I've been trying to fire up this thing for the last 3 weeks and have had different issues to deal with. Right now, I have no spark and I don't know why. I have visually inspected and independently tested the plug wires, ignition coil, ICM, ignition pick up coil, and wires leading to all parts. All these parts are brand new and everything checks out, yet I have no spark. I am using EBL and have tried a tune I put together and a base L05 tune to account for something I had possibly messed up in the spark tables and it made no difference. At this point, I'm out of ideas so any help you guys can give is much appreciated.

 

Any issues with grounding? I found that spark doesn't happen due to grounding issues. Check behind the passenger side cylinder head? There's a grounding point over there.

Now I'm taking that No spark means "no spark" at the spark plug (obvious statement). I know that I had issues with spark because I had forgotten about proper grounding of the engine electrical system. I had a smoking fused link remind me about that.

I really don't want to delve in more speculation beyond that as I'm not sure about my grasp on the topic. I mainly would like to show that someone has spent 30 sec's thinking about your issue

 

Have you replaced the module inside the dizzy? Mine went bad in my 84 and I got no spark at all.

 

Lets start at basics

Do you have +12 volts at the coil during cranking????

 

Teal, I haven't had any time to do more diagnosing with school and work but the next thing I was going to check was that I have the grounds in the right spot. Off the top of my head I can think of one ground on the back of the cylinder head and two on the firewall but I don't remember what they go to. I'll finally have some free time this weekend to work on it.

Ozz, this is a brand new motor with all brand new parts including the distributor, ICM, and coil so that's not the problem.

RF, I don't recall if I checked voltage or not but I do know I checked the coil's resistance and it was within spec.

 

Does anybody know which grounds are supposed to go on the engine and which go on the firewall. Or does it not matter? I want make sure I have them all in the right place and properly hooked up.

 

There are only two actual "Grounds" that I know of which cause problems. The first, is the mesh wire ground that's on the passenger side head and connects the motor to the firewall. The other is off the negative battery cable.

The rest of the grounds are built into harnesses as negative or neutral wires which you'll need a manual to trace.

 

The braided copper "mesh" wire is accounted for. the negative battery cable is grounded on the back of the a/c compressor bracket stud.

as for the rest of the grounds, there are two that i know of. Both of those come out of the main harness and are currently on the firewall on the passenger side. One is black w/white stripe and the other is solid black. Is that correct for them?

 

I moved the solid black ground from the firewall to the back of the cylinder head and that fixed my fans and a/c fan not working. still no spark though.

 

No Spark Condition (component check list). Please go through this list and check one by one and report your observations per this list. Troubleshooting requires that process steps are followed in a sequence so that correct course of action can be taken.

1) +12 volts at coil during cranking - measure with DVOM while cranking. No +12 at coil = no spark.
2) Bad ICM - can be tested at some parts stores or replaced with known good one. New aftermarkets parts are known to be DOA so look out!
3) Bad reluctor coil (inside distributor) - can be checked without removing dizzy by measuring coil resistance with DVOM. On very rare occasions magnetic reluctor ring may loose one or more teeth resulting in a bad misfire, but you will still have spark.
4) Bad 2-wire harness between dizzy and coil - inspect and check with DVOM
5) Bad ignition coil - check with DVOM and or replace
6) Bad rotor and or cap - inspect and or replace
7) Spark plug wires and plugs - measure spark plug wire resistance with DVOM and inspect. Replace if questionable.

//RF

 

[QUOTE=RFmaster;5428196]No Spark Condition (component check list). Please go through this list and check one by one and report your observations per this list. Troubleshooting requires that process steps are followed in a sequence so that correct course of action can be taken.

1) +12 volts at coil during cranking - dont believe I've done this. I have checked for 12 volts at the coil with ignition in run but not while cranking.
2) Bad ICM - Tested and passed at local parts store
3) Bad reluctor coil (inside distributor) - tested and within spec
4) Bad 2-wire harness between dizzy and coil - checked and within spec
5) Bad ignition coil - checked resistance and all within spec.
6) Bad rotor and or cap - brand new but inspected and dont appear damaged
7) Spark plug wires and plugs - measured resistance of wires and they are within spec. havent checked plugs but they are also brand new and i have an in-line spark tester so i will know if i get spark everywhere but the plug.

if i test for 12 volts at the coil during cranking and im not getting it, what needs to be done?

