I was lucky to have a friend at the parts store and i got him to take my pump back after i installed it and found it wasn't my problem. I was lucky, but took the chance. Give him some slack he's just trying to find his out his trucks problem. I know i've been in that position. And if you think he is wasting your time then stop replying to this post.

 

I may have been a bit harsh with my reply. Fern,sorry for any misunderstanding.

As for the engine light, what I was trying to say is the lack of fuel pressure will not store an engine fault code (and therefore give a light). Yes, the light does a self test and comes on every time you go to start the engine just to let you know it is working, but that is not a fault. This is a general assumption when someone posts "no engine light" which you yourself used in your original post, they mean no engien fault detected. You yourself said "the check engine light does not come on." If by that you meant the light is not coming on at all, you have an additional problem. It boils down to "do you have a fault in memory" or not? If not, then yes, a bad fuel pump can cause this.

As for not hearing the pump prime, once again, yes it could be a pump. As for the "no relay sound", that is not the audible hum you hear prior to cranking the engine, that hum is the pump.The ASD relay would only make a faint click (unless it’s going bad and arcing) for a millisecond when the key is turned from off to the run position. Both the relays you mention are usually in the engine bay (I'm not sure on your specific truck model) and not audible in the cab.

When you posted:

"I do not understand how the fuel pump would cause the test "Check engine" light NOT to come on, and prevent the ASD and fuel pump relays not to work.... I pretty well trace the problem to the PCM..."

Did you actually check the power and ground into and out of these relays with a meter, or just make an assumption based on sound. When I read your post, I assumed you only listened. If you did use a schematic and a meter, my apologies and you are then correct, the pump would not be the issue. If however you didn't, then the pump is an option.

To get rid of all assumptions, you should check if there are any faults stored in the PCM with a scan tool. With the tool, you can also test the engine light to ensure it is working properly and read any faults that are present that DONT cause an engine light to come on (yes there are some, but nothing that would prevent the engine from running). To use the tool you will however need the adaptor cable for your interface. It will be either a SCI or LH series connector. Most modern scan tools can read your SBEC system with the proper cable adaptor.

Also as I originaly suguested, check the fuel pressure at the rail. If there is none, then shoot the circut back to where the signal is missing. The PCM, the relay, the fuse, or the pump.

 

No problem, I can understand that it is difficult to read someones mind......
When I reread my thread, I can see that it could cause confusion...
I will resume: When the engine is cold, it does start and runs perfectly, I could drive forever.... When the engine is shut down, it will start OK for the next +- 10 minutes and then it will crank fine but NO start.
When this happens, the ignition key is turn to the ON position, there is NO test for the "chech engine" lite (I know the bulb is OK) and the ASD and fuel pump relays do not "click", I had them in my hands while the wife was doing the key thing......They were connected by the way.. Also, in this NO START situation, there is no O/P from those relays while cranking the engine, I did check with a DVM and proper schematics..

I check for codes using the ignition switch method, and the only code stored is"12" which relates to "battery was disconnected" I think.

When the engine is cool down again, it will start like a new one...

As you probably read in one of my reply, what I did is after bringing the engine to operating temp. and turning it off, I set up a fan blowing cool air on the PCM and kept turning the ignition key toON every 2 minutes for 1/2 hour and never got the situation described at the begining of the thread..... I will trythe same routine a few more times andif I do not get the NO START situation I have no choice but to think the PCM is faulty unless someone else has another possibility...
As you probably notice, I do not master the english languageas well asmost of you thus possibly creating some confusion..

Thanksyou all for your help..

 

Yes a 12 is as you said. Seeing you verified the power out of the relays the only other option is see if the coil side of the relay is getting power from the fuse. The PCM supplys the ground and you could also test to see if there is a ground at the other side of the relay coil. If not present, then yes it shure sounds like a PCM.
Good luck,
Kurt

 

I believe what Fern is saying that when she turns the key to "on" the "Bulb/Lamp Test" does not illuminate the Check Engine Light(CEL). If she does not get this than the computer is not powered up and neither is the fuel pump,etc.
Could be you have a bad ignition switch or its connector is melted. The switch is located in the steering column. Could also be a bad computer ground, loose/corroded computer connector/s or computer or even a bad battery connection or corroded cable. The 92's and up do not like any extra electrical noise floating around in the signal paths.

 

Thanks, you have just described the situation... I have not work on the Van for a while, bad weather and lack of time....
I was hoping for the ignition switch going bad but, would't be bad all the time, engine cold or hot??? Also, I do have proper voltages coming from the battery at the ASD and fuel pump relays when I turn the key to ON during a NO start situation... Where can I check to see ifthe computer is powered up??? I will try the following a couple of more times: "As you probably read in one of my reply, what I did is after bringing the engine to operating temp. and turning it off, was to set up a fan blowing cool air on the computerand then I kept turning the ignition key toON every 2 minutes or so for 1/2 hour and never got the situation described at the begining of the thread....."

If I do not get the NO START situation I have no choice but to think the PCM is faulty unless someone else has another possibility...

 

Fern,
Thanks for the info, you seem to be on top of things. I can check further into the wiring diagrams but I do know that the late 80's and early 90's were not good years for PCM's which had some bad parts in them.
The voltage could be at the ASD but is it getting a ground shot from the PCM to stay picked?

You have checked the connectors at the PCM for tightness and bent pins/corrosion?

What is the part# of the PCM?

 

My educated guess is that the PCM might have a cold or cracked solder joint. this would expand and contract with temperature changes.
when it won't start have you tried giving the PCM a gentle slam with your hand and see if it starts?


Description and Operation

PURPOSE

The Check Engine Lamp (CEL) is used to indicate immediate service of the engine control system is required.

The lamp will illuminate when the engine controller detects an open or shorted circuit, absence of current flow in an output device, or if the oxygen sensors are not switching.

OPERATION

The CEL illuminates when the ignition key is turned to the ON position and stays lit for 3 seconds as a bulb test.

When the lamp is illuminated it indicates the engine controller has entered limp in mode. When in limp in mode, the engine controller substitutes the reading from a functioning input for the failed input value.

Signals that can set CEL Lamp are battery voltage input, charging system, Manifold Absolute Pressure sensor (MAP), Throttle Position Sensor (TPS), coolant temperature sensor.

The CEL Lamp can also be used to display fault codes that have been stored in the engine controller memory due to a system failure.

 

This may help you also. Pcm's generally supply grounds for devices or recieve reference signals. Not the J2 circuit in Yellow comes from the ignition switch. I'll let you look at the relationship of the circuits. This diagram should also help you perform some more voltage checks. CEL is powered by the J2 circuit and the PCM gives it the ground shot for "Bulb Check". when the CEL does not come on, check for voltage on J2.

[IMG]local://upfiles/21718/9A6449B92F6245CBAED3079A1396A705.jpg[/IMG]

 

My check engine light wouldn't come on until the relays stopped ticking. and it wouldblink with them, problem was computer.