twinter82

Active Member
Just to make a change, I thought you lovely people may be able to help diagnose a running issue with my brand new (to me anyway) 3.9v8 with 127k miles and an LPG conversion (that i haven't been using - all of the following is based on running 95 Unleaded)

To start with, I found it was missing an air filter completely (empty air box), idleing high around 1200 and smelt like running it was rich. Also noticed a clicking from the driver footwell which sped up when accelerating.

Decided to do a service as lack of filter indicated it's not had the best of care. Put in an air filter, new HT leads, new genuine lucas rotor arm and dizzy cap, new plugs and oil change. Then engine started back firing, hesitating when trying to pull away and idling around 800 but going up and down like the moods of a manic depressive.

Indy mechanis suggested air mass sensor, so brand new one purchased and fitted. Idle is a stead 750 now, back firing gone but when cold really difficult to pull away without engine cutting out and through the rev range sounds quite rough still. Clicking noise from driver footwell is the main injector relay i've decided.

Will replacing the relay likely cure the problems, or is the fact that it is running at all mean the relay must be working even if it is noisey?
 
Just to make a change, I thought you lovely people may be able to help diagnose a running issue with my brand new (to me anyway) 3.9v8 with 127k miles and an LPG conversion (that i haven't been using - all of the following is based on running 95 Unleaded)

To start with, I found it was missing an air filter completely (empty air box), idleing high around 1200 and smelt like running it was rich. Also noticed a clicking from the driver footwell which sped up when accelerating.

Decided to do a service as lack of filter indicated it's not had the best of care. Put in an air filter, new HT leads, new genuine lucas rotor arm and dizzy cap, new plugs and oil change. Then engine started back firing, hesitating when trying to pull away and idling around 800 but going up and down like the moods of a manic depressive.

Indy mechanis suggested air mass sensor, so brand new one purchased and fitted. Idle is a stead 750 now, back firing gone but when cold really difficult to pull away without engine cutting out and through the rev range sounds quite rough still. Clicking noise from driver footwell is the main injector relay i've decided.

Will replacing the relay likely cure the problems, or is the fact that it is running at all mean the relay must be working even if it is noisey?

Hi,

Not sure how far you have got with this, before changing the relay, have a look for a crack in the manifold, my D1 makes the same kind of noise and I have a lovely crack in the manifold, tried to fix it with some e-metal, but it must not have set properly because it's blown through. Never mind I will just have to replace it.

Cheers

John
 
Hi,

Not sure how far you have got with this, before changing the relay, have a look for a crack in the manifold, my D1 makes the same kind of noise and I have a lovely crack in the manifold, tried to fix it with some e-metal, but it must not have set properly because it's blown through. Never mind I will just have to replace it.

Cheers

John

Hi, I found out that the cold starting problems only happen when running petrol - at low speed it runs ok on lpg. Above 50mph though it still hesitates a jerks like a cross between minor backfiring and wheels out of balance.

Tested relays for noise by running lpg and removing injector and fuel pump relays - noise was still there so now think it may be the lpg ecu?
 
Was the cap and rotor dealer gen not Lucas crap in a green box?!
Cold start prob is proberly coolant temp sensor
 
Was the cap and rotor dealer gen not Lucas crap in a green box?!
Cold start prob is proberly coolant temp sensor

Both genuine, ive heard that the v8 can be very picky about its electrics.

Any way to test coolant sensor or is it just replace and see?
 
have checked for air leaks ? my 5.0 ltr is a bitch if there's the smallest air leak . checking this is a no cost item you can tick off the long list of possibles !
 
have checked for air leaks ? my 5.0 ltr is a bitch if there's the smallest air leak . checking this is a no cost item you can tick off the long list of possibles !
Ive had a look but no obvious hissing noises. Is there a better way to check?
 

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