car only starts sometimes no spark

[coreydmc]

I am at a loss. Some days the car starts fine, others it wont start at all. I know it is not a fuel problem because i smell plenty of gas and hear the fuel components working. I checked the inertia switch and that is fine. When this first started happening i replaced the coil with a OEM bosch one from DMCH. My wires and dist cap are not that old. My fuses are also good. What else should I check for? My car is sitting in my driveway cause i cant get it started to pull in garage. I dont want to keep trying to start it because the cyl's are just filling up with fuel.

[David T]

Check the connections on the white ballast resistor on the firewall in front of the motor. Another possibility is a bad impulse coil.
David Teitelbaum

[jmettee]

RPM Relay? If there's no spark, other than the coil being bad or a disconnect in the wiring, the RPMs relay is the trigger for the ignition system. When they go bad, they have flakey soldiers that sometimes make connection & sometimes do not.

Got a second one to try out?

[opethmike]

As David said, check and clean up the ballast resistor connections. Also, check and clean up the connections on the coil itself.

[Bitsyncmaster]

Is your starting problem only with a warm engine?

Lots of things can cause starting problems. The more data you provide will help us narrow down the problem.

[coreydmc]

starting is only an issue when cold. ill clean the ballasts. where is the other parts located i should check?

[coreydmc]

is the impulse coil in the dist cap? ill also order another rpm relay. Should I get it from DMCH?

[coreydmc]

ok i checked the ohms on the impact coil. i unplugged the terminal wire going into the firewall and tested the coil side of the wire. i get 541 ohms. if it should be 600 or higher is this my problem. I dont think it is the rpm relay because i smell gas and hear fuel pump working. i also checked the inertia switch and fuses.

[Bitsyncmaster]

Does the engine fire at all when you have the problem?

[coreydmc]

when i turn the key and hold it for like 5 or 10 seconds the car will on RARE occasion sound like it wants to start. like it is getting a spark to ignite gas but then goes away. But this doesnt happen all the time. I also smell a lot of gas from the engine

[Bitsyncmaster]

Sounds like your getting to much gas. Check to see if anything is plugged into the hot start relay socket. Then pull the connector off the CSV and see if that cures your starting problems.

On my car, the only time I need the CSV is if the car sits for two weeks or more. Hot or cold otherwise it never needs the CSV and it starts better that way. I think after sitting, the injector lines drain or evaporate of fuel.

I've seen a thermal time switch fail so it always injected the CSV when starting.

Or it could be your CSV is not working at all. You test that by pulling the CSV out and put it in a jar. Pull your white ignition wire off the resistor and crank the engine for 5 seconds. You should see about an ounce of gas in the jar.

[coreydmc]

what socket in the relay compartment is for the hot start relay? also i mentioned earlier that my pick up coil in the dist. is only 540 ohms not 600. should i replace this?

[Bitsyncmaster]

what socket in the relay compartment is for the hot start relay? also i mentioned earlier that my pick up coil in the dist. is only 540 ohms not 600. should i replace this?

Your resistance is fine on the pickup coil. That reading is no cause for replacing it.

The hot start relay socket is a white socket way in the back of your relay compartment. Right at the back wall. It just has three wires from the harness holding it there.

[coreydmc]

ok i just went outside. I found the plug for it but there is no relay there. it is empty and was for the 15 years i owned the car. I just unplugged the csv and still nothing.

[Bitsyncmaster]

ok i just went outside. I found the plug for it but there is no relay there. it is empty and was for the 15 years i owned the car. I just unplugged the csv and still nothing.

The hot start relay should be empty unless you have my electronic hot start relay.

So your next step is to test if the CSV is working like I posted in the last thread.

[coreydmc]

ok. just to be sure i pulled a spark plug out and plugged it into the wire. I had my wife try to start car so I can watch to see if there is spark. And there is spark. ill test the csv.

[Ron]

Keep in mind that while you are checking things out, you can disturb a bad connection and not know you have 'fixed' the problem because the plugs are fouled...

[Kenny_Z]

Where'd you ground the plug to when checking? I'm guessing the block? Have you checked your grounds? Red had a hard time starting and stalled a lot until I changed my battery to chassis ground wire. I grounded the battery to the transmission and then the block to the chassis. It drastically improved the condition of my electrical system.

[coreydmc]

I grounded the plug to the intake manifold. My grounds are fine. I re-did them last year.

[David T]

If it is hard to start cold it could be a lot of things. If you are thinking it is spark related try shutting off the fuel pump and using a LITTLE bit of Ether. Or pull a spark plug wire and look for a big, fat, blue spark. A weak spark will make it hard to start. Could be a bad coil, cap, rotor, plugs, wires.
David Teitelbaum

[coreydmc]

spark looks good. ill text my CSV tomorrow. how about TTS? if it measures 30 ohms its good?

[coreydmc]

ok I unscrewed the CSV and put it in a jar. I held key for about 5 seconds and got plenty of fuel. So im guessing that is good? I also checked the ohms in the TTS and it measures about 30. Still not starting though

[Bitsyncmaster]

ok I unscrewed the CSV and put it in a jar. I held key for about 5 seconds and got plenty of fuel. So im guessing that is good? I also checked the ohms in the TTS and it measures about 30. Still not starting though

So you have fuel and spark. Either your not getting enough spark. Or your getting to much fuel. Or your spark it timed wrong but even with wrong timing you should get some indication of it firing.

If you have tried a little shot of either into the FD and still nothing then I would guess your spark to to weak.

[coreydmc]

i just want to double check myself. What is the best way to test the bosch stock ignition coil?

