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Shortcut: getting injectors to fire w/o pulling UIM

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Old 04-15-12, 06:53 AM
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Shortcut: getting injectors to fire w/o pulling UIM

Hey guys- just got an '89 GTUs that's sat since around 03. Old man I picked it up from already tried to get it running but failed. Has a new fuel pump, car's getting fuel and spark but won't start. If I pour fuel into the engine it starts and runs well until it's burned off.

Just to confirm
-S5 NA
-Fuel IS getting to injectors- cranked w/ fuel feed house removed from rats nest & saw fuel be pumped out during starting
-spark confirmed by bouncing tach during cranking
-compression passes the audible test of cranking w/ plugs out, and it also runs w/ fuel poured in.

Remember, this car has sat for nearly 10 years, so I'm really confident the injectors have degraded fuel remnants within them causing them to stick.

I'm looking for a way to get them to fire w/o pulling the intake. Basically, just get this car running as quickly as possible, so it can move under its own power until I have the time to go through it properly & have the injectors sent out & refurbed/radiator flushed/new coolant houses/etc. etc. etc.

What comes to mind is pulsing the injectors w/ an injector pulser at the plugs to the ECU.

Thanks!
Old 04-15-12, 07:15 AM
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you can pull the CAS and spin by hand and you should hear them firing.. but that doesnt tell you if they are clogged. if your getting spark and injectors are firing, and you know you have good gas in the tank, your best bet may just to try to push start it
Old 04-15-12, 11:23 AM
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[QUOTE=Landon303;11056000
What comes to mind is pulsing the injectors w/ an injector pulser at the plugs to the ECU.

Thanks![/QUOTE]

that will work. spinning the CAS will also work
Old 04-15-12, 11:37 AM
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the ONLY way to unstick dry rotted injectors that have stuck is to remove them and send them off for service.
Old 04-15-12, 12:57 PM
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^ +1

Plus, it's just good car maintenance.

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Old 04-17-12, 09:34 PM
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pulled a CAS from another car, so as to not mess up the timing, & I'm only hearing 3 injector pulses per rotation, where as on the other car which runs fine, i hear 6.

So definitely have one sticking.
Old 04-18-12, 07:27 PM
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OR one of your primary injectors has bad wiring. Like mabe someone installed a new injector clip at some time and made a bad solder connection on one of the wires?

IF you check each of the fuel injector wires AT the ECU plug with key ON you should have batt voltage........and if you do then I'm wrong about bad injector wiring being the problem.
Old 04-19-12, 07:15 AM
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3W - (Front primary)
3X - (Front secondary)
3Y - (Rear primary)
3Z - (Rear secondary)

See F1-8 -> Free 1989 FSM: Fuel and Emissions Control Systems (Non-Turbo)
Old 04-21-12, 01:16 PM
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Originally Posted by HAILERS2
OR one of your primary injectors has bad wiring. Like mabe someone installed a new injector clip at some time and made a bad solder connection on one of the wires?

IF you check each of the fuel injector wires AT the ECU plug with key ON you should have batt voltage........and if you do then I'm wrong about bad injector wiring being the problem.
Given what we know about the car and how tempermental these injectors can be I'd be willing to bet its just sticking. This car is 100% stock and it is highly unlikely that the injector clips have been touched.

I went through this whole ordeal when my car was leaning out under boost, using a spare CAS, testing voltage at the ecu, checking for continuity to the injector clips (which I has already replaced). Turns out the secondaries were just sticking. As it turned out, the reason WHY was a large amount of sediment had been sucked into the fuel system so that might be something to check on.
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