Just put in a new fass lift pump and vp44.

have no power.

Wont rev above 2250 RPM in overdrive

will rev to 3000 RPM with out overdrive.

really slow to get up to speed .

Not a lot of cash left to throw at the  old girl.

heart broken to see her sittin there

Hey guys I finally started probing tonight and I have some questions.

In the MAP testing procedure, step# 6.

I turned off key and disconnected ECM wiring harness.

Should I test pin 2 grey/red with the ignition on or off???

i tested with it off and got OL no ohms.

The Same thing With step# 7.

i tested with the Ignition off.

tested between pin 2 & 3.

again I got OL on my meter.

So if this is right I have to repair the shorts in my wiring????

Is it easier to run new wiring for the ground and signal wire to the ECM????

OR to go searching for the short in the harness???

I do have the 5 volts at the orange wire.

Any advise Would be appreciated 
 

On 5/13/2020 at 5:27 AM, Clyde said:

Hey guys I finally started probing tonight and I have some questions.

In the MAP testing procedure, step# 6.

I turned off key and disconnected ECM wiring harness.

Should I test pin 2 grey/red with the ignition on or off???

i tested with it off and got OL no ohms.

The Same thing With step# 7.

i tested with the Ignition off.

tested between pin 2 & 3.

again I got OL on my meter.

So if this is right I have to repair the shorts in my wiring????

Is it easier to run new wiring for the ground and signal wire to the ECM????

OR to go searching for the short in the harness???

I do have the 5 volts at the orange wire.

Any advise Would be appreciated 
 

I think Steps 6 and 7 are checking for shorts to ground on the signal wire, 6 is short to just a ground, 7 is a short to the sensor ground, and as you have OL then that is a pass technically BUT that OL could also be a broken wire I would be  checking continuity of signal wire back to ECM  and the sensor earth supply, check with engine off and check continuity down each wire separately so one lead one end, other lead other end, there should be very little resistance, wiggle wiring around in the harness while checking 

If you have an open circuit on either I would find the reason for this instead of just running in a new wire as the reason for the open may well cause you more problems in the future, you may well need to add a new wire but I'd find the cause first

I did do the continuity on the ground and the signal wire. Both circuits showed me continuity . .004 and .007.

Also I have the 5 volts to the sensor.

On step 3 when I read the signal voltage with the engine off and The key on ,I got .02 volts. 
Step 4 says do turbo charger test.

i don’t know how to do this.

but I do know what it sounds like if I have a boot off.

i also checked the impeller on the turbo. No mechanical looseness and spins freely.

what do you think before I bring it to someone and it costs me a pile of cash???

Is the signal generated by the sensor???

by taking the supplied 5volts and changing it by the pressure it receives???

Does this mean the sensor is bad???

Or the ECM is bad???

i have other sensors I can try
OR go straight to the ECM???

Ok, so you have 5 volt supply and you earth and signal wires are good.

I would now reconnect ecm and map sensor and do

1. Ignition on. Check for earth supply at the sensor, use a pin or paper clip and connect red lead, black lead to battery neg. Check for continuity.

2. Check sensor signal with engine running. Go into the map plug at signal wire, red lead, black to map earth wire you may need to make a longer test wire for this, see if sensor output changes with rpm and load. Mine at this point stayed at 2 volt

Thank you

So step # 2 check sensor signal under RPM and load.

yours stayed at 2 volts.

Does this 2 volts mean all is good with the sensor.(where it should be)

I will be doing this in the morning.

If both these checks are good ; Is the ECM fubared???

I will let you know what I find

Mine stayed at 2 volts, map sensor bad,  signal voltage back to ecm needs to change with manifold pressure, but it also needs to change correctly within what the ecm is expecting to see, for instance if its normal range is .2v to 5v and for whatever reason its .2 to 6v it ought to set a voltage high code or high boost code. I don't know what the normal range is on a good sensor though

Is the 0112 and 1475 still active and have you done the diagnostics on those ??

Also did you clear the codes after fitting the new sensors ?, I had to clear mine after fitting the new map sensor, it won't go off on it's own except after so many key ons 

I see in your previous posts that a buddy of yours has a scanner that can read data am I right ??  if so it might be worth checking data again on your new map as $15 is cheap, mine was over $100 and that was the cheapest I could find

It could well be ecm but it is worth checking everything else to death before the final condemn the ecm 

Edited May 17, 20204 yr by wil440

Both times I have had a map sensor failure it was easily visible on scan gaugeII. Zero movement of data being transfered even though I could make 2 or 3 pounds on the mechanical gauge. Easy to see with live data.

 

So.

Reconnected the ECM and the MAP sensor.

i followed your step 1 and I had continuity to the battery ground from the MAP sensor ground.

I then followed your step 2. Inserted two pins in the MAP sensor plug. One pin on the Sensor signal wire and the other on the sensor ground circuit.

started the truck and had .972 DC volts. Reved the truck to 1500 RPM  and watched the voltage meter go up to 1.207 ish volts.

Cleared the Codes and road tested and it still set the 237 and the 112 code.

Still in limp mode. No power Ect

PS I put some dielectric grease on the ECM plug and MAP sensor plugs.

what do you think???

 

BTW Dripley did you ever change out that MAP sensor for the cheap ones we found???

55 minutes ago, Clyde said:

BTW Dripley did you ever change out that MAP sensor for the cheap ones we found???

No sir I have not. These 70 hour weeks are taking its toll on this old man.

LOL yes I know what ya mean.

Let us know if ya ever get round to it.

take care

Any ideas On what I am up against???

I checked my map voltages with a snap on modis ultra this morning

 

key on engine off 0.6v

engine running, idle 0.6v  

engine running at 2000rpm 0.8v

 

these figures will be low as it's not ingear or loaded but if you checked yours the same you're higher than me, does the output change smoothly with rpm ?

 

Have you ran through the diagnostics for the 112 code yet ??  this code looks to be a quicker ecm pass or fail check