[Bitsyncmaster]

i just want to double check myself. What is the best way to test the bosch stock ignition coil?

Hard to test the output power of a coil. You can check the voltage on the two lugs (input) to the coil. When starting you should get around 5 volts or more across those terminals. When testing with just the key on and engine not running you get about 3 volts. When the engine is running you read a lot higher because the current is switching on and off and the meter reads an average voltage.

[coreydmc]

thanks for fast response. ill go outside now and test those contacts on coil

[DMC5180]

Grab the coil wire at the Boot and remove while someone else cranks the engine. :biggrin:

[Ron]

Grab the coil wire at the Boot and remove while someone else cranks the engine. :biggrin:Dang it Dennis, I was just going to suggest the same thing...;-)

Fowled plugs.

[DMC5180]

And measure the Arc Jump. More than a 1/2 inch should be SHOCKING enough :biggrin:

[coreydmc]

ok. when i use my digital multimeter on the 2 lugs on the coil this is what i get?

black meter lead on 1, red meter lead on 15
key off 0 volts
key on 2.4 volts

coil was just replaced 3 months ago from DMCH

[Bitsyncmaster]

ok. when i use my digital multimeter on the 2 lugs on the coil this is what i get?

black meter lead on 1, red meter lead on 15
key off 0 volts
key on 2.4 volts

coil was just replaced 3 months ago from DMCH

That is about normal. Depends on the condition of your battery. When you are cranking the starter, one of the coil resistors is bypassed so your voltage reading would be higher.

So your problem started without you doing anything to the car? Have you tried a shot of starter fuild (either) yet?

[coreydmc]

yes I also removed the air filter box and shot starter fluid inside intake manifold and still nothing. This is strange since car started last week. im at a loss. maybe I should start from the beginning again? should I replace pulse ignition inside dist?

[coreydmc]

im guessing my spark is to weak. what should I do?

[Bitsyncmaster]

im guessing my spark is to weak. what should I do?

You can try bypassing one or both resistors. I don't recommend you do this permanently but if it starts that would show you the ignition is the problem.

[coreydmc]

thanks for the tip. can you please tell me how to do this?

[Bitsyncmaster]

thanks for the tip. can you please tell me how to do this?

Connect the white wire to the white yellow wire on the resistor block. You can just pull those wires and jumper them together.

[coreydmc]

ok i just jumped them together and still nothing. i left the blue/yellow wire still plugged into resistor. I also checked my coil. Is this connected right? on the "1" is the white slate wire, on the "15" is white/yellow and just yellow. i seem to smell gas when i try and start

[Ron]

Keep in mind that while you are checking things out, you can disturb a bad connection and not know you have 'fixed' the problem because the plugs are fouled...
?

pull a spark plug wire and look for a big, fat, blue spark.

?

[coreydmc]

i did pull a plug. I assume is looks like a strong spark. are on my previous post does my coil seem to be wired up correctly?

[Ron]

Was the plug(s) wet? If so you need to pull them all and clean them up.... You can check their spark by plugging them into the coil or plug wire and grounding them with the block or a jumper cable... Of coarse every time you turn the engine over you are flloding it more and more (blow the holes out some with compressed air if you can). If it is actually flooding, you could remove one of the fuel pump wires and when the pressure goes down after sitting (or carefully release it), then hold the throttle AND metering plate open to help clear it out (watch out for "backfires"...which is your signal that it is probaably cleared out ;)

Yes, 15 on a Bosch is the primary's positive terminal (WY wire)...bypassed as Bitsy said should bring 12V to it, not hooked up of coarse.

[coreydmc]

so ill open the front trunk and remove access panel to fuel pump and disconnect one wire right? How do I release pressure?

[Ron]

Yes, and secure it of coarse -- Do the ground (-) side..if not sure wrap it with a little tape.

I'd put the cold start valve in a container and crack the fitting...then tighten it back. Replace the copper washers if they aren't new and keep an eye on it for a while just in case. It goes without saying to USE EXTREME CAUTION. And have an extinguisher handy. Really!!!

Clean/dry/check the plugs first or you will be wasting your time...

(Sorry for delay in response...our power keeps going in and out.)

[coreydmc]

ok im on it!

[coreydmc]

Thanks for all of your help guys! I finally got it running. I cut off the ends on the wires at the coil and the resister. Replaced them with new ends. I also repaired the wires on the TTS. I cleaned all the plugs and removed all the old fuel. Car started right up! I have a question though....on the ceramic resistor on the firewall there are 3 black wires grounded on the bottom of it.. Should I move them and ground to engine block?

[Bitsyncmaster]

Thanks for all of your help guys! I finally got it running. I cut off the ends on the wires at the coil and the resister. Replaced them with new ends. I also repaired the wires on the TTS. I cleaned all the plugs and removed all the old fuel. Car started right up! I have a question though....on the ceramic resistor on the firewall there are 3 black wires grounded on the bottom of it.. Should I move them and ground to engine block?

Good work. The grounds are just a place to make a common connection. The resistor block itself does not need to be grounded. So you can move those grounds to the engine block if you wish.

[Ron]

Thanks for all of your help guys! I finally got it running. :thumbup:

[BobLS]

Check the connections on the white ballast resistor on the firewall in front of the motor. Another possibility is a bad impulse coil.
David Teitelbaum

Thanks Dave. Car would either not start unless holding the ignition switch in just the right position between "Start" and "Run." Sometimes it would run and then just die as if it was out of gas or as if I turned off the ignition switch. I had tried/tested everything: fuel pump, inertia switch, relays, ignition electrical component replaced. Finally just R & R'd the ballast resistor wires. SOLVED! Took 20 seconds.