Fuel electrical FIXED!!!!REALLY long please read all... (Full Version)

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Fuel electrical FIXED!!!!REALLY long please read all...

  

fun2b1 -> Fuel electrical FIXED!!!!REALLY long please read all... (4/4/2008 6:18:27 AM)

does ANYONE know where the fuel prime connector comes from?????

fuel pump relay
#1- ground-0.0 ohms to ground  
#2- pcm fuel pump relay control- has continuity from pin "d1" (autozone 1996 wiring diagram printout) (black connector pin #1 on vcm green/white) but no voltage with key on or off
#3- + common point on relay which switches from #4(fuel pump prime connector) and #5(fuse#9 ECM Batt Cir)- works when shorted to 12v + source
#4- Fuel pump prime  connector... (WHERE DO I FIND THIS!?!?!?!) where does this come from or where is it triggered
#5- +12v power source- verified 12+v

also does anyone have the wiring diagram for this fuel circuit??? including fusible links and connector locations.. or even better a FSM for 1995 in pdf???? 
* edit #2 heres videos of the tests

video#1-http://www.youtube.com/watch?v=pVmtiqN-wKU
    #2-http://www.youtube.com/watch?v=20jKwJnSB5k
   

  
swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/4/2008 9:07:24 AM)

Please have patience.  There is no need to double post the same question in multiple sections.  I will get to this when I get home and have my references on hand.  While I am at work, I cannot answer things which I do not have direct first hand experience with.  Hopefully before then someone can answer it, but if not, patience must be excersized.[;)]

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/4/2008 9:40:31 AM)

yeah I couldnt delete the post I didnt' realize I put it in the engine tans section so I tried to post in the correct section.. as for patience... i do have some butthis fuel one jsut happens to be a bit of an issue at the moment.. (friday raining) tomorrow rain/ clearing sunday great day to fix it monday job and oh yeah the car inspection I was supposed to get on friday.......... it's not impatience it's urgency.. and desperation.. and as far as the other posts.. I'm on here and they were on page three... withno replies.. which I read from you was ok to bump if it hits page two with no replies.. so i was merely bumping....

*1 edit tho now that I think of it I have a few more questions to add...

what is the block on the driver side with all the ( what looks like fusible links)??
where I only have voltage on the #5 pin and theres a minimal spike on the "prime connector" which comes from the pcm.. could the pcm be causing the abs,brake,ses/hesitation issues?? 

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/4/2008 10:04:40 AM)

I saw no problem with your bumps, which is why I didn't comment on them.

*EDIT* - that sounds...  bad...  LMAO![:D]

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/4/2008 10:25:13 AM)

love my bumps all you want your'e still not gettin my sam adams:-P[sm=alcoholic.gif]

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/4/2008 5:50:05 PM)

I am not completely sure where the fuel pump prime connector is, but it may be in the instrument panel fuse block.

The relay is the one to the driver's side behind the glove box.

Here is the schematic for the fuel pump wiring:
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_fuel_pump_SC.jpg[/img]

fun2b1 -> INTERESTING!!!!!!!!!!!!!!! (4/5/2008 7:12:55 AM)

AWESOME but now I'm gunna soudn needy... :-( is there a schmatic available for the vcm,fuse block details, insturment panel details, and ground points(from other post about abs).. i checked continuity from the vcm to the relay socket (slight discrepancy between connectors onthe diagram you provided it has it labeled as C2 "blue" on the vcm red and blue are on the bottom.. gray and black are on the top and the wire comes from the top rigth side facing the truck I belive its the black connector..( not in front of me at the moment) )) but continuity from the green/white trace wire to the "coil" pin in the relay socket and measured 0.0-0.1 ohms.... which should be fine..but when I actually check for voltage..(I'm assuming 12v to pull in the relay coil ) key on engine off... and I have (whats in the video).. spikes to 0.151v then nothing...

*side note doesnt the abs control module get its feed from here"vcm" or is it jsut the parameters...

I have a second vcm the guy gave me ( and was charged $125 to program it to the truck) but he said it did the same thing.. wouldnt stay running long.. etc..(that was fpr) but he also said he had a hard time priming it.. he said he got it started when he replaced teh eprom in the vcm) I'm wondering if it's either the vcm dying or somethin with a harness at that point... but without a pinout of the vcm I'm kinda up craps creek... thanx for all your help:-)


btw
earlier post...* edit #2 heres videos of the tests

video#1-http://www.youtube.com/watch?v=pVmtiqN-wKU
  #2-http://www.youtube.com/watch?v=20jKwJnSB5k



edit#3 k few things....

-first I tried swapping the eprom(eprom#2 in vcm#1).. for giggles... didn't work..

-then I tried finding that damn connector.. well come to find out henr3 posted a howto on this awhile back and its a red wire with a female connector end on it... THATS THE FUEL PRIME CONNECTOR!!!!!!!!! it's a test line that goes to the normally closed side of the relay where the common goes to the fuel pump... so if you suspect your fuel pump is dead you hook this fuel prime connector to a 12+v source and if you hear the whirring your fuel pump is working... if not.. then chances are its dead... mine whirred so fuel pumpseems to be working..

