OK. Here’s a little background info first: The car is 1992 RS, 305 auto that’s been converted to TPI. It died on me while driving home from work a few weeks ago, died just like you turned off the key. Wouldn’t start back up and had to get towed home. There is no spark from coil while cranking.
I’ve replace the distributor, coil, cap, rotor, module, ECM, and pickup coil. I replaced the pickup coil before I replaced the distributor and the new distributor came with a new pickup and module.
I have 12v at coil with key on. The two wire harness between coil and dist checks out good. Coil is well grounded. All other grounds are ok. Still no help.
I unhooked the ECM and fed the harness back up into the engine bay to facilitate checking for bad connections. All the system grounds are fine, and the connections to spark module are fine. Still no start. The distributor is turning, and is installed correctly. There are no codes.

What else do I need to check out? This is really starting to bug me.

Thanks
Dave

 

are you getting fuel?

 

There is 42psi at the rail while cranking. Injectors are not firing, I assume this is because the ECM is not seeing a spark.

 

This sounds like it might be a VATS problem based on what your saying. vats will prevent the injectors from firing, but I think it will also prevent the car from cranking but not sure about that.

 

The VATS decoder reads the correct resistance during cranking. The module grounds the Start Enable Relay coil. When the start enable relay contacts close, voltage is allowed to the "S" terminal of the starter. The VATS module also sends an enable signal to the ECM. This signal allows the ECM to operate the fuel injectors during cranking. The SECURITY light will also illuminate for approximately five seconds, then turn off and remain off

 

I unplugged the ECM and pulled the pigtail back up into the engine bay so I could check all the wiring. I unplugged and tested each connection individually to its appropriate terminal at the ECM and also check every other ECM terminal to verify nothing was crossed (like having two wires frayed or something). Everything looked fine. I simply cannot find anything wrong with this car to cause it not to start.
As I've mentioned earlier, I've replaced nearly every ignition component except the plugs and wires at least once, and I've been through three spark modules. I took the two I have (new one and a known good one from a junkyard) up to AutoZone to get tested and they're both testing OK.
Several people have suggested VATS as a possible problem and I've always been able to dismiss it since the car will crank when turning the key. HOWEVER, I've been considering other possible culprits and taking another look at how the VATS system works. I found this diagram on this website in the tech articles section and it looks like maybe the ECM is depending on a signal from VATS to provide power to the spark controller. Is this too much of a stretch? Am I even reading this diagram correctly? Schematics aren't exactly my strong suit.
What do you think?
Thanks!

Dave

 

you are correct....if the VATS module was malfunctioning the car would not crank

 

Thats the real kicker... It will crank until the battery dies if you let it. My question is if a malfunctioning VATS module will cause a crank/no spark condition.

 

Dave

I have followed your saga from the sidelines. Couple of questions just to re-establish baseline:

1) Do you get spark at the end of the #1 spark plug?
2) Did you check your injectors' coil resistance (every single one)?
3) When you are cranking do you get injector pulse down (with a test light)?

//RF

 

no a malfunctioning vats will cause a NO CRANK condition only because the way it operates is that it completes the starter circuit to the solenoid....so hence if it didn't work or malfunctioned it would cause a no crank only....it isn't wired into the spark at all so it shouldn't cause a no spark.......i think you should recheck your cap, rotor, seating of the distributor shaft, plugs, wires....then if you have no spark you will have a starting place.....if you do have spark go back and recheck your fuel....it must be one of the two or both....if both then it's more than likely ecm related....just fuel could be many things as well as just spark.....just try to go back over it as if you haven't looked at anything before ( a pain in the *** i know) but you may find something you overlooked before...i find that when u can't figure it out it's usually the easiest thing in the world (hence why you overlooked it to begin with) i've done that many times
also please do give us a list of EVERYTHING you've checked already and DEFINATELY ruled out....
also even though you got a new ign module...it wouldn't hurt to go back and check it or try with another known good part because sometimes new parts are defective

 

RF Master,
Oooh, I have a saga now. I'm honored, I think. LOL.
1)No spark from #1, 2, 3, 4, 5, 6, 7, 8, or coil. No juice at all. Nothing. Tested with a spark tester.
2)I have not checked injector coil resistance. I find it hard to believe they all would have failed at the exact same time, but could one or two bad ones cause this problem? By the way, I am running a set of used Ford injectors. They're 19lb/hr and came off a Mustang. I got em off eBay for $50 as kind of a "test" set since I figured my stock Multecs had taken the dirt-nap after the car sat for three years. They had, and these Ford injectors seem to be working fine. I'll check their resistance first chance I get just to be sure.
3)No injector pulse while cranking, tested with a light.

