Hi guys, hope someone can point me in the right direction. I was driving home from work this afternoon, came around a hard right turn and the car died. Would not start back up. Had to get towed home, and it still won't start. It was raining pretty good, but the car has NEVER had any moisture related problems before. It went from running fine to dead in a second.
All connections to the coil, distributor, etc are good and tight. Plug and coil wires are good. The car cranks and is getting fuel. I have a steady 42psi at the rail while cranking.
I had just filled up the fuel tank while I was out for lunch, but the car ran fine on the way back to work and most of the way home, so I kind of doubt this is bad gas; especially since it won't fire at all and died so suddenly.

I've got codes 12, 13, and 15, but I've had them for a while now, just never got around to fixing a couple melted wires (they got a little too close to the driver's header). They throw a CEL when the car warm up to OT, and sort of hurt the fuel economy, but nothing ever like this.
Anyone got any ideas?

By the way, the car is a 1992 RS, 305, TPI convert. I did the conversion myself years ago and I've never had any problems realted to the swap.

Thanks for any help or suggestions.

Dave

 

code 12-no pulses to ecm=test code.code 13 oxygen sensorcheck for sticking or mis adjusted tps check wiring and connections from oxy sensor ,replace if needed. code15 coolant sensor circuit,check wiring anc connections ,replace if needed.also check wiring connections at ecm. hope this helps,later jimmy

 

The car has had the 13 & 15 codes for a while now. Like I said, all they do is cause a CEL when the engine hits operating temp. It prevents the computer from entering closed loop mode and kind of reduces fuel economy, but has never casued the engine to quit. The wires to the O2 sensor and coolant sensor in the driver's head touched the header and melted, thats why I have those codes.

I wonder more and more if the rain could have caused this, although I still think its unlikely.
Anyone else have any suggestions?

Thanks for the input so far.

Dave

 

try unhooking the neg. battery cable and wait 5 mins , rehook and see if resetting the computer helps,later jimmy

 

coil or pick up coil

 

First of all, thanks very much for the help so far.
I've replaced the ignition coil, pickup coil, and electronic spark control module. None of that helped.
I tried unhooking the battery for a few minutes to reset the ECM, and upon trying to start it, it did catch once, but only briefly. The engine didn't actually start.

I've got 12v to the coil, 42psi at the rail while cranking, and I know the injectors are firing because after cranking for a few seconds I can smell gas if I open the throttle blades manually. All connections look good, IAC and TPS check out good.

It kicked once after resetting the computer but didn't actually start. I starting to suspect bad ECM. What do you guys think? Am I missing something obvious?

Thanks in advance.

Dave

 

Pull a spark plug wire - connect in line spark tester. Have helper crank engine over while observing tester during cranking. Verify that you actually have spark during cranking. Also back probe injector connector with noid light. One side should be always hot (with ign key on) the other side should blink during cranking. Verify both and let us know what you have found.

//RF

 

I had a similar problem as what you first stated, exactly actually. When I first bought the car I would take a hard corner and she would cut out and lost all power but would actually still go, once you turned off and back on she would good again until another corner or sumthing.

It ended up being only the Fuel Filter, I would go ahead and spend 15 bucks on a new one and might fix ur problem.

Good luck.

 

I thought I had it fixed when I found a bad ground, so I spent all day yesterday fixing that, still nothing.

I'll verify the spark as soon as the rain quits, but I don't know what a noid light is, much less own or have access to one. Is there a way I can check the injectors with a multimeter? I'm 99% sure they're firing becasue I have good pressure at the rail, and I have a heavy gas smell after I crank for a few seconds. I'll check them anyway to be sure.

Fuel filter is about a month old, higly doubt thats the problem. This is not an intermittent problem; car is dead.

Thanks
Dave

 

Multimeter might not be fast enough to see pull down pulse - Injector has two wires: one is always hot when ignition key is on or start, while the other one gets 'pulled' by ECM to ground to activate injectors. These pulse are rather short in duration and most DVM will not see it (due to instrument internal averaging), while a test light will blink.

