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Very Hard "Cold" Start - 1994 S10 Blazer

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Old 03-19-2011, 03:31 PM
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Default Very Hard "Cold" Start - 1994 S10 Blazer

HEy Everyone,

Wanted to first start by saying thank you! Been a long time lurker and finally decided to jump in. I have gotten a ton of info off this forum, and its been a huge help.

Hoping the experts can advise me here on what the problem is with my 1994 S10 Blazer. W Vin. 130k miles. I have replaced so far my ignition module, plugs, wires, filters, cap, rotor. Fuel Pump seems to be running fine. No smell of gas in oil. Runs great thru all RPMS, idles a tiny bit rough. Almost like a small miss at idle. No engine codes. I contributed the idle to just a high mileage vehicle.

My problem is that in the mornings, the thing takes sometimes up to ten trys to start. It will fire for a second, then die. Fires for a second, then die. It fInally coughs/stumbles thru the start and idles up, fine for rest of day. Im guessing fuel? Do you think I should just replace the spider? Does anyone have a link to the walk thru for the spider replacement. I was hoping I could get some hints on where to start throwing money at it. Love the truck, and its in great shape.

Thanks for the help guys!

Chris
 
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Old 03-19-2011, 03:36 PM
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Step #1 - Test the fuel pressure. It needs to be greater than 55psi and should remain above 10psi 10 minutes after the pump shuts off. If it doesn't go high enough or drops off too fast, you could be looking at a weak pump and/or a leak in the system somewhere.
 
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Old 03-19-2011, 08:52 PM
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X2 on what swart said... Fuel press must be over 55. Seen it posted a few times.
 
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Old 03-21-2011, 04:28 PM
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I have a 94 with the "W" VIN and mine done the same thing when I first purchased it. The EGR valve was clogged and I replaced it. Usually if it is the EGR it will run rough at idol but wil smoothen out when driving down the road. You may want to take it off and clean it. It is located under the thorttle body where the air intake hooks up. Mine is still a little slow to start when cold but if I pump the gas two times, it fires right up.
 
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Old 03-22-2011, 12:35 PM
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Originally Posted by swartlkk
Step #1 - Test the fuel pressure. It needs to be greater than 55psi and should remain above 10psi 10 minutes after the pump shuts off. If it doesn't go high enough or drops off too fast, you could be looking at a weak pump and/or a leak in the system somewhere.
Ok did the pressure test, I am at 60PSI when running, and after 1 hour shuttiing down, I am still at 15PSI. I guess thats a good sign?

Chris

Originally Posted by ely0569
I have a 94 with the "W" VIN and mine done the same thing when I first purchased it. The EGR valve was clogged and I replaced it. Usually if it is the EGR it will run rough at idol but wil smoothen out when driving down the road. You may want to take it off and clean it. It is located under the thorttle body where the air intake hooks up. Mine is still a little slow to start when cold but if I pump the gas two times, it fires right up.
Ely im starting to think you may have the answer. I was gonna replace mine, until I saw the 200 dollar price tag! Unbelievable! I will try this today and see what happens.

Just a note on my pressure test. Sometimes when clicking the key to run and the pump cycles, it stops at 30 PSI, then I cycle the key again, and it will bump up to 50PSI before starting. Once I shut off, it IMMEDIATELY drops from 55PSI to 30, like within 1 second. Is a fuel pump in my future?Is that normal guys? Thanks!

Chris
 

Last edited by swartlkk; 03-22-2011 at 02:58 PM. Reason: *Combining Consecutive Posts* - Please use the EDIT feature to add additional information to your post and use the multi-quote feature to reply to more than one person.
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Old 03-22-2011, 02:56 PM
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Sorry, that's 50psi and 10 minutes. Typo'd that one. You have a leak. I would suspect a problem in the plenum.

Also, please use the multi-quote feature when responding to more than one person. Consecutive posting is akin to double posting and is prohibited by the rules of the forum (#4).
 
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Old 03-23-2011, 09:42 AM
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Originally Posted by swartlkk
Sorry, that's 50psi and 10 minutes. Typo'd that one. You have a leak. I would suspect a problem in the plenum.

Also, please use the multi-quote feature when responding to more than one person. Consecutive posting is akin to double posting and is prohibited by the rules of the forum (#4).
Thanks Swart. As an update , I replaced the EGR valve yesterday and the upgraded screen gasket. No difference this morning It does seem like the idle smoothed a little though, but not much. So should I look at replacing the spider? What else do I need with that?

Chris
 
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Old 03-23-2011, 09:51 AM
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You first need to verify that the fuel leak is internal to the plenum. Fuel problems are a VERY well documented topic on the forum. A little searching goes a long way.
 
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Old 03-23-2011, 04:06 PM
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I would say either the spider or the fuel pump. I have the EXACT same problem. You couldn't have described it better. In my case, I already replaced the spider and the problem still exists. I'm betting on the fuel pump now because I already know the sending unit is bad because the gas gauge reads 3/4 when I fill it. Also, I don't know if this helps or is relevant but my fuel pump doesn't make the humming noise I'm used to hearing on these trucks but instead makes a weird garbled noise. So yeah I would say check the injectors and the fuel pump. Let me know if you have any luck solving your problem! I plan on getting a new fuel pump when i get the money. Hopefully it will last until then!
 
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Old 03-27-2011, 07:49 AM
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Have a very similar problem, but it only happens when starting in the morning. Once I get through that it fires right off the rest of the day seems sitting overnight is letting something get too cold. The weather is going to warm up soon so I'll see if it does it only when it's cold out at night or just because it sat all night. Replaced the fuel filter which seemed to have some effect but it's still was hard to start this morning. Put new cap and rotor on, AEM cold air intake, PCV valve and will change the plugs when they get here. Seems to be firing just doesn't seem to be getting fuel.
 


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