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jazzmaster
jazzmaster, ASE Certified Technician
Category: Chevy
Satisfied Customers: 2540
Experience:  ASE .AUTO TECH FOR THIRTY-FIVE YRS,ELCTRICAL,FUEL INJECTION ETC.
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chevy astro I have a 1992 chevy astro van 4.3 vortec with

Resolved Question:

I have a 1992 chevy astro van 4.3 vortec with a no spark condition. I have no spark from my coil or fromt the plugs wires when starting
Submitted: 3 years ago.
Category: Chevy
Expert:  jazzmaster replied 3 years ago.
hi, what is the # XXXXX th digit of the vin code ?is it a W or Z
Customer: replied 3 years ago.
good question I dont knw right off, i got the van from a guy who said he replaced the timing chain and stuff, and he lost the Nbr cylinder with the distr out, he put the distrib back in and though he was off 180. i found no spark oming from the cap or coil and it is aligned to nbr 1 correctly
Expert:  jazzmaster replied 3 years ago.
does the rotor turn when you crank over the motor ?
Customer: replied 3 years ago.
to be honest with you i did not check that, i did take the cap off and tried turning the rotor and it felt solid in place, the distrib is flush and in place and i no up and down movement
Expert:  jazzmaster replied 3 years ago.
ok, check that if it does and the rotor point to the # XXXXX spark plug wire on the cap then take out the ignition module and take it to autozone to get tested also, check out the pick-up assembly in the distributor,to do this first check to see if the wires are intact then with an ohm meter check to see if there is continuity when you hook up the leads to both wires,if the rotor does not move check the drive gear on the dist and also the rod that goes from the dist to the oil pump ...guy...
Customer: replied 3 years ago.
ok we confirmed the rotor does turn we did chk continutiy from the wires going to the pickup tested ok, we did test the wire loom on the backside of pickup which is a 2 wire clip and we got coninutiy there I checked conitnuity from the pickup pins going in the module to the 4 wire loom going out to the ecm and I got conitnuity there
Expert:  jazzmaster replied 3 years ago.
you may have a bad ignition module ,you can either get it tested and/or I can give you a flow chart(trouble shooting) for an engine cranks but does not run situation but I will need the # XXXXX th digit of the vin code...guy..
Customer: replied 3 years ago.
is the ignition module the module in the distrib or the ecm module
Expert:  jazzmaster replied 3 years ago.
it is mounted in the dist ...guy...
Customer: replied 3 years ago.
ok i will get it testedm and i will get you the 8th digit what is the significance of that digit btw. also i want to continue working with you so that are paid when completed so if you could give me direction on contact as well ty
Expert:  jazzmaster replied 3 years ago.
I wll keep this question open so all you need to do is save the e-mail and clink on it ,the #8 th digit will give me the correct motor size ,there are two listed for this vehicle both are 4.3 L ,like I said there are flow charts for a no spark situation and this gives the process of elimination,by ruling and testing certain circuits ...guy...
Customer: replied 3 years ago.
ok if you wld plz send the diagrahm for trouble shooting
Expert:  jazzmaster replied 3 years ago.
I need the 8th number of the vehicle indenification number ,to get the right ones ....guy
Customer: replied 3 years ago.
the 8th digit is a W thank you
Expert:  jazzmaster replied 3 years ago.

I am sending these ,this is for the chevy with an 8th digit of W which is more common...guy...

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Customer: replied 3 years ago.
Hi Guy sorry for the delay. I took the ignition module to Autozone they tested it 3 times and it passed, I confirmed the rotor in dist is turning, I put in a fully charged battery, and I am still where I was previously with no spark, I checked the fuses. is there anything else to look for I.E. ESC or harness that may be disconnected. I am going through the no start you sent me today. Also is it possible to test a coil. I followed the pink 12 volt line into the coil and out from the coil to the module and it had 12 volts, I chked the pickup coil it had continuity, I also checked the white time wire from the coil into the module and back to the test lead and it had continuity. So now I am doing the others. I am just wondering if the doughead that gave me the astro left something unplugged he got lost and walla here we are.

