: 99 STS hard cold start. No codes, fpr tests ok and fuel is 44 psi running



Fathrington
07-01-14, 11:26 AM
This Car hasn't been driven much in the past 9 months. 147k miles. I recently changed the plugs with oem ac delcos, about a week later the hard cold start slowly became an issue. It started only taking a second or 2 longer, and now it often will not start on 5 seconds, then i stop try again and it will start. From then on when its warm it starts right up. No codes, so i am flying blind! I just changed the fuel filter last night and had the same issue this morning. I went to the junk yard and got a good looking fpr, put that on and its doing the same thing. it passes the test when i remove the vacuum line, no fluid comes out. The plug wires are packard, never heard of them, but the car at the junkyard had the same kind.
It gets 44 psi when running, and 40 in the on position. It does not hold the 40, and slowly drops, is that an issue?

thanks!:worship:

Ranger
07-01-14, 11:31 AM
It does not hold the 40, and slowly drops
That sounds like a bad check valve, but if it 40 and 44 psi, that shouldn't be a problem.

Fathrington
07-01-14, 12:10 PM
i was able to re-position the gauge so i could see it when turning the key. as soon as the key goes the the on position it jumps up to 50 psi for a second, then drops instantly to 40 psi, then a slow drop.

Submariner409
07-01-14, 01:47 PM
Packard Wire and Cable is an old, old, old GM division.

Back in '55 good ol' Packard 440 stranded copper core spark plug cable was the cat's meow - of course you couldn't hear the AM radio for the interference. Then came resistance plugs, then came EMI suppression cable.

That 40 psi at Key: ON is good; the slow drop is not. BUT that should not cause a long crank start. Fuel pressure specification in RUN is 41 - 47 psi.

Fathrington
07-01-14, 06:03 PM
so its a good idea to change the plugs? i was leaning in that direction. $65 for ac delco is that bad, but its all adding up.
thank you both for your wisdom!!!

Submariner409
07-01-14, 06:33 PM
Plugs are AC Delco #41-950, look in www.rockauto.com (http://www.rockauto.com). Also, buy a new $110 AC Delco (Packard) cable set. If they are original they're LONG overdue. You may find some oil on one or more spark plug shells. Normal: The cam cover well seal O-rings weep over time. I would use a tad of anti-seize on the first 3 threads of each plug, tighten to about 13 lb/ft. Use a toothpick to smear a small dab of silicone dielectric grease into the tip of each plug and coil tower boot. Both anti-seize and dielectric grease from any parts store.

Dismount the 4 coils and the ICM and make sure the coils and their bases are clean, the connectors are clean and tight, and the ICM ground wire terminals are clean and tight.

Your AC Delco Double Platinum plugs should cost about $36 + shipping.

Use this to make sure the plugs and wires are connected properly.

Fathrington
07-01-14, 06:51 PM
thanks sub. i used those exact plugs when i changed them a few weeks ago. had a few with a tad bit of oil. i connected the wires correctly, and the terminals on the coil packs looked brand new! that shocked me
i just ordered a set of ac delcos off amazon, was $54 shipped after 20% off. i will get them saturday.
the plug wires are marked with a paint marker, as well as my fpr. i think that means they were replaced at some time?

Submariner409
07-01-14, 06:54 PM
Not necessarily - my car has swatches of paint of every imaginable color on a LOT of parts and components. I think it's a QC type thing.

Fathrington
08-28-14, 09:26 PM
ok well it is still doing it after the wires were done. i also did a napa head gasket fluid test today just incase, passed.
so in total i replaced the plugs and wires with oem, fuel filter, cleaned the maf and TB, used 93 octane for a few tanks now, and charged the battery.
i have not tried a brand new FPR, but will order one soon.
Im wondering if the fuel pressure dropping when its in the on position is whats causing that.
Car runs good, mpg could be a bit better i think

Ranger
08-28-14, 09:55 PM
Do not replace the FPR unless it is leaking.

What is your fuel pressure while cranking?

Fathrington
08-28-14, 10:03 PM
i think its around 45 but ill have to check again. from what i recall when doing it over a month ago, it was 45 or so.
i was thinking maybe the bottom o-ring on the fpr could be cracked, would that cause the fuel to be pressed back to the tank?

