MAF - Running issues?
Discussion
Pass the Valium!
Ok, as said last visit, I have changed a load of bits, still misfiring, read the comments here and go to the garage to carry out the manifold heat checks as advised.
Now the car cranks, a good speed as always, but wont start. Fuel pump priming so checked for spark.
No spark at No1 plug, so pull coil lead from distributer cap, no spark here either!
Could this be the final straw.
Cheers
Frank
Had a coffee, and went back to the garage, no spark from distributer end of coil HT lead, check and 12v at coil with ignition on, so not ignition module?
Disconnected battery and changed the coil back to the old one, and it started! knackered new coil or ECU re set?
Anyway, idling nicely, doesn't seem to be missing at idle, went for a rev and hey presto, it revs cleanly!
Let it idle up to temperature, rev it, cough splutter, cut out, never done that before.
Re start, idles ok, connected rovergauge just in case, and now revs cleanly again. let it idle and a few revs every now and again, all seems good, fan cutting in and out ok, rover gauge now showing -100% on both lambdas, that's also new.
Read in Marks post about sticking bob weights, disconnected the vac pipe distributer to plenum no difference at idle, now for my next question. the vac pipe in question has a one-way valve, as I understand it, the plenum provides negative pressure when revving (vacuum) and this helps advance the timing, by "sucking" through the pipe. now if I blow down this pipe from the plenum end, it blows towards distributer, but not the other way round, although possibly not part of the problem, is this the wrong way round?
On idle or when revving the engine (no load) I can not feel any suction at distributer end of pipe.
Getting close to meltdown, I mean pub time!
Cheers
Frank
Ok, as said last visit, I have changed a load of bits, still misfiring, read the comments here and go to the garage to carry out the manifold heat checks as advised.
Now the car cranks, a good speed as always, but wont start. Fuel pump priming so checked for spark.
No spark at No1 plug, so pull coil lead from distributer cap, no spark here either!
Could this be the final straw.
Cheers
Frank
Had a coffee, and went back to the garage, no spark from distributer end of coil HT lead, check and 12v at coil with ignition on, so not ignition module?
Disconnected battery and changed the coil back to the old one, and it started! knackered new coil or ECU re set?
Anyway, idling nicely, doesn't seem to be missing at idle, went for a rev and hey presto, it revs cleanly!
Let it idle up to temperature, rev it, cough splutter, cut out, never done that before.
Re start, idles ok, connected rovergauge just in case, and now revs cleanly again. let it idle and a few revs every now and again, all seems good, fan cutting in and out ok, rover gauge now showing -100% on both lambdas, that's also new.
Read in Marks post about sticking bob weights, disconnected the vac pipe distributer to plenum no difference at idle, now for my next question. the vac pipe in question has a one-way valve, as I understand it, the plenum provides negative pressure when revving (vacuum) and this helps advance the timing, by "sucking" through the pipe. now if I blow down this pipe from the plenum end, it blows towards distributer, but not the other way round, although possibly not part of the problem, is this the wrong way round?
On idle or when revving the engine (no load) I can not feel any suction at distributer end of pipe.
Getting close to meltdown, I mean pub time!
Cheers
Frank
Edited by Franky boy on Sunday 3rd September 15:13
You can remove the vac pipe at the plenum end and suck on it and you will see the timing plate move that holds the trigger head with the dizzy cap removed if all's well - blowing is not the correct way of going about it as the pressure is always below atmosphere ie negative. You should not need any one ways valves. If you unplug the distributor end, you should feel a strong suck at idle, but the engine may die due to the extra air getting in. To test the bob weights, a simple strobe test will tell you if they are working, as you will see the timing advance as you rev the engine. Mind you wrong timing or lack of vacuum advance will not actually cause a misfire- just a loss of power or MPG.
As for coils- they have to be a very low resistance high power type to cope with firing 4 cylinders per revolution and the short dwell period, and if a different type (ie one for a 4 cylinder) is fitted it wont have the power needed and the spark will die as the RPM rises- just a thought.
Ive done a bit about testing the basic HT here:
http://www.g33.co.uk/pages/technical_ignition_syst...
As for coils- they have to be a very low resistance high power type to cope with firing 4 cylinders per revolution and the short dwell period, and if a different type (ie one for a 4 cylinder) is fitted it wont have the power needed and the spark will die as the RPM rises- just a thought.