David
Expert:  jazzmaster replied 3 years ago.
lets see if you find anything with the flow charts and diagrams ....guy...
Customer: replied 3 years ago.
ok guy using flowchart ignition system check I followed steps 1 to 4 everything checked all the wat through even to the point of connecting a test light to the tach lead and i saw fluctuation and also with a voltmeter. I got to refer to ignition system check 2a. I also tested the distr 4 plug from module all the way to the pcm and I had continuity there. so I followed the flow chart 2 times checking each step completly. Is it at al possile the coil is bad or the PCM which I hope not. But I did locate a PCM at a salvage yard and I checked the prom on mine which looked ok. Anyways I am gonna wait for steps from you. So far you have een right on which i appreciate greatly. Thanks, David
Customer: replied 3 years ago.
refering to my last text to you. I reached the last step and there was nothing to follow after that so i assume there is more to the flowchart. I also realized that all checks point to the coli, dist assemly as being good. so i gather we are following charts to diff areas now. Thanks buddy
Expert:  jazzmaster replied 3 years ago.

hi, do you have injector pulse? here are the pin-outs at the ecm check these out ,at this point I am more concerned if you have battery voltage with the key on at A6 B4 battery voltage at B1 C16 and grounds at A12 D1 D9 D10 , and at D16 there should be battery voltage with the key on ,also at the dk blue wires of the fuel injectors,on the other wire(s) at the fuel injectors there should be a pulsating ground signal when cranking over the motor ...guy...

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I printed these large and small to make sure you can see these

Customer: replied 3 years ago.
just so i am clear on the injector pulse chk am i going to a fuel injector to test this or am i testing that at the ecm/pcm. that would be at D16 I think for the injector driver ? also I did pull a ECM code of 12 which is normal with the exception of when cranking the engine and it continues the pause then 2 flashes it says this indicates no dist signal and I assume with no spark this would be the case ? Thanks I will be perform the following checks you sent me on Saturday. Thanks David
Expert:  jazzmaster replied 3 years ago.
you are going to be testing the wiring to the ecm and also testing for battery voltage (key on) and pulsating ground at the injectors
Customer: replied 3 years ago.
ok guy here is my findings key on A6,B4,B1,C16,D16 testing each point there is battery voltsge present, A12,D1,D9,D1O I found ground to chasis. the dk Blue wires I got pulsing but I was using a voltmeter and it was like .50 jumping up & down. It was not a hi voltage there at the dk blue. Also I noted that on the fuel rail I depressed the valve and I had no pressure and also while depressing the valve I got no fuel spray while cranking. So I am a lil frustrated to say the least. The guy said he did the timing chain and the car ran then he had some problem with it and when i got the van he said the distrib was out of nbr 1 and just redrop it. I paid 250 for the van originally for parts the guy seemed honest so do I continue or give up the ghost. the van is in great condiotn so advise me plz. I will gladly continue and pay for ur services. Thanks Guy... David
Customer: replied 3 years ago.
I also may not have been on the injector pulse. can you tell me where the injector harness is or can i chk it at the pcm. thanks
Expert:  jazzmaster replied 3 years ago.
graphicCircuit Description:
This chart should only be used if diagnosis in CHART A-3 indicated a CPI injector circuit problem.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

  1. This test will determine if the ignition module is generating a reference pulse, if the wiring is at fault or if the ECM is at fault. By touching and removing a test light, connected to 12 volts, to CKT 430, a reference pulse should be generated. If injector test light blinks, the ECM and wiring are OK.
  2. This step tests for 12 volts to the injector. It will also determine if there is a short to voltage on the ECM side of the circuit.
  3. This test checks for continuity to the ECM.
  4. graphic

Circuit Description:
When the ignition switch is turned "ON," the ECM will turn "ON" the in-tank fuel pump. It will remain "ON" as long as the engine is cranking or running, and the ECM is receiving distributor reference pulses. If there are no reference pulses, the ECM will shut "OFF" the fuel pump within 2 seconds after ignition "ON" or engine stops.

