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Username Post: 89 Blazer K5 TBI no spark no fuel        (Topic#348995)
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 11:49 AM - Post#2721400    
    In response to 89K5Shane

I get a solid ground when I test the connector across to the neg battery terminal. The ground isn't in the lug for the thermostat but on the bolt holding the ESC bracket.



 
Low priced Genuine GM Auto Parts
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 12:04 PM - Post#2721401    
    In response to CowboyTrukr

  • CowboyTrukr Said:
The electronics in the distributor do not rely on any grounding to the distributor body.




The factory schematics show the module being grounded through an attachment screw to the distributor body.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 12:08 PM - Post#2721402    
    In response to 65_Impala

When I test across the attachment screws to the dist body I get a solid ground I pulled one screw out and tested the screw hole to the body and its solid ground.



 
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 12:21 PM - Post#2721404    
    In response to 89K5Shane

  • 89K5Shane Said:
The only thing I can come up with is the pickup coil is producing a charge out of the truck when I hand crank it and nothing when its in the vehicle cranking.



This sure sounds like the root cause. At the very least, it needs to be confirmed the pickup coil is working before moving on and testing the rest of the system.

What voltage did you measure while hand cranking the distributor shaft?

What voltage are you looking for in the vehicle? From what I recall it should be over 0.25V so it can be measured with a meter, but it's certainly not very much voltage.

Did you resistance check the pickup coil?

Disconnect the coil from the module and do these ohm meter checks.
- test from each lead to the body of the distributor. This should read as an open circuit.
- test between the leads. You should see a constant resistance between 500-1000 ohms. keep checking as you flex the leads to check for a damaged wire or connection.




 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 12:28 PM - Post#2721405    
    In response to 65_Impala

If I hand spin the shaft I get .45v a/c and the resistance between them is 874. I have a spare brand new coil and it reads 810. I had the problem with the old distributor and am working with a brand new one now and have the same thing. There is something not allowing the pickup to generate power while it is in the vehicle.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 12:33 PM - Post#2721406    
    In response to 89K5Shane

I even disconnected the wire from the module and cranked the engine while attached to the pin on the mod and get nothing. It is my understanding that while spinning the pickup generates the signal to the module then it sends a ground signal to the coil to fire. What could cause the pickup not to create voltage while it is in the truck? This thing ran like a banshee for years and just died while on a drive and I have been fighting it for months.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 12:44 PM - Post#2721407    
    In response to 89K5Shane

While looking through old threads I saw something about the dist shaft becoming magnetized and checked mine. both the old one and the new one are magnetized. It looks like a Ford problem but I cannot find anything about GMs. Could this be a problem? The new one was magnetized out of the box.



 
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 01:06 PM - Post#2721410    
    In response to 89K5Shane

At this point make sure you provide as much detail on what you are doing as you can. Some detail may be the clue.

How are you testing it out of the truck? What kind of meter? Autoranging or fixed range? Where are the meter leads? Is the coil connected to the module?

How are you checking it in the truck? What kind of meter? Autoranging or fixed range? Where are the meter leads? Is the coil connected to the module? How long do you crank it?


What wire did you disconnect from the module? There are 3 connectors and 8 wires that connect to it.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 01:18 PM - Post#2721411    
    In response to 65_Impala

I am using a digital meter. I am disconnecting the pickup from the mod and testing across the 2 wires in the connector. When I spin the shaft I get my a/c voltage. I do the same thing with it in the truck and get nothing. When I am testing resistance I set it on 20k. I was a low voltage tech for years with the phone company so I have an understanding of electricity but this has me totally stumped. I like to figure things out instead of throwing parts at it but broke down and picked up a new dist thinking it would solve the problem. Any help would be greatly appreciated and rewarded with a cold beer if you are in the area someday.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 01:19 PM - Post#2721412    
    In response to 65_Impala

I cranked it for about 3 revolutions when it was in the truck and spun it like a top when it was out.



 
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 01:31 PM - Post#2721414    
    In response to 89K5Shane

It sounds like you are doing everything right. You did crank long enough you know the meter would have stabilized onto any voltage?

The voltage is proportional to the speed. So as an example, the output voltage when it's in the engine will be 1/10th your hand spinning voltage if the engine cranking speed is 1/10th the speed you spun it by hand. In other words, it might be a lot lower voltage when cranking compared to a hard hand spin.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 01:40 PM - Post#2721415    
    In response to 65_Impala

I repeated it on an 88 chevy truck I have and I get the voltage when cranking so I know it is supposed to work that way. Can you think of any reason no matter off the wall it is that it won't put out voltage in the truck? I put the new dist in my 88 and it worked perfectly then put the one out of it into my blazer and nothing....



 
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 01:45 PM - Post#2721416    
    In response to 89K5Shane

The shaft and pickup teeth not lining up vertically, but that doesn't make sense in multiple distributors.

You're testing with the pickup coil unplugged in both trucks?



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-18-18 01:51 PM - Post#2721417    
    In response to 65_Impala

I unplug the pickup from the mod and test across the connector. It doesn't make any sense at all... I get .41 v a/c when I put it in the other truck and zero in the Blazer. There wasn't any wear on the teeth and I pulled the valve cover to make sure I was TDC and it rotates like it should and lines right back up with #1 when I turn the crank 2 full revolutions.



 
65_Impala 
Very Senior Member
Posts: 3926

Reg: 12-29-02
01-18-18 04:09 PM - Post#2721434    
    In response to 89K5Shane

Ya, that makes no sense unless the Blazer cranks very slowly compared to the truck engine.



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-19-18 10:02 AM - Post#2721496    
    In response to 65_Impala

It doesn't make sense.. There has to be something interfering with the pickup coil. I am going to reroute all the wiring near the dist today and see if I can find anything else. Thanks



 
89K5Shane 
Forum Newbie
Posts: 26

Reg: 01-03-18
01-19-18 10:57 AM - Post#2721503    
    In response to 89K5Shane

I don't know the protocols on this site but would it be alright to start another thread on the pickup coil? My thinking is that somebody might have had the same problem and it might be more specific.



 
Low priced Genuine GM Auto Parts
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