Which fuel pressure diagnostic kit
02-21-2020, 06:36 PM
#1
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Which fuel pressure diagnostic kit
Looking for a "Universal" fuel pressure, fuel injection, testing and diagnostic kit. Currently working on an '87 S4, but would like to kit to be useable on early '86 and '83 as those are in que. Any recommendations would be appreciated.
Thanks,
Joe
Thanks,
Joe
02-21-2020, 06:41 PM
#2
Matco MFI6550 is what I have. Slight bit of overkill but I'll never need another one.
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worf928 (02-21-2020)
02-21-2020, 06:44 PM
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02-21-2020, 08:38 PM
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Folks who work on the CIS/K-jet cars need specific fittings and a block valve to set and test for system fuel pressure and control/WUR pressures at the same time, so the gonzo kits are a requirement just to get the right plumbing pieces. The L- and LH-Jetronic cars need just one adapter, the one for the front of the fuel rail. I think Rob E identified the thread pitch for the fuel rail cap at something like 16-1.5 thread, but don't hold me to that. Meanwhile, I bought a cheap/common gauge, drilled and tapped a used fuel rail cap, connected them with a hose, called it a day. For the later US cars that are not CIS anyway.
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GM uses a test point that has a Schraeder valve built in, and it's 1/4-28 threads. I drilled and tapped the cap with that size, and can use any run-of-the-mill gauge that will attach. Many POLAPS will free-rent you a fuel pressure test gauge kit, including this common GM-sized adapter. I use the cap and a 1/4" brass tube compression ferrule (plumbing aisle at the hardware store...) instead of the ball that normally does the sealing in the cap, and I'm good to go cheap.
One of our members made some very nice adapter collars maybe a decade ago, such that a gauge will attach easily right at the end of the fuel rail. I know that Roger had some made too, and Carl sold some for a while in a kit with a liquid-damped gauge included. User evidence (fires...) suggests that you shouldn't leave them attached beyond your testing needs, but the system works well for the basic pressure and bleed-down needs of the electronic-injection cars. Check with our vendors and see if one of them has the very basic gauge and fitting you need.
----
GM uses a test point that has a Schraeder valve built in, and it's 1/4-28 threads. I drilled and tapped the cap with that size, and can use any run-of-the-mill gauge that will attach. Many POLAPS will free-rent you a fuel pressure test gauge kit, including this common GM-sized adapter. I use the cap and a 1/4" brass tube compression ferrule (plumbing aisle at the hardware store...) instead of the ball that normally does the sealing in the cap, and I'm good to go cheap.
One of our members made some very nice adapter collars maybe a decade ago, such that a gauge will attach easily right at the end of the fuel rail. I know that Roger had some made too, and Carl sold some for a while in a kit with a liquid-damped gauge included. User evidence (fires...) suggests that you shouldn't leave them attached beyond your testing needs, but the system works well for the basic pressure and bleed-down needs of the electronic-injection cars. Check with our vendors and see if one of them has the very basic gauge and fitting you need.
02-21-2020, 09:00 PM
#5
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