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jazzmaster, ASE Certified Tech
Category: Car
Satisfied Customers: 2951
Experience:  ase certified--32 yrs experience
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79 Eldorado: stay plugs, wires..timing chain

Resolved Question:

I have an 79 Eldorado that will not stay running it seems to be getting way too much gas it will start and idle but the exaust is black smoke and gasses you out in a few seconds. We Put in new plugs, wires, timing chain temp sensors and some time ago a used computor. Any help?
Submitted: 4 years ago.
Category: Car
Expert:  Neal replied 4 years ago.

Hello I'm Neal and I am here to help resolve your issue. If I cannot help I will opt out and refer your question to another expert.


Have you replaced the o2 sensor? Have you made sure the catalytic converter is not the problem?

Customer: replied 4 years ago.
Neal: Thanks for trying but I think we need someone that would have worked on these cars when they were popular. The car was not equipped with an 02 Sensor and the convertor was replaced with a test tube years ago. They made the test tube for that reason.
Expert:  Neal replied 4 years ago.
Sorry, don't see many of those anymore!!! I will opt out and see if someone else can help.
Expert:  jazzmaster replied 4 years ago.

hi, my name is XXXXX XXXXX I will try to help you .

since you have done all that ,I dont see a mention of a tps sensor or egr valve.

try this first see if the egr valve is stuck open and check to make sure that there is no vacuum going to the valve at idle .

if that is good

then unplug the tps sensor on the throttlebody and see if that makes a difference.

these are about the only things that would make it run rich ,besides perhaps a big vacuum leak ...jazzmaster...

Customer: replied 4 years ago.
The EGR Valve has been blocked off and the TPS has been unpluged which should put it in canned makes no difference. just black smoke.
Expert:  jazzmaster replied 4 years ago.

did you check for a vacuum leak?

also can you take off the vacuum to the fuel regulator and see if it is wet from fuel or fuel coming out of the pressure regulator?

Customer: replied 4 years ago.
This is a repair facility and we have checked for all vacuum leaks, fuel pressure is 43lbs. Fuel pressure regulator doesn't have any leaks. With vacuum unhooked it goes to 55lbs. Put a noid light on injectors and all are firing as normal. When we take the plugs out they are soaked with fuel. Spark is normal. We replaced ignition module. Pretty much stumped at this point.
Expert:  jazzmaster replied 4 years ago.

wow ,that is weird let me think about this and I will get back to you very soon .jazzmaster ...

I am going to research this and I seem to remember having a vehicle like this awhile back ,be bcak soon

Expert:  jazzmaster replied 4 years ago.

I am thinking perhaps the map sensor or circuit .


The manifold absolute pressure (MAP) sensor monitors pressure changes within the intake manifold which are the direct result of engine load, speed, and barometric pressure. As pressure in the intake manifold increases, additional fuel is required. The MAP sensor sends this information to the ECU/ECM so that the length of time the injectors are energized is increased or decreased accordingly.

The sensor is mounted within the electronic control unit. A manifold pressure line is routed with the engine harness and is connected to the front of the throttle body at one end to the MAP sensor at the other end. .

check to make sure that the vacuum line to the sensor is not broke or not getting vacuum to the sensor

you have checked and done just about everything else ,this is the only other thing that would give you the issue you are having and makes sense ...jazzmaster...

jazzmaster, ASE Certified Tech
Category: Car
Satisfied Customers: 2951
Experience: ase certified--32 yrs experience
jazzmaster and 6 other Car Specialists are ready to help you
Customer: replied 4 years ago.
The map sensor is in the ECU and we p[ut a used one on it and made no difference but that don't mean it's not bad also. I have checked to get this one rebuilt so to make things more simple I will accept your answer and cancel the rest of the subscription. Thank You.

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