 

Disconnect ignition coil DC power plug - it should have a large gauge pink wire (#12AWG IRC) and a white wire - tachometer signal. Pink wire must have +12 volts when ignition key is in run and crank position. The ignition lock cylinder acts as switch and gets +12 volts directly from the battery via red wire. This side of ignition key circuit is protected with fuse link B in the engine bay. If this fuse link blows - nothing else will work in the cabin. It is uncommon, but ignition key cylinders have been known to fail with age - worn contacts.

Do a basic check before doing anything else - measure voltage at the end of that plug (pink wire) with respect to ground. Post your findings. Happy Thanksgiving.

//RF

 

Ok so I know it's been awhile since I've posted but I finally did some more investigating and testing on the car today. I downloaded a service manual for an 88 firebird and followed the chart it had for an ignition system check on the 305 TBI.

Step 1 was to check for spark at the plug. This was checked and all of a sudden i had spark. So we hooked the injectors up and tried to crank it. We heard it fire once or twice and then it would just turn over without spark. So we checked spark again, and this time we had none. So we moved on to the next step

Step 1A was to disconnect the 4 terminal distributor connector on ICM and check for spark. Still nothing.

Step 2 was to check for spark at coil with the tester. Still no spark.

Step 3 was to disconnect the 2 terminal distributor connector and check voltage on both pins with ignition in run. Both are supposed to have at least 10 volts and both have approx 11.5 so we were good there.

Step 4 was to reconnect the 2 terminal distributor connector and check the voltage from the tach terminal to ground with ignition on. Voltage should be 12 volts. I have .01 volts. So it appears my problem (or at least part of it) is an open in the tach signal wire.

Also during several of the tests while cranking, I noticed it would fire intermittently so we checked spark at coil several times and at a couple of the plugs. The coil would get spark and #3 plug would have spark but #1 wouldnt. Inspected cap and didn't find any damage, swapped #1 and #3 plugs and wires, and still had no spark on #1. I'm not sure if this helps confirm the tach signal issue or not. This is just what I'm experiencing when testing. Also fwiw, my WUD has an RPM reading when turning the motor over and my tach does bounce around a bit. Both seem to read about 150-200rpm... That was as far as I got today due to running out of daylight so hopefully next weekend I can delve further into this tach signal issue. Do any of you have any info regarding the tach signal wire as I don't really know much about it and/or what it does and how exactly it factors into the ignition system.

 

Happy new year
By the looks of it you may have intermittent coil. It gets warm from couple firing events and develops open in the primary coil. This why you see 0.01 volts at the tach end. The tach terminal is connected to ICM pin C which pulls coil terminal to ground, completing the circuit and firing it. To check this right after you observed no spark condition disconnect both black and gray connector and measure coil resistance between coil A to B sets of terminals - it should read very low resistance ~1.0 Ohm. If not replace a coil.

With engine stopped and ignition on you should see +12 volts at tach lead. See section 2-30, Figure #14 of Chiltons manual.

//RF

 

During cranking, battery voltage will droop due to large amount of current sucked up by the starter motor. Better to say that the coil should be powered by battery voltage--or close to battery voltage.
I would suggest that basic checks of the ignition module and the reluctor can be better done at home than if handed to some underpaid bozo at a parts store. See home diagnosis procedure linked-to below.
You should have very near battery voltage. 11.5 is low, if the battery is fully-charged. However, the ignition should operate to less than 10 volts, so although it may be "a" problem, but it's not "the" problem.

Or the ignition coil itself. Better test both the coil and the harness. Coils and harnesses on external-coil/small cap HEIs seem to fail at about the same rate.

AFTER you get reliable spark at the coil, you can investigate problems on individual cylinders. Don't get ahead of yourself.

Not exactly. The ignition module does connect the coil to ground which causes current to flow in the coil windings, but the "firing" of the coil is what happens when the module DISCONNECTS the ground, stopping current flow and collapsing the magnetic field in the coil.

