make a ruckus!

I'll start a new thread in a few days on how to deal with this new issue, need to walk away from it for a few.

I thank you all for the help.

 

When you do get ready to go at it again, the 3.1 is a larger version of the 2.8 with a few improvements. One issue both have is the timing gear. You either have two iron gears with a funky little spring tensioner that fails, or you have an iron crank gear and a nylon toothed cam gear from which the nylon teeth eventually peel. The new set will have an iron crank gear and a mild steel cam gear. Why the OEM couldn't build it this way, I can't begin to imagime. Be aware, the 2.8 & 3.1 are interferrence engines. this means that when they lose cam timing, valves and pistons can touch. it's very difficult to determine when this has happened without getting into the valvetrain. In the cases where i have dealt with this, I found bent push rods.

You may want to remove the valve covers and check this out before you take the time to replace the timing gear(timing gear referring to the set). Once you have the push rods out, you can do a quick leak down test. The valves will all be closed in this condition and there should be no air coming out the intake or exhaust. be aware, the push rods are different lengths. Take care to lay them out as you remove them in order to be sure each one goes back to where it came from.

 

ThanX ASE doc, I had that interference though in my mind, but hoping it wasn't so.

I will pull the push rods and see if the are bent. What would be the minimum compressor size needed to do a leak down test?

I guess at that point I can get the cam phased, hoping it would just spin by hand as there will be no pressure on the lifters at this time

And steel gears for sure!!!!

 

Compressor size isnt much of an issue. If there is no valve damage, there wont be much air movement. For the test to be valid, you will need to rent or borrow a leak down tester and follow the directions carefully.