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Another 3.4 dohc issue by ricksmastermix
Started on: 07-04-2013 05:37 PM
Replies: 10 (210 views)
Last post by: ricksmastermix on 07-07-2013 05:19 PM
ricksmastermix
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Report this Post07-04-2013 05:37 PM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
I recently swapped a 3.4 dohc engine into my Fiero based Corson Spyder. It's run well for a few weeks, but when I went to start it this afternoon, it wouldn't fire up.

The engine turns over smoothly and the fuel pressure is good (Read with a mechanical gauge at the fuel rail entrance,) so I'm assuming the fuel feed is good and that the problem is due to no spark.
Does this sound familiar to anyone? Where's a good place to start troubleshooting?

Thanks.
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ltlfrari
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Report this Post07-04-2013 07:32 PM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
Throw some starting fluid down it's throat. If it does not at least fire, that confirms no spark. After that start chasing power leads to make sure you have power to the ignition module. Also check wires from the crank sensor on side of block to the coils.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

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KY87fierogt
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Report this Post07-04-2013 09:21 PM Click Here to See the Profile for KY87fierogtClick Here to Email KY87fierogtSend a Private Message to KY87fierogtEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ricksmastermix:

The engine turns over smoothly and the fuel pressure is good (Read with a mechanical gauge at the fuel rail entrance,) so I'm assuming the fuel feed is good and that the problem is due to no spark.
Does this sound familiar to anyone? Where's a good place to start troubleshooting?

Thanks.


First I am not an expert....this is just my opinion!

Never assume! You have fuel pressure, but are the injectors firing?? Could still be fuel related. Is it flooding during extended cranking? Smell fuel?

The only way to determine if you are getting spark is to test it.......IK checking plugs in a DOHC 3.4=pain in the,....well you already know.

Is it even trying to start....hitting?
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ricksmastermix
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Report this Post07-04-2013 10:51 PM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's not even trying to fire. If it doesn't respond to the starting fluid, I'll start tracking the loss of spark (Thanks, Dave.) IF IT DOES RESPOND TO THE STARTING FLUID, I'll start looking into the injectors.
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tesmith66
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Report this Post07-05-2013 09:28 AM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
How and where did you mount the coils? Do they have a good ground? What year DOHC did you use? The wires on the 24X crank sensor behind the balancer (94 and up) can be damaged easily (ask me how I know this). I would focus on the ignition module first.

------------------
1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

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ricksmastermix
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Report this Post07-05-2013 03:52 PM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
It's a '92 engine with the coils mounted on the passenger side of the engine bay. None of the plug wires are very long and the engine ran fine for the first few weeks. Might be worth check the ground on the coil pack.
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ricksmastermix
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Report this Post07-05-2013 07:37 PM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, I just towed her to the body shop for some paint touch up and door adjustments. I'm heading to Florida with the family for a week and my paint/body man had a window of time, so I'm taking advantage.
This gives me a week to plan my troubleshooting strategy. Any suggestions are appreciated.
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Robert 2
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Report this Post07-05-2013 10:43 PM Click Here to See the Profile for Robert 2Send a Private Message to Robert 2Edit/Delete MessageReply w/QuoteDirect Link to This Post
Check the fuse for the fuel pump relay .
2nd from left to right top row .

[This message has been edited by Robert 2 (edited 07-05-2013).]

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ricksmastermix
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Report this Post07-07-2013 09:56 AM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
I can hear the fuel pump run when I turn on the ignition and I have the correct fuel pressure (I have a mechanical fuel pressure gauge in front of the fuel rail.)
All that being said, it's easy enough to check the fuse. I suppose the fuel pump could be making noise, but malfunctioning, and the fuel pressure is maintained for a long period after the engine is shut down. However, it's more likely to be injectors not opening or no spark.
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KY87fierogt
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Report this Post07-07-2013 04:21 PM Click Here to See the Profile for KY87fierogtClick Here to Email KY87fierogtSend a Private Message to KY87fierogtEdit/Delete MessageReply w/QuoteDirect Link to This Post
Did you get a chance to confirm no spark?
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ricksmastermix
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Report this Post07-07-2013 05:19 PM Click Here to See the Profile for ricksmastermixClick Here to visit ricksmastermix's HomePageClick Here to Email ricksmastermixSend a Private Message to ricksmastermixEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm on vacation this week. I found an old thread that indicated the Fuel Pump fuse, Ignition fuse and Injector F1 & F2 fuses need to be replaced with higher current fuses with this swap. I'll verify this with Eric (Who did the harness.) The solution may be just that easy (Fingers crossed.)
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