Typically more like 0.5--0.6 ohms on an HEI coil primary.

Second half of article. Article was written with in-cap coil HEIs in mind, but most of the info is valid if the test points are changed to reflect the physical layout of the small-cap/separate coil HEIs.
http://www.chevelles.com/techref/ftecref5.html

 

Schurkey - thanks for expanding on the basics as I usually do not have the luxury of time to get into full details of secondary coil current induction from a sudden collapse of a magnetic field when ICM opens (ICM acts as a switch) primary coil negative terminal.

Most low cost DVM's will have difficult time reading below 1 Ohm, besides getting past terminal contact resistance. Coil primary windings check should be used as an indicator - to get accurate coil resistance measurement would take a four wire DMV (HP34410) setup, but then again this is outside most people capabilities.

//RF

 

ground the batt to the block ,not the ac bracket which is conected to the intake with a rubber gasket . this has been some peoples problem in the past . think outside the box . when you disconected all the wires (electrical plugs ) did you pull on the wire instead of the plug? just think of everything you did from start to finish .

 

So even though the coil ohmed out within spec on my initial test, low voltage on the tach signal wire means a faulty coil? Also, I don't kow what you mean by "measure coil resistance between coil A to B sets of terminals". What are the A and B terminals?

I don't have a Chiltons manual for the car so I don't know what that figure is you're referring to. But during the diagnosing, with engine stopped and ignition on I had .01 volts at tach signal wire.

 

Thanks for the added info. How exactly do I test the harness? The only thing I know to do would be to tear the dash apart and check continuity at both ends of the tach lead.

 

That is the factory location for that ground and it doesn't even reach the block. Unless you are referring to a ground that is on the wiring harness at the back of the engine, in which case it is on the block. There is no rubber gasket on the A/C bracket...This car has been sitting for almost 4 years. It'd be impossible to try to remember how I disconnected a plug or every little thing that I did when I took it apart, though I tried to keep everything as neat and organized and labeled as possible for reinstall.

 

Schurkey is likely referring to the two-wire pigtail between the coil & distributor. The wire likes to break inside of the insulation where it exits the coil connector. And it can't be seen as being broken.

RBob.

 

I have checked the two wire connector and i have continuity there. I think i tested the tach signal at the wrong spot. I unplugged the single wire connector and checked voltage there and i had 12V. So it appears the ignition coil is working as it would since I have continuous spark at the coil.

After some testing today, my dad got a portable ignition system that bypasses the ignition coil (although previously i was getting consistent spark from the coil). All it does is get power from the battery and send spark to the distributor on command. Initially with the 4-wire connector on the ICM was connected, we would get fuel but no spark. With it disconnected, we would get spark but no fuel. We grounded pin A on the ICM to see if we were able to drive the injectors manually. After this, with the 4-wire pin connected, we had both spark and fuel but at this point the battery had had enough so it still wouldnt fire. I honestly don't know what we did to make it work that last time or why the 4-pin connector was determining why it would or wouldn't spark or get fuel. Does this make sense to anyone?

FWIW, on my EBL WUD I constantly have 0* on the SA meter regardless of the position of the distributor or whether or not the set timing connector is hooked up or not. I do have 0* set in my tune. Since I've never run EBL on a working car I don't know if this is supposed to be like that or not. Does that potentially mean anything in regards to why it won't start?

 

When you disconnect 4 wire connector ECM does not receive DRP pulses - and since ECM controls injector firings based on DRP pulses this explains why you do not get fuel injectors to fire. Without DRP present EBL is showing 0 deg (initial ignition timing) since ECM does not know engine is being cranked over. Distributor and coil by themselves generate spark. ECM is not required under 400 RPM. Once engine RPM exceeds 400 RPM ECM begins to control timing. If you get consistent spark during cranking this indicates that coil and ICM are functioning. So what happens when you connect 4-wire plug to distributor??

//RF

 

What is DRP?

EBL has shown 0* since I've been trying to start the car. That's with 4-pin connector plugged in, unplugged, tan EST wire plugged in and unplugged, distributor rotated in several positions, etc.

