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Too much fuel................

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Hi gang.

Couldn't get the beast started and i think we found out that there is far to much fuel getting into the chambers.

We took the plugs out 2 or 3 times to dry off and clean.

Every time we tried to start it up, It would show a slight sign of trying to fire up but then die as there was too much fuel getting in.

As stephen said there could be a few things why this is happening. Another reason i was told since yesterday afternoon is the coolant temp sensor is faulty. So i'm gona try and unplug it to see if it makes a diff when i get time.,

Just wondering if anyone else has any thoughts on this?

The plugs where soaked with petrol everytime we cleaned them.

Cheers DC

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Just unplugging the CTS will make the ECU think the engine is cold and cause extra fuel to be injected, making things worse. A faulty CTS will make the engine rich enough to start but then too rich to run as it warms up.

If you think the CTS sensor is faulty disconnect it and fit a 200 ohm resistor to the plug, this makes the ECU think the engine is hot. Also check the CTS circuit is complete back to the ECU pins.

Above is for both hotwire and flapper.

If it's a flapper plug off the fuel feed to the ninth injector.

You have checked for a good spark? During cold start poor sparks not firing the rich mixture will give the impression of too much fuel.

If there is a tremendous amount of fuel in the cylinders check out the injector circuits for earth contacts. With just the ignition switched on there should be battery voltage at both terminals of the injector plugs.

Have fun,

jw

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http://www.carelect.demon.co.uk has a list of suggestions. The CTS as already described is a favourite.

I don't think you will have the cold start injector on the plenum. For those that do (3.5) just unplug the electrical connector.

Also be sure the rotor arm & dizzy cap are genuine parts. Pattern parts are simply not an option & are the cause of many V8 running problems.

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Another top contender is that your RPV (Fuell Pressure releief valve) er "Isn't"

Check fuel pressure, as if the PRV Jams you can get up to 100+ PSI rather than the 28-34psi you really wnat

Even if CTS is gone should still run IMHO, just VERY Rich.

V8s often just stop due to knackered parts ie lack of servicing, what cond / age / make is the coil dizzy cap rotor arm and plugs and leads ? a combo of these can often mean it refuses to start and as a result looks as though its overfuelling ?

Have a lookie at the 2x diagnostic manuals I have put in Tech forum

Nige

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Thanks folks for the input. All welcome. Ok update. Removed the fuel pump fuse as suggested also from a mate,

The rangie nearly fires up but then loses the notion, when i put in the fuel pump fuse back in for a fraction of a sec, again, it nearly fires up. It just wont catch. Done this for about ten minutes but it just wouldn't catch.

After noticing that there was some smoke coming out from the engine and the manifolds where quite hot along with the jump leads i decided to stop trying.

Any more thoughts with this new info?

Dizzy cap new. Spark plugs new, HT leads new, coil? dont know but i have a new OEM one ready to fit.

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Thanks folks for the input. All welcome. Ok update. Removed the fuel pump fuse as suggested also from a mate,

The rangie nearly fires up but then loses the notion, when i put in the fuel pump fuse back in for a fraction of a sec, again, it nearly fires up. It just wont catch. Done this for about ten minutes but it just wouldn't catch.

After noticing that there was some smoke coming out from the engine and the manifolds where quite hot along with the jump leads i decided to stop trying.

Any more thoughts with this new info?

Dizzy cap new. Spark plugs new, HT leads new, coil? dont know but i have a new OEM one ready to fit.

1st I would now Check the fuel pressure

2nd Are you sure the timing is correct ?

3rd Check the TPS

Can you just coinfirm flapper or Hotwire ?

Nige

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1st I would now Check the fuel pressure

2nd Are you sure the timing is correct ?

3rd Check the TPS

Can you just coinfirm flapper or Hotwire ?

Nige

Bearing in mind i'm not clued up on how to do these things, nor do i have any special tools. How would i check the fuel pressure?

Not sure the timing is correct.

Think it's hotwire............how can i tell?

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It refers to the airflow meter (the lump between air filter and plenum), inside it will either have a flappy bit or a heated wire to measure the air going past it.

The flappy ones, if you poke the flap with the ignition on the fuel pump should run (this may be handy for your testing). Don't poke the hotwire :P

Fuel pressure regulator could be another culprit - stick an inline filter in the return line (from FPR) and see if fuel is returning to the tank. If it's stuck shut it will be a small or no flow. It should gush past at idle.

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"Another top contender is that your RPV (Fuell Pressure releief valve) er "Isn't"

Check fuel pressure, as if the PRV Jams you can get up to 100+ PSI rather than the 28-34psi you really wnat

Even if CTS is gone should still run IMHO, just VERY Rich."

