Truck does not start well..? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

squint · 10-06-2005, 03:05 PM

I know this is kind of a generic question .. but any info is appreciated..

I just put a new 350 engine in about 8 months ago.. and I have been having some starting problems. The engine starts fine once its warmed up.. and runs awsome once its running.. however when i go to start it after its been sitting for a day.. it does not fire up right away..

The engine turns over for about 10-15 seconds before it finally fires.. I have tried every trick in the book with the pedal.. Holding it down.. feathering it.. not touching it at all.. nothing makes it better.

A couple things to note..

1. I have a Carter Comp. 650cfm Carb.. ( electric choke )
2. I just changed my fuel line about 3 months ago.. ( it was doing this before then though )
3. once it starts it does not hesitate at all.. it fires right up
4. It parked in an under-ground parking.. so its not cold at all..

Any ideas?.. pls pls.. I hate starting it this way .. sounds like a p.o.s..

Thanks..

hobbz · 10-06-2005, 04:03 PM

are you sure the electric choke is closing on a cold start?

a28doc · 10-06-2005, 04:36 PM

sounds like the fuel pump is leaking down and not holding pressure after sitting a bit so it takes a bit to get gas back to the carb
Doc

squint · 10-06-2005, 08:17 PM

Great ideas.. Is there an easy way to test these theories out?..

koreric75 · 10-06-2005, 10:26 PM

I had the same problem, scrapped the old mechanical fuel pump and went with a Holley electric fuel pump, i just turn the key on and give about half a pump and it fires right up.

a28doc · 10-06-2005, 11:44 PM

you have to put a fuel pressure gauge between the pump and carb and fire it up then let it sit for awhile to see if it leaks down
Doc

squint · 10-07-2005, 01:52 AM

Is the fuel pump inside the tank?.. I have 2 tanks.. and it does it no mater which tank i have selected.. ??..

squint · 10-07-2005, 02:44 AM

Ah.. never mind.. I just looked it up ..

I will pick up a new HP fuel pump on saturday and see if that makes a difference..

bobs86silv · 10-07-2005, 08:46 AM

Before you start it for the first time after sitting, pull the air cleaner off, and hold the butterfly on the carb open with your finger. Manually operate the linkage on the side of the carburetor a few times. Look down in the carb and see if you can see gas squirting into the carb, two good streams. If you dont have good squirts from your accelerator pump, you dont have gas in the bowl. That will atleast help you with isolating your problem.

good luck
robert

TrainD5115 · 10-07-2005, 10:59 AM

Could be a problem with your electric choke. See if it is closing when the engine is cold. If it is not closing properly there is not sufficient vacuum for a cold engine to start. A warm engine will start fine as you are describing. I would do this first before getting into a new fuel pump but checking to make sure fuel is getting into the carb is also a good idea too as previously stated.

squint · 10-07-2005, 02:46 PM

Thanks..

I will check both of these out tomorrow..

if there is no gas in the bowl.. does that mean its the fuel pump?..

Grim Reaper · 10-07-2005, 10:34 PM

Quote:

Originally Posted by squint

Thanks..

I will check both of these out tomorrow..

if there is no gas in the bowl.. does that mean its the fuel pump?..

NO. And there will be no fuel pressure between pump and car if its not running either so disregard any of that stuff above. Carbs don't hold fuel pressure. It is impossible for fuel to be sucked out of the carb back through the pump. Fluid simply doesn't flow uphill on its own and if the line did create suction it would suck air or pull the float valve shut. that said if its not parked level there is a VERY small chaince you could back flow some fuel to the pump but the truck would have to be VERY off level to drain enough that it wouldnt start.

Its either got a bad accelerator pump like bob said, mis adjusted choke or the fuel bowl is draining down into the engine or out on the manifold. All three would have the symptoms you describe.

Fuel bowl draining is a common complaint on Quads. The casting plugs in the bottom of the float bowl will start to leak with age. a Quick coat of JB weld will take care of it on the Quad. I have never messed with a carter but I would think it may have a similar casting plugs.

I would start by doing what bob recommended and looking for the prime shot of fuel. No priming shot then either the accelerator pump is not functioning or the float bowl is draining. Either way its time to pop the top and see.

