gremlins in my blazer...

Iv got a 99 2dr blazer 4.3 vortec auto 4x4, she runs amazing. Doesn't spit sputter or bog down. But damnn she is sper hard to start. Once warmed up she'll start right up fine. But normally with a cold start I have to hit it with starting fuild. But once it starts runs flawless and will start back up. I put a new gas cap on, plugs,wires, cap, fuel filter..basically gave her a good tune up thinkin it was just old plugs or wires. Haven't tested fuel pump but wats weird is the pump doesn't prime until after I turn key off then I hear it kick on for 10 seconds or so. It kicks on when I try to start it. But when I just turn the key one notch it doesn't come on. I really don't think its a fuel pump issue due to how great it drives. 80mph down the high way with no issues... sooo why in the h+ll is my blazer soooo hard to get started? Fuel pressure reg? Temp sensor? Crank sensor? I'm stumped...what r y'all thinkin?

Just seems like it doesn't hold pressure, or doesn't prime...

[cincygman]

Have you tried turning the key on, without starting the engine, then off, three or four times to see if it primes the system? And really, starting fluid on a gas engine? Not good at all........

[race10]

[QUOTE=cincygman;And really, starting fluid on a gas engine? Not good at all........[/QUOTE]

I've heard this a couple of times can anyone tell me what the big deal is?

[jwend]

Originally Posted by cincygman

Have you tried turning the key on, without starting the engine, then off, three or four times to see if it primes the system? And really, starting fluid on a gas engine? Not good at all........

I knew that on a diesel starting fluid is bad.. real bad.. but gas too? Then what good is it?

[Flxratd]

Originally Posted by jwend

I knew that on a diesel starting fluid is bad.. real bad.. but gas too? Then what good is it?

beading up tires

[GPER]

I use ether for the first start of the year on my lawn mower, and snow blower if it doesn't start after the 3-4 pull. The snow blower is 30 plus and the mower is 28 years old.

We use ether when needed on diesel engines, always use in small amounts and don't heat the motor after it has been shot with ether. You can ether lock a motor.

[krawlin85toy]

have you ran a scanner across the ecm, had that before and found it to be a coolant temp sensor. it read a higher temp even when the temp outside was cold.
Mine read 80 deg. and temp outside was 36 deg.once the engine was warm it was fine. my two cents on this...

[blazerbrad]

I believe the issue with ether on a gas engine is in regards to it being a modern version with some sort of multiport fuel injection. Same issue on diesels. The air intake on these only carries air, not an air and fuel mixture like an older carb or TBI mixture, with the injectors squirting fuel into the cylinders only at very specific intervals. When you spray ether into the air intake it basically injects a flammable mixture into the cylinders whenever the intake valves are open and cause issues like pre-detonation.

The other potential issue on diesels is the glow plugs or grid heaters igniting the ether, which can really cause issues. I have used ether several times on my diesel but always manually disconnect the power feed to the glow plugs to make sure they don't come on.

[carwash]

Put a manual fuel pressure gauge on the system. Get it started, let it run till you get consistent fuel pressure, then shut it off and see if the system bleeds pressure off. The fuel pump check valve in that system shouldn't leak off any more than 10 psi within 10 minutes. If it bleeds off that much in 10 minutes, then you have a bad check valve in the fuel pump, meaning the system is losing it's prime every time it sits. Therefore that pump has to work like crazy to get fuel to your plenum before it will fire.

Just one possibility.

When running its at 61psi. But I get 0 with key on but not started. Iv tried the whole key on off 50 times to prime it but it doesn't work. N I. Can crank it all day n it just won't start til I barly n I mean barley spray fuild.. I just spray a tad bit n its enough to kick it n it fires up n runs fine. I don't just dump fluid in lol.. I think its getting worse too cause now somtimes it won't start even after warmed up. I drove home from work today turned it off went inside got my stuff n went to leave again n it wouldn't start even tho it was fully warmed up still. I guess ill just end up doing a fuel pump in it.

S far as using starting fluid I know its bad but I use very very little, but ie have no choice I have nothing else to drive to work n no way to get rides. So I'm just trying to get by until my taxes come in so I can go buy parts.

[C.P.]

I know some earlier 90's GM's used oil pressure to control the fuel pumps. I don't remember the specifics, but we had a Pontiac Transport van with a fuel pump relay wiring issue that WOULD NOT turn the fuel pump on until you cranked it long enough to build oil pressure. I forget what we had to fix to straighten that out.