Submariner409
08-29-14, 10:31 AM
If the fuel pressure was 40 - 45 psi cranking/running that's the correct figure - regardless of how much fuel the FPR was bypassing - and it always bypasses fuel: The pump moves a LOT more fuel than the engine ever needs - round and round and round - pump, lines, FPR, lines, tank and so on.

Did you also remove and clean the 4 coils and the ICM ? Dirt/grime on the coils and ICM holds moisture (condensation) on cool mornings - hard start. The ICM ground cable is another source of trouble - good, clean, tight terminal connections necessary.

Coil - wire - plug diagram - necessary.

Fathrington
08-29-14, 10:43 AM
i did not, but the connections looked brand new, which amazed me. i will check the ground connections now

Ranger
08-29-14, 11:44 AM
Doesn't sound like your problem is fuel related.

Fathrington
08-29-14, 11:55 AM
ok i just cleaned the ground cable for the icm. i took the whole icm off to inspect it, seemed ok, no cracks. i did notice there was wear on both sides of the icm where the ground goes, in the shape of the ground. so that means its been on both above and below the icm. i dont recall ever putting it on below it, so could that be the issue maybe? does it go below?
when i just tried starting it was the same, long.
i live in florida so its pretty humid, could the icm be going? i noticed maybe small gaps where the icm screws in, should i try tightening the screws?

drewsdeville
08-29-14, 02:41 PM
Fuel pressure bleeding coupled with extended crank symptoms - I would verify where that fuel is being bled off. If an injector is leaking fuel into the manifold, the flooding is causing your extended crank. If the check valve leaks, the system has to re-prime itself every morning, causing the extended crank.

If there is a flexible section of fuel line, test by energizing the fuel pump, then crimping the feed line shut.

If pressure now doesn't bleed, it's the check valve, which is may your problem. Verify by cycling the key twice before cranking to see if it starts normally (or try a shot of starting fluid to see if it shortens crank time).

If fuel pressure does still bleed, fuel is leaking into the manifold and causing your hard start. You've eliminated the FPR, so then you'd have to check for an injector leak.

Fathrington
08-29-14, 04:39 PM
i cant seem to find a flexable fuel line on the car.
i just took the fpr completely out and inspected the small o ring under the filter, there is a crack or 2 in it.
would that cause the fuel to leak into the manifold?

Ranger
08-29-14, 04:46 PM
If it is leaking into the manifold, you should see fuel at the nipple or in the vacuum line (or at very least, smell it there).

Fathrington
08-29-14, 06:19 PM
i just went to the junkyard and got 3 more fprs, mostly for the bottom o-ring.
still hard cold start when i swapped one out and still looses psi when in the ON position.
if it was a leaking injector, would it cause hard warm starts also, as it starts in 1 second when its warm.

edit: there was quite a few northstars there, so i could pull a pump off one for $30 or so.
is this a difficult job? i have the access panel in the trun and i think a few at the junker do also

Ranger
08-29-14, 10:02 PM
Yes a leaky injector would cause a hard warm start. Much like trying to start a carbureted car with the choke on.

Pull the fuel rail, but leave it attached to the supply line. Turn the key on momentarily to see if one is leaking.

Removing the pump on a car with an access panel is not hard, but that's not your problem.

Fathrington
08-29-14, 10:42 PM
ok so should i now check the injectors? do i need to buy new orings for them if i pull them?
i do not have a problem with hard warm starts though, starts right up in 1 second. only cold hard starts, sometimes as close to an hour after being run, but anything under 1 hour it starts right up fast.

Ranger
08-30-14, 11:24 AM
If you have no hot start problems, then it is unlikely you are leaking fuel into a cylinder or the manifold.

Fathrington
08-30-14, 01:27 PM
always starts up super fast when hot.

JoeTahoe
08-30-14, 02:17 PM
always starts up super fast when hot.

How does it start after sitting hot for awile? Sounds like the pump check valve is not holding.

Fathrington
08-30-14, 02:28 PM
it starts to get the hard start after about an hour or 2 of it being driven around. Under that time it will start right up fast

Ranger
08-30-14, 09:44 PM
Next time you expect a hard start after sitting, turn the key on for 2-3 seconds to energize the fuel pump and pressurize the system. Then turn it off and back on again for another 2-3 seconds and then see if it starts faster. If it starts faster, that would confirm Joe's check valve theory.

