20 Most Recent 1991 Cadillac DeVille - Page 6 Questions & Answers

I would assume the wires are on wrong,wouldn't you ,it back firesDid it do that before any work was done?

have the intake air temp sensor checked by a computer

MOST LIKELY THE HEAT SHEILD FOR EXHAUST

Go to you tube and youll find videos that can help you, i allready did, and they help me a lot, god bless you..

need to start with do you have any obd code with key turned on caddy is more complex system than most , check fully charged battery, and not a jump start, and battery is in very good condition .disconnecting battery would only clear codes leaving you with nothing to go on hopes this is some help to you.

21 & 18 is the OBD I fault codes?Whats is XP 10 Diagnostic Code Reader, some ODB reader tool?

have you lost power is the engine running hotter do you hear a rattling noise from your exhaust is your check engine lite on

This is a standard GM starter wiring diagram.

ohm your ignition key resistens and buy a resistor and place in connector under dash where steering column is, will have connector with to small wires, insert proper resistor in connector on eiring side not key lock side and that will by-pass pass key system

We do not have electrical diagrams here at fixya , it is copyrighted material.