88 comanche hard start or no start when cold

[cruiser54]

Okay. Then you cycled the key a few times and started it? If so, how did that work?

[ctxj93]

57 minutes ago, cruiser54 said:

Okay. Then you cycled the key a few times and started it? If so, how did that work?

Yes 2 10 second cycles as suggested and it started as shown in my video. 8 second crank time. Tomorrow I will try with just 1 key cycle and see if that makes any difference. 

[ctxj93]

15 hours ago, ctxj93 said:

Yes 2 10 second cycles as suggested and it started as shown in my video. 8 second crank time. Tomorrow I will try with just 1 key cycle and see if that makes any difference. 

Tried it again today with just a single key on, and crank and the start time was the same, 7-8 seconds 

[cruiser54]

You're losing pressure/prime somehow. 

[ctxj93]

On 1/27/2021 at 7:38 PM, cruiser54 said:

You're losing pressure/prime somehow. 

I'm  wondering if one of my trusty old mustang injectors is leaking down into a cylinder overnight. I have a set of 746s on the way. The fuel pump came from my parts MJ which always started quickly. I also replaced the in tank rubber hose when I swapped it in. 

 

I guess I just don't understand how if my issue is losing prime, why doesnt it make difference cycling the key a few times? Same start time regardless of key cycles. Wouldn't that make up for ant prime lost over night?

[cruiser54]

Somehow I misread your previous post. 

 

There are other contributing factors.

 

 

Starter speed

Battery condition

Major ground connections at the block

Distributor being indexed improperly

Sync generator in the distributor bad

Condition of plugs, wires, cap and rotor- ALL being replaced every 30,000 miles with quality parts

[ctxj93]

1 hour ago, cruiser54 said:

Somehow I misread your previous post. 

 

There are other contributing factors.

 

 

Starter speed

Battery condition

Major ground connections at the block

Distributor being indexed improperly

Sync generator in the distributor bad

Condition of plugs, wires, cap and rotor- ALL being replaced every 30,000 miles with quality parts

Does my starter sound slow/weak in this video ?

[ctxj93]

I threw some jumper cables on it to try to rule out a weak battery this morning. It cranked like hell but wouldn't start. It's a balmy 9 degrees here today.

 

Following some suspicions I've had recently, I poked around with the meter on the distributor connector until my hands stopped working. I'm not seeing any voltage at the blue and grey/tr wires. It's supposed to have 5v AC correct?  

 

I know I've read that they will start with no sync signal, but usually not well. Kind of seems like my situation here. 

[Ωhm]

18 minutes ago, ctxj93 said:

It's supposed to have 5v AC correct?

 

Only the Crank Position Sensor (CPS) will generate AC voltage, not the SYNC sensor.

 

Circuit for SYNC sensor.

[ctxj93]

18 minutes ago, Ωhm said:

 

Only the Crank Position Sensor (CPS) will generate AC voltage, not the SYNC sensor.

 

Circuit for SYNC sensor.

Ah, I was following the LungHD test procedure for the sync sensor.  He says you should get 5v across those 2 wires. I figured it was a reference voltage? 

[cruiser54]

They start just fine with no sync signal. Just crank a bit longer.

What was the temp outside the other days before using jumper cables?

Are we comparing apples to apples? 

Is your starter covered in engine oil by chance? 

[ctxj93]

48 minutes ago, cruiser54 said:

They start just fine with no sync signal. Just crank a bit longer.

What was the temp outside the other days before using jumper cables?

Are we comparing apples to apples? 

Is your starter covered in engine oil by chance? 

It was around 30 the other days.  We are indeed comparing apples to oranges, I just had to give it a try! I will see if the starter is covered in oil. 

 

Another thing I've noticed is that I defintiely don't hear the 3 sec fuel pump prime every time I cycle the key.  I also don't get the buzzer every time I cycle the key. Sometimes I get both 5 or 6 cycles in a row, and then the next time, maybe a weak buzzer without the  prime, or just nothing at all. Even if I don't hear the pump prime, usually it will still start. The other day when I recorded the cranking video, and the next day I when I was out there again, I heard the pump prime both times. Does this sound like an ignition switch issue? 

