BodybyFisher

Check for a clogged CAT, they have been known to clog up, it happened to me on a 91 4.9. Bang the CAT with a rubber mallet and see if you get a rattling noise. Pull the distributor cap and have a look at the rotor and cap for cracks, carbon tracking and burn throughs. What do you mean by you lost both codes but 7.0? Its not porous in the cooling jackets that the supplement is used for, it is to make sure the cylinder sleeve o-ring doesn't leak allowing coolant into the crankcase. Why do you need to convert?, there is a way to make farenheit the default Check fuel pressure with a gauge attached to the fuel rail and report your results. If you can check the fuel pressure when the problem occurs that would be ideal.

Can't do anything without fuel pressure, you installed the cheapest fuel pump, verify fuel pressure to eliminate it from a potential cause. I don't know how a leaking vapor line could stop you from doing a basic diagnostic fuel pressure test, your complaint is missing and stalling, something low fuel pressure would cause. Did you stop fuel from being pulled into canister? Does this line run to the top of the fuel pump? You removed the tank without checking fuel pressure?

This is good to know, thanks

Explain how the before and after Eldorado dyno testing was done. Questions: Was the test done the same day?, if not how time between the tests? Was the ambient temp the same on both tests? What were the HP numbers for each run?, for each vehicle? Were both cars base engines? Thanks

I think this paragraph is your key. Also, #2 above "Important"

When I speak of orientation i speak of where the spring, seat, mount and strut sit from above, looking down at the strut, that they are each sitting in their required location 'on the circle'. Refer to the manual, not the old strut, the old strut might have worn and moved.

I can only offer this, did you get the orientation correct between the strut, spring and strut mount? There should be an illustration in the manual

This is true with the electronic struts. Were these electronic struts in 85? He might be getting a ALC message related to the air leveling suspension. He can pull codes, but pulling the codes for the suspension was a little involved on the 85, and might involve interpreting flashes once in suspension diagnostic mode. My oldest manual is 88.

Explain what you mean by standard KYB shocks, are they air shocks? These cars are level balanced with the air shock, it is a necessary part of the suspension. I do not know who would replace an air shock with a 'standard shock'. If you ever put 4 adults in the car you will be on the ground, and if you hit a pot hole or dip in the road good luck. The car is designed to be at a specific 'ride height'. The air leveling component is necessary. Did one of these mechanics suggest this? And why KYB? Please provide more details.

I have upset many people refusing to jump them. And while the owners manual gives instructions on how to do it, not me! I do not like the strain placed on the alternator on either vehicle. This is why I have AAA for emergencies, a battery charger, a trickle charger. You only need to change this alternator once to know, you do not want to do it again too soon. A dead battery is a huge current draw. See this ALTERNATORS ARE NOT DESIGNED TO CHARGE DEAD BATTERIES https://www.optimabatteries.com/en-us/experience/2012/08/fact-alternators-are-not-designed-charge-dead-batteries

You can check the oil pressure switch and its connector first. I would replace it with an ac delco to remove it as a potential problem. Use an OEM ac delco oil filter, it has been calibrated for your engine. Does the oil pressure message/light go out when the rpm increases above idle? Typically we see these engines have internal leaks like the case half seal, main bearings etc, that drop the oil pressure at idle, just enough to cause a flicker in the summer months when the engine is hot. Be sure the cooling system is keeping the engine cool. Oil thins out when it is hot, dropping the oil pressure just enough. Stock oil pressure spec is 10 psi at idle, the oil pressure switch is set to come on at about 6 to 7 psi. As the engine ages clearances widen, and internal leaks occur that drop the pressure enough to trigger the light. I think the pressure is 30 psi at 2,000 rpm, but don't quote me. If any engine work has been done that required removal of the crank pulley, torque it to spec, the balancer traps the oil filter drive and turns the pump, if this bolt is loose oil pressure will be compromised. You might have the crank pulley bolt loosened and tightened to spec to eliminate it as a cause. However, it will be necessary lock the engine from turning with a special tool that engages the teeth in the flexplate keeping the engine from turning. If he is using synthetic get it out and use standard mineral oil. Synthetic flows 7 times better and will drop the oil pressure at idle just enough to turn the light on. Try using Rotella 15W40 diesel engine oil, not the synthetic. That will help keep the oil pressure a little higher and help with the oil light flickering. If you can't find Rotella look for Mobil DelVac 15w40. Diesel oils also have a higher concentration of zinc which is a anti-wear compound, the 32 lifters are the rubbing element type and cause significant oil sheer and the increased zinc is good for them. Good luck. Keep us posted

Post the codes here, the AC may need to be recharged and the tire monitor sensor battery is probably dead.