3G Junkie,
Cap and rotor are fine (new). Distributor is installed correctly. PLugs and wires are about 4 years old, but the car sat most of the time. Not that it matters, I'm not getting spark from the coil.

Parts I've replaced:
ECM
Cap
Rotor
Coil
Ignition module
PIckup coil
Distributor (after replacing module and pickup on stock dist).

Things I've checked:
All system grounds are good, engine is well grounded.
12v at coil with key on.
Battery is good.
pickup coil on new distributor checks out good.
I have two ingnition modules, the one that came with the new dist and a known good one from the local boneyard. Neither will start the car but both test good.
Rotor turns while cranking the engine/engine builds oil pressure while cranking... timing chain must be ok.
Key switch appears to be working properly.
I checked and cross checked every wire of every sensor against its termination at the ecm plug, every connection checked good. Nothing was "leaking" over into another sensor or connection (no broken/frayed wires touching each other).
No blown fuses.

No doubt it has to be an obvious problem, and I thought I had it when I noticed the magnet in the top of the distributor was shattered (don't ask me how it happened). Thats why I replaced the distributor.
This thing is driving me crazy, and its typical with this car. She doesn't like me at all. I don't call her "Christine" for nothing!

Thanks for the responses, I welcome any suggestions.
Dave

 

i read in another forum somewhere that there is a fuse in the driver side fenderwell toward the front...(or was it passenger) not 100% sure...anyway that fuse is for the fuel pump.....but from what i understand it also controlls half of the ecm......possibility? hmmmm i'm stumped without physically being able to look at the car......but if it's a no spark/ no fuel problem it a. could possibly be that it's not sending fuel because of the no spark...or b. there's some kinda ghost in ur engine LMFAO....i'm truly stumped here

 

Yeah man, I'm stumped too! And at this point, I'm not ruling out the ghost

That fuse is mounted to the passenger fenderwell. It was the first one I checked and its good. I think the injectors aren't firing because the ecm is not seeing a tach signal... which is related to the "no spark" condition.

The problem, and the knowledge that all my wiring checks out ok, really leads me to think its the spark module, but I have two... one is new, the other used but known to be good. I picked it up at the local boneyard (just to keep as a spare) and ran it on the car to make sure it was good. Both are testing good. I guess I could pick up another new one, but I don't really see the point if I have two good ones.

Dave

 

you said it's a new coil correct? have you checked the resistance of the coil to the manufacturer specs.......cuz you said you had primary voltage key on

 

Yes, both the new coil and the old one tested within spec and are well grounded. I also forgot to add that the fuel pump is also working, I have steady 42psi at the rail while cranking.

 

i'm totally stumped........hmmmm now you have me researching LOL cuz i really wanna know what's up

 

David

In order to get a spark you do not need ECM. When cranking (under 400 RPM) EST module inside distributor is operating in stand alone mode. However, external harness shorts may affect its performance and operability.

Step 1
I would verify that you are getting +12 volts to the ignition coil while cranking. I know that you have +12V with ignition key in run position, but do you have +12 while cranking???