The pump will deliver fuel to the TBI unit where the system pressure is controlled to about 62 to 90 kPa (9 to 13 psi). Excess fuel is then returned to the fuel tank.

The CPI pump will deliver system pressure that is controlled to about 370-440 kPa (54-64 psi). Excess fuel is then returned to the fuel tank.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

  1. Turns "ON" the fuel pump if CKT 120 wiring is OK. If the pump runs, it maybe a fuel pump relay circuit problem, which the following steps will locate.
  2. The next two steps check for power and ground circuits to the relay.
  3. Determines if ECM can control the relay.
  4. The oil pressure switch serves as a backup for the fuel pump relay to help prevent a "no start" situation. If the fuel pump relay was found to be inoperative, the oil pressure switch circuit should also be tested to determine why it did not operate the fuel pump.

 


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ok, let me know if you have a throttle body with 2 injectors on it , or if you have the cpi unit which has a wiring connector in the top of the motor ?

Customer: replied 3 years ago.
I found the connector dark blue wire/pink 2 wire connector. it does pulse. I hear a faint click where the fuel pump is not a buzz but just a click.so all tests so far complete but no spark haha. wait to hear from you for next steps. thanks
Customer: replied 3 years ago.
I found the connector dark blue wire/pink 2 wire connector. it does pulse. I hear a faint click where the fuel pump is not a buzz but just a click.so all tests so far complete but no spark haha. wait to hear from you for next steps. thanks it is a cmfi system as well
Expert:  jazzmaster replied 3 years ago.
I need you to test for fuel pressure ,please ,I need to know if ,for one you have it and two,if the oump will run for 2-3 seconds when you first turn the key on ,to do this take off the gas cap and have someone turn the key on ,you should hear the pump run for 2-3 seconds ,I think you may have two problems ,that the ecm is fried and that the pump(fuel pump) is bad ,also I need to know if there is a throttle body and it has 2 connectors ,one for each of the injectors?one should have a dk blue wire and the other a green wire
Customer: replied 3 years ago.
guy I have no fuel pressure at all. While cranking with the fuel rail valve pressed in i get no fuel bubbling out or fuel spraying whatsoever and I don't hear the pump when i am cranking the engine for 2-3 seconds I hear a click at the tank when turning the key on but i hear no buzz or hum from it at all. I just tested this again I either can't hear the pump during that 2-3 seconds because the engine is cranking. i only hear a click at the tank when engaging the ignition to on. I found the fuel injector connector and it does pulse up and down while cranking.
Customer: replied 3 years ago.
further info I took the fuel filter clips off and cranked the engine and no fuel poured out. I suspected the fuel pump first off but not the ecm/pcm. wait to hear from you ty
Expert:  jazzmaster replied 3 years ago.

,ok at the connector at the tank disconnect that and on the harness that comes to the fuel tank sender unit connnector test the grey wire for battery voltage with the key on,it should read battery voltage for 2-3 seconds,then crank the motor over it should read bat voltage,if that is good the black wire is ground check this for a good ground and then while cranking the motor over see if it still has a good ground reading ,it it does then the pump is bad ,now back to no spark ,when you tested the pick up coil in the dist ,did you ohm out the pick up? that is hook up the ohm meter to each one of the wires ,it should read o.oo ohms or so ,if it doesnt that may be giving you a no spark situation

graphic

Customer: replied 3 years ago.
I will test the fuel connector on sunday. on the pickup coil I did ohm it out and it showed 556 ohms. according to the manual it says anything between 500 and 1500 ohms is good an open wld be bad and a low ohmage wld be a repalcement as well. Now I tested the 2 pin lead point to point as it showed in the manual and this is the connector that plugs into the ign cntrl mod on back inside the dist under the rotor. I am positive I tested that thing twice. Every thing we have done I have done twice chking for anything i may have missed. I will let you knw on sunday what I found on the fuel pump. Thanks David
Expert:  jazzmaster replied 3 years ago.
also see if the ohm readings change when you turn the rotor or tap the motor over
Customer: replied 3 years ago.

