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2.8 no start. by AL87
Started on: 12-13-2013 02:21 PM
Replies: 14 (299 views)
Last post by: AL87 on 12-31-2013 12:18 PM
AL87
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Report this Post12-13-2013 02:21 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
okay, im just making sure Im getting this right.

fire at coil, but not at plug.
pump primes. (didn't check pressure yet)

things to check are, cap, rotor, and wires correct? distributor pickup?
nothing else should be the problem... maybe timing?
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Midn1ght Driv3r
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Report this Post12-13-2013 03:05 PM Click Here to See the Profile for Midn1ght Driv3rClick Here to Email Midn1ght Driv3rSend a Private Message to Midn1ght Driv3rEdit/Delete MessageReply w/QuoteDirect Link to This Post
One of the biggest failures is the ignition module on the distributor if you haven't checked that out yet.
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phonedawgz
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Report this Post12-13-2013 03:12 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you truly have spark at the coil but not at the plug about the only thing that can happen is the rotor has a hole burnt through it. It will appear as a dark spot. That or moisture inside your cap or a shorted coil to dist wire with the spark jumping out of the wire.

[This message has been edited by phonedawgz (edited 12-13-2013).]

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AL87
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Report this Post12-14-2013 04:25 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
okay, time to do an ohms test.
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AL87
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Report this Post12-14-2013 05:40 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
I got fire going to the cap.
still didn't check all the wires for any breaks.

but I have fire rhere too.. so somewhere its not getting put to the plugs
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phonedawgz
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Report this Post12-14-2013 06:04 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
When dealing with high voltage an ohm meter is only somewhat helpful. The ohm meter measures the resistance at a very low voltage. The spark operates at a high voltage. So lets say there is a micro-hole in the rotor. Because there is an air gap between the metal of the rotor and the dist shaft the ohm meter will read infinite ohms. But the spark will still jump to ground there.

When the ICM fires the coil the voltage in the coil will build until it finds a place where it can jump to ground. If you check for spark by holding the wire away from the block the voltage will increase the farther the wire is from the block. So perhaps your testing procedure is changing as you change from the coil to the spark plug. Note also - a spark plug installed in a cylinder will need even much higher voltage to fire. So if you are testing by using a timing light and you are't getting a spark with the wire connected to the plug but you can get a spark outside the cylinder that is because inside the compressed cylinder more voltage is needed. So bad insulation in the coil can give you an situation where you can get spark outside the cylinder but when connected to a plug, the higher voltage needed is above the defect in the coil and you no longer get a spark.
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Patrick
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Report this Post12-14-2013 06:10 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by phonedawgz:

... inside the compressed cylinder more voltage is needed. So bad insulation in the coil can give you an situation where you can get spark outside the cylinder but when connected to a plug, the higher voltage needed is above the defect in the coil and you no longer get a spark.


I was taught a long time ago that the spark needed to be strong enough to jump a 1/4" gap outside the cylinder.
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AL87
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Report this Post12-16-2013 02:06 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
what about the ignition pickup?

how can I test that?

its on the new style distributor with star points instead of the fingers like the old design.
so it shouldn't be that old.

just did a quick read, I saw on the msd website that a pick up should be measuring about 500-700 ohms if good.
will check to make sure.

Im almost positive now its the cap and rotor. but the guy Im doing the work for wants me to go through THE WHOLE checklist before he opens up his wallet.

[This message has been edited by AL87 (edited 12-16-2013).]

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AL87
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Report this Post12-18-2013 04:12 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
okay, so replaced the cap and rotor, getting spark to the plugs now.
checked fuel pressure at 43psi leakdown was down to 40 in 5min and stayed there for another 5min.

fuses are all good. (namely the injector fuses.)

I checked 12V with a test light on the injector harness and this is what I got.

Pink/White: 12v key on/constant
green: nothing even when cranking
blue: nothing even when cranking
Pink: 12v Key on/constant
purple/white: 12V when cranking only
Tan: nothing even when cranking

I'm assuming What im seeing by the above test is that one of the banks isn't receiving signal.

where to check next? the harness hub by the battery looks suspect of some possible bad wiring, but I don't think that's a problem

Also, what else should I check?
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AL87
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Report this Post12-20-2013 04:33 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
should I check signal at the ecm?

I'm thinking about running a new wire to the half of the injector harness that isnt getting signal.
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AL87
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Report this Post12-27-2013 04:57 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
i think its the ecm or a broke wire, I would like someone to confirm on what my reads were for the wiring harness to the injectors.

I think i'll just run a new wire to get her fired up but I'm concerned about the wire routing, if the wires going to the injectors go through anything else. ex relays, sensors, senders, etc.

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AL87
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Report this Post12-30-2013 01:12 AM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'm just going to do a voltage signal test at the ecm for the injector bank that isn't firing, if I have signal, then I know there's a break.

either that or an ohms test on the wire to check for a break or high resistance, I'll probably do both. since one tests the wire, and one the ecm signal to the injector bank.
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AL87
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Report this Post12-31-2013 03:17 AM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
idk, like magic this car started to get signal to where it needed. the electrical system checked out. I guess the pins needed to get cleaned.

decided to recheck everything. and it was good.
it turns out the plugs were rusted so bad, the ground wasn't good enough to jump the spark on the firewall side.
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Gall757
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Report this Post12-31-2013 11:17 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Are you telling us it is fixed?
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AL87
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Report this Post12-31-2013 12:18 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:

Are you telling us it is fixed?


yeah, pretty much. I pulled the related connectors and re-seated them. and all of a sudden I had signal to the injector bank that wasn't getting any.
everything checked out fine after that, so I checked the last thing after the electrical issue was solved, which was the plugs.
changed them all out at the proper gap and then she fired right up, timing was off so I re-set that, and now she's nice and healthy.

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