Step 2
Disconnect the four pin connector from distributor. By disconnecting 4 wire plug from dizzy, which actually plugs into EST module, will force EST to operate in bypass mode. IOW, bypass wire (Pin B on EST, brown-white wire) is disconnected and the EST line is pulled to ground through a resistor inside the ignition module.
As you recall from previous postings dizzy uses pick-up coil/crank sensor to generate pulses which are amplified and shaped by the EST module. These pulses are amplified and are used to control switch circuit which power up a magnetic field in the ignition coils primary winding that, when collapsing, will induce a high voltage in the secondary winding. Theory of operation is simple enough and consequently for every crank sensor/pick-up pulse, ignition coil is triggered – spark is produced.
This test configuration is referred to as a bypass mode or EST module mode of operation and it does not receive timing offset information from ECM nor does it send DRP pulses back to ECM. In this mode, timing advance is built into the ignition module, and since DRP pulses never reach ECM it will not fire injectors. With four wire plug disconnected at the dizzy ECM should also set Code 42. It is not a problem at this stage since we are trying to get a simple spark from your ignition system!
Connect sparkplug tester to the coil output HV wire – the one that goes to the center post of the dizzy. If all components with in distributor (EST module, Pick up coil is correctly plugged in) you should see a spark. If not, you have a problem in your dizzy-coil combo.

//RF

 

HOLY CRAP............THIS SAME THING HAPPENED TO ME TODAY!!!!!!!!

im thinking i have a bad starter or something....and u guys are talking vats, timing and distributors,etc. the funny thing is....i just got my car from the mechanic yeterday.... (pwr steering leak and a vacuum leak and a misfire)

i told him that my car is showing signs of shutting off.....and YUP it happened on the busiest road in miami.

lets all put our heads together and figure this out. we are solving for 2 cars now. SAME PROBlem LoL

but my motor is brand new....i just have old components from the old 305.

i was driving along and it just turned off like you would when u get home.

 

Samething for me im about to replace pic up coil because my mechanic said its only reading at 3 something ohms i guess

 

Pick up coil should read between 500 to 1200 Ohms - 3 Ohms - we have a problem. To replace pick up will require dizzy removal.

//RF

 

I will let you guys know how it goes

 

Good news, bad news, and some new problems:

RF,
I tried that test you told me about: unplugging the 4 wire pluf from the dist and testing for spark. Got a good strong spark off the coil. So then I firgured what the heck, I've checked all my wiring and its good; so I pugged the dist back in and hooked up a noid to the number 1 injector and cranked again. I'll be darned, I got an injector pulse and the car tried to start. In fact, it did start but I had to hold the accelerator to keep it running.

Now lets rewind to the day it broke down. I was on a road with a 35mph speed limit, coming up on a very sharp 90* turn. I had to brake for this turn, obviously removing my foot from the gas. After making the turn, the engine quit.

Now the car will run, but to keep it running I have to keep my foot on the gas. It will rev just fine, and it will idle for a few moments, erratically, and eventually die. It will start right back up.
I haven't set the base timing yet, and no doubt thats at least part of the problem, but now I ask you this: what are the symptoms of a malfunctioning IAC? Also, my set of noids came with an IAC tester, and it appears to be getting a good signal, but when I unplugged it I noticed the connector was in bad shape. Really bad shape. I'll try replacing the connector first, but I really think something is up with the IAC.
Thoughts? Opinions?

Thanks!

Dave

 

hmm......something i hadn't thought about was exactly that...the IAC.....the only thing there would be you would still get fuel.......but now you are saying that you are getting fuel and the car dies now after letting off the gas which could possibly be a sign of IAC trouble....check your base timimg first.....because if it's that far off that alone could be the whole problem....but if it isn't it's definately a good point to look into lol

 

I'll try setting the base timing first. And then move on to the IAC.

Don't know why the car decides to start all of a sudden... I've been trying to figure this out for about three weeks.

 

electronic spark control my problem well i will see tomorrow im gonna grab about 10 from the junk yard

 

Well, Crap. I went back outside to set the timing and now it won't start again. No spark at all.

 

it's that damn ghost dave i hate it when that happens

 

No kiddin' 3G. There is definitely a ghost in the machine somewhere and I just can't figure it out.
I tried testing for spark with the distributor disconnected from the ecm and got spark. It was a good strong white spark. So I plugged the dist back in and still had spark, then tried cranking again with a noid hooked up to #1 injector and had pulse. I took the testers back off and hooked everything up and the car started right up, but ran poorly and wouldn't idle well. I think it just needed the timing set.
I had to remove the coil so I could loosen the distribuor bolt, but I reinstalled the coil and no spark again.
Apparently, I have an intermittent failure somewhere. Well, its a pretty premanent failure I guess, this was the first time it even tried to start in close to a month, but I seem to be back to square one.