JoeTahoe
08-30-14, 11:42 PM
Next time you expect a hard start after sitting, turn the key on for 2-3 seconds to energize the fuel pump and pressurize the system. Then turn it off and back on again for another 2-3 seconds and then see if it starts faster. If it starts faster, that would confirm Joe's check valve theory.
Ranger is correct just turn it to run than back to off and run again count to 5 and turn to Start

Fathrington
08-31-14, 10:51 AM
now we are talking! best cold start its ever had since this problem started, only about 2 seconds or so!
so time to change the fuel pump? There are a few at the junkyard, so i should have a few options. Anything i should be looking for on a used one? Are there any special tools i will need?
Thank you guys so much for your help!

Ranger
08-31-14, 12:46 PM
Any used part is going to be a gamble.

There is a "special" lock ring tool to remove the lock ring on the top of the tank, but a brass drift or screw driver and hammer will turn it off.

http://www.denlorstools.com/shop/wpimages/GM_Fuel_Pump_Assembly.jpg

http://ww2.justanswer.com/uploads/heavychevy396/2012-03-18_231719_remove_lock_ring_fuel_pump.jpg

JoeTahoe
08-31-14, 05:01 PM
now we are talking! best cold start its ever had since this problem started, only about 2 seconds or so!
so time to change the fuel pump? There are a few at the junkyard, so i should have a few options. Anything i should be looking for on a used one? Are there any special tools i will need?
Thank you guys so much for your help!
I would not buy used. Too much of a gamble and my luck it would be bad. Check out rock auto and look at ac delco

Submariner409
08-31-14, 06:32 PM
Yup ^^^. www.rockauto.com (http://www.rockauto.com)

The Airtex, DELPHI, UltraPower and AC Delco modules are all OEM units - just depends which box it is in. Airtex and UltraPoaer may come with an upgraded (HD) 4-blade electrical connector/pigtail theat gets spliced into the existing body harness. Diagrams included.

Fathrington
09-03-14, 05:21 PM
so the ultrapower is the cheapest option at $100 shipped, but it says its for the y vin, but i have a 99 sts so that is the 9 vin, will it not work? this is my fathers car, i am fixing it for him then selling it, and ive already put a couple hundred in it so far. He really wants me to put a junkyard pump in for $20. I may be able to convince him to let me buy the ultrapower pump for $100. the job looks pretty easy to do, the only thing i dont get is how do i get the floater in the hole with the pump

MoistCabbage
09-03-14, 05:28 PM
There are no pump/level sending unit differences between VIN Y/9 cars.

JoeTahoe
09-04-14, 11:08 AM
so the ultrapower is the cheapest option at $100 shipped, but it says its for the y vin, but i have a 99 sts so that is the 9 vin, will it not work? this is my fathers car, i am fixing it for him then selling it, and ive already put a couple hundred in it so far. He really wants me to put a junkyard pump in for $20. I may be able to convince him to let me buy the ultrapower pump for $100. the job looks pretty easy to do, the only thing i dont get is how do i get the floater in the hole with the pump
The float is attached to the fuel module you just have to turn with module to get it out. On that note I would by new.

Fathrington
09-12-14, 04:44 PM
ok, i have the new pump, but i cant seem to get the lock ring off. it moved a few mm but it seems stuck. any suggestions? im using a hammer and chisel

edit: just sparyed with pb blaster, will let it sit then try again shortly

97EldoCoupe
09-12-14, 05:05 PM
Once they get rusty they often don't move. Be careful (I know you know this) with a hammer and chisel around a fuel tank. I try to use something to absorb shock and prevent sparks, such as a hardwood block and a hammer against the lock ring.

In Ontario (rust capital of the world, yet one of the best places to live) sometimes the lock ring tabs that are integrated into the fuel tank rust away. At that point; the only real fix is to replace the tank. I'm hoping this isn't the case with yours.

The penetrating oil is a very good start- hope it goes smooth for you.

Fathrington
10-10-14, 09:09 PM
FINALLY got it off.was going to take it to a place this morning to remove it for me, but my battery was completely dead. So i re thought it, took out some channel lock pliers, and after finding the right channel to use, and a couple tries, popped right off. New pump is in. pump came with 3 o-rings, i only used one since the old parts only had one. the only ring it had when i removed it was in between the tank and the pump. im not sure if the other o-rings should be used or not.
Still does not hold fuel pressure in the on position, but tomorrow morning will be the real test, if it starts fast. wish me luck!