Power Loss 79 Seville

[Ranger]

You have to start with the basics and then go through the process of elimination. CHECK THE FUEL PRESSURE!

[Sergey21]

Originally Posted by cadillac_al

Hi Sergey, I almost pulled all my hair out when I first got my fuel injected Seville. I'll try to save you 40 hours or so. It's been a while and my memory is a little foggy because I switched to a carb on my 78. My Seville was the first car I ever saw that could drown a set of new spark plugs without ever starting. That car has an idle air compensater valve(not sure of exact name) that is known to go bad or it could be gummed up. If I remember right it is right on top of the throttle body and has a plug on it. I think it twists out or something. That will definitely cause it to stall until warmed up.

I will check that out right now!

Originally Posted by cadillac_al

If you keep having problems you may need to invest in a fuel pressure gauge. I spent many hours trying to figure why my car would start for a second and then die. This may be how I drowned my plugs. Once I borrowed a fuel pressure gauge I saw that I had good fuel pressure with the key on but when I turned it to start, the fuel pressure died. I think I had to change the ignition switch that time.

Going to autozone now, to borrow that kit.

Originally Posted by cadillac_al

You might want to double check the fuel pump wire. It runs around the rear of the gas tank and I think it's green. Just make sure what you can see isn't frayed or spliced like mine was. That caused me some intermittant starting problems. Sometimes it would die while driving down the road and I finally found that if I wiggled the wires on the cpu, which is located next to my big foot and accelrater pedal, that it would start again.

Seems fine.

Originally Posted by cadillac_al

At this point, I think you should check your plugs to be sure they aren't too wet and see if it has fire. If you do get it started, just let it idle until it's warm enough to drive to see if there are any other driveability problems that may be affecting the starting and cold idleing. Good luck.

Plugs are great, performance autolites, clean, not wet, and get a good spark.

[Sergey21]

Checked pressure, all is good. Changed fuel filter.

[carnut]

I've read all the prior posts. I was a service advisor at Cadillac when this car was 3 yrs old. They would develop a failed coolant temp sensor and when it failed, it would tell the computor the car was not warmed up even on a warm restart. That would gas foul the spark plugs and cause excess cranking to start. This sensor is located next to the thermostat housing. The air temp sensor is located at the rear of the intake manifold. The part number is the same so swap these sensors to see if cold start improves. Also the cold start valve in the center of the throttle body under the threaded stud can fail electrically and not allow high cold idle. Normally this engine starts cold and idles at almost 1200 rpm, then as this cold valve heats up electrically it lowers and the idle speed decreases to approx 600 rpm. If the cold start valve is faulty or is not getting a voltage signal the prior owner could have adjusted the air screw incorrectly in the front center of the throttle body. The cold start valve is no longer produced and is Cadillac specific. The coolant and air temp sensor is still available I believe? Also below the distributor mounted on the shaft under a tin cover are two sets of trigger points to fire left bank injectors then right bank injectors. If they are covered in engine oil from years of use, they might affect injector firing timing. Get a factory service manual before you buy ANY parts to get familiar with how this engine gets its fuel and air. Hope this helps. If all else fails get an intake manifold/carb from a Olds 350 and a mechanical fuel pump and swap it out.

[Sergey21]

Originally Posted by carnut

I've read all the prior posts. I was a service advisor at Cadillac when this car was 3 yrs old. They would develop a failed coolant temp sensor and when it failed, it would tell the computor the car was not warmed up even on a warm restart. That would gas foul the spark plugs and cause excess cranking to start. This sensor is located next to the thermostat housing. The air temp sensor is located at the rear of the intake manifold. The part number is the same so swap these sensors to see if cold start improves. Also the cold start valve in the center of the throttle body under the threaded stud can fail electrically and not allow high cold idle. Normally this engine starts cold and idles at almost 1200 rpm, then as this cold valve heats up electrically it lowers and the idle speed decreases to approx 600 rpm. If the cold start valve is faulty or is not getting a voltage signal the prior owner could have adjusted the air screw incorrectly in the front center of the throttle body. The cold start valve is no longer produced and is Cadillac specific. The coolant and air temp sensor is still available I believe? Also below the distributor mounted on the shaft under a tin cover are two sets of trigger points to fire left bank injectors then right bank injectors. If they are covered in engine oil from years of use, they might affect injector firing timing. Get a factory service manual before you buy ANY parts to get familiar with how this engine gets its fuel and air. Hope this helps. If all else fails get an intake manifold/carb from a Olds 350 and a mechanical fuel pump and swap it out.