Lets assume that there is nothing actually wrong with any components of the ignition system. What else should I be checking?

Dave

 

Dave

Take metal brush wheel to coil mounting posts. Scuff them until you see fresh metal. Do the same on the coil mounting bracket. Repeat above for dizzy hold down clamp, mounting boss, hold down bolt and dizzy ring flange. Get high quality dielectric Tune-Up grease which protects electrical connections from oxidation. You can get a high quality dielectric Tune-Up grease from marine supply house, for example: 3M 08946 silicone paste. Liberally coat all mating surfaces and mounting bolts with it. After securing all components dab silicon grease on the outside of the mated parts. This will prevent moisture from penetrating mechanical junction.

//RF

 

don't feel bad big dave.....the ghost appeared in my car today.....from nowhere the lower rad hose went out on me.......not TOO unexpected considering that it hasn't been driven in two years......but it was totally random cuz i checked it before i fired it up.....friggen ghosts...so i replaced the water pump just to be ahead LMAO...anyway i hope that you get it runnin soon.....

 

RF,
So you're thinking something isn't grounding well? I've used my DVM to verify my coil is well grounded, and I'm getting no resistance there... that being said, I'll admit the brackets are far from clean and your suggestion sounds plausible. I'll give that a try as soon as I can.
Thanks very much for the suggestion.

3G,
Sounds like we need to get together and have an exorcism or something .

Oh the trouble we go through to enjoy these older cars

Dave

 

I got kinda of the same probelm. i have a 90 camaro V6. Bought it last week
friend need to get rid of it so wtf I bought it.Thinking simple fix maybe two days work and its a good running car again. Not at all. Its the
"Camaro from Hell", Ive been working on it for atleast a week.
Before I bought the car my friend took it to a shop they replaced fuel pump, battery and alternator. They didnt know wtf the car had either.
The car cranks but wouldnt turn. I went for the computer its good. fuel its good. spark is good. So I went for the distributer cleaned it out put in a new ignition module and BOOM it finally started. but while it was on I saw the temp. it got to 220 and fan didnt start up. I quickly touch the distributer and it was super hot and the car just died and would not start again.

Thats the progress today atleast got it to run. Now I am thinking its the cooling system. Its gets so hot and burns the ignition module. the fan didnt do anything. So tomorrow going to try it again with the a/c and see if the fan kick in.

But THIS Car is from HELL. most of my buddies told me everything I did this **** should start. Anyways hope this helps.

 

I am also having an issue with not getting fire from the coil. I was reading in my repair manual and it said the pre coil should read infinity, doesn’t that mean it should read like there is no resistance at all? I checked my pre coil and it is like an open circuit no resistance at all. is this my problem?

 

Pickup coil should read several hundred ohms (usually about 650-800) between the 2 wires like RFMaster said, and infinity (as if the meter leads are free, not hooked to anything) from either wire to ground.

If the meter never moves when hooked up to the pickup coil on any of its ranges, then the pickup coil is bad.

The "main" coil, the big one, should read a very low resistance like less than 1 ohm, from the Batt terminal to the Tach terminal; and some 10,000 ohms or so from the spark terminal to its frame. The frame should be grounded.

 

I replaced the pre coil and it is now getting fire, and running. Thanks for the help

 

'big dave'.. did you get your car figured out?? i am having trouble with my 87 305tpi camaro so i did a search for 'pick up coil' and stumbled across your thread. my car does the exact same thing as yours. sometimes it will fire and run just fine (FOR WEEKS) and then one day it will just crank (no fire.. for weeks!) and then out of the blue it runs fine again. i have replaced the module and am getting ready to change the pick up coil. i have also replaced the cap, rotor, and coil. i am confused and wondering what you came up with..

 

I did get it sorted out. I've been driving and enjoying it all summer long. My Accell coil failed and apparently shorted out the ignition module. Thanks to two bad distributors and three bad ignition modules from AutoZone, I had a hell of a time finding the problem. Finally got it going with some step-by-step, in depth diagnostics someone from this board sent me. So I've got a new coil, new distributor, and new ignition module.
Hope this helps ya man, good luck!

Dave