//RF

 

Sounds logical. No doubt the injectors are firing a couple times a second even while cranking. Guess I'll find me a noid light. I did a search and now I undestand what they are.
Would someplace like Autozone, Advance, or Pep Boys carry one? Or are they a you-gotta-order-it sort of thing?

Dave

 

you can pick them up just about any parts store,even wal-mart has them in automotive.you said you found a bad ground ,be sure the ones on the back of both heads are tight (9/16 wrench fits) later jimmy

 

Yeah, it was the one on the back of the driver's side head that was bad. That was an adventure. Thought sure that would be it too, but no dice.
The weather here has been awfully cold the last couple days and my garage is too full of crap to bring the car inside to work on so I gotta wait for the weather to break. Haven't even looked for a noid light yet, but I think I will today.

I was talking to my cousin (a Mustang guy, but very knowlegable) the other day, seemed to think that if the ecm was bad, which I'm thinking it is, I would not get fuel OR spark. But I'm 99% sure the injectors are firing. Could a bad ECM still fire the injectors but not provide spark?

Thanks
Dave

 

A simple answer is NO

EST module in distributor controls timing and spark generation during start-up (i.e under 400 RPM). Distributor EST module also sends a DRP signal back to ECM telling it how fast engine is turning. For ECM to fire injectors it must have DRP pulses. No DRP, no injectors firing. EST are known to fail - no spark, no injectors. When you get spark and no injectors - start checking, harness, (4-pin connector) ECM and make sure that injectors get +12 Vdc on one side.

///RF

 

Thanks for the help RF. It was a little warmer yesterday and I got chance to look a little more. All my wiring looks good, and I know my grounds are good. I bought a spark checker, no spark. I picked up a set of noid lights today at lunch and will try when I get home, but it seems like the injectors probably won't be firing after all since there is no spark.

I'll reply again after I check te injectors when I get home.

Thanks for the help fellas!

dave

 

 

vats, theres an article on the homepage that explains how to check it,i cant explain like the article.mine did this at the gas station couple weeks ago.later jimmy

 

hey dave, I,m going through the same exact issue right now and replacing almost the same stuff...I'll le you know if I stumble onto anything.I think a vats failure gives code 53 but only while its going on..keep me in mind and I'll do the same.My posting is in the ecm secion.good luck man

 

VATS prevents injector firing since it is controlled by ECM. Ignition is a stand alone system and should generate spark regardless of VATS. Basic rundown of VATS - the vats module detects the key, if the correct key resistance is present 2 things happen - the vats module will ground a starter enable relay allowing the engine to crank and it will also send a signal to the ECM (30Hz square wave), and ECM will then enable the injectors. If it's cranking then vats isn't the issue

Spark generation - are you getting +12 at the coil with ignition key in run /start??? Check for broken wires, connector pins between dizzy and coil, spark plug wire resistance?
Is Rotor & Cap in good shape??
Center contact?


//RF

 

I agree, I don't think this is a VATS problem either. The thought crossed my mind, enough so that I even tried the other key thinking maybe the resistor was bad, but that had no effect either.

I do have 12.3v at the coil. Wires look good, contacts are clean, connectors are tight.
The plugs, wires, cap, and rotor are about 4 years old, but only have about 5k miles on them (the car doesn't get out much). I find it unlikely that all wires would fail simultaneously. The cap, rotor, and center contact look fine (they're Accel pieces, say what you will but their products have served me well). I do have a spare cap I could throw on just to check, but again, I also find it unlikely a bad cap/rotor would cause such a sudden breakdown. Its not like the car coughed and sputtered and finally wouldn't run anymore... it was like turning off the key.

I think I'll go forward with a new ECM, they're not all that expensive, and I'd rather do that before I got yanking the wiring harness to look for bad wires. I'll let you guys know if that fixes it.

Thanks
Dave

 

If it were a VATS issue, then you would have no crank. The VATS module disables the starter enable relay, fuel pump and injector pulse. So if the VATS was malfunctioning, the engine would not even crank, you would have no fuel pressure. I found out the hard way and replaced 2 starters, ignition switch, nuetral safety switch, then finally realizing it was VATS. Check your ignition control module located on the dist. Thats what was wrong with mine when it just died out on me while driving. Any autoparts store will check it for free and a new one isn't too pricy.

