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Thread: Newbie With a 1983 G Series Van & 6.2

  1. #101
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    Quote Originally Posted by DmaxMaverick View Post
    It could be the IP, but I don't know. It could be air, which hasn't been eliminated. Eliminating the IP would be simple: Just replace it (and you may still have a problem with air). Eliminating an air leak requires a process, but a lot less expensive than replacing the IP. If you have a leak, and replace the IP, you still have to fix the leak.

    What I would do, knowing what I know about your truck at this time:
    Plug in the block heater.
    Connect a battery charger (charge, not trickle).
    Install a clear line loop at the fuel return outlet at the pump.
    Verify the HPCA is getting power on a cold start with key ON. It's the other wire connected to the IP (not on the throttle, if it has a TPS).
    Come back after 2-4 hours after connecting charger and block heater.
    Injector lines tight, and everything ready for a "normal" start. Crank engine in 15 second intervals (with 5 minutes rest). Watch the fuel return clear line loop. The fuel should push out any air, and you should not see more bubbles. If more bubbles, back to step 1: find/fix the leak.

    It started and ran before, which means the IP and injectors are, at least, minimally functional. Something caused the fuel volume to diminish or stop enough to not continue running.
    Sorry I don't mean to jump to conclusions regarding the potential for air in the lines, as I said I am now under a timeline to get this thing moving and grasping at any simple fix.
    Anyway, I bought some clear line, a fuel cap & schrader valve and will commence to build a tank pressurization setup and check the lines. Considsering the configuration of the van, I cannot get a good look at the IP, but from what I can see there should be ten lines on it; eight (one for each injector) one supply from the secondary filter and one return line to the tank. Is that correct? Diagrams and pictures are not clear on this. I just want to ensure I hook up the clear line in the right spot.

  2. #102
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    OK, the return line is more obvious than I thought once I could get closer to the pump, so I put a clear 1/4" line and some tight worm drive clamps on there and with 20 seconds or so of cranking the line filled up to the peak and started draining back down. Now, initially there were some bubbles, but by the time I was cranking it a third and fourth time the bubbles were tiny bubbles. What kind of bubbles are we talking about that would cause problems?
    I went ahead and made a pressurization cap for the tank, that is next.

  3. #103
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    Most of the fuel that passes through the IP goes out the return. Very little fuel, especially at idle and no-load, actually goes to the injectors. Any bubbles passing through once it's purged, means air is entering the IP through the supply. It doesn't take much air at all to foul the high pressure fuel injection process. The actual high pressure circuit from the IP to the injectors is a very small volume. Once the engine is running and at higher RPM's and load (like revving), any air leak will allow MORE air in than while just cranking.

    Pressurizing the tank is a good way to locate leaks. Don't expect a huge spray or stream. Most will appear as area(s) of wetness or slow drips. If the leak happens to be the fuel pick-up assy (gage sender, and a common suspect on older rigs), it won't leak externally.

    Also, make sure your fuel cap is for Diesel, and the vent is working properly. A gasser cap will fit, but it will not vent properly, and cause all kinds of issues that will look like something else (like a failed lift pump or IP, or a leak).
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  4. #104
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    Still working. While cranking it would fire up occasionally (LOUD without the air cleaner in place) and push a bunch of bubbles through the clear line at first and would eventually settle to the tiny bubbles.

    Went ahead and pressurized the tank, went underneath and cannot find any source of a leak; no wet spots where lines join, nor at either filter or at either pump. I've got a 6 amp charger hooked to it for now, along with the block heater. I will step away for a bit and return to check the clear line once it has had time to heat up/charge.

  5. #105
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    Quote Originally Posted by DmaxMaverick View Post
    Most of the fuel that passes through the IP goes out the return. Very little fuel, especially at idle and no-load, actually goes to the injectors. Any bubbles passing through once it's purged, means air is entering the IP through the supply. It doesn't take much air at all to foul the high pressure fuel injection process. The actual high pressure circuit from the IP to the injectors is a very small volume. Once the engine is running and at higher RPM's and load (like revving), any air leak will allow MORE air in than while just cranking.

    Pressurizing the tank is a good way to locate leaks. Don't expect a huge spray or stream. Most will appear as area(s) of wetness or slow drips. If the leak happens to be the fuel pick-up assy (gage sender, and a common suspect on older rigs), it won't leak externally.

