No Start issue 1988 CS 2.8/4t60 *UPDATE*

[NOHC_WBody]

Fuel pump is good, MAF sensor new, MAP sensor/o2 sensor new, new coil packs/ignition module, new crank sensor

 

There is fuel pressure at the rail, but no spark on any plug when grounded to the block.

 

The car has no stored trouble codes.

 

Could this be a PCM issue?

 

If so, does anyone have a MAF PCM?

[DaveFromColorado]

this is gonna sound stupid, but my old Buick did the same thing (2.8/440T4) and it turned out to be the "DIS" fuse in the fuse block under the hood (on the passanger side)

 

--Dave.

[NOHC_WBody]

Alright, I got it started, using some spray ether in a can. It ran for a few minutes, died and threw a code.

 

It's 6-4...I can't find a listing for code 64. Shit.

 

Anybody help a guy out?

[Robby1870]

When I get home from work I'll check on the code 64.

[NOHC_WBody]

I got the code 64, it's a MAP sensor low voltage.

 

Now, it'll start, but die immediately.

[Justin]

CODE 64

Manifold Absolute Pressure (MAP) Sensor Circuit

(Signal Voltage Low)

 

Valid only without speed density update performed. Doesn't even show up otherwise.

[Robby1870]

CODE 64

Manifold Absolute Pressure (MAP) Sensor Circuit

(Signal Voltage Low)

 

Valid only without speed density update performed. Doesn't even show up otherwise.

 

So, that means his 88 never had the update? Hmm...sounds like its time for an update and new MAP sensor.

[NOHC_WBody]

Valid only without speed density update performed. Doesn't even show up otherwise.

 

OK..Speed Density update? I'm assuming there's an issue/recall with the MAF, what is changed on the car in the update?

[Canada]

The early MAF systems didn't work that well. So there was a speed density upgrade that the newer models recieved. It basically amounts to removing the MAF sensor and installing an IAT sensor in its place. This means the engine is strictly operating on the MAP sensor to know how much air is entire the engine.

 

The code is for low voltage. This means the PCM thinks there is high vacuum in the engine. You could have a couple problems.

 

#1. MAP sensor not getting power.

#2. MAP sensor not getting ground.

#3. 5 volt reference line to PCM is open/shorted.

#4. Faulty MAP sensor.

 

I would have you check the vacumm lines if the voltage was high.....meaning that the PCM or sensor was seeing atmospheric pressure, but its not, so the lines should be good.

 

Will the car start if you hold the throttle slightly open?