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Fuel + Spark but Still Starting Issues by FieroLou
Started on: 04-03-2015 08:05 PM
Replies: 10 (204 views)
Last post by: FieroLou on 04-05-2015 01:51 PM
FieroLou
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Report this Post04-03-2015 08:05 PM Click Here to See the Profile for FieroLouSend a Private Message to FieroLouEdit/Delete MessageReply w/QuoteDirect Link to This Post
I recently picked up a new 86 SE V6. I found out after purchasing it, that it was very hard starting cold. It would take a few seconds, or sometimes a few attempts of cranking to get it to finally fire up. Knowing it hadn't been driven much over the past 15 years, I decided to do a tune up. New AC Delco plugs, wires, dist cap, and dist rotor. Once I was done, I went to fire it up and now it won't start.

The car cranks. It will crank normally for a few turns, and seem to "bog" down briefly before cranking strong again. I have checked fuel pressure. It primes to 40 PSI. Once the pump turns off, it settles down to ~10 PSI. Once I'm done cranking it, the pressure appears to be over 40 by the time I make it to the gauge, it again will settle down to ~10 PSI. Fuel pump sounds very quiet compared to my Duke Fiero. The relay does click. I have been unable to get it started with starting fluid ( a few second spritz after the air filter and then some cranking).

I figured it may be a spark issue. I tried replacing the Ignition Coil, same problem. I replaced the ICM, no help. Finally, I grabbed a spare spark plug and tested on cylinder 3's wire grounded to the engine. I have a spark...

Pep Boys tested my battery to be OK. 515 CCA.

I am completely at a loss. Does anyone have any idea where to look next? Thanks

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1985 Pontiac Fiero 2M4

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Csjag
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Report this Post04-03-2015 08:10 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your fuel pump could be going bad, are the plugs wet when you check them, the fuel pump does some weird things when its on it way out. Did you change the timing or adjust it?
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Report this Post04-03-2015 08:12 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post

Csjag

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Also be sure the plug wires are on the correct locations on the new distributor
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Gall757
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Report this Post04-03-2015 08:26 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
You are talking about at least 3 problems....

1. your fuel pressure is dropping off too fast...there is a leak somewhere, possibly in the tank, but maybe the pressure regulator or the injectors themselves.
2. your spark is maybe visible, but not good enough to light up the starting fluid.
3. your fuel pump relay may be inop. and your backup circuit was actually starting your car....it is the oil pressure switch, and takes some cranking to activate.

Go back over your installation of new parts and confirm the wires are going to the right places....the rotor is not 180* off, and the cap is not pinching any wires at the bottom. Pull a plug and look for black...or fuel...or whatever.
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FieroLou
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Report this Post04-03-2015 10:51 PM Click Here to See the Profile for FieroLouSend a Private Message to FieroLouEdit/Delete MessageReply w/QuoteDirect Link to This Post
What can I do to locate the source of a potential gas leak in the system? How could I rule out injectors etc?

I don't think any issues pertain to the fuel pump relay, as I believe it is working, but I will switch it to the AC relay to see if it makes a difference.
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Mike Gonzalez
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Report this Post04-03-2015 11:10 PM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by FieroLou:

What can I do to locate the source of a potential gas leak in the system? How could I rule out injectors etc?

I don't think any issues pertain to the fuel pump relay, as I believe it is working, but I will switch it to the AC relay to see if it makes a difference.


Pinch the rubber return line with vice grip see if the pressure still drops off. if not your regulator is bad. If so, prime it to pressre and pinch both lines, if it drops injectors are leaking, if not fuel pump/check valve is gone.

Generic test, but it works.

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Patrick
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Report this Post04-03-2015 11:33 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 Mike Gonzalez:

Pinch the rubber return line with vice grip...


Am I the only one that squirms when I see that recommended with 30 year old rubber fuel lines?

I understand the theory behind the suggestion (and I'm definitely not singling out you, Mike), but I'd never do that to my own Fiero(s).
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Mike Gonzalez
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Report this Post04-03-2015 11:43 PM Click Here to See the Profile for Mike GonzalezClick Here to Email Mike GonzalezSend a Private Message to Mike GonzalezEdit/Delete MessageReply w/QuoteDirect Link to This Post
LOL, i know, but it work and ive never seen one get damaged from it. I guess if your not careful it could, but it doesnt take much.
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tshark
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Report this Post04-04-2015 12:10 AM Click Here to See the Profile for tsharkSend a Private Message to tsharkEdit/Delete MessageReply w/QuoteDirect Link to This Post
...

[This message has been edited by tshark (edited 09-08-2018).]

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theogre
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Report this Post04-04-2015 12:29 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:
Am I the only one that squirms when I see that recommended with 30 year old rubber fuel lines?
I understand the theory behind the suggestion (and I'm definitely not singling out you, Mike), but I'd never do that to my own Fiero(s).

Nope... vise grips etc can easily damage new hoses, old hoses more so.
You need long nose and only enough force to pinch the hose close.
Keep sharp edges away from fuel hose. If needed use a file/grinder and kill the edges etc.

Or just go to parts stores, HF store, etc and get hose Pinch-Off tools. many are only a few dollars.
example
http://www.harborfreight.co...clamp-set-65116.html
Lisle 2-Piece Hose Pincher Sets 22850 sold thru many places

either case, you need to pinch-off the hose far from the ends. Pinch-Off too close to the ends and ends could cut inside of hose.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)


The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

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FieroLou
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Report this Post04-05-2015 01:51 PM Click Here to See the Profile for FieroLouSend a Private Message to FieroLouEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did the described procedure. It appears to be a leak within the gas tank. I'll be dropping the tank and replacing the pump and trying to figure out what's going g on in there.

I'll also be replacing the battery. I can't manage to jump it after running it down attempting to troubleshoot the car. Any suggestions as to what battery I should get?
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