Argosy24
MI
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The oil pressure sender is on the left side towards the front of the block just above the pan.
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JeepBus
Vancouver, BC
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john2005 wrote:No solution yet. The injectors spray fuel to start but after a few seconds then engine dies. The ECU is not sending signal to injectors. The fuel pump relay seems to be ok and fuel module keeps fuel pump on before I startup more then 20 seconds if I wait before startup. Issue may be the oil pressure switch - I have not located it. I see on the internet that after engine starts the Ignition Control Module has to send ECU signal to maintain injector operation - either that is bad or the oil sending unit is bad. I need to find oil sending sensor. It should be on left side of block but how far down? What is the sensor on the oil pan? It seems to just clip on a plastic cylinder? Need some help for sure - I am in the boon docks so not close to town and very weak signal for internet on my cell phone modem too. Any more info on oil sender - more exact or specific location appreciated.  .
The oil pressure sensor is on the back of the block near the distributor. It's not likely to be the problem though.
The sensor by the oil pan on the passenger side is the knock sensor.
The problem is most likely the ESC (spark control). Once they fail the ECM doesn't know the motor is cranking and it won't fire the injectors.
If you want more detailed info send me a PM and I'll step you through the factory GM trouble shooting process and give you the ECM pinout voltages so you can trouble shoot this properly.
2004 Discovery 39L
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Argosy24
MI
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Top of a 454 Chevy. No sender near the distributor, not even a port for a sender. Big block manifolds cover the valley front to back to the outside of the block. Maybe you are thinking of a small block or the port above the oil filter?
The passenger side is the RH side. The oil pressure sender is on the LH side of the engine, near the front, just above the pan.
If the ESC failed how is the engine firing? Possible, stranger things have happened but usually they will fail completely or run until hot then quit.
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JeepBus
Vancouver, BC
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Argosy24 wrote:Top of a 454 Chevy. No sender near the distributor, not even a port for a sender. Big block manifolds cover the valley front to back to the outside of the block. Maybe you are thinking of a small block or the port above the oil filter?
Thats a picture of a non TBI motor. A TBI intake is a little different. That said you're right I was thinking of a small block oil pressure switch. They're located in the back of the block (at the top of the bell housing right below the distributor)
Quote:The oil pressure sender is on the LH side of the engine, near the front, just above the pan.
This is correct for a big block
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Argosy24
MI
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The same engine with only the air cleaner removed.
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JeepBus
Vancouver, BC
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john2005 wrote:1990 pace arrow -Chevy RV 454 TBI H.E.I. - engine cranks but will not start unless fuel is poured directly into TBI unit-then engine starts hard but stalls when this little fuel is used up - fuel pump tested ok- fuel filter ok - fuel in gas line ok - TBI sprays a little gas when key turned to start but not enough to start engine and no fuel there after when I can get engine started. No sensor errors from ECU computer have been detected? Fuel is good as generator starts right away using same gas- what can cause this issue?
OK I re-read this again. Just to be sure I understand...
- When you turn the key to the "on" position does the check engine light come on as normal? (comes on for a second or two then turns off).
- When you first turn the key on the fuel pump should run for a couple seconds to prime the system then shut off. You should also see a quick squirt from the injectors. Sounds like this is happening correctly.
- When you're cranking you should hear the injectors clicking and see some fuel squirting from them. If you don't see this pull the connectors off the injectors and put a test light on there. With the key in the "on/run" position there should be 12v at the injectors. With the engine cranking the test light should flash on/off as the ECM grounds out the injector to fire it. If the ECM doesn't fire the injectors check to make sure you have 12v on pin C9 of the ECM. There should be 12v here only when the motor is cranking (trying to start).
- Do you have a scanner? If so check the Throttle Position Sensor to see if it's reading over 2.5volts. Also check the Temperature sensor to make sure it's reading a normal temp (roughly the current outside temp - If it's -30 then the sensor needs to be replaced). If the TPS or the temp sensor are dead then they will cause starting problems.
- If it hard starts when you pour some fuel in then you have some spark. Have you tested to see if it's a strong consistent spark (a few sparks then nothing is a weak spark)? Sometimes when the EST fails it will give a weak spark.
Oh and FYI on the oil pressure switch. It's meant to be a backup to the fuel pump relay. If the fuel pump relay fails the oil pressure switch will turn the pump on once it detects oil pressure. It won't be the problem here.
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JeepBus
Vancouver, BC
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Argosy24 wrote:The same engine with only the air cleaner removed.
What year is that motor? '87? Looked like a rochester carb base to me.
This is an Edelbrock TBI intake for a BB Chev. "Performer #3764 is a stock replacement/street legal part for 1987-90 Chevy/GMC trucks with Mark IV 454 c.i.d. throttle body injected V8 engines. Accepts stock EGR in stock location."
I haven't played with enough BB TBI motors to know all the quirks but I've swapped quite a few TBI 4.3 and 5.7L motors into other vehicles.
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Argosy24
MI
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TBI was a mid year change in 1989 on the big block. The engine in the picture is a 1990.
350 and 454 both used the 220 TBI, different injectors. The 454 used a heater (you can see the coolant line below and between the TBI supply and return lines) under the throttle body that had a pattern similar to the Quadrajet. The manifold pictured would be a bolt up for a TBI without the heater.
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semiretiredDIY
WA state
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Joined: 12/15/2008
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Argosy24 wrote:Pressure on a 454 tbi system is 9-13 psi.
The ecm will normally run the fuel pump for 2 seconds on start to prime the injectors but the 454 has a 'hot fuel handling module' which will run the pump for 20 seconds because of vapor lock from a hot start.
Check power to the fuel pump relay coil, see if it is dropping out. It sounds like the fuel module or connections may have a problem. I have in front of me one each shop manual, printed in USA General Motors Corporation page 4A-14 fuel pressure should be (26 to 32) psi for the 454 engine. The fuel pressure on my 454 TBI checks out within those specs.
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JeepBus
Vancouver, BC
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semiretiredDIY wrote:I have in front of me one each shop manual, printed in USA General Motors Corporation page 4A-14 fuel pressure should be (26 to 32) psi for the 454 engine. The fuel pressure on my 454 TBI checks out within those specs.
*shrug* I have in front of me a factory GM service manual that says the fuel pressure should be 9-13psi when tested at the outlet side of the inline fuel filter. 
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