 

Just perform couple of checks before shelling money for a new ECM.

Does your Tachometer wiggle a bit when cranking???
1) If does not - I suspect that the two wire harness between dizzy and external coil is defective. (Your car is equipped with 8-pin compact module, small hat HEI). Get a DVM and ohm out pin to pin the two wire harness.
2) Check coil ground - coil uses intake manifold (mounting bolts) for ground return. It is possible that your intake manifold has a resistive path (rust, oil, paint, etc).

3) Disconnect center HV lead from dizzy - do you get spark when cranking???


4) EST modules are known to be DOA from factory.

//RF

 

Zero resistance on the two-wire harness between coil and dist. Zero resistance on the coil ground. New ECM, no effect. I've had three different EST modules on there, still nothing.
Center HV Lead from Dist??? Do you want me to check spark straight from the coil? Sounds like a good idea. I'll try that.

Dave

 

Yes - check and verify that HV coil output has spark! - step by step debugging.


There is one more possibility. I know that you've replaced your pick-up coil (the white-green wires that plug into EST, inside dizzy) Check coil resistance - it should be in the range between 500 -1500 Ohm. If it open - must replace. Also check vs. ground. If it is shorted to ground it will never work as well!

//RF

 

I think the coil is normally shorted to ground, and the circuit is broken to discharge the coil. A test light across the terminals should blink while cranking. I think.....

 

Which coil are you referring to??? Ignition coil that generates HV -spark or pickup (aka reluctor coil)?

Ignition coil has two windings - primary and secondary. Primary windings are low voltage windings with one side tied to +12 Ignition (PINK wire) while the negative terminal is tied in parallel with secondary winding negative terminal to EST module C terminal. HEI module use a pass through transistor to pull negative terminals to ground. When that happens the current flows through primary coil - inducing secondary HV voltage. Spark happens.

Pickup coil uses rotating rotor to vary magnetic field - thus inducing current in the pick-up coil. Ignition module uses zero voltage crossing detection do determine if rotor is rotating. There is an old thread regarding its operation on TGO.

//RF

 

The bottom line is that the ingnition setup is independant of the ECM. It can operate with no ecm at all.

Hower, the ECM does "take over" spark timing by applying a 5 volt signal to a pin on the module. The module then looks for pulsed input from the ECM to control timing, rather then using the fixed timing built into the module.


To remove the ECM from the equation, disconnect the EST connector (the brown on near the firewall) like you were setting timing. That will force the ignition to become standalone.

If you have power where you need it and everything is wired correctly, it should spark.


If it doesnt spark, you will have to verify the 12 volt supply to the module, the ground to the module, power to the coil, and pickup coil wiring.

 

I put my spark tester on the HV lead from the coil, no spark from the coil. I've looked at every connection I can find to verify nothing came unhooked. I've checked every wire I can get to without removing the wiring harness from the car. I can't find anything wrong. I am getting 12v to the ignition coil with the key on.

What are the three relays on the firewall on the drivers' side, next to the brake booster? I remember before I converted to TPI (car was originally TBI) changing an ignition module that was on that bracket... and there were only two relays. The wiring diagram in my Haynes manual says there is a spark module there, but I can't see one. I also know Haynes manuals have been known to be wrong.

Could there be anything else wrong with the distributor? Could I have assembled it incorrectly while replacing the pickup coil? What about the key switch? Sorry for all the questions, but I'm at a loss here. I've checked and rechecked everything I know of that could be wrong.

Thanks a lot for the help so far guys!

Dave

 

Hey David

The relays on the firewall next to the booster are unrelated to ignition system. Out of the two one of them is Fuel Pump relay (look for gray #12 AWG wire), the other is a Main Cooling fan relay. A square looking black module is ESC module used in conjunction knock sensor to tell ECM when engine knock takes place. A third relay is possibly a MAF burn off relay.