Ive done a bit about testing the basic HT here:
http://www.g33.co.uk/pages/technical_ignition_syst...
Edited by blitzracing on Monday 4th September 12:48
Edited by blitzracing on Monday 4th September 13:27
Thanks for the help, borrowed a temp gun and located a loose plug lead.
I've now changed or checked so many things I can't actually remember the order but the car started to behave itself and start running OK, drove to a wedding with the gf on sat, parked up, Sunday morning different story.
Now the car will not start at all, the AA membership is certainly paying for itself.
The current situation is, live at coil, but no spark, live at injectors but not switching/firing. Cranking over healthily.
The AA chap thinks it could be a distributer based problem.
I'm not having much luck with the car at the moment!
Your thoughts and comments welcomed.
Cheers
Frank
I've now changed or checked so many things I can't actually remember the order but the car started to behave itself and start running OK, drove to a wedding with the gf on sat, parked up, Sunday morning different story.
Now the car will not start at all, the AA membership is certainly paying for itself.
The current situation is, live at coil, but no spark, live at injectors but not switching/firing. Cranking over healthily.
The AA chap thinks it could be a distributer based problem.
I'm not having much luck with the car at the moment!
Your thoughts and comments welcomed.
Cheers
Frank
I have a distributor that never let me down for 34,000 miles, so I thanked it by changing to coil packs.
What I am not sure is if I still have the rotor arm, ignition amplifier and cap, as i loaned a bag full of bits to a fellow owner with similar issues to you, and he bought a few bits off me when he worked out his issue, and gave me the rest of the bag back. I can have a look later on today when I am home again.
If it would help I can send you my bag of bits to try (assuming you know how to change a distributor and get the position of the new one right). I also have a couple of coils, etc I can include, and a set or two of plug leads.
What I am not sure is if I still have the rotor arm, ignition amplifier and cap, as i loaned a bag full of bits to a fellow owner with similar issues to you, and he bought a few bits off me when he worked out his issue, and gave me the rest of the bag back. I can have a look later on today when I am home again.
If it would help I can send you my bag of bits to try (assuming you know how to change a distributor and get the position of the new one right). I also have a couple of coils, etc I can include, and a set or two of plug leads.
It could be the ignition amplifier or the connection to it then. Its bolted to the side of the distributor, and it amplifies the tiny signal you get from the trigger head inside the dizzy to a level it can be used to switch the coil. They cost about £20, although the original Lucas ones are hard to source now, and the pattern ones are not that reliable. Im sure you will find plenty on ebay- they are also used on the Mini metro. Just check if yours has a two or three pin connector on it.
Hi, thanks for the info.
Does the distributor/ignition module control the switching of the injectors, the AA guy used a tester and told me that they weren't switching but had power.
Having spent so long trying, without success, to get the car running nicely, would now be the time to say enoughs enough and go aftermarket ECU?
I have been looking at Megasquirt, I see there are a few places that provide a complete kit, I am more than capable of installing one. Would it make the car nicer to drive and more reliable? I am happy to spend the cash if it is beneficial and doesn't de-value the car.
Just a thought.
Cheers
Frank
Does the distributor/ignition module control the switching of the injectors, the AA guy used a tester and told me that they weren't switching but had power.
Having spent so long trying, without success, to get the car running nicely, would now be the time to say enoughs enough and go aftermarket ECU?
I have been looking at Megasquirt, I see there are a few places that provide a complete kit, I am more than capable of installing one. Would it make the car nicer to drive and more reliable? I am happy to spend the cash if it is beneficial and doesn't de-value the car.
Just a thought.
Cheers
Frank
Although the lucus system isnt that bad when its working i think id rather spend the money and go aftermarket. The problem is these cars were wired poorly from the factory so that does not help.
There are various systems on the market but the megasquirt seems very good value to me and easy to diy install.
I can only see it being a positive step on the cars value etc, a lot of people look for the sensible mods.
http://www.extraefi.co.uk/products/RV8_kits.html
We holiday in cornwall every october half term so if you were still struggling i could bring down my ignition bits including dizzy and ecu if it helps.
Blitzracings G33 site has some good 14cux manuals with in depth test procedures that may help.
