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2.8 long crank before start (sometimes) by AL87
Started on: 08-11-2013 10:59 PM
Replies: 27 (1545 views)
Last post by: 2.5 on 11-15-2013 09:05 AM
AL87
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Report this Post08-11-2013 10:59 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
sometimes I have to crank for about 5 seconds or more before my car fires up.

and on another note, sometimes the cold start injector makes it "explode" right into high idle.

Im thinking that there might be something possibly clogging the cold start injector sometimes.

I have an adjustable fuel pressure regulator, and wonder if I should adjust the top screw in or out of the fpr assembly.
(I might be a little low on fuel pressure after the fuel pump primes.)

the ignition works, I have an msd 6al, and I just checked, modified and re-gapped the plugs to take advantage of the more powerful spark.
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phonedawgz
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Report this Post08-12-2013 12:19 AM 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
Is your fuel pump relay working?

Many times the fuel pump relay quits working and the fuel pump ends up getting power through the back up oil pressure switch. That results in a few cranks before enough oil pressure is there to turn it on.

Turn your key on and listen for the fuel pump. It will come one the first time you turn the key to on. It might not the second unless you wait at least 45 seconds. It should however come on for two seconds every time you bump the starter.
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AL87
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Report this Post08-12-2013 01:17 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
 
quote
Originally posted by phonedawgz:

Is your fuel pump relay working?

Many times the fuel pump relay quits working and the fuel pump ends up getting power through the back up oil pressure switch. That results in a few cranks before enough oil pressure is there to turn it on.

Turn your key on and listen for the fuel pump. It will come one the first time you turn the key to on. It might not the second unless you wait at least 45 seconds. It should however come on for two seconds every time you bump the starter.


You are asking if the fuel pump primes the fuel rail with pressure? Yes, it does, every time.

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olejoedad
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Report this Post08-12-2013 07:20 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
With a cold engine, check for 12V on the the tan wire on the cold start injector switch with key in "start" position.
If no power, check for 12V on the purple/white wire on the cold start injector switch, key in "start"position position.
If no power, check the fusible link by the starter solenoid for continuity.

[This message has been edited by olejoedad (edited 08-12-2013).]

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AL87
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Report this Post08-12-2013 07:08 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 olejoedad:

With a cold engine, check for 12V on the the tan wire on the cold start injector switch with key in "start" position.
If no power, check for 12V on the purple/white wire on the cold start injector switch, key in "start"position position.
If no power, check the fusible link by the starter solenoid for continuity.



the car is my daily driver, I dont see why it would be the fusible link, it just cranks and fires up right away, and sometimes... not soo much.

but then again, my question, why is this issue intermittent?
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olejoedad
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Report this Post08-12-2013 09:27 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
You mentioned your cold start injector.

I gave you the electrical troubleshooting proceedure.

Do with it what you want.
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NetCam
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Report this Post08-12-2013 09:38 PM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
You said sometimes it does this. Is it only when the car has been sitting for a short period of time after running it? If the car starts up really well when you start it for the first time in a while, but then requires quite a bit of cranking after sitting for a short while, it could be a leak in your injectors and you need to blow the unburnt fuel out before it will fire up.
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AL68
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Report this Post08-13-2013 12:00 AM Click Here to See the Profile for AL68Click Here to Email AL68Send a Private Message to AL68Edit/Delete MessageReply w/QuoteDirect Link to This Post
My 86 GT had an intermittant long crank problem, swapped in known good injectors, cold start injector & switch, fuel pump (pressure was good) - all the usual possiblities - no change.

Found this thread (grounds) on adding ground straps (I ran two, one by the battery tray ground to the waterpump, one from the pump to the trunk hindge) - problem fixed!
Starts right away every time, it seems to run smoother too.
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AL87
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Report this Post08-13-2013 12:45 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 AL68:

My 86 GT had an intermittant long crank problem, swapped in known good injectors, cold start injector & switch, fuel pump (pressure was good) - all the usual possiblities - no change.

Found this thread (grounds) on adding ground straps (I ran two, one by the battery tray ground to the waterpump, one from the pump to the trunk hindge) - problem fixed!
Starts right away every time, it seems to run smoother too.


I have the same setup, with the grounds. I even have more underneath...

and I KNOW EVERYTHING WORKS... its my daily driver... just... this intermittent problem has me stumped... ALTHOUGH...
I could just for he heck of it... I could try swapping the relays.
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AL87
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Report this Post08-13-2013 12:54 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 olejoedad:

You mentioned your cold start injector.

