Thread: 14cux guru's backfire issue.

Originally Posted by discowhite

the oe lr ecu dose work with out vacume advance, ive done it on several of my v8's.

im wiring up a new ignition module tomorrow.

cheers phil

The LR ECU will certainly work without the vacuum advance, because it has nothing to do with the ignition system, if you run a motor (any motor) without any form of spark advance you will encounter the problems you describe.
Hook up a timing light and rev the motor and see how for the spark is retarded at say 2000rpm.
If you dont have a computer (ECU) that controls spark advance, then you most certainly need Vacuum and Mech. advance to control spark advance, Regards Frank.

righto, just talked to john davis, who built the motor. the motor was orignally built to take efi.
i wont repeat what he said about the carb/efi cam differances

i explained what it was doing and what ive done and he stopped me half sentance and said it was the MAF and ECU were not capable of delivering the correct air/fuel ratio and the only way to get around it was to fit a 3.9maf and a chipped 3.9ecu. spose that would explain why with the temp sensor unplugged the dead spot went and the surging wasnt as bad.
i told him i would just refit the haltec that was on it, again i cant repeat what he said about haltech's either

anybody need a brand new vac advance unit?

cheers phil