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1995 Crusader 454 XL TBI Fuel Injection no fuel pressure and erratic voltage to pump

T

toy4two

New member
Wondering if anyone has a clue on this. I have a no start condition on the port 7.4 454 TBI fuel injected engine. Fuel pressure measures at zero just before the TBI injection assembly on the intake manifold.

I hear fuel pump prime on key turn. I measure 12V at key turn only for priming, then it goes to zero, when I turn key and cranks its dropping to 9V and is really erratic jumping up and down.

I cannot find a fuel pump relay on this engine to replace.

Pulling fuel pump off engine and connecting to 12V it runs fine and sounds strong with good suction (air) on fuel line intake port.

I was thinking this is an oil pressure switch issue but I've been told the XL, unlike the earlier 454 does not use oil pressure switch to allow power to the fuel pump. I still bought a new switch since its not terribly expensive for this model, unlike the earlier "pig tail" oil pressure sensors for Crusaders. Please correct me if I'm wrong.

Any clue why my voltage woudl fluctuate to the fuel pump. New fully charged batteries, but addmittidly the engine sounds weak and tired turning over.
 
If your fuel pressure is ZERO at the TBI inlet, it won't run...

Hearing the pump 'prime' with the key on indicated the fuel pump is running but it may not be delivering fuel...which means it has an internal issue or there is something amiss in the plumbing back to the fuel tank...you can always use a vacuum gauge on the suction side to see whats happening there...

Pretty certain there is a relay but its not the common auto type...look up a GM 14089936 relay to get an idea what it looks like. with the pump running in the prime mode, it suggests the wiring and relay are ok. every ECU controlled Crusader (based on the BBC) that I've seen uses the relay to control the pump...the carb'ed models use the oil pressure switch to control the fuel pump...and they have had a couple versions there.

Regarding the 'doesn't sound good turning over' - its possible connected to the voltage fluctuations at the fuel pump...and could be due to corroded battery cable connections...so it's likely worth the time to clean up both ends of all of the battery cables...you can sometimes find the bad one by cranking the engine for several seconds and then scanning each cable end with an IR gun...the crusty ones usually get warm very fast.
 
obtained the very hard to find metal fuel pressure lines, full TBI rebuilt + new injectors and external fuel tank and it runs great.

The problem was mostly the fuel quality and a clogged anti-siphon valve with ethonol "jellies"
 
no but you can buy Crusader 454 manuals in electronic format, I especially recommend the troubleshooting ones, on ebay from Lakeland Auto and Marine
 
Check voltage AT the Battery terminals while cranking....if it drops below 10.5 while cranking, battery is either shot or needs a good charge...
 
put on a new fuel/water seperator filter and run it off an external tank, this garbage they sell for gasoline these days degrades within a few monthes, corrodes aluminum fuel tanks, and gets lower fuel mileage.

I see outside of California you can still get actual gasoline and not this E10 trash. $1200 pumping out and disposal later my boat engine is running perfect again.
 
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