curtalert89

okay so i have a 1988 v6 2.8 mpfi, it had a vacuum leak so i replace all the lines, when i would drive it the check eng light would stay off until i would slow down to a stop light or whatever and wouldn't turn off until i hit about 50 mph or higher, so i removed the top plenium section and put it back together and after that the check eng wouldn't come on, that was a week ago and for the last few days the check eng light will come on while driving and stay on, and when id turn off the car the light would go away and not come on, then randomly the next day of driving it would come on. today it comes on as soon as i turn on the car, it idles really low and rough and when driving it and letting off the gas the rpms drop really low, also now when idleing it puts out a light blue smoke, and on my way home about 5 blocks from my house i was pushing the gas and it would gut out, i could only just barely push on the gas to go and that was if i kept it in 2nd gear, and if i pushed down even more, it seemed like no gas was getting to the motor. ive looked all over on the threads but idk what im looking for and not much time to read through, im fixing to have to head back out on the road for work.

Any help on this matter would be GREATLY appreciated.

fasteddi

iTrader: (2)

Try to see wha code the car is showing for the check engine light

The paperclip trick goes like this, find your ALDL connector under the dash, about knee level, on the right hand drivers side. Remove the cover by pulling straight back, (your cover may not be there due to a stupid mechanic's inability to put things back to original conditions)!! As your looking at the connector, the top two (side by side) right hand holes are terminals A and B. Unbend the paperclip, with the ignition off, insert one end of the paperclip into the A terminal and the other end into the B terminal, then turn your key to the on position (do not start your car) the fan should start to run, and then the service engine soon light should flash!! Watch the flashes, it will flash once, then pause, then flash twice, it will do this three times, then it will flash any stored codes in the same fashion, (ie: Code 32 would show up as three flashes followed by a pause, and then two flashes) once it flashes the stored codes, it will start the process all over again!!

Let us know what code number it is throwing out

curtalert89

thats a helpful trick, its throw a 21, 32, 34, 42, 51

fasteddi

iTrader: (2)

Wow thats alot of codes!
Here a list of codes
https://www.thirdgen.org/service-eng...ht-error-codes

fasteddi

iTrader: (2)

I dont like your code 51. Its a prom error. Im not sure but that could be a bad bad thing. Someone will chime in and help i hope..but heres my thoughts, incorret prom, incorrectly installed prom, defective prom, or defective ecm. Have you ever taken the ECM out or put a chip in it??

curtalert89

well if the prom is bad i have an extra ecu from another 2.8 car that i can plug in

fasteddi

iTrader: (2)

What year was the other 2.8L? The connection just could be bad if youve ever played with the ecm.

curtalert89

its from the same year as my car, but i will check the connection, to correct the code 21 do i just adjust the volts going to it i have a meter, i set it to .54 like i read in other posts but it may have moved, how do i fix the other codes 32.Fault in barometric pressure sensor circuit OR Fault in exhaust gas recirculation valve diagnostic switch OR Fault in electronic vacuum regulator valve, 34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor),42.Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit,... iv replaced my MAF sensor about 4 moths ago, i dont think it would be out, but i dont know how to check to see if it went to crap, i got a warrenty on it tho. but i need help in the right direction to fix the other codes

project89

iTrader: (1)

if the ecm is identical and so is the prom in the other ecm u have replace the entire ecm and prom, then check for trouble codes.

if the ecm in the car is bad now it can cause the high/low voltage readings so trying to fix those without seeing if the ecm itself is bad will have u chasing ur tail.

since u have a backup ecm plug that in and drive the car and see if any codes come back

curtalert89

sweet, ill go do that now and ill come back and give the verdict

curtalert89

All the codes are gone except 32. Is it my vacuum selenoid switch? Idk where t berametric thing is at?

XxXChrisGXxX

iTrader: (1)

Try removing the vacuum line from the EGR, solenoid, TBI, and vapor canister and blowing out the vacuum line with compressed air (not to much, and not into the fuel regulator vacuum line). Also, while the line is off the EGR push the diaphragm up that is under the EGR and make sure it moves freely.

project89

iTrader: (1)

more then likley the soiliniod is bad, most of them go bad as they are now 20+ years old.

but there is the off chance that the egr valve or egr tube is cloged, this will also set that code

for the ecm to set that code heres what happenes.

the ecm openes the soiliniod to apply vacume to the top of the egr valve to pull it open,then the ecm looks for an air fuel ratio change from the o2 sensor to verify the egr valve has opened

first thing is to check the vacum lines to the egr soiliniod and valve
next thing is to make sure the egr passages arent pluged or blocked
next step is to apply vacum to the top of the egr and make sure the valve moves(u can do this by putting a vacum line from the back of the intake directly to the port on the egr valve at idle, if the egr valveworks and the lines arent pluged the motor will sound like its a big block with a massive cam at idle, do not drive the car like this it sounds like this cause its running extreamly lean)
if that test shows u it works then its going to come down to a bad soilinoid or a o2 sensor

curtalert89

nice i will check all that in the morning, i think i may know part of the problem, the line that goes from the solenoid to the egr is a hard plastic line and it melted a little bit, i can still blow through it but its pretty tight. i will check all the other stuff to.