-EDIT-

Found this:


one last thing....

the 3 wire oil pressure sending unit also controls the electric fuel pump...

the center wire is for the gauge...

the outer 2 wires are the fuel pump circuit... one wire is fused constant power... the other runs to the same circuit as the fuel pump relay provides... why do i know this... a few weeks ago.. one friend dropped by.. the battery kept draining overnight.. when i stuck my head under the hood.. could hear the fuel circulating.. the oil pressure switch had broken internally.. kept the fuel pump running with the key off..

the fuel pump relay is controlled by the ecm.. when you turn the key on.. the ecm turns the fuel pump relay on instantly for 2 seconds... this primes the system... during cranking .. the ecm commands the fuel pump relay on also... within seconds of the engine starting.. the oil pressure comes up enough to close the fuel pump circuit in the oil pressure switch to keep the fuel pump running as long as there is oil pressure..


Read more: http://forums.hotrod.com/70/8118227/...#ixzz1nKpy0S4C

[dougg01]

As the current owner of my 4th model of these, I can speak with some authority.

What carwash said is true, but likely a redundant step at this point. My 99 had these exact symptoms. The pump will run the truck, but start is a witch. I taped my trusty FP gauge to the windshield and tested it out on two seperate occasions and let it sit there while the system bled down when I got back home. The pump can't maintain a constant volume/pressure over time. The pressure is accurate for the most part, but when you actually throw a serious load at it (pull a long hill on cruise) it can't deliever the volume and the pressure wavers. It bleeds down slow at first, but then drops like a stone. No residual pressure at all >4-6hrs. Otherwise the thing is fine...it seems.

the other two things it could be are the regulator is leaking fuel (and that could be getting into your oil). If your oil smells more 'gassy' than you expect that could be your culprit. Unfortunately you can't always see that it's leaking through the intake with the TB off. R & R on that isn't too bad.

The spider could be partially plugged and the little poppers just not delivering when cold. Those little farts a witch to clean too and the plastic is prone to breakage due to exposure. There is a service kit available at AdvanceAutoParts for getting in there and replacing the o-rings on everything (which I advise).

I did the FP regulator (it was leaking, just not very bad yet) and some other stuff and the condition seemed to get better, but really hadn't. Fuel pump. It's not a hard R&R. you need to clean up the hoses good and get them pliable. If'n you don't you'll cuss a lot. Don't forget there are 3 lines on top, two electrical connections, and basically two bolts holding that thing in. Removing the rear shock on the driver's side also helps with visibility and cuts down on the 4-letter-words when trying to drop it and shove it back up there.

Good luck with it.

Yea I drove it two hrs to indiana n two hrs back with no issues running 70 to 75mph, I'm wondering if its a bad check valve in pump? Not sure if these have some sort of check valve... I checked my oil doesn't smell gassy to me. N I've checked pressure every where n they all read fine. I did the temp sensor n crank sensor for ****s n gigles. No changes. It has goten worst. Now even warmed up it will not restart. I did pull a 99 tank pump n wiring harness from a junk yard today. But I really don't think its a pump issue. But maybe I'm wrong. Also the gas lines are all new I had to replace one that had a small leak so I had new gas lines put in from tank all the way to intake. I'm wondering if the regulator is stuck open so fuel go in and then right into the return line or somthing. Idk at thisp point lol

I under it and found somthing very interesting. tucked on top the tank was two wires. I traced one to harness and one up to the ground on the battery. These aren't stock wires, these are solid blue. Some one diffently ran them. Looks like they by passed theharness and almost hard wired the pump. Any ideas why some one would do this?

Yepp I found more wires. Looks like the whole pump is rewired some how. Almost like its wired into the wiring harness for lights. Haha some one did some serious redneck engineering on this.

[Patrick45015]

About starting fluid it is so flammable it pre detonates, you can here it a lot of times causing a knocking. Its like spark knock or pinging on low octane. Its possible you can blow a hole in the piston. That being said Ive never actually seen it happen or heard anyone say they had it happen. WD 40 is flammable and a lubricant. I have used it as starting fluid. Spray carb cleaner works really well and cleans. I have never heard a knock from carb cleaner. I use it testing for fuel issues at work.

[Coppertop]

Originally Posted by Flxratd

beading up tires

Yep,it's a bomb...

Please do not try this at home.(Standard Disclaimer)
Nick

Na I don't need a mechanic I need a new car! Shoulda kept my 90 sami lol, iv got a new fuel tank with a new pump in it for 150 at a junk yard ever found the receipt for both inside the blazer lol. I also pulled the entire wiring harness that runs all the way back to pump n lights. So tomorrow I'm gonna drop the whole tank and swap it all out. Any pointers to doing this swapp or tricks?... never done a chevy pump just my wrangler 89cj.

By the way I picked up a fp regulator 50 bucks new... is it gonna be a ***** to put in?

No I'm not. Hard startin is only two thinks, fuel pump or reg. I did the pump today. Didn't help. So now I'm doing regulator. Plus a lot of these parts were due for a change any how.

Hey guys. Did the reg today... fixed my problems. Thanks for all the help n info n adviced!!!

[Red Dog]

So tear it all back down and take back all the things that you did not need to replace. Congtats all the same.

Like I said... all them parts needed to be replaced anyways lol.