-then for more giggles I swapped out the vcm(vcm#2 with eprom#1) well I get everythign connected and put the key in and turn it on to prime it.. the relay is clicking like crazy along with the brake lights and abs lights like a loose wire... (dunno if its loose or the old vcm#2) but after a little bit its primes and stops i turn it over it starts.. but after a few minutes it dies..no warning.. jsut dies. it'll prime and start right back up again.. I'll post another video.. so my question..

is this looking like a vcm... or ground or loose harness????


keep in mind this vcm (vcm#2) I've never tested.. the guy I bought it from said he thoguth that was the issue too.. and he replaced it and paid a shop$125 to program the eprom for the truck..... I dont knwo what else could make the truck stall out periodically..
any ideas???

please and thank you in advance

edit#4

k well this will be the last update for now I will post the solution once i find it... the truck starts and runs... tho when i went out this morning and stuck the key in to prime it... the relay clicked on and off about 3-4 times in abotu 2-3 seconds.. then it click on and held till it primed and shut off and started right up
so I guess I'll dirve it for now.. (ALOT of backed up side work from not having a vehicle).. and when I get a chance and a warm day to strip it down and actually FIX it...lol but if anyone has the same issues.. like swart said  check ya grounds... the fuel pump prime connecter is by the fuseible link box on the driver side inner fender wall.. look around under the harness it'll be a red wire with a female connector... you can tap it right to the termi

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/14/2008 11:57:50 AM)

hmmm 4th page... 9 days... no replies or solutions.. BUMP... yell at me if you must.. desparate times call for desparate measures.. perhaps i have the only blazer that has ever had this issue???? any ideas...????

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/14/2008 3:06:23 PM)

Is the voltage signal fluctuating at the VCM output to the relay (C2-blue F6)?  How about the oil pressure signal to the PCM (from the schematic I posted above)?

Have a look at the following images:
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM_Blue_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM_Blue_2of2.gif[/img]
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM_Red_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM_Red_2of2.gif[/img]

Sorry you had to go through all of that updating, but man..  If it falls off the first page, bump it.  The stigma against consecutive posting is when someone does it within 24 hours of the prior post for no reason other than they forgot something.

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 8:38:02 AM)

ahhh gotcha on the posting.. um the thing is those charts dont apply to my vehicle.. but where did you find them cuz I've been looking for something like that I have the alldata diy subscription but I can find anythign like that on it.. and I have 4 connectors.. gimme an hour or so to get pictures... ignore the crimps that was me tying to bypass any possible shorts... if it worked I'd do a proper patch ( solder, heat shrink and silicone sealant )  but it didnt.. so I still have to do a proper patch once I get it running. as for the oil pressure switch.. i hear the relay erratically clickin over once pressure builds up.. but before even with engine cranking i had no click from the relay at any point..(oddly it would say oil pressure wasnt building)... but when I put my foot on the gas... and then cranked it would build pressure.. jsut low.. but enough that it should have started.. and now i have 2 issues... my fuel pump relay is pretty sporratic more often then not it clicks but doesnt seem like a good connection.. and I've done this with both relays and tested themm right with battery voltage they both work fine... and now I have no spark... coil tests fine... dunno if I can test icm without a computer.. and jsut got a NEW set of wires cuz most of them were out of spec...(3weeks old) bosch premium wires 4th set in 2 years .. correct me if I'm wrong the vcm controls both spark and fuel signals correct?.. vcm tells icm when to fire ic... and vcm controls fuel prime... then oil pressure switch controls fuel pump once pressure builds.. and I can almost certainly say the oil pressure switch is working because I (being the genius that I am ) had someone crank it while i "sniffed" the exhaust... good thing noone was smoking near it.. holy crap....yeah its got gas... so any idead where I can find those charts with my connectors?
[image]http://i260.photobucket.com/albums/ii17/fun2b1/IMG_1594.jpg[/image]
[image]http://i260.photobucket.com/albums/ii17/fun2b1/IMG_1593.jpg[/image]
[image]http://i260.photobucket.com/albums/ii17/fun2b1/IMG_1589.jpg[/image]
[image]http://i260.photobucket.com/albums/ii17/fun2b1/IMG_1590.jpg[/image]
[image]http://i260.photobucket.com/albums/ii17/fun2b1/IMG_1592.jpg[/image]

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 9:18:15 AM)

Ok, I pulled those from the most common VCM-A setup, but you have the PCM setup.  95 was truely a VERY screwed up year!

I'll grab the other ones tonight.  Hopefully I can do it the same way I grabbed those with minimal rework, LOL.  I got those from an AllData service DVD I have access to.

