Jump to content
classicbobtail

3.9efi backfiring no power

Recommended Posts

Hi Guys, 

New to the forum, i have a 1992 3.9efi bobtail and it has all of a sudden after 40 mins of driving started to backfire and lose power to the point i had to limp it home at 25-30 mph, wouldn't go any faster. It has the original tank in the back and the pump has got noticeably louder at the same time. Any suggestions of where to start please. Are the pumps known to fail? It doesnt over heat and was idling/driving perfectly until it kicked down over taking someone on a dual carriage way.

Thank you

Edited by classicbobtail

Share this post


Link to post
Share on other sites

I'd bung on a new fuel filter to start with, if that has no effect then you'll need to have a look at the fuel pump in the tank... there should be an access hole under the rear carpet (boot)... If the tank is steel then there could be loose rust in the bottom blocking up the pump, and if it's plastic there still could be a lot of crud in the bottom.

Share this post


Link to post
Share on other sites

It'll be plastic at that age, but as above, filter then inspect tank and then replace the pump.

If it is an old pump just replace it anyways, they aren't that expensive and the work to access the tank is not that bad, but you wouldn't want to do it twice.

Share this post


Link to post
Share on other sites
4 hours ago, classicbobtail said:

It has the original tank in the back

Not sure if that means it's in it's standard position or sitting in the boot area above deck, in which case the pump should be a lot easier to get at!

Share this post


Link to post
Share on other sites

92 should have an in tank pump.  I think there should be an access panel in the rear floor.

Share this post


Link to post
Share on other sites

My 94rrc did almost the same a few months ago. Seemed to be running perfectly, then stopped at roadworks and the engine was just runnning, but did not respond to throttle. Eventually stopped. Taken to my garage , they initially thought fuel starvation, current pump is 3 or more years old. Turned out to be failed distributor. LR cost is 1400 quid plus, but my garage source after market ones, take them to bits check all the connections for dry joints etc, ignition amplifier had to be moved as originally with coil. All good now, cost 150 quid!

Share this post


Link to post
Share on other sites
6 hours ago, classicbobtail said:

i have a 1992 3.9efi bobtail

6 hours ago, classicbobtail said:

It has the original tank in the back

Is there room in bobtail to have a standard under floor tank??

^ and you wouldn't be the first one to discover that the ignition amplifier can fail, although to be fair it is clearly marked LUCAS which should be a warning of impending doom ;)

Edited by miggit

Share this post


Link to post
Share on other sites

Be aware that backfiring will wreck the airflow meter.Back when LPG was all the rage and people were fitting sh%%y cooker ring systems on them I diagnosed loads of them.Decent replacements were not cheap then...

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy