Misfire after rotor change

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rkl786
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1991 230ge 463 model with lpg system installed.

A few days ago I replaced the distributer rotor, unfortenly after that my Gwagen now started misfiring.

I can turn the gwagen on and have it idle, but if I put a little bit of gas the rpms fall 5 and the gwagen starts to act as if it is cutting out. If i floor the pedal then it would act normaly and then misfire once it hits 15-20 rpm. 

This only happend after I changed the rotor, I went and put back its old rotor but the issue is still the same. I replaced the distributer cap, ignition cables, and spark plugs today since they were due to be relaced either way, but my gwagen is still misfiring.

Did I place the rotor wrong? Just take off the cap, pull the rotor and put the new rotor on correct? Any adjustments needed?

Thanks

g wagon g
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Re: Misfire after rotor change

Hi Does it start up perfectly smooth and tick over fine???


Yes there are different rotor arms but if it starts perfect and all the rest is new i would doubt thats the problem


I would think you have left a vacuum pipe off or some breather hose disconnected. I would think something has been disturbed if all the leads and stuff fitted fine

Let me know and i will give some more easy suggestions but start here first. Why did you replace the rotor arm in the first place???. I am assuming the vehicle was running ok to start with and it was just the rotor looked bad????

Pistonhead
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Re: Misfire after rotor change

I can not see much that could have gone wrong to cause a misfire.

Generally more information is required.

If as you say it idles fine; is that on LPG or Conventional fuel. Does the fault occur on either fuel consumption?

Changing the rotor requires only to lift the cap and re-fit after; is the cap sitting properly on its seat, there is only one proper fitting for this. Has the vacuum pipe been disturbed from the vacuum unit on the distributor - this should not have the drastic effect you describe.

Questions to ponder on:-

1) Has the distributor been moved? I.E. is the ignition timing correct?

2) Have any of the wires on the ignition coil been disturbed?

3) A very remote likely hood but is the distributor noisy? If so it could have broken an internal spring. Checking timing under different engine speeds could help identify any mechanical advance issues.

4) I can not remember the inside of the 230GE distributor as these were rare to work on in the UK but check to see if the chopper (the bit which replaces contact breaker) in the distributor is firmly fixed on the rotor shaft.

Generally need more information from you.

rkl786
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Re: Misfire after rotor change

sorry for the delay. Unfortenly I don't have any lpg in my tank to try it out.

So far I changed the ignition coil with a spare I had, but this didn't do anything.

The distributor was moved but this also didn't have any affect.

Right now the idle is quite low as once it turns on it will idle at just  a little bit over the 5 rpm mark. Any attempt at pressing the gas pedal shuts the car off. Could it be a faulty distributor?

Pistonhead
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Re: Misfire after rotor change

At the moment the would suspect the fuel pump relay. Distributor fault are highly unlikely but not impossible. That is if there are no other issues with false air leaking into the induction system.

rkl786
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Re: Misfire after rotor change
Tried another fuel pump relay, no change. Currently the gwagen doesn't want to turn on anymore. I will double check the vacuum pipes.
Arnie
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Re: Misfire after rotor change

check that the fuel-pump is actually running. you should hear it for about 3 secs after turning ignition key to position II.


There is a cam-shaft sensor, which the fuel-pump relay uses to keep the engine running. It cuts off the fuel when engine is not running. This is also used to time the ignition, so this may be the problem. It's located at the rear of the cylinder head.

Pistonhead
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Re: Misfire after rotor change

I am very sorry; I have seriously blundered here. 

I wrongly assumed your car was a W460 ( I have a bad tendency NOT to properly read). I now learn it is a W463. These were not a UK import so my knowledge is not up to scratch here at all. You have indicated that the distributor has been moved, so I wonder if it is still the same engine as in the W460 - 230GE.

To save me research work what is the engine code you have?

Arnie is very clued up so he could be correct in saying there is a camshaft sensor fitted.

If the engine is not turning at all now; put the battery on a trickle charge to bring the battery power as I suspect it is the battery that is flat if not then failure could be starter or engine. Turn engine by hand to rule the latter out.

g wagon g
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Re: Misfire after rotor change

This will be something simple


Firstly get someone to wind the engine over with a spark plug in the lead resting on something metal and see if it is sparking


Secondly and be very careful either set a fuel pressure gauge in the pressure feed line for the fuel


You will turn the key on and hear pump for a few seconds as people have said and fuel pressure should be around 40 psi


If there is no fuel pressure or very little crank engine and see if its still the same


You will tell if its is the ignition or fuel circuit with these simple tests


You never said why you changed the rotor arm????? or i missed that bit. Was there a problem before you changed over parts


So if it sparks ok connect some jumper wires to fuel pump and dont get any sparks etc and have a fire extinguisher ready if you dont know what is what. Or get a circuit tester on fuel pump to see if its getting a 12volt feed when required

A gauge for fuel pressure will tell you if all is ok. It will run on 18psi so anything more is good
You should hear pump if you have your ear close to it while someone turns ignition on

.
Connect feed to fuel pump briefly and see if it runs ok or not at all. If it runs fine look for wiring issues


If it does not run get back to us all and we will help

rkl786
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Re: Misfire after rotor change

Pistonhead wrote:

I am very sorry; I have seriously blundered here. 

I wrongly assumed your car was a W460 ( I have a bad tendency NOT to properly read). I now learn it is a W463. These were not a UK import so my knowledge is not up to scratch here at all. You have indicated that the distributor has been moved, so I wonder if it is still the same engine as in the W460 - 230GE.

To save me research work what is the engine code you have?

Arnie is very clued up so he could be correct in saying there is a camshaft sensor fitted.

If the engine is not turning at all now; put the battery on a trickle charge to bring the battery power as I suspect it is the battery that is flat if not then failure could be starter or engine. Turn engine by hand to rule the latter out.

 

Sorry for the delay, had some time these two day and went and worked on the Gwagen. The engine code is 102.989, yes the battery was just flat.

 

 

 

rkl786
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Re: Misfire after rotor change

g wagon g wrote:

This will be something simple


Firstly get someone to wind the engine over with a spark plug in the lead resting on something metal and see if it is sparking


Secondly and be very careful either set a fuel pressure gauge in the pressure feed line for the fuel


You will turn the key on and hear pump for a few seconds as people have said and fuel pressure should be around 40 psi


If there is no fuel pressure or very little crank engine and see if its still the same


You will tell if its is the ignition or fuel circuit with these simple tests


You never said why you changed the rotor arm????? or i missed that bit. Was there a problem before you changed over parts


So if it sparks ok connect some jumper wires to fuel pump and dont get any sparks etc and have a fire extinguisher ready if you dont know what is what. Or get a circuit tester on fuel pump to see if its getting a 12volt feed when required

A gauge for fuel pressure will tell you if all is ok. It will run on 18psi so anything more is good
You should hear pump if you have your ear close to it while someone turns ignition on

.
Connect feed to fuel pump briefly and see if it runs ok or not at all. If it runs fine look for wiring issues


If it does not run get back to us all and we will help

I agree, I feel as though its something very simple. The rotor was changed due to inspecting the cap for another problem. I notice the old rotor had quite a bit of wear on it and figured it could use replacing. I check both fuel pumps and they are working. Someone else told me that I may have moved the rotor and it may be out of sync and its not hitting the spark plugs  when it suppose to.