I seems to remember one of the 2 relays flapping around in the footwell that play up is responsible for injector functions too.
There are various systems on the market but the megasquirt seems very good value to me and easy to diy install.
I can only see it being a positive step on the cars value etc, a lot of people look for the sensible mods.
http://www.extraefi.co.uk/products/RV8_kits.html
We holiday in cornwall every october half term so if you were still struggling i could bring down my ignition bits including dizzy and ecu if it helps.
Blitzracings G33 site has some good 14cux manuals with in depth test procedures that may help.
I seems to remember one of the 2 relays flapping around in the footwell that play up is responsible for injector functions too.
Edited by Belle427 on Monday 11th September 20:28
Hi, thanks for the offer, if I'm still in the same situation I might take you up on it, although think that megasaquirt might be the best option.
ExtraEFI is the company I saw the kit from, need to find out if it has a base map included and how/what to do with the distributor as I'm pre serp and I understand this runs the oil pump.
Will call them tomorrow
ExtraEFI is the company I saw the kit from, need to find out if it has a base map included and how/what to do with the distributor as I'm pre serp and I understand this runs the oil pump.
Will call them tomorrow
Franky boy said:
Hi, thanks for the info.
Does the distributor/ignition module control the switching of the injectors, the AA guy used a tester and told me that they weren't switching but had power.
Having spent so long trying, without success, to get the car running nicely, would now be the time to say enoughs enough and go aftermarket ECU?
I have been looking at Megasquirt, I see there are a few places that provide a complete kit, I am more than capable of installing one. Would it make the car nicer to drive and more reliable? I am happy to spend the cash if it is beneficial and doesn't de-value the car.
Just a thought.
Cheers
Frank
yes is the answer to that- the pulse from the coil is used for the RPM reading on RoverGauge, and it controls the injectors pluses and the fuel pump. So if you have lost the amp, rovergauge will show no RPM, and the fuel pump light will be red when you crank the engine. You should find the fule pump runs for a second or two when you turn on the ignition, and then it will stop. It will only restart when the engine is turning and the ECU gets the ignition pulse, so dont confuse the initial pump "on" from just the ignition on, cranking pump on state.Does the distributor/ignition module control the switching of the injectors, the AA guy used a tester and told me that they weren't switching but had power.
Having spent so long trying, without success, to get the car running nicely, would now be the time to say enoughs enough and go aftermarket ECU?
I have been looking at Megasquirt, I see there are a few places that provide a complete kit, I am more than capable of installing one. Would it make the car nicer to drive and more reliable? I am happy to spend the cash if it is beneficial and doesn't de-value the car.
Just a thought.
Cheers
Frank
Hi Mark,thanks for the info.
Am I right to assume that there will still be live leaving the amp going to tacho feed/ ecu even if amp is stuffed.
Have tried starting with fuel pump permantly on using RG made no difference.
Would a multi meter pick up pulses if amp ok?
Which ever way I go it would be good to get to the bottom of it and besides, what an education, learning loads.
Cheers
Frank
Am I right to assume that there will still be live leaving the amp going to tacho feed/ ecu even if amp is stuffed.
Have tried starting with fuel pump permantly on using RG made no difference.
Would a multi meter pick up pulses if amp ok?
Which ever way I go it would be good to get to the bottom of it and besides, what an education, learning loads.
Cheers
Frank
The coil has a 12 volt feed on one side on the +. The amp connects to the negative side, and normally grounds the terminal to make current flow in the coil as the engine rotate. When the rotor passes the trigger head, it disconnects the coil from ground, and this generates the spark as the coil discharges. - this is the same as a set of points. The ECU picks up the switched signal from the -ve side of the coil as a signal to say the engine is rotating, so no amp signal, no rev counter, and no fuel pump after the initial turn on pulse the pump gets.
Edited by blitzracing on Wednesday 13th September 16:32
The heat does get to them, there was a topic started a few weeks ago with hot start issues and they relocated the amp away from the dizzy
It may be worth doing the same if your confident enough, i think there is a relocation kit available too but am unsure if its the one below or not.
http://www.simonbbc.com/ignition_modules_and_spare...
It may be worth doing the same if your confident enough, i think there is a relocation kit available too but am unsure if its the one below or not.
http://www.simonbbc.com/ignition_modules_and_spare...
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