Heres a whacky one for you, 99 GMC gremlins ?? - S-10 Forum
 
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post #1 of 14 Old 11-05-2018, 05:56 PM Thread Starter
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Heres a whacky one for you, 99 GMC gremlins ??

99' lowered stepside sonoma 2.2 manual.

Ok, I'll start from the beginning. Ever since ive had this struck, it is a hard start. So for example, hop in to go to work in morning, truck fires right up like normal. But once you drive it, and go to restart it, it cranks for probably 10sec and i'll hit the gas and its sputters and starts. Kinda like trying to start a carburetor car when the carb or choke is out of adjustment.

Seems like 9hrs is the magic number. Once the truck sits that long, it seems to go back to normal for that first start.

BUT! When its raining, or wet out, it fires right up ALL the time, just like a normal truck would. 2sec crank and start.

I changed TPS, and IAC. No improvement.

Ok, thats the first gremlin.

Next, when cruising on extended trips (trips farther than my daily commute) 25mi+ I noticed my batt light would come on.
I tested the batt with the truck running and all acc's on, and was getting some 13.4 and around there. So, I threw a new alt on. (the old one had a slight squeak anyways) (I also installed a new heater blower motor at the same time, cause the old one was going out)

Now NEW PROBLEM. During my daily commute, after the truck warms up (about 5mi's) the truck cuts out on occasion. And its almost always during a left turn, or coming out of a left turn. For instance, i'll be coming up to a left turn, i'll pop it out of 4th, brake into the turn, down shift into 2nd or 3rd (depending on which turn) and immediately upon pressing gas, it cuts out. It will cut out all the way getting into the 4th gear. But eventually clears up.

It is almost a perfect guarantee to happen on a left turn. It has happened ZERO times on a right turn (ive tried!). It has happened at a 4way stop going straight only a couple times. Stopping, getting into 1st, going straight, and cuts out all the way up to 4th then clears up once rpms get up.

I just couldnt drive it like that, so trying diff things, I threw the old Alt back on it. And the cutting out was not eliminated, but reduced by probably 75%. Its atleast manageable now.

So, the latest things ive tried. I'll go into a left turn, pop it into 3rd, slowly accelerate and it starts cutting out, so I turn the wheel to the right and every time ive done that so far, the cutting out STOPS immediately. Every time. wtf

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post #2 of 14 Old 11-05-2018, 06:30 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

hmm- check fuel pressure and then check the ground at the tank. and don't forget a leak down test

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Last edited by Jayhawke; 11-05-2018 at 06:30 PM. Reason: add info
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post #3 of 14 Old 11-05-2018, 06:37 PM Thread Starter
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Re: Heres a whacky one for you, 99 GMC gremlins ??

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hmm- check fuel pressure and then check the ground at the tank. and don't forget a leak down test
good call. I checked fuel pressure. it checks out good. running and static.
I tried to check the fuel pump ground, but could not find the ground. Im thinking it is in the harness on this year of truck. The only ground I found was a strap going from filler neck, to frame. No wire going from frame to tank/sending unit.
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post #4 of 14 Old 11-05-2018, 07:07 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

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good call. I checked fuel pressure. it checks out good. running and static.
I tried to check the fuel pump ground, but could not find the ground. Im thinking it is in the harness on this year of truck. The only ground I found was a strap going from filler neck, to frame. No wire going from frame to tank/sending unit.
Does it hold fuel pressure though? Leave the gauge on it for 30 about minutes after the key is turned off. Then, check pressure reading on the gauge again but do NOT turn key on before looking at the gauge. If it has lost more than 1 or 2 psi in that 30 minutes time frame, that is an issue.

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post #5 of 14 Old 11-05-2018, 07:08 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

Look on the driver side frame towards the rear. It's on the inside vertical surface.