Hi guy,

 

I had voltage at the fuel pump and while cranking, The ground stayed stable. The volate I read at the fuel pump was about 7 volts and it cycled while cranking. The pickup coil ohmed at 733 and while cranking the ohms cycled while cranking.

Expert:  jazzmaster replied 3 years ago.
there should be 12 volts or battery voltage at the fuel pump even when cranking it oversee what the bat voltage is and then what you have at the pump
Customer: replied 3 years ago.
will do ty
Expert:  jazzmaster replied 3 years ago.
also on the ignition check flow chart did you get to bottom on the left side ?
Customer: replied 3 years ago.
Hi Guy, I didnt even see the charts you sent so I will print them out and follow them both through on Tues. On the fuel pump I cldnt reach the connector so I spliced into the grey wire that was in a wireloom with 2 blacks and a purple wire. According to what I read the grey should be the hot. When the key was turned I had no voltage and while cranking it jumped up to 7.89 volts and pulsated as the engine cranked then when stopped cranking the voltage left. I will follow all the chart you have listed above and advise. TY Guy
Expert:  jazzmaster replied 3 years ago.
also check the ground wire that comes off of that wire harness ,this grounds to the frame near the tank and connector,sometimes these need to be cleaned and reattached ,this may be part or whole of the problem....guy..
Customer: replied 3 years ago.

Hi Guy,

 

I think we have it nailed now. Using the chart for no fuel and providing 12volts to the fuel pump test lead the fuel pump does not run. Using the chart A4 following all the steps to completion it states that D16 if a light is on to check the connection at the ECM D16 so Guy I believe we have a bad fuel pump and ECM because I ran the test procedures to the exact letter. Let me know what you think buddy. Thank You David

Expert:  jazzmaster replied 3 years ago.
I would think it is the fuel pump ,if you ran bat voltage to the test lead and the fuel pump did not run ,you need to check if you have that voltage at the connector at the pump ,if that reads bat voltage then it is the pump,in that case put in a pump and now see if it starts and runs ,if not then you may have to use the flow charts again ...guy...
Customer: replied 3 years ago.
Guy it could be the fuel pum causing the entire problem or you mean repalcing the ECM and Fuel pump then seeing if it starts. I just wanna be clear on replacement procedures.
Expert:  jazzmaster replied 3 years ago.
no the pcm should not be replaced at this time ,put bat voltage to the test lead for the fuel pump and then recheck the voltage at the connector at the pump,it should read bat voltage and if it does then replace the pump,the pcm controls just the 2-3 second prime to the pump when the key is first turned on ,then once running it switches to going through the oil pressure switch ,but if the pump doesnt run and there is bat voltage going to the pump when you put bat voltage to the test lead ,then the pump is bad ...guy..
Customer: replied 3 years ago.
That I understand but I have the no spark issue which I followed chart A-4 as well and that indicated at the end of testing bad ECM. So I thought I had 2 problems Guy.
Expert:  jazzmaster replied 3 years ago.
sorry about that ,I forgot about the spark issue ,if you follwed the charts and they pointed to a bad ecm ,then ,yes ,you have 2 problems ,and need to replace the ecm/pcm as well if it pointed to that as the solution ...guy..
Customer: replied 3 years ago.
Guy I followed the A4 chart completely twice top to bottom and then checked the D16 connector to the ECM. I tested coninuity from circuit 430 to the B5 and flexed the harness with no loss. So I believe the ECM is the issue now for the ECM. Take another look at the A4 chart you sent me and let me know. I am pretty convinced now of the two problems your the expert and you have not been wrong thus far thanks David
Expert:  jazzmaster replied 3 years ago.
yes if the light was on then the ecm is more than likely bad
jazzmaster, ASE Certified Technician
Category: Chevy
Satisfied Customers: 2540
Experience: ASE .AUTO TECH FOR THIRTY-FIVE YRS,ELCTRICAL,FUEL INJECTION ETC.
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jazzmaster
jazzmaster
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ASE .AUTO TECH FOR THIRTY-FIVE YRS,ELCTRICAL,FUEL INJECTION ETC.