If you get a good shot of fuel then verify that you are getting the choke closing the correct amount. On a Quad you want about a 1/8 inch gap and it should pop to about a 1/4 inch gap once it fires off and then slowly open over about a 3 minute span. I would think the carter would be very similar adjustment.

If the choke looks correct then I would double check your base timing and look for vacuum leaks.

coolram · 10-10-2005, 06:19 AM

I agree with Grim Reaper in checking the choke plate adjustmentand on the Q-jets leak down when they age(carters aren't as bad bu they can leak down too).One thing to check is the cold start operation of the choke(is it getting voltage and closing the plate)then once you've done this and adjusted it for cold start go back once she warms up completly and make sure the plate opens all the way.I had a '79 T/A that would run fine until she warmed up then all she would do is idle any throttle and she would die.problem was the choke plate wasn't opening up and on a 2nd gen T/A it's a pain to get to the carb.

woody96 · 10-10-2005, 07:55 AM

Could there possibly be a problem with the ignition module (electronic ignition.....if you have it...) going bad......mine is doing that and my mechanic (I don't know carbs...) told me the ig. module was giing bad.....tap it with a screwdriver---fires right up....this might be the problem maybe???? This make sense or is my mechanic wrong???

squint · 10-10-2005, 02:16 PM

I dont have any aftermarket ignition module.. I have stock HEI distributor/ignition system.

woody96 · 10-10-2005, 04:02 PM

Doesn't it have an IgModule?

squint · 10-10-2005, 04:57 PM

yes... but i believe its all enclosed in the Distributer... Maybe Im wrong?..

squint · 10-10-2005, 08:46 PM

Well.. I took the air cleaner off and pumped the gas from the engine bay.. I can see the gas pouring out of the 2 front jets.. .. I fired it up ( again took a few seconds to fire ) and the choke was enguaged.. i watched it as it slowly came back up.. once it was fully open i bliped the throttle and everything was normal.. i shut it off and she fired right back up like a charm..

So this leads me to believe that
1. My carb is good.. ?
2. My Fuel pump is good .. ?
3. .. I have no idea what else could be doing this other than maybe what woody96 is saying .. but with HEI i think the ignition module is all inside the Distributor.. correct?..

Any ideas?..

Also I notice.. if i crank it over for about 3 seconds then stop.. then crank it over again it starts up.. but if i just keep cranking it it will take about 5-6 seconds..

Thanks..

squint · 10-11-2005, 03:17 PM

Anyone else have any ideas?..

woody96 · 10-11-2005, 04:55 PM

My Dist has the Ig Mod on the outside.....it did it to me again today.....and then all of a sudden, cranked like a charm....choke and all is working fine.......maybe this Ig Mod thing has something to it......

squint · 10-11-2005, 08:27 PM

Hmm.. ok but how can I test this theory?.. If the Ign. Module is inside the distributor.. do i just bang on the distributor?.. ???

squint · 10-11-2005, 08:53 PM

Is it hard to change this Ignition Module?.. I just checked the price.. its fairly cheap to replace.. as long as its not too difficult to change.. anyone know how to do this on an HEi distributor?

static22 · 10-11-2005, 11:30 PM

Did it do the same thing before you changed the motor? Does it try to fire within this 5-6 seond time frame? Was the same carb on the old engine as well? Have you tried replacing the spark plugs?

squint · 10-12-2005, 01:49 AM

No it never did this with the old engine.. It fired right up. no gas needed..
and no it does not usually fire.. it just turns over and eventually fires.

woody96 · 10-12-2005, 08:22 AM

I wish I could help here, I may call my mechanic guru today and get some scoop.....

10-06-2005, 03:05 PM	#1
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Truck does not start well..? I know this is kind of a generic question .. but any info is appreciated.. I just put a new 350 engine in about 8 months ago.. and I have been having some starting problems. The engine starts fine once its warmed up.. and runs awsome once its running.. however when i go to start it after its been sitting for a day.. it does not fire up right away.. The engine turns over for about 10-15 seconds before it finally fires.. I have tried every trick in the book with the pedal.. Holding it down.. feathering it.. not touching it at all.. nothing makes it better. A couple things to note.. 1. I have a Carter Comp. 650cfm Carb.. ( electric choke ) 2. I just changed my fuel line about 3 months ago.. ( it was doing this before then though ) 3. once it starts it does not hesitate at all.. it fires right up 4. It parked in an under-ground parking.. so its not cold at all.. Any ideas?.. pls pls.. I hate starting it this way .. sounds like a p.o.s.. Thanks..

