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Welcome to justanswer.com My name is XXXXX XXXXX online automotive technician. Reading your comments. I will be right with you.Thank You, Leon
Need the year, make, and model please; and include engine size please and thank you.
1980 Cadillac Eldorado 6.0 litre TBI. I have burned two ECM's I am tring to troubleshoot before cooking another. Fuel presure at the schrader valve is 10 PSI and the fuel filter is new. Have checked and repaired bad vacuum lines. No signal to trigger injectors. Car started and ran rough for about 5 minutes after replacing ECM then quit. Have located MAP and Barometric sensors and measured reference voltage at 5 volts. With harness plugged in the third wire in the harness from the ECM to each sensor read .02 volts, with the harness unplugged still have 5 volts reference voltage but the thrid wire reads about 4.80 volts. Have unplugged TPS to see if there was a change but everything stayed the same. Reference voltage at the TPS is 5 volts. Pluged back in the TPS reads 1.4 volts at closed throttle and 5 volts at WOT
Thank you for the information. I am looking in into this for you. I need to look at the specs and wiring schematic. I will get back to you, Leon
Just Answer is asking for feed back but I have not recieved anything from you to give feedback on. Can you help?
thank you for your patience. I am going to be on all day tomorrow and will have your information .
There is suppose to be a vacuum line going to the map sensor i sent a diagram to show you where the map vacuum line at throttle body to map is routed. please check and/or replace this line and recheck voltages.
Thank you, Leon
Thanks for the diagram, it will help a lot
Long story short. Replaced burned out ECM with new one. Car ran roughly for about 5 minutes then quit. Restarted and ran really rough then quit agian, would hot restart. Fuel pressure at trottle body 10 psi, fuel filter has been replacedReference voltage to MAP and BARO sensors 5 volts, return voltage 0. No signal from ECM to injectors, Power to injectors but no pulse from test light hooked to injectors when cranking. TPS reference voltage is 5. Voltage with throttle closed 1.4, with WOT 4.8. Vacuum lines have been checked, bad lines repaired.
be right with you
i am reading your comments
Fuel psi is with in spec
Are you getting the same reading when the map vacuum is hooked up , correct
Have not been able to check fuel psi with engine runnuing
But you have 10 psi key on correct
Fuel pressure measured at Schreader valve.
ok here is a chart to test the map/baro sensor, but what has me is no injector pulse. while you look at the map test and chart, i am going to check on the crank and cam sensor situation for ya
you are going to use the ALL at top readings for testing
Take your test light to the terminal "R" on the 7 pin ignition module and see if this provides a reference pulse with test light. This pulse is sent to ECM indicating engine RPM and crankshaft position. With out this The ECM will not fire injectors.
let me know what you find out, so i will know which direction to go, Leon
Do you have any questions?
Now you find out how much I know, what do I use to test the MAP and Baro sensors. Also I take it that the "R" pin is in the harness that pluggs into the side of the ECM
I also run into reference to the oxygen sensor. As far as I can see there is not ine on this car, should there be?
i thought you knew how by the readings you gave me above
yes you have o2 sensor here
i am going to give you a schematic and connector if i can find it- to help you check the map
How did you get the readings you sent me from above?
R - is at the igniton module
i will see if i have diagram too, of this for you.
ignition mod is in the distributor just to remind you
this is for testing the baro/map
going to find ignition mod pin and electrical chart for you
let me slow down and ask a stupid question - the vehical does not start correct?
do you have spark?
but no injector pulse to pulse fuel correct?
just making sure we are on the same page
I ask cause we need to find why the injectors are not working to give you the fuel needed to run engine
To get the Map and Baro sensor readings I used a multi meter. Used the ground wire in the plug and tried terminals in the plug until I got a reading.I am also using a Haynes manual for reference. The diagrams you sent, are they generic, my car is a 1980 Eldorado with a 6.0 liter TBI motor. The vacuum chart you sent me gives values for different altitudes so I think that the car needs to be running but I cannot start it
that is correct and we will start with the no start. I was confused due to the original comment to justanswer.com was asking us "
I was giving you an answer to that question - then now the car does not start. I am sorry but i have to help you with the no start condition first.
OK I need you to check the ground
yes the 1980-81 are the same
my charts are from a professional source
check the ground to ecm
is there any codes ?
Yeah my bad, I'm getting frusterated with this car but don't want it to beat me. Yes I have spark. Earlier testing showed power to the injectors but no pulse. When I replaced the ECM I could see fuel squirting into engine. It ran rough for a short time then quit. I restarted, it ran then quit and stopped squirting fuel. Again power at the injector but no pulse when cranking. Want to find problem before burnning another ECM.
yes a bad ground on this car has been a problem. Do you by your book were the ground to ecm is?
sorry does you book describe were the ground is
have you checked the fuses?
check this fuse
Here is what you need to start is to check the ground to ecm.
2. check terminal R at ignition module for pulse this is done by looking at the ignition model for pin R and then re install cap then probe the wire to pin R and crank engine. Does the test light pulse?
But first check all fuses at relay box and inside car.
Currently the ECM is just hanging under the dash. There are two ground cables attatched to the body, one goes to the bracket that the MAP and Baro sensors are mounted to and the other goes to a mounting stud on the back of the ECM. I thought the connection between the body ground and the ECM was poor but not so, however the connection between the body grond and the Sensors was poor as the mounting bolt that the ground cable was attatched to at the sensor bracket was srtipped. I replaced the bolt and the connection is now tight.
ok i found the ECM diagram
hold wjile i get this together for you and it shows the ECM ground and pin R
I don't think I have checked this fuse. I will have to locate it and check it. Do you know what amperage it should be?
I see i would to check the ground strap from engine to fire wall if you do not see it near the passenger side then run a jumper wire from engine to a good body ground for ol time sake
in the diagram it reads 15 amp
i am here
Things are going good here but I have to sign off, got to go to bed, have to travel early tomorrow (my job) gone for a few days. Will you be available when I get back?
yes, when will you be back? and you must rate me for us to stay connected
three days i will be on in the evening
Are you there
Yes and thank you, XXXXX XXXXX a lot of good info out there and I think I have found some
Thank you for your assistance. I was able to start the car but it needed a 40 amp boost to get it going. I guess a new battery is in order. I still have issues that I think I can work out but if needed can I call on you again?