: 98 cadillac eldorado 4.6 engine questions



Tom Thomas
08-18-10, 12:53 PM
I have a 98 cad. with 4.6 northstar engine. I just removed the engine a had to install the time serts in the engine block, just like everyboby else.... new head gaskets bolts and everything else. I started the car yesterday for the first time and it is idling rough. But its not over heating lol. Whats the first thing i should look for? Try or do?


Thanks

Tom

zonie77
08-18-10, 01:11 PM
Did you replace plug wires? They are usually failing by the time the HG's go and the extra handling makes them fail. New plugs? Clean and check the coils? All the injector wires on right?

A couple of times cam's wound up 1 tooth off but I don't think it caused a miss. You would have to search and that can be a miserable experience.

joe_mn
08-18-10, 01:41 PM
was it running ok before you pulled the heads? have you ever checked the plenum gasket for cracks? seems to be a good place to start. checking valve timing means pulling off the valve covers.

Tom Thomas
08-18-10, 02:10 PM
Did you replace plug wires? They are usually failing by the time the HG's go and the extra handling makes them fail. New plugs? Clean and check the coils? All the injector wires on right?

A couple of times cam's wound up 1 tooth off but I don't think it caused a miss. You would have to search and that can be a miserable experience.

No i did not replace wires, but will check. If the timing was off 1 tooth would it still run? When i get about 3000 to 4000 rpm's it seems to get a little better.

But I took extra time making sure the timing was set correctly. And yes it was running smooth before I replaced Head gasket... : )

Tom Thomas
08-18-10, 02:39 PM
And my codes are:
P0155
P0300
P06023
P1638

Thxs.

Submariner409
08-18-10, 05:07 PM
Your engine has no plenum. (2000+). Did you replace the coils and wires according to the pre-2000 Northstar plug wiring diagrams posted many times in here and up in Deville and Seville ???

Go back to the DTC sticky thread and post the code definitions.

joe_mn
08-18-10, 05:27 PM
dooh. i saw 98 at thought seville but its a eldo. so its the same as my 96 STS, motorwise. my car ran fine before headgaskets and had a miss after. comes and goes. no codes now. new delco plugs. wires are maybe 5yrs old. new intake gaskets. only has a miss at idle.

zonie77
08-20-10, 05:49 PM
And my codes are:
P0155
P0300
P06023
P1638

Thxs.

P0300 is a miss. I'd change plug wires. You can mist them with water in a completly dark garage and watch for arcing.

It will run with a cam a tooth off. It would be low on power.