All of this sounds bang on the money. It was running very rich as there was a build up of black deposit on every spark plug.

So checking the relief valve..................................bit of hose.................connect to where fuel should be carried back to tank. make sure with ignition on that it's returning fuel by putting temp hose in bucket???

Sound ok??

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So checking the relief valve..................................bit of hose.................connect to where fuel should be carried back to tank. make sure with ignition on that it's returning fuel by putting temp hose in bucket???

Sound ok??

That works, although I splice one of these

ff100.jpg

into the return line so you can see the flow without having a bucket of petrol. Remember the return line is the one from the PRV, not the open end of the fuel rail. Fuel pump will only run with ignition on AND the AFM flap poked open a bit (if it's a flappy type), not sure what the hotwire equivalent is.

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1st

Apologies for talking "Jargon" I hate it when people help me and talk at a level that I know is prob helpfull but I don't understand a word :lol:

So,

Lets see if you have a "Flapper" system or a "Hotwire"

Looking at your engine, does it look anything like this :

post-22-1192539324_thumb.jpg

The bits that will help us know and advise are :

1. Look at the Plenum (big lump at the top of the engine :P) on the LHS does yours (as this) have the 9th injector going in to the LHS Top or is this "Not there ?

2. RHS of the Plenum, follow the big black hose to the Air Flow Meter - is you like this ?..ie big lump of silvery metal with a black plastic cap on the top, or is it a smaller and sort of more 'box shaped' with a flat top, sometimes with writting on it ?

3. Does the Plenum have 3.5 or 3.9 on it or maybe (as mine here - nothing)

4. Look at all the hoses in front of the plenum, just off centre and to the slight left is a silvery lump with a hose coming off it and going into the plenum - is this on yours ?

Post up, then we can help, at least them we will know which system you have !

Nige

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Hi, ive been following this thread with interest as I have a similar problem ongoing with my 3.9 with hotwire efi

The symptoms are-starts ok and revs freely with no load,splutters and occasionaly backfires under load.

When the problem first started it would run well for 20-30 mins then play up,now its rough from the off.

When the problem began I was about 100 miles from home but was able to nurse it along by constantly feathering the throttle.

So far I have replaced-plugs,leads,dizzy cap,rotor arm and coil,also borrowed and fitted a known working ecu,also put in a distributer with standard amp on side,(was running with an RPI power amp).

I have tried running it with the coolant temp sender disconected,same with plug to 9th injector.

The fuel returning to the tank sounds plentiful. My brain hurts!

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Ok update. Went down today and started to do the easy stuff i can do. Removed the Throttle position sensor. Removed the air flow meter plug. removed the fuel pump fuse to prevent further fuel getting in. Cranked the engine over a while to get rid of excess fuel. Nothing going on.................

Remembered from the weekend that the rotor arm had some travel on it when we removed the dizzy cap. So...........i took off the dizzy cap again and cleaned the arm. Put it back in and turned it clockwise so it locked in a solid positon.Tried starting again, nothing, put the fuse back in as i was cranking and it roared into life!!!!

So i put all the sensors and stuff back together and let her idle for 15 mins.Now my battery light has come on very faint whilst she is running so i've now been told my altenator is dead :(:(:(

Here she is in all her glory. Canny thank you guys enough for chipping in. Just wish there was more people closer to me.I am thinking it's the hotwire......................

DSC01600.jpg

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Hi, ive been following this thread with interest as I have a similar problem ongoing with my 3.9 with hotwire efi

The symptoms are-starts ok and revs freely with no load,splutters and occasionaly backfires under load.

When the problem first started it would run well for 20-30 mins then play up,now its rough from the off.

When the problem began I was about 100 miles from home but was able to nurse it along by constantly feathering the throttle.

So far I have replaced-plugs,leads,dizzy cap,rotor arm and coil,also borrowed and fitted a known working ecu,also put in a distributer with standard amp on side,(was running with an RPI power amp).

I have tried running it with the coolant temp sender disconected,same with plug to 9th injector.

The fuel returning to the tank sounds plentiful. My brain hurts!

I know what you mean Nick.

The fuel return is actually quite easy if you have the wee bits to do it. I was lucky enough to have a guy who knows a fair bit about these things (self taught) and he described and showed how to check it out.

If your anything like me it's the thought of making something worse rather than better...............................along with wanting to set fire to it :D

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When you turn the rotor arm gently by hand there should be some movement. When released it should return. This indicates the mechanical auto advance/retard mech in the bottom of the dizzy is working - the weights have springs attached.