Getting back to ignition - no spark. I have gone back through the thread and I am not sure what else that we have overlooked. The only thing that comes to mind is that either pickup coil, EST module, or main coil are defective. The two wire harness was checked out OK. The only other thing that I can think of is that somehow magnets used in reluctor ring are no longer there or possibly can not provide strong enough magnetic field. IOW, reluctor coil is no longer subjected to varying magnetic flux, no di/dt.
Measure reluctor coil windings resistance - it should be between 500 to 1500 Ohms (when disconnected from EST module). If you remove dizzy from engine you can actually verify that reluctor coil is working properly by slowly turning rotor while observing resistance - it should be varying as induced current will be affecting DVM readings. .
If you have spare dizzy - now is the time to drop it in as a sanity check.

//RF

 

hey dave, i agree with rfmaster,i went back thru all the threads. the coil gets mentioned a lot.my son read it too(only 17,but really good on cars) he remembered on his camaro that the coil did this same thing when his sister had the car.after i thought about it ,its was doing exactly the same as yours.i know on these coils that if they lose their ground they wont spark at all(put new 1 on camaro,didnt ground no spark) run a temporary ground to the coil from neg. on battery.i definitely understand the frustration part of it too.man ,as soon as i wrote that something popped in my head.on the camaro steering column theres a plugin on top of it(the wiring for switch) had to replace this, did same as yours.had a bad connection i could squeeze it together with my hand it would start,just a thought.man i hope this car cranks for you,later jimmy

 

when I had my motor with just bolt on parts I had a problem a few times where the car would just shut off on its own. It is a 90 GTA. Everytime i brought it to get the comp on it or read the serv. eng. codes it came back as either the TPS (which i changed over and over) or the O2. Eventually I changed the main comp (which was only about 250 at the time dont know what it costs now). After that, problem solved. This is going back 8 yrs but if my memory serves me correct the computer will definately stop your car from starting. Now if I were you I would definately take these guys advice over mine but it is not an expensive part to replace. There is also really no way to damage when installing so if it does nothing return it.

If you are interested I never turn down an opportunity to show off my engine.....take a look

https://www.thirdgen.org/forums/engi...-car-what.html

 

OK. This has become a really long drawn-out thread, so just to save everyone some reading here's a quick rundown:
Car died one afternoon on way home from work. It was raining, but I don't think that had anything to do with it. The car has never been flaky in the rain before. It was running perfect, no problems at all, then quit like you turned off the key.
I've replaced:
Ignition Coil
Pickup Coil
Spark module (under cap) Actually replaced this twice.
Distributor cap
I cleaned the contacts on the rotor (didn't have a spare laying around)
ECM
I have no spark from No1 cyl or coil, checked with an inline spark checker. Injectors are not firing, verified with noid light. I've verified 12v to the coil and zero resitance to ground. Two-wire harness from coil to dizzy checks out fine. I have the distributor installed correctly. I did find one bad ground on the back of the engine and repaired it. Short of removing the engine harness from the car, I've checked every wire I can get to and can't spot any problems.

RF, just to clarify, there is no longer a square flat module by those relays, there was when the car was TBI, and I remember having to change it once several years ago, but I converted to TPI since then. For the conversion I used the hardware, wiring harness, and computer from a running donor. I replaced the fuel pump and knock sensor with new Delco parts. I reused my stock TBI dist.

I'll pull the dist when I get home from work and check it out again. My old ignition coil and the new one checked out OK.
By reluctor, I assume you're referring to the pickup coil?
I wish I had a spare dist to try. I really don't have the money for a new one right now, but there's a junkyard nearby, maybe that would be worth a shot.

Thanks again fellas!

Dave

 

Dave

Take a look at the following link:

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

There are additional checks that you can perform.