    Also, make sure your fuel cap is for Diesel, and the vent is working properly. A gasser cap will fit, but it will not vent properly, and cause all kinds of issues that will look like something else (like a failed lift pump or IP, or a leak).
    No Diesel marking on the cap, and it is black so I have to assume it is a gasser cap. Would it work better with the cap removed if it is a venting problem?
    I was worried about a leak up on top of the tank, no way for me to track that down short of removing it. As for the tiny little bubbles, are you saying that they are a cause for concern? I know when bleeding brakes you want a line of pure fluid, no bubbles of any kind so I assume the same for this, though with brakes a little air will still allow the brakes to function, if a bit mushy. I had hoped that the amount of air I think I am seeing would at least allow it to run, even if only roughly (enough to get it out of my neighborhood and back to the storage yard.
    Bubbles while cranking

  6. #106
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    Well, after all that the results remain the same. It starts and immediately dies. There are no longer any bubbles in the return line, so I think I've got the system air tight and bled.

    Will an electric inline pump overcome the failed IP? because that was what was in there when I started this whole episode and I removed it when I replaced the lift pump.

  7. #107
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    Disregard this, since you are getting no air.

    Looks like you still have a leak, somewhere. Once the return line is free of air, it should stay that way. No bubbles. Little or big. None. The slug of air when you first start cranking is what settled out since the last attempt. The little bubbles are real time. Are you continuing to get air in the filters?
    Last edited by DmaxMaverick; 05-13-2017 at 15:11.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  8. #108
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    Later models (90-something?) had green fuel caps. All of them earlier were black, and may or may not be labeled. If your cap is questionable, they're cheap. Otherwise, running with it loosened will allow it to vent. I don't think that's the problem now, at any rate (it doesn't run long enough to make it a problem).

    An electric pump should not overcome any failures of the IP. A proper electric pump would perform no better than your mechanical pump, but an electric pump that will push the fuel at a much higher pressure (like a gasser pump) might. A healthy IP will draw enough fuel for idle and low power, with a failed lift pump. None of this explains the start and die situation. A failed IP doesn't explain it, either. If an IP can start, it should continue running, at least minimally. Keep monitoring for air. I have nothing else at this time.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  9. #109
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    Missed it, but before we go any further I want to thank you very much for all of your help the past few days.

  10. #110
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    I am throwing in the towel for the night and probably sending it to a mechanic on Monday.
    Things like this is the reason why I prefer working on motorcycles.

  11. #111
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    Howdy
    A couple easy things to try....run a line bypassing the secondary filter directly to the primary. So your line will go from the LP to filter to IP.
    How much soft line is in place before the LP?
    Can you run your feed line to the LP from a separate source, like the boat tank or motorcycle tank? It this works it will get you to the yard.
    I am wondering if you have allot of soft line before the LP if it is sucking it down enough to restrict fuel flow.
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  12. #112
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    Tried the boat tank to no avail, so I am dead in the water. Getting a tow in the morning.

  13. #113
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    So the mechanic has confirmed that the IP is bad so he are working on a quote to remove & send to the injection shop in Clearwater (apparently they are THE injection pump shop in the area). He also mentioned that the new lift pump was not functioning. When I removed the old one, I used the grease on the actuator rod trick to hold it back in there when I installed the new one. Of course once its on, is there any way for me to confirm that it is in fact actuating the lift pump? Is there anything internally that a PO could have disabled, or that may have ceased to function causing the lift pump to not operate? As I understood it, there is a cam connected to the crankshaft which pushed the rod against the arm of the pump, and the spring under that arm returns the rod as the cam turns away.

  14. #114
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    With the LP CONFIRMED not working. I wonder how they tested the IP?
    In my experience those Mechanical LPs are pretty solid. If you got the rod in place, I would want to see it verified DOA. More likely that it is struggling to get fuel. This seems to be the common problem, fuel supply to the engine. Whether it is a tank pick-up problem, Lift pump or injector pump problem. Since you had the truck running at one time I would not be so quick to jump into an IP.
    1996 Chvy 3500 CCDWLB 6.5 Heathed, NO vac, marine injctrs, ARB bumper, BIG pipe, 3" lift, bright lights, bypass oil system.
    1986 Chvy 6.2 M1009 blazer RAM AIR, Headers, Custom interior
    2001 Chinook RV, V10 gas
    1974 John Deere 1530 diesel tractor
    1993 John Deere 455 Diesel lawn mower
    1967 GTO, 1989 Honda Transalp
    2009 VW Jetta TDI, flashed and piped, 6speed, fun car!
    1998 6.5 suburban, stock, daughter's
    1993 6.5 3500 CCSWLB GM8, Heathed, big exhaust, gauges, Son's

    1984 6.2 ATS turbo 3500, SCDWLB - Son's
    3 kids, 1 wife, 1 dog
    Gunsmith, Tactics Instructor, Fabricator USMC 87-93 Semper Fi!

