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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    My squarebody is 1987 454/TH400 R20 3/4 ton 2wd 3:42 suburban. My gmt400 is a 1993 350/4L80E k2500 3/4 ton 4wd 4:10’s suburban. Was a fire dept truck and base, base, base Cheyenne model. Tailgate with vinyl bench seats, rubber floor mat, manual windows and locks, w/t single headlights, no...
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    Are there other things I can use from a gmt400? I have my 1993 K2500 350 tbi/4L80E that was totaled, but the drivetrain and interior are in great shape. Also, I can’t find your build thread for some reason.
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    My 454 truck has the same fan. It runs all the time as soon as the key is turned to ON. From this thread I’m guessing something isn’t right with that?
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    I already replaced it, those were pics when I took the one that was in there out. I’ll look into the alcohol for flushing, thanks.
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    Thanks. Yeah, I’m torn btwn spending $ to try to flush stuff vs. just replacing with parts that’ll have better heat transfer, etc. I do like the idea of clean, r134 sized heat exchangers, but if they are already large enough, and not much more than buying a bunch of cans of flush it makes...
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    Thanks for those pics, helpful.
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    This is the sticker on it. I didn’t have much luck getting anything from it online.
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    I was trying to find that compressor and from pics I found it was listed on a straight-6 engines truck I think. I couldn’t cross reference it to the 454, so wonder if it’s been swapped. The lines look like they may not be original to the truck? I’m not bothered with originality as long as...
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    Vintage Air Gen V (5) or replace existing compressor, etc., for 1987 R20 Suburban?

    Hi all, I bought this clean 1987 R20 454 Suburban a couple months ago. The AC didn’t work, and when I hooked my gauges up only had about 10 psig on the low side. It had r134 fittings already, but I went ahead and replaced the schrader cores and replaced the orifice tube and o-ring. Pulled a...
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    1987 454 TBI down on power, runs good otherwise

    So following up on the solution. The thermostatically controlled flapper on the air filter housing didn’t have the hose running down to the shroud on the exhaust manifold to supply heat and open the flapper. So the engine was choked for air. I wedged a rag to hold the flapper open and it runs...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    So to close the loop, I repaired those two positive wires and the issues went away. Scanner can talk to ecu and reports no codes now. Truck starts and runs normally now (besides the idle not quite being dead smooth). I’m going to pull the tbi and rebuild it and replace injectors (Delco) and...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    Could be onto something here, lol. Wires were pinched by the sheet metal starter heat shield.
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    So from tracing the circuits on the schematic, it looks like I should have always on +12v at two pins on the bulkhead connectors. Circuit number 2. Only one of the pins has continuity to the positive terminal (the connector in row Y in this pic). The other one, at the bottom left, does not...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    It looks to have a remanufactured ecu if that helps point to something.
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    The truck starts and runs on starting fluid. I don’t know which circuits are powered with the key in each position offhand. Does every fuse have power to one side of it all the time? I’m new to this platform so don’t have the background knowledge of reading posts for decades like on my BMWs...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    I pulled each fuse out of the block and individually checked each one using my meter in continuity check mode. I checked both ecu fuses again after that as well. I’ll check again. Guess I’ll pull the glovebox and see if I can check the wires from ecu to the ALDL connector for continuity.
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    It was about $250, apparently one of the only hand held tools that will read the ecu live data. https://www.ebay.com/itm/235344132189 OK, so it was partially user error, even tho it has internal batteries and powers up, you MUST have the 12v adapter plugged into it also. It works on my...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    Alright, so I bought a good scan tool that can read some of the live data from the ECU as I figured that would be useful in the long run. And, it reads the codes as well. It’s an OTC 3211 (same as Bosch 1300 and Actron CP9690) and it doesn’t recognize that it is attached to the truck/ALDL...
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    1987 454 TBI down on power, runs good otherwise

    It will speed up with engine speed, but it feels like it only has 100 hp. Slow to accelerate, and if it kicks down it just won’t accelerate until you let up and let it upshift and give it gentle gas. I posted sone videos of the injectors in this thread and you can see one side looks poor...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    Yeah, I’m a little leery of frying the ecu. I have a fluke that has a simulated analog output (bar graph on the bottom of the screen), I’d think it’s pretty well buffered to stop you damaging things you are taking readings of. If the pulses are pretty slow I should be able to watch the...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    I built a device to pull and reset the blink codes on my w124 Mercedes, I bet it might work fit this. Looks like pin 4 is the data out, I’ll look into that more. Or I could get a cheapy flash reader, but I was looking at Amazon and they seemed hit or miss. One might say “73 to 95 chevy” and...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    The truck physically has no check engine light. Not no light flashes, there is no light actually present on the vehicle, so I can’t short pins and get a light that is not physically there to flash. I have felt up behind the speedo and there are openings, but no bulb, no bulb holder, no wires.
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    There is no check engine light. The ALDL connector must have a pin that sends +12v out to a reader. If I knew which pin I could hook up a light.
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    I removed and put back the main battery ground and the lights, etc., came back. Still zero fuel spray. There is no check engine light (at least that I can see when ignition is turned to ON or feeling behind dash for a loose bulb. I have the bezel off and am going to pull the cluster to see...
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    ‘87 454 TBI, NO Fuel spray, HAS fuel pressure, has 12v @ injectors, has spark

    You wouldn’t happen to have that handy, or a link? I just found a site with service manuals, but it only has 1986 and 1988. Not sure which is more in line with 1987 since that seemed to be the year things changed...

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