[cruiser54]

Not really. 

Refresh all the connections on the starter relay.

 

 

[ctxj93]

So I got the old brick out today for a trial run.  I've attached some pictures of the data stream. Does anything jump out at you guys? 

 

-stays in open loop 

-exhaust reads lean the whole time

-inj stayed just above 5

-O2 sensor hovered around 2.3 when warm,

-MAPvac around 60 

-spark advance around 15-16

-fuel sync- the little + sign just flickered, not sure what that's supposed to do 

-LT/ST fuel trim stayed at 128

[jdog]

How long did you run out for? The 02 staying in open loop throws a red flag, with that in open the other reasons don't mean much

[ctxj93]

39 minutes ago, jdog said:

How long did you run out for? The 02 staying in open loop throws a red flag, with that in open the other reasons don't mean much

Probably 5-10 ish minutes.  Enough time to get up to operating temp and then some.  I found the o2 testing procedure, I'm goin to go lay in the snow in a bit and take some readings. The voltage moved around a little but certainly wasnt ranging all over the place quickly. 

[Ωhm]

May or may not solve your problem but O2 Sensor is a vehicle maintenance item. Replace every 82,500 miles.

[jdog]

58 minutes ago, Ωhm said:

May or may not solve your problem but O2 Sensor is a vehicle maintenance item. Replace every 82,500 miles.

Is that what the mileage is on those timers?

But yeah I agree they are common to go out(at least for me)

[ctxj93]

1 hour ago, Ωhm said:

May or may not solve your problem but O2 Sensor is a vehicle maintenance item. Replace every 82,500 miles.

 

Thanks guys, I tested it with a  Meter and got like 4.5 ohms A to C and the voltage B-C matches the scanner read out. Here's a short video of it in real time. It attempts to go into closed loop, ST Inj goes up to 255 and goes back into open. 

 

 

[Ωhm]

1 hour ago, jdog said:

Is that what the mileage is on those timers?

maintenance reminder light reset procedures.pdf

[ctxj93]

So I went out and checked the truck side of the o2 harness.  I followed this procedure which I think is an old referenced Cruiser post. 

 

"BUT before you blame the O2 sensor make sure it has good wiring, and make sure the proper voltage is feeding it, by turning power on, engine off to read the engine off voltage feeds (12-14 volts on the orange wire, and 5 volts on one of the two black wires), and ensure the ground wire (power off) reads less than 1 ohm to the battery negative post." 

 

I found that I do not have 12v at pin A (orange wire) with key on engine off, I do have 5v reference at terminal C, again with Key on and engine off. 

with the engine running I have battery voltage at pin A and 5v at pin C. 

 

does this indicate a bad relay, or possibly an issue with the wiring?

 

 

[Ωhm]

4 minutes ago, ctxj93 said:

does this indicate a bad relay, or possibly an issue with the wiring?

I don't think so. Pin_A supplies 12vdc from the relay for the O2 Heater. Pin_C supplies the 5vdc from the ECU for the sensor part of the O2S. Pin_B supplies ground for both of the these.

[ctxj93]

3 minutes ago, Ωhm said:

I don't think so. Pin_A supplies 12vdc from the relay for the O2 Heater. Pin_C supplies the 5vdc from the ECU for the sensor part of the O2S. Pin_B supplies ground for both of the these.

Supplies 12v running? or key on truck off?

[Ωhm]

46 minutes ago, ctxj93 said:

Supplies 12v running?

 

Pin_A is a tricky circuit because its a Fuel Pump Relay Feed (HOT). So with KEY ON, Pin_A is HOT for 2-3 seconds, but with ENGINE RUNNING, Pin_A is HOT all the time.

[ctxj93]

44 minutes ago, Ωhm said:

 

Pin_A is a tricky circuit because its a Fuel Pump Relay Feed (HOT). So with KEY ON, Pin_A is HOT for 2-3 seconds, but with ENGINE RUNNING, Pin_A is HOT all the time.

Gotcha thank you.  My leads arent long enough and I'm not fast enough to turn the key and combat roll under the long arms in under 3 seconds!