RE: 96 blazer no start please help tring to work on it friday night

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RE: 96 blazer no start please help tring to work on it ... - 1/31/2008 9:01:32 PM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online SCFI == Sequential Central Fuel Injection It is what the '96-mid'02 4.3L has for a fuel injection system.  It describes the injection spider with its centrally located injector pack housing 6 injectors in a common housing.  Each injector feeds fuel through tubes down to pressure actuated poppet nozzles in the intake runners directly ahead of the intake valve in the cylinder head. CPI == Central Port Injection This is what the '92-'95 motors had for fuel injection.  Same spider arrangement with a single central injector feeding 6 individual pressure actuated poppet nozzles at each intake port. The newer mid'02-current motors have an MFI (multiport fuel injection) spider which moved the electronic injectors out to the intake ports removing the somewhat problematic poppet nozzles from the equation.  This injection spider is a direct replacement for the '96-mid'02 SCFI spider. As far as your problem, I still would be curious as to how the voltage at the pump is reacting.  Too low of voltage can cause this same scenario.  Could be something as simple as a corroded connector... < Message edited by swartlkk -- 1/31/2008 9:06:46 PM > _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to thegr81) Post #: 21

RE: 96 blazer no start please help tring to work on it ... - 1/31/2008 9:04:59 PM    Ridinblazer   Posts: 24 Joined: 1/24/2008 Status: offline i already checked the connectors there fine (in reply to swartlkk) Post #: 22

RE: 96 blazer no start please help tring to work on it ... - 1/31/2008 9:28:09 PM    Ridinblazer   Posts: 24 Joined: 1/24/2008 Status: offline well i think that the fuel pump is most likely answer so im going with tat (in reply to Ridinblazer) Post #: 23

RE: 96 blazer no start please help tring to work on it ... - 1/31/2008 9:31:34 PM    thegr81 Posts: 2621 Joined: 1/16/2007 From: PHOENIX,AZ Status: offline Yes I would go with the pump so replace that and let us know the results we like when people repair something and come back to let us know the outcome!!! _____________________________ 2001 2wd 4.3 vortec v6 "I'm not fat, I'm a minitrucker" (in reply to Ridinblazer) Post #: 24

RE: 96 blazer no start please help tring to work on it ... - 2/7/2008 2:25:13 PM    Ridinblazer   Posts: 24 Joined: 1/24/2008 Status: offline Well  installed the fuel and it runs and the pressure hold and when i turn the key it kicks right up to 60 lbs instead of 40 ilbs but, its running rough and the check engine light is blinking (in reply to Ridinblazer) Post #: 25

RE: 96 blazer no start please help tring to work on it ... - 2/7/2008 5:15:04 PM    rriddle3 Posts: 1339 Joined: 12/22/2006 From: Fort Worth,Texas Status: offline Have the code read, but I'll bet it's a P0300 (misfire). _____________________________ 2002 Blazer LS 4dr 2WD Auto Trans Hypertech PP III Programmed Flowmaster 50 Series Delta Flow Muffler, C6 Corvette Exhaust Tip TYC Elegante carbon fiber tail lights (in reply to Ridinblazer) Post #: 26

RE: 96 blazer no start please help tring to work on it ... - 2/9/2008 9:29:27 PM    Psychropod Posts: 338 Joined: 5/23/2007 From: Baltimore, MD Status: offline My '96 is having a similar issue as Ridinblazer's.  I plan to replace the filter and WAS going to also replace the fuel pressure regulator -- but after reading all these posts, I think it would be smarter to get a fuel pressure gauge first, then while replacing the filter, determine conclusively whether the problem is coming from the FPR or the fuel pump prior to performing any more repairs. I've noticed that it is gradually taking more and more attempts before the engine starts, so I'm a little worried that if I don't take care of it soon, it won't start at all. One thing Kyle pointed out that concerns me is the fuel pump voltage.  Is there any way to test this, seeing as the pump is inside the frickin' tank? And even if you can test it, doesn't that still mean you'd have to get the thing out before you could repair it (meaning you might as well replace it at that point)? Last (Ridinblazer), I think it is REALLY weird that you suddenly got a misfire code after replacing the fuel pump. Could this mean that the new pump is now pushing too much fuel?  (It seems like the more you learn, the more confusing it gets.) < Message edited by Psychropod -- 2/9/2008 9:39:53 PM > _____________________________ Raphael (in reply to rriddle3) Post #: 27