10-06-2005, 04:03 PM	#2
hobbz Registered User Join Date: Jun 2005 Location: ashland, ky Posts: 632	are you sure the electric choke is closing on a cold start? __________________ Hobbz-Garage 1987 Short Step 350/350

10-06-2005, 04:36 PM	#3
a28doc '87 V20 4x4 Join Date: Jun 2004 Location: South Western Ohio Posts: 1,073	sounds like the fuel pump is leaking down and not holding pressure after sitting a bit so it takes a bit to get gas back to the carb Doc __________________ '86 K5 Blazer 4x4 FOR SALE '87 v20 4X4 '99 S10 Blazer 4X4

10-06-2005, 10:26 PM	#5
koreric75 83C10SWB Join Date: Sep 2005 Location: Bossier City, Louisiana Posts: 69	I had the same problem, scrapped the old mechanical fuel pump and went with a Holley electric fuel pump, i just turn the key on and give about half a pump and it fires right up. __________________ Koreric75 2003 Suburban Z-71 4x4 5.3L 83 C10 SWB FOR SALE 350ci/700Raptor Jr Picture&Progress Page

10-06-2005, 11:44 PM	#6
a28doc '87 V20 4x4 Join Date: Jun 2004 Location: South Western Ohio Posts: 1,073	you have to put a fuel pressure gauge between the pump and carb and fire it up then let it sit for awhile to see if it leaks down Doc __________________ '86 K5 Blazer 4x4 FOR SALE '87 v20 4X4 '99 S10 Blazer 4X4

10-06-2005, 08:17 PM	#4
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Great ideas.. Is there an easy way to test these theories out?..

10-07-2005, 01:52 AM	#7
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Is the fuel pump inside the tank?.. I have 2 tanks.. and it does it no mater which tank i have selected.. ??..

10-07-2005, 02:44 AM	#8
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Ah.. never mind.. I just looked it up .. I will pick up a new HP fuel pump on saturday and see if that makes a difference..

10-07-2005, 08:46 AM	#9
bobs86silv Registered User Join Date: Apr 2005 Location: Sedalia, Mo Posts: 326	Before you start it for the first time after sitting, pull the air cleaner off, and hold the butterfly on the carb open with your finger. Manually operate the linkage on the side of the carburetor a few times. Look down in the carb and see if you can see gas squirting into the carb, two good streams. If you dont have good squirts from your accelerator pump, you dont have gas in the bowl. That will atleast help you with isolating your problem. good luck robert __________________ 86 Silverado SWB 350/350/3.08 9.7-1 Forged pistons Eagle Rods Eagle Crank Zero Deck Balanced Blueprinted 180cc DART Heads Roller Rockers RPM Intake Demon Carb Flowtech Headers 400HP/400TQ

10-07-2005, 10:59 AM	#10
TrainD5115 North Coast, baby! Join Date: Jun 2004 Location: Toledo, OH Posts: 437	Could be a problem with your electric choke. See if it is closing when the engine is cold. If it is not closing properly there is not sufficient vacuum for a cold engine to start. A warm engine will start fine as you are describing. I would do this first before getting into a new fuel pump but checking to make sure fuel is getting into the carb is also a good idea too as previously stated. __________________ Brad 79 Scottsdale C20 350/350 3.73's Still running full CA smog gear!

10-07-2005, 02:46 PM	#11
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Thanks.. I will check both of these out tomorrow.. if there is no gas in the bowl.. does that mean its the fuel pump?..