Is this a question on how to remove the headrest?

Maybe the clue is that your son OFTEN used the car to jump start his 85 Corvette. A dead battery puts a very heavy load/draw on the car doing the jumping. Ask your son how he performed the jump. If he connected the jumper cables to both cars and THEN started the Cadillac, he might have melted or overloaded the ignition switch contacts or a relay. With all of the electronics and computer, I have been reluctant to jump any car, its best to remove the battery, charge it, then reinstall. You need a schematic to diagnose this but I can't help but think the ignition switch is the problem.

Odd problem and 'fix'. Its not likely any spray would penetrate beyond the lock cylinder and security key chip contacts into the switch itself. I will try and get a schematic and look to see what might cause this.

@herownbagger What is the status, did you hook up a fuel pressure guage and check the relay? One other thing comes to mind, consider that the exhaust is restricted, the CAT can self destruct and clog the outlet. Do you hear any rattling when the engine idles? I had a clogged CAT on a 91

Wow But why not fix the carb/trans kickdown?, it makes me think it's something not easily solvable. This car didn't come stock with a Holley carburetor, that would be tossed over my shoulder for the OEM Rochester / Carter carburetor and controls

I am very busy and will read the above and reply in detail. But, looking at a relay means very little. The fuel pump constantly draws power, it clicks on every time the key is turned on. A defective pump can draw excessive current damaging a relay. There are contacts in there that can pit and burn over time from increased resistance. Replace it with a known good relay. Even swap in the same relay from a non critical system as a test. BE SURE TO WATCH THE RELAY'S ORIENTATION, ONE SIDE IS POWER, THE OTHER LOAD. Watch for corrosion on contacts and sockets in a car that old. We need fuel pressures to move forward.

Report back your fuel pressure Tell me your history, why did you replace your fuel pump?, you said it died?, explain. If you have no fuel pressure gauge how did you know it died? Fill us in on the history. You might be experiencing the same problem you experienced before the pump was changed. How did he test the relay?, did he test it with a load on it?

I hear you, but there are places to skimp and places not to skimp, dropping the tank is a pain a job you don't want to do twice. Please let us know what the pressures are, look over the regulator again also. This is your regulator, start engine, pull vacuum hose off, hold piece of brown paper bag in front of nipple, rev engine, if it spits any fuel, its bad. Also, check to see if you have a fuel pump relay, I am pretty sure you have one, if it has burned contacts or is corroded you can get pump motor intermittents, high resistance, etc. It might have been the problem from the beginning.

It won't make a difference if its under load. You need the fuel pressure at those two points. Based on this it looks like you bought an economy pump. Given that they are discussing the pump diameter, strainers, flanges and that the tank has to be dropped to replace it, I would have gone with an OEM AC DELCO or Delphi unit and not risked quality or fit issues.

What is the fuel pressure at idle and at 2,000 rpm? This is important. Keep in mind that just because the pump is new that there is a possibility that it is defective. What make of pump did they install do you know? A fuel smell is usually an indication that the regulator is bad, but you did say that this happened after the fuel pump went in correct? Check the fuel filter to make sure they snapped the quick disconnects solidly. No leaks around the fuel filter? Get under the car and inspect for leaks in front of the fuel tank in the center (left to right center). Can you check for diagnostic codes? Are there any check engine messages?

See KHE's post above

Have you checked the fuel pressure regulator? I don't know this engine, what is this a 4.5L? Locate the fuel pressure regulator, with the engine idling/running, pull the vacuum hose off the regulator, if it spits fuel, its diaphragm is damaged, replace it

I did a little research and found that BBSX, is superceded by BHMU according to info at this link https://forum.tunerpro.net/viewtopic.php?p=13643