RE: 96 blazer no start please help tring to work on it ... - 2/10/2008 10:49:56 AM    Ridinblazer   Posts: 24 Joined: 1/24/2008 Status: offline Well it didnt get a misfire code right away it kinda ran rough b4 but i didnt bother with n e thing... once i replaced the fuel pump i also did a tune up i replaced cap rotor and wires no plugs .... and it ran ok after but still had the usuall mis to it and then within the next xouple days it just got worse so i decided to check out the plugs and they where junk so i replaced all but the one by the intermiate shaft for now and its running like a dream i am going to by a swivel to get at that one or take the shaftout.. but thats what my problem was (in reply to Psychropod) Post #: 28

RE: 96 blazer no start please help tring to work on it ... - 2/10/2008 11:00:20 AM    rriddle3 Posts: 1339 Joined: 12/22/2006 From: Fort Worth,Texas Status: offline Very good, I hope that wraps it up for you. _____________________________ 2002 Blazer LS 4dr 2WD Auto Trans Hypertech PP III Programmed Flowmaster 50 Series Delta Flow Muffler, C6 Corvette Exhaust Tip TYC Elegante carbon fiber tail lights (in reply to Ridinblazer) Post #: 29

RE: 96 blazer no start please help tring to work on it ... - 2/14/2008 9:30:45 PM    Psychropod Posts: 338 Joined: 5/23/2007 From: Baltimore, MD Status: offline Yeah, Ridin...glad to see your ride is A-OK now.   I still haven't done anything with mine, because the weather hasn't been on my side.  There's been near-constant rain and ice during the past week, and I don't have a garage.  However, the weather just got nicer today and is supposed to hit the 50s tomorrow, so I plan to do the fuel filter replacement this weekend. I noticed that there is a box-like structure just underneath the left bumper end. I suspect the filter is under there, although I may decide to inspect the length of the fuel line first before opening it up.  I'm assuming this is something they stopped doing after '97, because my Haynes manual didn't show anything like that.   I also decided that I won't get a gauge unless replacing the filter doesn't resolve the problem, because then it would be cost-effective to buy the gauge and determine immediately whether it is the regulator or the pump that is the culprit.  Meanwhile I've been shopping around for pumps, so that I'll be ready to buy one if I need it. Has anybody seen this aluminum fuel pump before?  They claim that it is a direct replacement that works better than stock.  I noticed there were a few negative customer reviews, but note that their vehicles appear to be the wrong ones.  One '96 Blazer owner gave it good reviews.   < Message edited by Psychropod -- 2/14/2008 9:35:48 PM > _____________________________ Raphael (in reply to rriddle3) Post #: 30

RE: 96 blazer no start please help tring to work on it ... - 2/15/2008 5:22:37 AM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online Your fuel filter will be basically inside the frame rail under the driver's seat (or somewhere close).  It is in front of the fuel tank.  The box you are talking about is the EVAP canister. About that fuel pump...  I would be very skeptical as to whether it would work.  If you are feeling adventurous, go for it, but it will require modification of your sending unit for it to be used.  I love the last comment in the page - "can see better fuel consumption"...?  That's good!  Is the guy comparing fuel consumption from when the car wasn't running due to a faulty fuel pump?  LOL _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to Psychropod) Post #: 31

RE: 96 blazer no start please help tring to work on it ... - 2/15/2008 5:43:07 AM    Psychropod Posts: 338 Joined: 5/23/2007 From: Baltimore, MD Status: offline Very good point on that last commenter, Kyle!  Didn't think about it that way... I consider myself an adventurous guy, but not when it comes to repairs that require removing the gas tank.  I want it to work right the first time.   LOL So do you think my best bet is to go with a stock GM part? Does GM make a performance version of the stock part?  For that matter, would a pump designed for a 350 work in a 4.3 Vortec? _____________________________ Raphael (in reply to swartlkk) Post #: 32

RE: 96 blazer no start please help tring to work on it ... - 2/15/2008 5:51:03 AM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online Tanks are different.  Fuel pumps very rarely max out and are continuously circulating fuel through the system.  At some point if you were to max out the stock pump, I would recommend you install an auxilliary inline fuel pump, but not until you have the need. As far as I know, there are no GM performance pumps available.  I would recommend an AC Delco pump though. _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to Psychropod) Post #: 33

