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V8RangerBoy
Well-Known Member
- Joined
- Dec 3, 2007
- Messages
- 203
- Vehicle Year
- 1994
- Transmission
- Manual
That's good news. The PCM is what closes the fuel pump relay to enable the pump, so no need to jump to conclusions. We at least know that part is working.
Just to clarify, when you say fuel is flowing, we are talking like a mini-garden hose, correct? Again, a pressure test is ideal, but if nothing else, it should come out in quite a stream.
Spark, fuel, compression, and reasonable timing of the 3 are what we need. You've checked spark, at several plugs, so that sounds correct. Compression doesn't fit the circumstances. You have verified that the fuel pump is working. You have verified power to the injectors, but haven't verified that the PCM is capable of pulsing them. Because you say the plugs are dry, this is the next place to go.
The options for testing pulse are somewhat thin. As I said before, it's possible to check them with a test light but not recommended as the load of a bulb can damage the driver in the PCM. The correct method is with a noid light, which is similar to an LED and is designed to mimic the load of an injector. It is possible to hear the injectors 'click' as they pulse if you use a stethoscope, but that can be difficult to distinguish accurately. You can monitor the signal with a scope if you have one, but I doubt that. Lastly, you could remove the injectors from the rail to actually watch them spray. That's alot of work and really only verifies what you have seen with the dry spark plug.
I will go ahead and take a 'probably-accurate' guess that there isn't a pulsewidth. In that case, the testing equipment required probably exceeds what you have access to... The next step involves monitoring and verifying sensor inputs and PCM outputs with at least a scanner. We only charge 1 hour to diagnose something like this, unless it gets into melted wiring or other abnormal circumstances, which is $75.00 here. I recommend taking it to a shop at this point - otherwise you are left with just buying and replacing parts 1 by 1 and hoping for the best, which can get tremendously more expensive than paying a diagnostic charge. Make sure that if you do decide to take it to a shop, that you tell them what happened when the vehicle quit running and everything you have replaced or tampered with. We often get customers that think they will save money by only telling half of the details, and that only aggravates the situation! Be honest and upfront and hopefully they will help you out.
I'll gladly keep trying to help you where I can, but as I said, correctly testing things from here on is probably beyond the tools you have.
Just to clarify, when you say fuel is flowing, we are talking like a mini-garden hose, correct? Again, a pressure test is ideal, but if nothing else, it should come out in quite a stream.
Spark, fuel, compression, and reasonable timing of the 3 are what we need. You've checked spark, at several plugs, so that sounds correct. Compression doesn't fit the circumstances. You have verified that the fuel pump is working. You have verified power to the injectors, but haven't verified that the PCM is capable of pulsing them. Because you say the plugs are dry, this is the next place to go.
The options for testing pulse are somewhat thin. As I said before, it's possible to check them with a test light but not recommended as the load of a bulb can damage the driver in the PCM. The correct method is with a noid light, which is similar to an LED and is designed to mimic the load of an injector. It is possible to hear the injectors 'click' as they pulse if you use a stethoscope, but that can be difficult to distinguish accurately. You can monitor the signal with a scope if you have one, but I doubt that. Lastly, you could remove the injectors from the rail to actually watch them spray. That's alot of work and really only verifies what you have seen with the dry spark plug.
I will go ahead and take a 'probably-accurate' guess that there isn't a pulsewidth. In that case, the testing equipment required probably exceeds what you have access to... The next step involves monitoring and verifying sensor inputs and PCM outputs with at least a scanner. We only charge 1 hour to diagnose something like this, unless it gets into melted wiring or other abnormal circumstances, which is $75.00 here. I recommend taking it to a shop at this point - otherwise you are left with just buying and replacing parts 1 by 1 and hoping for the best, which can get tremendously more expensive than paying a diagnostic charge. Make sure that if you do decide to take it to a shop, that you tell them what happened when the vehicle quit running and everything you have replaced or tampered with. We often get customers that think they will save money by only telling half of the details, and that only aggravates the situation! Be honest and upfront and hopefully they will help you out.
I'll gladly keep trying to help you where I can, but as I said, correctly testing things from here on is probably beyond the tools you have.