  15. #115
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    As I'm understanding it, the mechanic noticed there was no fuel at the secondary filter so he bypassed the LP with an electric pump. Once he got fuel to the IP, the IP was not consistently delivering fuel to the injectors.

  16. #116
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    Been a while since I updated this. After the injector pump rebuild we drove this a few times but kept chasing an electrical drain. I think there is a short in the glow plug circuit because it constantly cycles on and off while running. I assume it was continuing to do so while it sat, though we parked it at our new house and what with remodel work on the house itself we haven’t touched it in several months, so the batteries are dead again. Also, I bought another Chevy van RV with the same 6.2 in it which is in better shape than the 1st one, but has an alternator mounting bolt broken in the head. More than likely I’ll pull the engine from the 1st van since put so much effort in to it and scrap the remaining hulk.

    That being said, any sage advice for pulling this massive engine out from the van? Remove hood, grille, radiator, front clip, unbolt trans and headers at the exhaust and yank with a strong lift I imagine. Thoughts?

  17. #117
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    Simplify your life. Ditch the 83 GP controller system entirely, and install a 85-93 OEM controller. Don't look back. An alternative is to ditch the automatic GP system, and install a manual system. A HD relay (Ford starter relay, or any relay capable of 10A exciter, and 100A throughput), a momentary switch and some simple wiring is all that's required.

    If the GP system is "grounding", that's a problem independent of the GP system operation, or anything else. Check the battery load with key off. The GP system shouldn't be getting any power with the key off, so even if it has a short, it shouldn't be shorting anything. Aftermarket accessories or a hacked electrical system is a much more likely suspect.

    A cycling GP controller is the function of the temperature switch. They will, normally, cycle a few times after a start, but that should stop, completely, once the ECT is 120-140F+. If the cycling is rhythmic, rather than random, the controller/relay is doing it's job correctly with bad input (temp switch). If it's random, poor wiring is more likely.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  18. #118
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    I actually installed the later GP switch from Kennedy and it still cycled rhythmically. I also upgraded the plugs themselves to correspond to the shorter cycle.
    Yes the wiring was hacked (or rat-eaten in some cases) all to hell. If I recall correctly, when we first got the van I inadvertently touched the terminals on the original GP controller with a screwdriver and got a spark, and I don’t think I had the key in the ignition. But it’s been a long time since then, my memory may be faulty.
    I haven’t had time to pull the doghouse on the “new” one to check the GP controller, it’s an 84, has about 1/2 the mileage and at least from under the hood the harness and everything else looks a lot cleaner.

  19. #119
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    Quote Originally Posted by DmaxMaverick View Post
    Simplify your life. Ditch the 83 GP controller system entirely, and install a 85-93 OEM controller. Don't look back. An alternative is to ditch the automatic GP system, and install a manual system. A HD relay (Ford starter relay, or any relay capable of 10A exciter, and 100A throughput), a momentary switch and some simple wiring is all that's required.
    To this point, is there a good write up in here? I’ve searched but it must be buried deeper in some older posts than I have the time to find it. I wouldn’t hesitate to simplify this system with a dash switch, just need a little guidance. It wasn’t covered in the DPF maintenance book I bought.

  20. #120
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    Only the "hot" side of the relay/controller is always hot. If you shorted it, it can burn the fusible link (between the controller and firewall/battery junction), or damage the pole contacts, but little else.

    The manual GP mod is so simple, it doesn't actually require any guide or complicated instruction:

    Install the relay, grounded to the body or frame, in close proximity to the left/rear of the engine compartment (anywhere is fine, it's just that this is where most are located, even modern Duramax trucks). The relay selection isn't critical, but we recommend the Ford relay/solenoid because they are capable, reliable, inexpensive, and can be found nearly anywhere, although you could use any that is of minimum rating. Run Batt+ to one large pole (minimum 10 AWG, or use the original healthy lead), and the other large pole goes to all the GP's. Run Batt+ to the small pole, through the momentary switch. Wire the original exciter lead to the GP pole, and it will illuminate the GP lamp on the instrument panel (this will show actual power to the GP's, rather than just an energized system). Done. Any more description complicates it beyond necessity.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

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