Rangie backfiring, etc under power

[Blueboy]

Hey folks,

First real problem with the Rangie. Under aggressive acceleration or load, backfires, snorts, and other nasty stuff.

And idles like shit until warm.

New plugs, wires, rotor, distributor cap and still runs really poorly.

Intake manifold gasket and seals also replaced.

Any ideas?

1994 LWB 4.6 stage III RPI engine with tornado chip.

Thanks!

 

[ERover82]

Fuel pressure?

 

[JohnC]

idles like shit until warm - maybe temp sensor ????

 

[kk88rrc]

idles like shit until warm - maybe temp sensor ????

x2 coolant temp sensor for the idle issue
Does it backfire snort etc all the time or only cold?

 

[Blueboy]

Thanks folks.

Fuel pressure?

will have this checked for sure

x2 coolant temp sensor for the idle issue

didn't think of this one

Does it backfire snort etc all the time or only cold?

don't normally push it too hard when cold so only tested this when warm. However, the engine just isn't running "clean" at any temperatrure. It is almost like the timing is way off.

Appreciate the help guys.

Taking it to a shop on the 7th and will offer these suggestions.

 

[jims95]

Disconnect the harness at the MAF. The truck will run using the TPS. If it runs good, hook up the MAF again. If it starts backfiring again, disconnect the harness at the MAF. If it runs good again, you have a bad MAF.

 

[Blueboy]

Thanks - also saw this when searching DWeb.

Tried it and no difference.

Ran poorly connected and disconnected.

 

[rover4x4]

Keep digging. Mine too...

 

[4Runner]

Try your ignition coil if you have a spare or can borrow one. I chased a partially shorted coil for a couple of weeks. Speaking of timing… did you check yours to see that it didn't move? Also check what everyone else has mentioned. All good advice.

 

[XCELLER8]

add the ignition amplifier module to the list of possibilities....they normally dont fail till they are hot......but this IS a Rover...lol

 

[Blueboy]

After going to 2 shops with no resolution sent the Rangie up to Maine. It will be interesting to see what is found.

 

[kk88rrc]

What all did the shops tests? How old is the fuel filter?
Going back up to ECR?

 

[jims95]

When the rotor was replaced, was the "air gap" setting checked, or did it get knocked of adjustment? The "air gap" setting does affect ignition, and fuel injection performance, with regards to the signals seen at the ECU.

 

[AfiRover]

CUX? or GEMS ?

if cux its the GOD for sacken dizzy
did any one check the timing ?

 

[rover4x4]

Mine started doing this when I had a pertronix distributor installed

 

[cosmic88]

May be worth checking the small plastic retainer at the top of the distributor shaft. The inverted top-hat looking clip has a tendency to disintegrate or just pop off after two decades of use.

Do you know the part I mean?

 

[Blueboy]

Do you know the part I mean?

Thx - distributor is about 5 years old and less than 10k miles so thinking that part should be ok.

 

[Blueboy]

if cux its the GOD for sacken dizzy
did any one check the timing ?

yep - twice.

all is supposed to be in order.

thx

 

[Blueboy]

When the rotor was replaced, was the "air gap" setting checked

not sure. good point though. Mechanic is a well respected Rover tech so guessing yes.

thx

 

[Blueboy]

How old is the fuel filter?
Going back up to ECR?

Brandy new LR genuine fuel filter.

Yes - there now waiting for some room in the shop to open up for the gang to check it out.

Really want this to be done right and they worked on this engine before shipping to Switzerland.

It ran awesome when it first came over and for the 5 years all over Europe.

So looking forward to getting it back to where it should be - a 4.6 RPI Stage III with about 275hp!

Very curious to what it is - probably just a loose wire.....

thx