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95 Blazer Hard start when cold

12-07-2004, 11:58 AM
When cold, my blazer will take several tries to start and then will run rough for a few seconds. After that, it runs excellent. And, if I try to start it when hot, it will start right up.

I am thinking it is either the fuel pressure regulator/injector assembly or the fuel pump or the fuel filter but how will I know for sure?

It would be easy and cheep enough to change out the fuel filter and see if it helps. If it doesn't, how can I determine if it is the pump or regulator assembly? Any ideas?

12-08-2004, 05:13 PM
The only true way to test the pump is with a fuel pressure connects to the schrader valve on your fuel line..

12-09-2004, 01:49 AM
It will be a factor of all of them probably.

But the starting thing is definitely the CPI injector not regulating the pressure properly, the fuel filter is probably plugged as well.

12-09-2004, 08:42 AM
Thanks for the help, guys. The fuel filter did not seem to help. I have the new CFI spider unit and will install it tomorrow night. I do not own a fuel pressure gage...I know I probably should get one instead of throwing parts at it.

I'll let you know if the spider unit fixes the problem...if not, I'll attempt the fuel pump. The fellow at CarQuest said the the fuel pump for the 1995 4.3 is only $100....does this sound right? I had heard that these were closer to $300...maybe he is going to sell me the wrong pump?

If I do not notice any washing from leaking gas around the spider unit, does this necessarily mean that the existing unit is OK? Or, is this washing just one of the potential failure areas on these units? I appreciate your help.

12-09-2004, 10:36 AM
Sounds like a Fuel Pump bud, 100 bucks is right for that year. A weak pump will cause hard starts early cause it takes a bit to pump enough preasure to the pop it valves.. u should have a minimum of 57 1/2 pounds.
id say odds 8 out of 10 your issue is the pump.. the Crab assembly will run u about 300 bucks.. If u want to be sure go buy a guage for 50 bucks and try it out or borrow 1.

P.S. It is also common that after u replace 1 of the units Either pump or crab the other has better odds of going out. Ive also ran into problems of new units going out and to solve that issue i buy the Ac delco replacments which have life warranty.

12-09-2004, 11:40 AM
[QUOTE=AttentiontoDetail]Sounds like a Fuel Pump bud, 100 bucks is right for that year.

I wish my 98 blazer fuel pump was that cheap, my pump you have to pay for the sending unit also, kit cost 450 bucks :(

12-09-2004, 03:23 PM
Washing = Bad

12-09-2004, 03:34 PM
Hi Blazer LT - My question was not worded very well. I understand that washing is bad and that it indicates that there is a leak. I am wondering if the CPI unit could still be bad even if there is not evidence of any leaks?

12-09-2004, 03:38 PM
It still could be.

If it isn't regulating the pressure properly at over 56psi, it will cause the start problem as well.

Make sure your battery is up to charge as well.

Should be over 13.4volts with the engine off.

12-09-2004, 03:42 PM
I appreciate all the help, I hope to have it all done on Saturday and will post back with my findings/ results.

Thanks again.

12-09-2004, 03:51 PM
Make sure you use a new upper plenum gasket as well.

12-09-2004, 04:06 PM
Yep - I picked one of those up alreadyl. I am also thinking I might as well clean out the EGR while it is easy to get I'll pick up an EGR gasket, too. I have never had any trouble with the EGR but I sure have read about a lot of carbon problems from others.

12-09-2004, 04:11 PM
When you remove the plenum cover, you will see your front EGR port will be almost plugged.

Clean it right out.

12-14-2004, 12:43 PM
Thank you all for your help. I replaced the injector unit & nut kit and it fixed my problem. The passenger side bank was washing and it was causing a hard start when cold condition. All is well now. 180K miles and running strong and not burning any oil yet.

12-14-2004, 12:58 PM
Replace your oil ASAP.

It is impregnated with gas.

Trust me on this, also don't use a fram or pennzoil oil filter.

12-14-2004, 01:11 PM
I thought about this. But I did not smell any gas on the dip stick...probably a good idea though.

12-14-2004, 01:19 PM
Not probably, it is a definite thing to do when you swap them in.

The longer you wait, the more damage you are doing.

01-15-2005, 11:48 AM
Help! I replaced my CPI unit and nut kit about a month ago. It solved the problem and has been running well. Recently, though, I have been smelling gas. Today, I removed the plenum and found puddles of gas on both sides. With the key on, I am unable to find any leaks. Where is this gas coming from? I checked each of the poppets and they are "clicked" in tight. Are these poppets susposed to have an Oring? - I don't remember seeing them on the old unit. Do I have a defective unit?

01-15-2005, 03:27 PM
No o rings for the poppets.

You indeed might have a bad injector.

Did you use o-rings for where the nut kit inserts into the injector?

01-15-2005, 03:36 PM
Yes...I used Orings between the nut kit lines and the injector unit. I just went and exchanged the CPI unit for another new one and installed it. Will drive it tonight and hopefully I will not smell gas when we return back into the garage. I also changed oil again in case it had gas mixed.

01-20-2012, 06:06 AM
Replace your oil ASAP.

It is impregnated with gas.

Trust me on this, also don't use a fram or pennzoil oil filter.

I have a Lumina APV with a cold start problem also, and was just researching other posts when I read yours. I am curious: why not a Fram or Penzoil filter? What oil filter do you recommend?

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