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I have a 1994 GMC Jimmy with a 4.3 cpi engine. About three months ago it started taking forever to start. It went from starting on the 1st key turn to now it takes at least 10 to 15 seconds to start. I was wondering if anyone else has had this issue and what they did to fix it. Thanks in advance.
 

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Things I would check, fuel pump relay, fuel pump pressure. If the relay is bad you will need extended cranking, the oil pressure switch will kick in and back up the relay after you get enough oil pressure. At least that's how it works on my first gen 2.8 not sure if its the same on yours.
 

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I don't believe that's an issue on the 2nd gens...or any 4.3. Most likely cause is low fuel pressure.
 

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Yep looks like Rhotpursuit is correct yours does not have the same oil pressure switch (just looked it up) which Is a good thing because they always end up leaking.
 

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I don't want to contradict you two, but the 1994 CPI (so do other years and engines) do indeed have a fuel pump relay, AND an oil pressure switch. The relay is outboard of the brake booster on a bracket with the tuning valve relay. The FP relay has a grey wire to it, that's how to identify the correct relay.
EDIT: The FP relay location I describe here is for the Utility body. The 94 pick-up body is of course the 2nd gen, and the relay location is different, but it has one, and the wire colors are the same. Grey, grn/wht, blk, orange. The OP has a Jimmy, so it is a 1st Gen, and his relay will be located as above.

A really easy way to check the FP relay is turn on the key and listen for the pump to run for 2 seconds and stop.

A really easy way to check the oil pressure switch is to start it cold, let it run a few seconds and shut the engine off. The fuel pump should continue to run for a few seconds while the cold oil pressure bleeds off. The colder the oil, the longer the FP will run.

I've worked with 4.3's in everything it was put in except the G-Body. In every case (S/T-series, C/K-10 pick-up, and M/L Astro Van) the fuel pump circuit has both a relay and an oil pressure switch.
 

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Well if I was always right it would bother me but alas I'm just not that good. I know that's how it works on First gen but no idea about 2nd gen and know their oil pressure switch is different. So hey Hyenad check it out and see if the relay is the problem. You may be able to swap a relay from something else to test.
 

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Been there Done it
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On the 2nd gens the oil pressure switch was a redundant parallel circuit and was eventually dropped on the later ones.
 
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