RE: 96 blazer no start please help tring to work on it ... - 2/15/2008 8:35:02 AM    Psychropod Posts: 338 Joined: 5/23/2007 From: Baltimore, MD Status: offline Okay, Kyle. If I need a pump, I'll take your advice and get the stock AC Delco.  Thanks again. _____________________________ Raphael (in reply to swartlkk) Post #: 34

RE: 96 blazer no start please help tring to work on it ... - 2/17/2008 9:26:42 PM    scrachead   Posts: 7 Joined: 2/17/2008 Status: offline Hello Everyone , This is my first post so i hope i do ok for all of you and any help on posting will be appricated. I have a 95 blazer with simular fuel psi problems. I have changed the cpi spider and nut kit because of a leaky FPR . What made me change it was ,the blazer was very hard to start at first than wouldn't start at all and looking inside i could see washing on the passenger side around the FPR and the fuel pressure was low 40 to 45 psi. and drop to around 20 psi with key off. The confusing part was sometimes it would hold and othertimes it would not.  After installing the spider and nut kit and supply lines, i reconnected the fuel pressure tester and found that i still had the low fuel pressure. There was no leakage from the installed parts so i put the thing back together and decided to check the fuel filter and pump . I put a test gauge on the supply line before the filter and found the same psi 40-45 psi. I than reconnected the supply line and figured its the pump. Just to see if it might be a voltage drop and after reading about it here, I ran a direct 12 volt feed to the pump test lead under the hood driver side and found that if i intermittently tapped the wire to the voltage source  ( battery positive side ) I could bump the pressure up to 63 psi. I cannot bump the psi up by bumping the key to on. At the first crank of the engine at 63 psi it would try to start but the pressure would drop instantly to 45 to 50 psi. . At the low psi I could get it to start using starting fluid. The pump runs when i turn the key to on , i hear the relay in the glove box click and  once running i show 55 psi  fuel pressure while the engine is running and it runs real smooth.  Anyone one have thoughts why i can Bump the pressure up to 63psi and the pump won't do it normally. I'm really not wanting to have to drop the tank yet and i would like to cover all the bases. (in reply to swartlkk) Post #: 35

RE: 96 blazer no start please help tring to work on it ... - 2/18/2008 4:53:04 AM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online This sounds like a problem with voltage drop to the pump which could be from corroded connections or broken wires.  However, it could also mean that your pump is toasted and needs higher voltage to start correctly, but once its warmed up and running off of alternator voltage (>13.5V), it runs fine. How far does your battery voltage slip to when you try to start your truck? _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to scrachead) Post #: 36

RE: 96 blazer no start please help tring to work on it ... - 2/18/2008 7:22:30 AM    scrachead   Posts: 7 Joined: 2/17/2008 Status: offline Hello : Last night i bumped the pressure up yo 63 psi and decided to call it a night . this morning the fuel pressure gauge had droped to 20 psi . I will be checking the voltage that you suggested in an short time. I did however connect on of those portable battery jumpers you can buy . i connected it to the direct feed to the pump, the pump starts but needed to be bumped to 60 psi. I than kept the pump running and tried to start it and again it dropped to 45 psi. does the pump have a check valve in it ? just asking , but i think the pump must be the bad egg. (in reply to swartlkk) Post #: 37

RE: 96 blazer no start please help tring to work on it ... - 2/18/2008 7:31:36 AM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online So you needed to start and stop the pump a few times to get the pressure to 63PSI?  Is that correct? And yes, there is a check valve in the pump that holds pressure in the lines. _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to scrachead) Post #: 38

RE: 96 blazer no start please help tring to work on it ... - 2/18/2008 7:35:34 AM    scrachead   Posts: 7 Joined: 2/17/2008 Status: offline yep   yes (in reply to swartlkk) Post #: 39

RE: 96 blazer no start please help tring to work on it ... - 2/18/2008 7:40:43 AM    swartlkk Posts: 14532 Joined: 5/1/2005 From: Waterloo, NY Status: online This definitely sounds like a failing fuel pump.  You should not have to bump start it for it to reach is maximum working pressure. _____________________________ Kyle- 04 Rainier My Restoration Projects Please Do Not PM for Tech Help (in reply to scrachead) Post #: 40

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