Werid starting issue

[taylorlike88]

So I have a gmc safari love the dam thing to death but recently it's bin having a issue starting. I have found you have to blip the key to the start position to get it to start and if the battery is under 13.2 volts it will crank but not start. Also noticed that its like the motor misses on the highway and when it's cold out it has a hesitation in the low end. Don't know if I missed something after doing the headgaskets.

I have a parts van I've been swapping parts with (parts are expensive up here in Canada) tryed changing the distributor and the coil. Did the plugs before I did the heads (bosch quad points) so don't think there the problem. The only other think I can think of is that the pipe that brings exhaust gas up to the intake has bin removed and capped off.

I'm starting to run out of ideas just want it fixed so a can put a comand start I'm it, it's starting to get cold up here

1997 safari awd 250xxxkm

[AstroWill]

Cranking is a good thing. Now you need to find out if you are missing spark or fuel. One of the quickest ways to check if fuel is your issue is spraying some starting fluid into the intake. Next, check to see if you are getting strong reliable spark. Then work from there.


We should make a flowchart for this stuff ;)

[MI_Ghost]

You will need a strong coil with those plugs. I am not sure the factory coil has enough energy for that style plug.

[AstroWill]

You will need a strong coil with those plugs. I am not sure the factory coil has enough energy for that style plug.

That doesn't make sense to me, could you expand on that?

[MI_Ghost]

You will need a strong coil with those plugs. I am not sure the factory coil has enough energy for that style plug.

That doesn't make sense to me, could you expand on that?

Air gap plugs need a higher voltage coil because of the larger gaps involved. Multi electrode technology has not lived up to all the hype that surrounds them.

The factory coil is approx 30K volts compared to the 40K-48K volts of the MSD and Accell coils.
Carbon string plug wires which are great for reducing radio noise also break down and add resistance further reducing spark voltage. Carbon tracking in the cap and rotor adds even more resistance to the point where you might only be getting 20K volts at the plug tip.

If you are running multi electrode, air gap plugs you need higher voltage from the coil to get proper spark.

[AstroWill]

You will need a strong coil with those plugs. I am not sure the factory coil has enough energy for that style plug.

That doesn't make sense to me, could you expand on that?

Air gap plugs need a higher voltage coil because of the larger gaps involved. Multi electrode technology has not lived up to all the hype that surrounds them.

If you are running multi electrode, air gap plugs you need higher voltage from the coil to get proper spark.

I didn't realize that they had a larger gap, the last set of mutli-electrode plugs I put in(Taurus) seemed to have about the same gap.

[MI_Ghost]

Normal plugs are usually .032-.035 gap.
Air gap plugs are commonly .050-.060 range.
The guys on the bike forum I follow are finding out that the weak ignition systems do not work well with these fancy plugs.

[AstroWill]

Normal plugs are usually .032-.035 gap.
Air gap plugs are commonly .050-.060 range.
The guys on the bike forum I follow are finding out that the weak ignition systems do not work well with these fancy plugs.

OEM ones for my 03 are .060 so it sounds like they are the same.

[taylorlike88]

Forgot to add that it ran rich for a long time because of o2 codes so would damaged cats cause any of that. But I'll try normal plugs and see where that puts me.

[WimpTech]

I H A T E those fancy plugs, good ole Delco R44xls for me!

BTW- check the fuel filter, sounds clogged, all the same symptoms as my 99 had.

[chevymaher]

Forgot to add that it ran rich for a long time because of o2 codes so would damaged cats cause any of that. But I'll try normal plugs and see where that puts me.

No but running rich damages the cat and clogs it.

[taylorlike88]

Could it be a vacuum leak?

[chevymaher]

Could it be a vacuum leak?

Hard to tell half throttle doing 75 mph somewhere. What does it read idling and is it steady.

[MI_Ghost]

All these fancy computer programs are not my strong side.
I would greatly appreciate if someone could explain the gauges program. What is it?

[AstroWill]

https://play.google.com/store/apps/deta ... owl.torque

Torque light/pro, very handy with a cheap bluetooth OBD2 adapter.

[dchan51360]

Since you have a parts van and you say it happened when you swapped the heads, do a leak down. Check for pressure at the rail. You might try a sea foam cleaning but I find that's only temporary. If you have not upgraded to a multi port injector, I'd be reaserching spider, fuel regulator problems. The "starts when quick kick on ignition but no start with long crank" sounds like sticker poppets and not enough pressure to keep them firing.

[WimpTech]

4.8Hg is 2.3psi for all us gringos. What do you get at idle? If not at least 16psi (33Hg+) then you probably have an issue.
Do the fuel filter yet? Mine went stupid when I ran it low on gas, sucked up garbage, now does what yours does.

[TurnNburn]

4.8Hg is 2.3psi for all us gringos

Well not really. 4.8 inches of mercury is a measure of vacuum and pounds per square inch measures pressure and I don't think are interchangeable. If they were I could imagine saying -2.3 psi but I have never heard of it used that way?

[WimpTech]

Ohhh, my bad, I was thinking that's the other UOM for vacuum that us gringos use, like KMH vs MPH.
So if that is the same UOM, then shouldn't it idle at over 16Hg?

[TurnNburn]

I stand corrected, I have never heard of it used this way but Wikipedia says your right

In English units: 1 inHg60 °F = 0.489 771 psi, or 2.041 771 inHg60 °F = 1 psi.

https://en.wikipedia.org/wiki/Inch_of_mercury