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My 91 Seville was terrific right till the end

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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An interesting side note:

The smog tech commented that he saw a spark jumping from a plug wire to a hose clamp.

I looked where he pointed later in the dark garage and spotted it also.

I had recently noticed an almost undetectable seat of the pants stuttering when flooring it.

So I'm replacing the 6-7 years old plug wires, (Lifetime warranty from NAPA.(autoparts not wine)

BTW that latest red wine, Menage a Trois from Folie A Deux winery is really good!

Now back to the story:

Replacing the plug wires on the sideways engine is a real dog.

At least that's what my knuckles tell me!

I also found one of the old wires had burned away at the distributor cap so a new cap today also.

The best part is it passed the smog test with flying colors!!

Edited by bobb
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Yes, the plugs and wires on the firewall side of the engine are tricky and you can cut your hands on the screws that penetrate the firewall, but wear gloves with the fingers cut out and that helps I found. They make some very good gloves, check out walmart

Its a good engine, I had a detonation problem for awhile but once I replaced the EGR valve and cleaned the passages that problem was gone. The engine can have a #1 main bearing knock at times but its just a nuisence problem. My only issue was the water pump that did not last long.

By the way the Menage a Trois from Folie A Deux is good, I have had it

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I loved my 4.9 in my 93 Seville. Plenty of all over power. It was a sick motor when I sold it though.

I had a check engine light on and did not know at that time how to check codes. I took it to our neighborhood shade tree mechanic and he said that it just needed some injector cleaner. I went to the gas station and put some in with a full tank. With in a couple of weeks I noticed that I was going through ALOT of gas...But my DIC still showed normal economy. I started monitoring it's fuel used vs what I put in at the pump. On a full tank there was a 2-2.5gal difference. I took the car into a shop to have it examined for a fuel leak and nothing. So, I took it to the Cadillac dealership service department. Their explanation was that the injector cleaner had eaten away some rubber in the injector so that more fuel was being released into the cylinder on every pulse. The computer calculated the fuel with factory numbers while the amount was now higher hence the difference. Maybe the service guy was full of BS but it was the only thing that could make any sense at the time.

Caddy_Grill.jpg2008 DTS
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One of the pain in the *** areas is when you pull the old wires off the plug,

the metal part inside the wire can break and leave a part on the plug terminal.

Not bad on some engines, but with the plugs deepin there it can be difficult to get off.

So far I left two in the front and it took a few minutes to feel why the new wire wasn't pushing on.

I hope I can rotate the rears more to break them loose so it doesn't happen with some back there.

Bob B

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I loved my 4.9 in my 93 Seville. Plenty of all over power. It was a sick motor when I sold it though.

I had a check engine light on and did not know at that time how to check codes. I took it to our neighborhood shade tree mechanic and he said that it just needed some injector cleaner. I went to the gas station and put some in with a full tank. With in a couple of weeks I noticed that I was going through ALOT of gas...But my DIC still showed normal economy. I started monitoring it's fuel used vs what I put in at the pump. On a full tank there was a 2-2.5gal difference. I took the car into a shop to have it examined for a fuel leak and nothing. So, I took it to the Cadillac dealership service department. Their explanation was that the injector cleaner had eaten away some rubber in the injector so that more fuel was being released into the cylinder on every pulse. The computer calculated the fuel with factory numbers while the amount was now higher hence the difference. Maybe the service guy was full of BS but it was the only thing that could make any sense at the time.

I went through the same thing when I first bought the car and the DIC didn't agree with the actual gas used.

It turns out that if the injectors are not metering the right amount this happens.

I tried two cans of Techron in a half tank. (if one is good use two NO Don't do this again!)!!

The windings were getting bared and shorting out internally.

There are two multi plugs on the side of the engine that feed the injectors, With a digital ohmmeter you measure each one for 16 ohms.

I had several with 5-6 ohms.

I won't use the injector cleaner again, but will use Chevron gas with it in.

Bob B

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With the onboard diagnostics you can test the injectors for balance by turning off one at a time while watching a tach or just feeling the miss.

You can also check for flow balance with a pressure gauge hooked to the rail.

And a remote jumper to the fuel pump activate pigtail by the windshield washer reservoir.

I found a leaking injector the day before the smog test with the injector flow test. When You check a cylinder the gauge goes down a certain amount but one of mine continued to drop when it should have stopped.

I tested it several times and it failed two out of three times.

You gotta love the onboard computer.

regards,

Bob B

Edited by bobb
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