Ok, carnut, I appreciate your reply and concern. Although I have already swapped out my Coolant Temp Switch (Sensor) and the starts are still hard. It was faulty because the contact was half way broken off and corroded. The fast idle valve, or the choke heater, is also OK. I have cleaned it, and brushed the contacts, it idles very high when it starts, and you gotta drive this boat for quite some while for the idle to go down. I havent swapped out the Air sensor yet. And I will definitely look into cleaning those two things. Once I actually figure out their coordinates based from what you're saying.

Once again carnut, I appreciate your reply and concern, and very thankful.

And since the car was sitting for 4+ years, it still hasnt been tuned properly meaning; Oil is still old, brake fluid is like water, radiator fluid is yellow and stinky and is very terrible. Transmission fluid should most likely be changed also, because I believe it slips sometimes, and is very jerky. So, this upcoming paycheck I will go ahead and take care of all that. And see how it goes. However, I dont think it will have ANY effect on cold starts.

[Sergey21]

Update with good and bad news. Ok, start with the good. I took the caddy to a mechanic yesterday, he charged me 55 bucks to take a look at it...and believe it or not, he did something...and now my car runs full power with all 8 cylinders. Weird. I think he might have messed with the timing or something. Because my timing was indeed off. I really know the feeling of a 5.7 V8 now. Now, my transmission shifts really smooth...and all the goodies.

The bad: After the mechanic had a look at it, the timing chain is loose and it slacks when hard accelerating. My cruise control doesnt work, nor did it ever. The mechanic said that my Cam Shaft is ground down too much, and will soon (presumebly now) need to be replace, with the cost being around $800 with labor.

Also one of the old bads: CAR STILL HAS BAD STARTS AFTER IT SITS!!! And now I found out that cylinder 2 and 4 get flooded because of an open valve or something. Quote "The MaKaNic" I also confirm this because I took the # 2, 4 cylinder spark plugs out and sniffed them, and they smelled like fuel.

Ran compression test on all cylinders, cylinders came up with 145 - 150 psi. Car does have more pull now, definately, but the start problem is getting to me and needs to be kicked in the ass and out of my life.

Lol, some guy said, "Dude, I think you're better off selling the car!" My response was F*** YOU! Because this caddy is truly one of a kind, and I have big plans for her. Plus I've come a long way with this caddy now.

[Ranger]

the timing chain is loose and it slacks when hard accelerating.

Could be worn timing gears. When they are badly worn and with too much slack in the chain it can skip a tooth on hard acceleration, throwing the valve timing off.

[racecardude310]

I KNEW IT WAS TIMING :-D

haha sorry

[cadillac_al]

I'm going to go out on a limb, without looking for a manual, and say that Seville doesn't have a cam position sensor. It gets its fuel signal from the distributer. Those Olds 350's had plastic coated timing gears to keep them quiet. The plastic crumbles and gets sucked into the oil pump, but it usually doesn't block the flow for a long time. A lot of those Oldsmobiles will run a long time with worn out timing gears but I can see how that might cause a problem for the fuel injection.

Now that your timing is set correctly, does it start any easier? does it still idle high? I'm still not clear on how it can idle high and stall when you put it in gear. It sounds like you will get it sorted out slow but sure. The wet plugs in #2 and 4 might be a leaky injector. If I get a BIG BIG shot of ambition this year, maybe I'll put my fuel injection system back on. Good luck.

[Sergey21]

Originally Posted by cadillac_al

I'm going to go out on a limb, without looking for a manual, and say that Seville doesn't have a cam position sensor. It gets its fuel signal from the distributer. Those Olds 350's had plastic coated timing gears to keep them quiet. The plastic crumbles and gets sucked into the oil pump, but it usually doesn't block the flow for a long time. A lot of those Oldsmobiles will run a long time with worn out timing gears but I can see how that might cause a problem for the fuel injection.

Now that your timing is set correctly, does it start any easier? does it still idle high? I'm still not clear on how it can idle high and stall when you put it in gear. It sounds like you will get it sorted out slow but sure. The wet plugs in #2 and 4 might be a leaky injector. If I get a BIG BIG shot of ambition this year, maybe I'll put my fuel injection system back on. Good luck.

Yeah with the timing set now, the car has A LOT more power, and it starts A WHOLE LOT BETTER! WAAAY BETTER! It does have any kind of hesitation at all, nor does it want to die. I LOVE IT! Now it drinks more gas though