10-10-2005, 06:19 AM	#13
coolram Registered User Join Date: Oct 2005 Location: South Carolina Posts: 8	I agree with Grim Reaper in checking the choke plate adjustmentand on the Q-jets leak down when they age(carters aren't as bad bu they can leak down too).One thing to check is the cold start operation of the choke(is it getting voltage and closing the plate)then once you've done this and adjusted it for cold start go back once she warms up completly and make sure the plate opens all the way.I had a '79 T/A that would run fine until she warmed up then all she would do is idle any throttle and she would die.problem was the choke plate wasn't opening up and on a 2nd gen T/A it's a pain to get to the carb. __________________ '73 C10 CST LB Two-tone,454 TH400(rebuilt 350-4bbl in now)12 bolt posi Factory A/C Tilt.She was my Dad's truck for 15 years. '95 Jimmy SLS 4dr 4WD 4.3/4L60E/K&N FIPK/MSD/Dynomax catback '92 Capri XR2 Turbo 1.6/5 speed '70 Monte Carlo SS454 454/TH400

10-10-2005, 07:55 AM	#14
woody96 Registered User Join Date: Jan 2005 Location: Chapin, SC Posts: 392	Could there possibly be a problem with the ignition module (electronic ignition.....if you have it...) going bad......mine is doing that and my mechanic (I don't know carbs...) told me the ig. module was giing bad.....tap it with a screwdriver---fires right up....this might be the problem maybe???? This make sense or is my mechanic wrong??? __________________ "Fighting for our freedoms....." Last edited by woody96; 10-10-2005 at 07:56 AM.

10-10-2005, 02:16 PM	#15
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	I dont have any aftermarket ignition module.. I have stock HEI distributor/ignition system.

10-10-2005, 04:02 PM	#16
woody96 Registered User Join Date: Jan 2005 Location: Chapin, SC Posts: 392	Doesn't it have an IgModule? __________________ "Fighting for our freedoms....."



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10-10-2005, 04:57 PM	#17
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	yes... but i believe its all enclosed in the Distributer... Maybe Im wrong?..

10-10-2005, 08:46 PM	#18
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Well.. I took the air cleaner off and pumped the gas from the engine bay.. I can see the gas pouring out of the 2 front jets.. .. I fired it up ( again took a few seconds to fire ) and the choke was enguaged.. i watched it as it slowly came back up.. once it was fully open i bliped the throttle and everything was normal.. i shut it off and she fired right back up like a charm.. So this leads me to believe that 1. My carb is good.. ? 2. My Fuel pump is good .. ? 3. .. I have no idea what else could be doing this other than maybe what woody96 is saying .. but with HEI i think the ignition module is all inside the Distributor.. correct?.. Any ideas?.. Also I notice.. if i crank it over for about 3 seconds then stop.. then crank it over again it starts up.. but if i just keep cranking it it will take about 5-6 seconds.. Thanks..

10-11-2005, 03:17 PM	#19
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Anyone else have any ideas?..

10-11-2005, 04:55 PM	#20
woody96 Registered User Join Date: Jan 2005 Location: Chapin, SC Posts: 392	My Dist has the Ig Mod on the outside.....it did it to me again today.....and then all of a sudden, cranked like a charm....choke and all is working fine.......maybe this Ig Mod thing has something to it...... __________________ "Fighting for our freedoms....."

10-11-2005, 08:27 PM	#21
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Hmm.. ok but how can I test this theory?.. If the Ign. Module is inside the distributor.. do i just bang on the distributor?.. ???

10-11-2005, 08:53 PM	#22
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	Is it hard to change this Ignition Module?.. I just checked the price.. its fairly cheap to replace.. as long as its not too difficult to change.. anyone know how to do this on an HEi distributor?

10-11-2005, 11:30 PM	#23
static22 Registered User Join Date: Apr 2004 Location: oklahoma city Posts: 62	Did it do the same thing before you changed the motor? Does it try to fire within this 5-6 seond time frame? Was the same carb on the old engine as well? Have you tried replacing the spark plugs? __________________ Shaved '77 Silverado

10-12-2005, 01:49 AM	#24
squint Registered User Join Date: Jul 2005 Location: Vancouver Posts: 195	No it never did this with the old engine.. It fired right up. no gas needed.. and no it does not usually fire.. it just turns over and eventually fires.

10-12-2005, 08:22 AM	#25
woody96 Registered User Join Date: Jan 2005 Location: Chapin, SC Posts: 392	I wish I could help here, I may call my mechanic guru today and get some scoop..... __________________ "Fighting for our freedoms....."

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