Every other time previous to today when I've tried to start the car with the 4-pin connector plugged in, I've had intermittent spark at the plug. Today, I've gotten consistent spark with that ignition box hooked up and after we somehow got both fuel and spark to work with the 4-pin connector in, it tried to bust off. However, the timing was still way off and battery had pretty much had it. We will try again tomorrow with a fresh charge and see if we can to start up now that there is consistent spark and fuel.

 

DRP = distributor reference pulse. This is a signal ICM generates to tell ECM when it fires ignition coil. ECM figures out engine RPM based on this input signal from ICM.

 

With the ignition box hooked up and 4-pin connector plugged in, we still have intermittent spark at the plugs. That would seem to indicate a problem with the cap, rotor, or wires but there is nothing wrong with them. Could that mean its a ground issue somewhere? If so, where do I need to check?

 

Take a small ruler, position it vertically and mark #1 cylinder wire position on the dizzy flange body. Pull your dizzy cap off, turn engine with a breaker bar until balancer is right against 0 deg (TDC). Also, make sure that you are on compression stroke on #1 cylinder (or rotor will be pointing 180 deg away from #1). The rotor tip should align vertically right against #1 cylinder mark (on dizzy flange body). If it is between two cylinders that may explain why you are getting sporadic spark at spark plugs. However, you should be getting consistent sparking from coil to dizzy during cranking. Simple check just to rule out bad parts.


//RF

 

afternoon update: ignition coil was faulty. Replaced it with a stock replacement and now spark is strong and consistent at both the coil and plug. However, it still won't fire. I have fuel and spark and timing is dead on at 0* (checked with timing light). All it does is turn over.

 

So it was a coil after all!

Just make sure that your base timing is at 0 deg TDC on a compression stroke of the #1 cylinder. It will not fire if dizzy 180 deg out!!! Just make sure - please!!! I had this sort of thing before on more than one occasion.

//RF

 

So I got it to start today. I think the distributor was out 90* or so. Still trying to get it to run right 100%. My timing in the tune is set to 0* but the car wont run on anything less than 15* according to EBL. I'm still trying to figure out all the functions and how to use it so other than the WUD, I don't really know how to use the other displays and what they mean.

Thanks for all the help over the past several months. I really appreciate it.


fyi, this new motor is a 350 with LT4 hot cam, 113 vette heads, and holley TB and TBI intake.

 

yep dizzy was out 180* ... For anyone with no spark issues, i made a video on this very thing in my youtube channel look me up "klowny69" ...and please subscribe..I'm in the process of putting alot of thirdgen videos in my channel..also check out my 91 camaro!!

for the computer question..with the est wire disconnected you should set ur initial timing at 6 degrees..then hook everything back up..thats what the computer knows to be ur initial timing..and tune from there.

 

Initial timing on the factory L03 is 0*. The TPI's are 6* I believe. However, I was asking specifically what it should be with the LT4 hot cam as I couldn't get it to run on anything lower than about 15-18*. I didn't realize that cam required so much base timing.

 

The base timing is only used during cranking. With those heads & cam setting it to 6* BTDC should work better then 0*. Be sure to set the BIN's "SA - Initial SA" parameter to the same value that the distributor base is set to.

There is a supplied calibration with SA tables for those heads. Be worthwhile to copy them into whichever BIN you are currently using.

RBob.

 

^yes!

 

My initial effort was to try 0* and the car wouldnt run. I haven't been able to get the car to run on anything less than about 15* initial SA. I am already using the SA main and extended tables for the 113 heads. Should I be using all the tables that have SA prefix?

 

Just the Main & Extended SA tables. When you set the base timing do it on a warmed up engine with no other loads. Start the engine with the EST/BYPASS open. May need to use a little pedal to keep it running until the IAC retracts some.

To decide the best base setting, if it windmills when cold, need more. If it kicks back when hot, need less.

Nothing wrong if it ends up being 8* or 10* BTDC. Although, it does limit the lower end of the available SA. Can only go about 3* less then the base setting.

RBob.