Idles only with map censor unpluged and when you put it in gear to pull off it pops and has no power when you hold brakes it just want go. Replaced map, heat censor, throttle positioner, everything in distributor including plugs & wires. By the way this is a automatic transmision.
The center near the EGR solenoids, it has a single vacuum line and a connector going to it. You have to test the voltage reading of it, back probe the center wire, the voltmeter should read the right voltage at the altitude you are located at. Here's the chart:
Can vary +/- about .04 V
Altitude above sea level Voltage
0 1.59V
1000 1.56V
2000 1.53V
3000 1.50V
4000 1.47V
5000 1.44V
6000 1.41V
7000 1.38V
Most likely a clogged fuel lie, filter, or obstruction at fuel pump in tank. Also check tank venting and cap that might create "vapor lock".
Sounds like the EGR valve is stuck open or has a piece of trash caught in it, holding it open. Had a similar thing happen on an 1988 Astro van.
If it idles only with map sensor unplugged, then test the MPS sensor.
You will better troubleshoot the problem by connecting the car computer module(ECU) to an ODB II code reader.
If you want to do it yourself, you need a code reader like the ones here.
This will return error codes that can tell you what the problem, is.
Sure that your car has a mainfold pressure sensor , and you need to replace it, here is the part.
×
That is not a map sensor(mass air flow) it is a barometric switch also know as a mps(manifold pressure sensor)
Does sound like the timing belt
Hello
The engine
and transmission in this cars drive train are fully
electronically controlled by a computer called the PCM (Power Train
Control Module). Whenever a problem like this occurs the computer
stores a record of the problem (there are of course some exceptions
to this, like the fuel pump, engine coolant temperature sensor and
MAF sensor for instance) in the form of a fault code in its memory,
to read these fault codes you must have the systems memory scanned
with a special tool. Once the fault code(s) are read you then must
perform the appropriate diagnostic testing to find and resolve the
problem(s) DO NOT REPLACE ANY PARTS UNTIL A TRAINED TECHNICAIN
HAS DIAGNOSED THE PROBLEM TO AVOID SPEDING YOUR HARD EARNED MONEY ON
PARTS THAT MAY NOT CORRECT THE PROBLEM
40 views
Usually answered in minutes!
That was one of the first things I checked. I was driving down the road and when I got to a stop sign to turn the fan belt came off and had no steering. I then turned around and went back to the house and the power steering pump bolts on the bottom of the engine had broke off. I replaced the two bolts and put another serpentine belt on. Since this time i have check to make sure that the distributor is timed up properly. But before this belt was throwed off it was running fine.
This 1988 Chevy 350 has a map sensor(manifold absolute pressure) and it set a code 31,33 or 34. my has never set a code at all except 33 because it is not hooked up. If I clear the codes and hook the sensor up it want idle at all and you have to pat the excelerator to keep it running.
Does anyone know what cause my 1988 Chevy 1500 with a 350 engine @ automatic transmision want idle unlrss you unhook the Map sensor and when you put in gear it pops thru the throtle body like it is out of time. i am in alabama so the engine has a smog airpump going into the exhast. This pumps seems to be operating properly.
My 1988 chevy truck will not idle with out unhooking the Map sensor. It does not have a MPS on it at all as far as I can tell. Even if the sensor is unhooked it still idles rough and when you put in gear it cuts off if you dont pat the gas. It has no power even to pull on a set of ramps. The timing is corect and all plug wires are right,All of this started when the serpentine belt broke while driving down the road because the power steering pump bolts broke on the bottom of the bracket. Fixed this and it hadn't run since. Have replaced all sensors including everything in distributor,the injector and presure regulator. throttle position sensor,coolant sensor,oil presure sensor. wondering if the airpump on this engine would have anything to do with it not runing.I had a 1989 and a 1990 1500 with 350 engine that did not have this pump on them.
×