I gave you the electrical troubleshooting proceedure.

Do with it what you want.


I did some thinking, and IF it was the fusible link that had popped, I wouldn't get good fire... EVER.
but I do get a good fire sometimes. and my fuel pump primes every time I turn the key on.

something just doesn't fire the cold start injector sometimes. last thing I didn't check was the relay.

I did some testing on the oil pressure, and the engine fires as soon as the oil pressure sender registers pressure.

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Damorgan
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Report this Post08-13-2013 01:14 PM Click Here to See the Profile for DamorganClick Here to Email DamorganSend a Private Message to DamorganEdit/Delete MessageReply w/QuoteDirect Link to This Post
Have you tried replacing your fuel filter? Its only like a $10-$15 fix and it sounds like it might be your problem, thatd be one of the first places Id think to look and it probably needs replacing anyways
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AL87
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Report this Post08-13-2013 01:18 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 Damorgan:

Have you tried replacing your fuel filter? Its only like a $10-$15 fix and it sounds like it might be your problem, thatd be one of the first places Id think to look and it probably needs replacing anyways


everything is about a year old, and no less, I cleaned the tank properly, and installed a replacement fuel pump.

HOWEVER, could the IAC and TPS have any effects?

I know my tps gives my ecm problems, and theres always been a hesitation on takeoff because of it.
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olejoedad
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Report this Post08-13-2013 01:30 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by AL87:


I did some thinking, and IF it was the fusible link that had popped, I wouldn't get good fire... EVER.
but I do get a good fire sometimes. and my fuel pump primes every time I turn the key on.

something just doesn't fire the cold start injector sometimes. last thing I didn't check was the relay.

I did some testing on the oil pressure, and the engine fires as soon as the oil pressure sender registers pressure.


The cold start injector circuit has no relay. When the starter solenoid is energized, power is applied to the cold start injector switch. If the coolant temp is below 95°F, the switch energizes the cold start injector.

Check the fusible link at the starter solenoid for a soft spot. It is possible for the link to be open (burned), but make intermittent contact, like a small break in a wire. Not common, but possible.

The trouble shooting proceedure I posted earlier will verify the operation of the circuit. If it tests bad, wiggle the wire from the solenoid to the injector switch to see if it will test good. If it tests good, wiggle it to see if you can get it to test bad.

Intermittent electrical can be a pain....

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AL87
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Report this Post08-13-2013 02:00 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 olejoedad:
Intermittent electrical can be a pain....


AMEN*

Okay, well. I will have to test this later, the car is hot, had to do some other tests*

I'll look into it asap!
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AL68
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Report this Post08-13-2013 10:58 PM Click Here to See the Profile for AL68Click Here to Email AL68Send a Private Message to AL68Edit/Delete MessageReply w/QuoteDirect Link to This Post
Have you watched the fuel pressure on a gauge during a cold start when it starts hard? The pump check valve might let the fuel line drain back into the tank, the pump would have to fill the line then build up enough pressure to start the engine. It might take cranking a several seconds for full pressure.
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phonedawgz
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Report this Post08-14-2013 02:56 AM 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
Hey you two are brothers of different mothers.
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olejoedad
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Report this Post08-14-2013 06:55 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by AL68:

Have you watched the fuel pressure on a gauge during a cold start when it starts hard? The pump check valve might let the fuel line drain back into the tank, the pump would have to fill the line then build up enough pressure to start the engine. It might take cranking a several seconds for full pressure.


There is no check valve in the fuel delivery system. Key 'ON' energizes the fuel pump for a few seconds to build system pressure for starting.

But, the question is valid.

Have you checked fuel pressure after key 'ON', but prior to starting?
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AL87
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Report this Post08-14-2013 02:50 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
 
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Originally posted by phonedawgz:

Hey you two are brothers of different mothers.


Lol, okay, I wasn't the only one to see that! ^_^

I'm thinking of swiching my name over to 07 or 13. idk yet...

Fuel pressure is as follows... during prime, pressure reaches 45psi, and stays there.

During idle, its 40

[This message has been edited by AL87 (edited 08-14-2013).]

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olejoedad
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Report this Post08-14-2013 03:34 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your fuel pressure is good.

If key 'On' primed the pump, your fuel pump relay is good.

Checked the CSI circuit yet?