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post #6 of 14 Old 11-06-2018, 08:20 AM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

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I tried to check the fuel pump ground, but could not find the ground. The only ground I found was a strap going from filler neck, to frame. No wire going from frame to tank/sending unit.
On a 99 it's there somewhere. Sounds like you found (or didn't find, actually) your problem.
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post #7 of 14 Old 11-06-2018, 02:00 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

Yeah, the ground is on the drivers side frame back by the bumper.


The hard start sounds like leaky injectors. You can try starting it with the gas to the floor to see if that helps . . . this is the clear flood signal to the ECM. The cutting out sounds like bad wiring that develops an open when the stress is applied to a harness in the turn. Might want to wiggle all of your wires when it's idling to see if you can make it cut out.

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post #8 of 14 Old 04-21-2019, 01:19 PM Thread Starter
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Re: Heres a whacky one for you, 99 GMC gremlins ??

Thanks for all the replys. I have the 'cutting out' issue fixed. A loom of wires that hangs across the drivers side of motor, was rubbing on the a/c bracket. A black and a green/white wire were rubbing intermittently.

(Pic is after I stripped the black wire to deox and repair it.)

Still working on the screwed up hard start issues. Im gonna look better at the fuel pressue. Because some times the truck starts just fine. On occasion. So it could be im checking f/p on the good times. Truck wont even start this morning, so nows a good time!
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post #9 of 14 Old 04-21-2019, 02:01 PM Thread Starter
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Re: Heres a whacky one for you, 99 GMC gremlins ??

Ok. Got home to work on this pile. And guess what. She started right up. I can never seem to check the fuel pressure when she's acting up.

Anyways, Rechecked the fuel pressure. It is about 42psi running. I turn the truck off and it rests at 37psi. At about 8minutes its at 30psi. At 20min its at 20psi.

So I tried to start and it at 20psi, took about 5sec of cranking and cough and sputtered and finally started. Unfortunately I couldnt watch the pressure gauge as I was cranking.
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post #10 of 14 Old 04-24-2019, 12:41 PM Thread Starter
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Ok. Looks like my system wont hold fuel pressure. Any thing I should check first?

I do know the fuel pump is new. The guy said it had this problem before he changed the fuel pump. He was trying to figure it out also.
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post #11 of 14 Old 05-08-2019, 11:12 AM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

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Originally Posted by 327amc View Post
Ok. Looks like my system wont hold fuel pressure. Any thing I should check first?

I do know the fuel pump is new. The guy said it had this problem before he changed the fuel pump. He was trying to figure it out also.
If the fuel pump is new and the fuel system has no obvious leaks, I would start with the injectors or regulator.

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post #12 of 14 Old 05-20-2019, 09:34 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

I have the same hard start. It'll start fine for first start of the day but after it gets warm and sits for a little bit it cranks and cranks. Usually give it throttle so it wont crank as long. Truck has new injectors, plugs and wires, ignition module (went bad a couple weeks ago). I've fuel pressure tested it and it doesn't leak off quickly.

Here is a post I made before on my hard start
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post #13 of 14 Old 05-20-2019, 10:33 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

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I have the same hard start. It'll start fine for first start of the day but after it gets warm and sits for a little bit it cranks and cranks. Usually give it throttle so it wont crank as long. Truck has new injectors, plugs and wires, ignition module (went bad a couple weeks ago). I've fuel pressure tested it and it doesn't leak off quickly.

Here is a post I made before on my hard start
You still have problems with your pressure.

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post #14 of 14 Old 05-20-2019, 11:30 PM
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Re: Heres a whacky one for you, 99 GMC gremlins ??

If it start normally when cold, but is hard to start when warm, hook up your scanner and see what the coolant temp is reading when warm.
A bad coolant temperature sensor will tell the pcm to add more fuel than necessary thinking it is a cold engine. Essentially flooding it.
And as mentioned above if you put throttle near wide open while cranking that signals the pcm to cut back on fuel to clear the flooding and helping it start.
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