If your rotor arm doesn't do this then the mech is disengaged & that will be the running problem (or it is rusted solid!). Remove the base plate to examine & reattach. Base plate is held on by the three tall towers that the plastic flash cover screws go into).

When pulling a rotor arm off you MUST press down on the reluctor (the 8-pointed star thing under the rotor) to stop this happening. If you don't it is highly likely to happen. That info is NOT in either the Factory or Haynes manuals. It doesn't show the mech either.

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Never had the plastic cover off thats under the dizzy cap. Do i need to take this off to get to what your talking about?

"Remove the base plate"...............................Don't really know what the base plate is (sorry for being daft)

If i have a full talk through it'll make more sense to me. Remove dizzy cap. Take out the 3 screws that hold the plastic cover in place that protects the points inside................Remove points? base plate??

Many thanks for the reply, but still struggling to understand what i need to do. Think the main problem is with the rotor arm.

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OK, without an exploded diagram this could be tricky - but basically you have the rotor arm, then the plastic cover, then the pickup & reluctor (spiky) wheel - the pickup is mounted to the base-plate, then under the base plate are the bob weights and springs that give you mechanical advance. If you yank the rotor arm off, you can dislodge the springs from the bob weights so they don't spring back, giving you the wrong timing and causing poor running that can change from day to day depending on where the bob weights wobble in their unsprung state.

This isn't quite it but it gives you an idea:

ld44a.gif

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Ahh ha!!

Talk that i can understand.

Ok got ya now. So it is just a case of removing it all one by one carefully, so will i notice that the bob weights are clearly out of position?

Fingers crossed.

Many thanks again for taking the time to reply.

DC

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The rotor arm can often "Bond" itself quite well the the shaft, as Fridge says many people get hold of the arm and then pull "Up" and have to tug it to get it off, the result is internally the bob weights come off.

The ONLY safe way to remove an arm is to have a screwdriver (flat type) pushing down on the edge of the shaft( there is a handy "Step" just below the arm on the shaft where the screwdriver can lock into and push down as hard as or harder down than you are pulling.

Back to your prob maybe ?

Remove Dizzy cap.

When you "Twist" the arm you should find the tip of the rotor moves say 10-15mm and then springs back, if it is either solid, or "Flops" about with little or no resistance then you may have pulled the bobs off.

It can be a right piggy getting them back on, but if you remove the dizzy from the engine - don't even THINK of doing this with it in the engine :lol: and have a clean work area as there are lots of small deliacte bits for you to lose put safely on one side :P

The "Base Plate" is the big silver steel plate under the main dizzy gubbins, this has 3 screws (??) on it and when this comes up you'll see with a torch and a squint if all is not right, you then just need some long nose pliers and a trainedd spider with long legs and a bucket of patience to get them all back in place, not difficulat just tricky :)

If you take the dizzy apart take a good look as to what goes where and just go slowly

But 1st check if the rotor arm has resistance and a bit of spring when you twist it.....

Nige

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It does have slight resistance, but when i turn it clockwise, it clicks into a good solid positon, if i leave it to return it's kind of floppy and not too secure. When i took the cap off, i turned it clockwise for it to click into a good positon and the engine started. Not sure if it was in the "floppy" position before..........

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Er :huh: Doesn't exactly sound right :lol:

With the dizzy cap off and twisting the clockwise there should be "resistance" and a sound I can't describe :lol: but its like your moving gearing sort of nouise, the arm should spring back not be floppy, theres nothing for it to "Click Into" as such, that does sort of worry me :huh:

Maybe you are going to have to have a poke inside it - theres little more you can do to be sure other than the twisty test :(

nige

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When i have time what i'll do is take a pic of the rotor arm sitting at one position then turn it and take a pic of the other position.

There is defo a bit of resistance. Maybe i'm just not describing it properly.

When you let go of the arm it automatically goes back to it own position, but if i turn it it will sort of lock into another position...................................make sense?

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When you let go of the arm it automatically goes back to it own position, but if i turn it it will sort of lock into another position...................................make sense?

Whatever it's doing, it doesn't sound entirely right. It's possible one spring has popped off (this happened to dad's) which gives a bit of spring and a bit of sticking and rather hit-and-miss running.

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Well this is my priority then when i get time at the weekend.

If it fixes my running problems then i'll be a happy chappy.

P.S. looks like alot of soot type stuff came out the back end when i had it running last night. I did give it a good rev and it sounded rough. The soot is on the road. So would this suggest the rich mixture?

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