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AL87
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Report this Post08-14-2013 05:06 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
 
quote
Originally posted by olejoedad:
Checked the CSI circuit yet?


NOPE.
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AL68
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Report this Post08-14-2013 09:17 PM Click Here to See the Profile for AL68Click Here to Email AL68Send a Private Message to AL68Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by olejoedad:


There is no check valve in the fuel delivery system. Key 'ON' energizes the fuel pump for a few seconds to build system pressure for starting.

But, the question is valid.


The pump has a check valve built into it to keep fuel from siphoning back to the tank when the pump is off - otherwise the fuel pressure would drop to zero as soon as the key is shut off.
When the valve starts going bad the fuel lines can empty back into the tank overnight, sometimes intermittantly. The only way to tell is to watch the pressure when it won't start.

The pressure may only rise to 10-20 psi when first turning on the key because it has to fill the lines - not enough to start the engine.
Cranking opens the injectors, dropping the pressure a little more. After a couple seconds the pump catches up & there is enough pressure to start the engine.

I've had several GM pumps act like this at my shop over the years : the fuel line is empty, If you turn the key on/off a few times to fill the system & build up pressure, then crank it over & it starts right up.

 
quote
Originally posted by AL87:

Fuel pressure is as follows... during prime, pressure reaches 45psi, and stays there.

During idle, its 40



Fuel pressure looks fine key on/running but was that the pressure reading while cranking while it would not start?

If the pressure is 40-45 while cranking & it won't start the pump is good, problem is something else.

[This message has been edited by AL68 (edited 08-14-2013).]

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olejoedad
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Report this Post08-14-2013 11:00 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did not know that, thanks for the knowledge!

(I just went out to the shop and pulled a pump off the shelf and tried to blow backwards through it!)

Learn something new every day!

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AL87
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Report this Post08-14-2013 11:51 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 AL68:


Fuel pressure looks fine key on/running but was that the pressure reading while cranking while it would not start?

If the pressure is 40-45 while cranking & it won't start the pump is good, problem is something else.



I'll have to check another day.
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AL87
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Report this Post08-26-2013 11:32 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 did figure out that the ground running from the block to the negative terminal has acid leaking through it, and that because of this the threads stripped from me trying to tighten them, also, I cant pull the bolt out that holds the cable.

I guess its time to break out the grinder, put a cutting disc on, and have at it.

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AL87
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Report this Post11-13-2013 11:39 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 re timed the motor to the correct spec grounding the diagnostic terminals.

I checked the wiring going to the cold start injector, and no power, whatsoever through it while the fuel pump primed, or even during cranking. somewhere in the harness there is the problem.

I do not know where the cold start injector wiring goes from the injector harness.

when is the power supposed to be applied to the cold start injector, and for how long?
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jon m
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Report this Post11-14-2013 05:31 AM Click Here to See the Profile for jon mSend a Private Message to jon mEdit/Delete MessageReply w/QuoteDirect Link to This Post
I read a thread a few months back where a member had increased the spark plug gap and claimed better performance, gas and mileage - he had gone from 0.40 to 0.60 (bear with me on this) 0.40 being the advised gap.
this thread came with a bit of mixed opinion (I will try and find it and post it later)
I decided to go half way and re gap my plugs to 0.50 just for curiosity and to play safe etc.

what I found is the car would fire up within 1 to 2 seconds - so this was an improvement to me because originally my car would take, like yours a good 5 seconds to start.

As you have re gapped your plugs I would look somewhere else.

does it still take a good 5 seconds to restart after the engine has been warmed up ?

jon

[This message has been edited by jon m (edited 11-14-2013).]

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AL87
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Report this Post11-14-2013 11:39 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 chopped off half my electrode-ground finger thing... and increased the gap to .050, I'm also running the msd 6al system so I get a fatter/longer spark.

I don't know whats up with this, idk if its partly a tps problem or what... I chopped off the wiring going to the cold start injector, and everything seems fine now, starts up no prob...

[This message has been edited by AL87 (edited 11-14-2013).]

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Report this Post11-15-2013 09:05 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by NetCam:

You said sometimes it does this. Is it only when the car has been sitting for a short period of time after running it? If the car starts up really well when you start it for the first time in a while, but then requires quite a bit of cranking after sitting for a short while, it could be a leak in your injectors and you need to blow the unburnt fuel out before it will fire up.


I agree, wonder if ti does this when cold started.
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