//RF

 

I just pulled the dizzy again and did a couple of those checks you gave me RF. Everything looked fine except one thing. When I tested the pickup coil, it initially read 719, then when I turned the distributor shaft slowly it would jump around as I expected. Somtimes read as high as 3000 and as low as 109. The faster I turned the shaft, the worse it got, until it just read infinite. Then when I stopped turning the shaft, it would return to 719.
I can feel magnetic resistance whenever part of the star passes a corner of the pole piece.
Check out the picture I've attached. It really doesn't do it justice, but you see some cracks in the magnet... actually the magnet is shattered. Its hard to tell for sure, but it looks like its in about a dozen pieces.

Maybe I got a faulty pickup from the parts store, its unlikely in my opinion, but it does happen. My main concern though is the broken magnet... In my mind that's gotta be screwing up the magnetic field enough to cause the pickup not to trigger the coil.
Let me know what you think.
Thanks
Dave

 

David

A broken magnet is the problem! A while back we helped a gentleman in Spain with a similar problem:

https://www.thirdgen.org/forums/tech...ht=distributor

A broken magnet would cause erratic signal to EST module. Pickup (reluctor) coil appears to be fine - this is indicated by variation in DVM readings (per your observation in your last post). The easy fix is to get another unit (rebuilt or from JY). From your photo it appears that you have original issue dizzy. Later versions have slightly different construction, but magnets must not be shuttered.

//RF

 

Jeez, I'm so glad I finally found the likely cause of my problem. I was beginning to think I was going crazy. I knew all along that once I spotted the problem, it would be obvious and I'd wonder how I missed it. It was, and I do

I've had the dist. out three times, and the cap/rotor off probably 10 times. NEver noticed that cracked magnet until last night.

I'll hit the junkyard as soon as I can, probably Saturday. I will post my results.

Thanks so much for the help!

Dave

 

dave ,it happens to the best of us. ive done it, anyone who works on cars has done it. lots of times its right under our noses,cant see it for looking at it. good job hope this fixes it,later jimmy

 

Please excuse the following rant:

WTF? Just installed the new dist and still no spark. I'm about to toss a match in the gas tank. This car is cursed.

Thank you for your cooperation.

I guess when we get some warmer weather I'll be pulling the entire wiring harness from the engine compartment to check each and every wire. Thats the only thing I haven't done.

Dave

 

a bad pick up can cause instant death to the ignitiong control module I would warranty that and see what happens, or atleast sest it with a module tester. Just an educated guess, but it would be an easy fix

~Couch

 

David

Is dizzy turning????
'New' parts are sometimes defective....
Ignition Coil defective
+12 Volts at dizzy during cranking???

//RF

 

dave ,man it seems like im not the only one who has bad luck sometimes. i cant believe this,but like rf said sometimes new parts dont work.i can definitely understand the frustration.ive reread all the post again, i honestly dont see what were missing.i know im repeating myself,but are you sure the coil is grounded good?also is the engine grounded good? i know you fixed the grounds on the heads, but is there a ground strap coming from the body(firewall) or the chassis.keep us posted later jimmy

 

Yes, dist. is turning, and oil pressue will build while cranking so my timing chain is fine. The dist is installed correctly... will need to be timed but its close enough to start the car.
I tested the pickup in the new dist before installation, good.
Coil checks out good, and it has a good solid ground.
I repaired one bad ground on driver's head. When I say it was bad, it looked questionable so I improved it. It was probably fine though.
Ground strap present, in good condition, and perfect continuity from engine block to negative side of battery.
12v verified at coil with key on. I don't have an assistant to check coil voltage while cranking... I can enlist one of my buddies though.
two-wire harness from coil to dist checks out good.
No codes in ECM other than "12"
No blown fuses.
I'm thinking my problem has to be in the 4-wire harness from the spark module, or possibly something's up inside the car somewhere, like the key switch itself.

I'm starting a new project this weekend, so the Camaro will have to wait a couple more days before I can work on it again.

Dave

 

Time to resurrect this one.

So I'm about done with my other project (motor swap on my brother's '73 'Vette) and I'll probably get a chance to play with the Camaro some this weekend.
I'm down to thinking this can only be a bad connection at this point because all my hardware checks out ok. So here's what I'm gonna do:

I'm gonna unplug the wiring harness from the ECM and feed it back up from behind the fender and into the engine bay (this section of the harness is also suspect since its more exposed than what's under the hood). That way I'll have easy access to both ends of the harness. I'll unplug each and every connector and check continuity through the harness to the ECM. I plan to start with the grounds, then move on to the ignition related components.
Hopefully I won't have to remove much of the harness when/if I find the problem to repair it.
So what do you think? Anything else I should check while I'm doing this?

