Just got a 90 deville that I am having a hard time with had a bad radiator ran good before and now runs very rough and back firing from the back of the motor cant give it gas or it dies changed the plugs map sensor no lights on dash it was running good when cold then it would run hella rough once it got warm now it runs rough on start up not drivable its driving me nuts its 4.5 when I bought it it ran great and drove great any insight would be much appreciated
You probably have a couple of bad injectors. You can check their resistance, or even better - take a screw driver or a stethoscope and listen to each of them. They should be ticking pretty rhythmically.
Well I changed the cap and rotor now it starts runs great but when it warms up it starts to run hella rough again everyone keeps saying the egr valve or something else ???? Im going crazy
There should be no EGR flow at idle. If there is it will cause a bad idle or a stall, but that will happen with a cold or hot engine. How old are the plugs & wires?
Ok didn't know that well I changed the plugs now I need to change the wires I dont think its getting good spark cause its now loading up and backfiring through the throttle body
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I HOPE you used genuine ACDelco plugs -
and NOT some cutesy - designer -
8 tip - V shape - candycane striped plugs -
that flash with LEDs -
same with the cap - rotor and wire set -
don't cheap-out - get the ACDelco stuff -
and be done with it -
Ok I've replaced the wires finally found out how to get the codes and im pulling e30 e34 and e52 ive already replaced the map sensor and I know the e52 will be on but how do I erase the codes also I've tried timing it but can't see the timing mark on the pulley and the timing light don't seem to be steady beat not sure what to do
Hi, Welcome to the forum. I find invaluable info here so I visit frequently. FYI, I've had my 90 for @ 1.5 years, drove half way across the country & dropped @ 4.5 G's in svc (not including reg maintenance). This car is at the age where things need to be replaced. It's definetily worth it if your up to it & appreciate the car. Good luck! I'm sure once u resolve these issues, more will arise (maybe big or small), stick with it, it's a good car.
The timing light not being at a "steady beat" indicates that the spark is not reliable. So you've replaced spark plugs and plug wires...what about the distributor cap and the rotor? I think that the cap and rotor should be changed as well...these deliver the spark to the spark plug wire. When getting the cap, be sure to get the one that uses four screws, no the four spring-loaded clips.
When switching the distributor cap, you will have to remove the coil and install it into the new cap. It's not a difficult job, just try to keep everything clean and dry in the process.
All right I think I narrowed it down to maybe the fuel filter and battery igot it started ran with no hesitation but still not much power when I give it throttle and as soon as I unhooked the jumper cables it changed the way it ran also when I shut it off it wont crank just clicks and try's to turn over but wont im hoping that will cure it .....but im making progress yeah
:noidea: I don't know if that means timing or EGR problem.
Please updater your profile to show your year and model so we know what we are talking about. The original thread is about a 4.5.
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