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 10:17:53 AM)

ummm I'm hoping you have vcm-a and pcm confused.. because all of the wiring diagrams that most fit my vehicle have been from vcm-a....  color codes and pin locations on vcm-a harnesses

heres a post I found on obdii.com





#14106 - 01/22/02 09:02 PM [image]http://www.obdii.com/forums/images/icons/default/smile.gif[/image] Re: 1995 Blazer

Finz Finz
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Registered: 01/21/02
Posts: 3





[image]http://www.obdii.com/forums/images/moods/default/offline.gif[/image]
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Thanks for all the inputs. I received an E-mail of how to tell the difference between VCM and VCM-A. For those who are interested; VCM has (3) larger cable assemblies side by side, and a forth (assumed pwr cable) also in horizontal line. The VCM-A has (4) larger cable assemblies double stacked 2 & 2, one over each other, with what I'd call the pwr cable centered on top row, (5) total. The VCM-A also shows ribbed heat sink fins vs flat for the VCM. VCM-A has connections on Pins 2,4,16 on the schematic, while VCM shows pins 4,5,6,9 as being populated. Since VCM has no pin 2 connection this would not have a chance of working on an OBDII scanner. Only the VCM-A has a chance. Since I know someone else who has a 95 Blazer also can't read out codes with the Actron scanner, I'm not suspecting a computer problem just yet. At least at this point I can tell the scanner sales folks I've got a VCM-A. I'm getting closer!

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 1:16:15 PM)

yeah, sorry, my mistake.  Going from memory and typing fast while at work.

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 1:49:27 PM)

ok kool.. and I found two issues.. one is the oil pressure sensor terminal C has 0Volts key on or off.... though terminal GR21 has 12 volts and fuel pump relay terminal 5 has 12 volts all orange wire from fuse #9 ..just as soon cut it and patch in a new feed from a clean spot by the vcm pin GR12... and the second issue I have is a little odd (like this whole darn thing isnt) well the ignition coil control/driver module terminal C had 7.5-9.0 ohms, 0.006 volts with the key in the run position...even with a new ground paralleled to it... same results... with the key off.. it has 0.0 ohms...0.000 volts.... so where do I go from here??? it says on the schematic this is a ground...  can I jsut cut this and abandon the black wire(wherever its shorted to ) and install a clean ground of my own????  these would both explian the stalling while running.. ops... and the no spark.. icm... no ground... or weak ground signal.... sound like a plan???.. otherwise I think I'm looking at ripping out a good chunk of the wiring harness and laying it on the ground.. and wire by wire going thru the damn thing... looking for nicks or abrasions or sharply bent wires that could have possibly broken in the insulation... so OTHER THAN THAT.. how do the other ideas sound????

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 4:55:42 PM)

I'm afraid that without being there, seeing what you are going through, it is very difficult for me to offer up an opinion of what is the proper way of going through this stuff.  Wiring problems are one of the MOST challenging problems that anyone can come up against in a modern vehicle.  I am not fully sure that I could even research the problem enough with the references I have access to inorder to be able to help you more with the limitations that are present (over the internet vs. in person).

Attached below you will find the connector views for the VCM-A setup:
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_5pin.gif[/img]
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_black_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_black_2of2.gif[/img]
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_blue_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_blue_2of2.gif[/img]
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_gray_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_gray_2of2.gif[/img]
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_red_1of2.gif[/img][img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_red_2of2.gif[/img]

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 5:12:04 PM)

awesome thanx for the info..  and yeah I'm assuming as much wihtout being present its hard to diagnose.. and like I said before << licensed electrician... the small question I have I didnt SEE any splices for the ignition coil ground.. so that should be a clean singular ground coorect.. and if so... I can snip and patch on my own... but I have a gut feeling theres something pretty mangled in the harness.. cuz none of this answers the prime relay issue....
does this at least SOUND logical?? provided my back feels better tomorrow I'm going to implement these things and give it a ****in whirl.. the thing I'm not sure of is why when the key is on I get a resistance to ground on the coil connector.... very odd.... but alas I will post my findings.. maybe this was a more common issue with the 95s... since I've found at LEAST 4 with the same issue...  but none of them posted results... this doesnt take into account how manyjsut burned the trucks for being such a pita...lol

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 5:23:09 PM)

This might help:
[img]http://i11.photobucket.com/albums/a187/swartlkk/general%20automotive/th_95_VCM-A_IGN_SYS.gif[/img]

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 5:34:15 PM)

yeah I have that thats the diagram I'm refering to with terminal C of the icm...  but would it be safe to say????.. key on or off that shouldn't affect resistance????... that should jsut be a solid clean ground????
....( the resistance indicates to me that wire is shorted in the harness somewhere to another wire... or few)

swartlkk -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 5:43:08 PM)

Yes, that would be a proper assessment.  I would be worried that it might be shorting with some other wires in the harness...  Maybe find where that ground is in particular and what wire at that ground location is the one that runs to the ICM and cut it there as well as at the ICM.  If it is shorting out inside the harness, you really should find out where...

fun2b1 -> RE: ANYONE!!! FUEL PRIME CONNECTOR?!?!?! (4/15/2008 6:06:47 PM)

yeah I'm gunna work on that tomorrow provided I can move I dunno what I did today but I did somethign to my back.. drugs, alcohol and a heating pad later... I'm still in a lil bit of pain.. so this may be waiting a bit longer... but Ithelps to be able to bounce ideas off others.. and it helps knowing I have a lead and a direction to head on.... thanx for the help.. I'll be posting every step...:-P

  

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