Dave

 

I am going to assume you have wiring diagrams....

Instead of pulling the whole harness, just disconnect from the ECM, and use a jumper wire in the ECM connectors between two of the wire on the four wire Distributor connector. Use the VOM under the hood, and test those two wires. Bad? Switch the jumper wire to one of the other wires on the four wire connector, and try again. Should be able to determine if you have a bad wire, or two, without having to remove the whole harness. (save that for if/when you find a bad one.....)

 

I'm having a similiar problem - wondering what your solution was?

 

[quote=Big Dave;3628059]Time to resurrect this one.
I'm gonna unplug the wiring harness from the ECM and feed it back up from behind the fender and into the engine bay (this section of the harness is also suspect since its more exposed than what's under the hood). That way I'll have easy access to both ends of the harness. I'll unplug each and every connector and check continuity through the harness to the ECM. I plan to start with the grounds, then move on to the ignition related components.



Dave
Instead of performing a Kama Sutra on your harness perform a static - key in run position, engine stop, all sensors connected voltage check by back probing ECM connector Pin A1 through D16. Which ECM do you have in your Camaro? There are voltage charts for each type. It is a simple check that can yield useful trouble shooting information.

//RF

 

My 84 firebird finally died last night; I had resurrected it about 2 wks ago; got another 2+ wks left on the 30 day temp registration. Carquest tried to sell me a whole computer for $117; I said I'd continue troubleshooting. So I went to Autozone and got the cheap Duralast for $19; turns out I have the 7 Terminal not 4 Terminal Ignition Module. Paid the $9 difference for the 7 terminal.

My symptons were when taking it on the freeway past 55mph, it would lose power, like it was choking on too much gas or no gas at all; in the street level it was fine. But not last night; no sooner that I got the ignition module that it died on my 4 times on the way home - coasted into the driveway -nice!

This is a 4barrel carb; it doesn't have a Mass Air Filter (MAF) does it?

Going to try and get it replaced tonight.

 

I already did the Kama Sutra thing . Really not that big of a deal. Everything checked out ok. I've also replaced the connectors at the coil. I am running the stock TPI ECM for speed density cars. 1227730 I think is the part number. Stock memcal for a 1992 Z with a 305/auto.

I've also double double checked my grounds, and did finally find a loose one, but thst didn't fix the problem either.
I've also gutted my interior to check all the interior wiring. Having a little trouble getting the dash back in, but didn't find any obvious problems. I was expecting to find some chewed wires because as soon as I removed the dash pad I found some chewed plastic and mouse poop. But alas, everything looked fine. Pristine, in fact.

Also, I disconnected where the engine wiring harness connects to the driver's firewall, just to look for a bad connection. It was a mess. I should have taken a picture but didn't. There was all this black crud in there, looked like grease, but MUCH thicker, almost a putty if you will. It appeared to be some sort of sealant to keep moisture from getting to the contacts as there was a lot more on the back of the connector. Some brake cleaner and a few q-tips and all the contacts look good as new. I've still got my interior gutted so I didn't get to see if would start. Is there any wires in that connector (the one on the driver's firewall, below the relay braket, its held on by one 1/4" bolt) that would cause me to lose spark if one or more of the contacts were so dirty?

Dave

 

That was old dielectric grease and you need to put some new back in there to prevent corrosion of the contacts.

 

OK, I've never seen 16 year old dielectric grease, so I don't really know... but are you sure? This stuff was the consistancy of tar, only harder, and I could see where it was almost completely covering some of the contacts.
Brake cleaner alone would have dissolved dielectric grease on contact... I had to scrub this crap off with q-tips. It was odd. It makes sense, obviously, to use a sealer there, but this stuff was n-a-s-t-y.

Dave