S1 misfire under load
Discussion
helllppp!!!
my s1 has developed
-a bad misfire when I try anything more than gentle acceleration.
-a reluctance to fire when cold starting.
this has occurred since resetting the valve clearances
then immediately running out of fuel on my way to fill up.(d'oh)
pump sounds a little slower than before.
air hose has just been replaced (probably running with air leak before I bought car)
spark plugs are new old ones were sooty
dizzy, cap and ht leads 6 months old
any suggestions?
my s1 has developed
-a bad misfire when I try anything more than gentle acceleration.
-a reluctance to fire when cold starting.
this has occurred since resetting the valve clearances
then immediately running out of fuel on my way to fill up.(d'oh)
pump sounds a little slower than before.
air hose has just been replaced (probably running with air leak before I bought car)
spark plugs are new old ones were sooty
dizzy, cap and ht leads 6 months old
any suggestions?
hang on - one thing at a time, I might be simple but I need to get this straight.
1. The car was running fine before?
2. Then you reset the valve clearances?
3. Did you change the spark plugs at the same time or was that before or after it started running rough?
4. Did you fix the air hose at the same time as the valve clearances? (I take it you mean the corrugated hose between the air flow meters and the throttle body?)
5. What colour are the spark plugs now? Are they all the same?
6. (Silly Q but it happens to us ALL) are you absolutely absolutely sure that the spark plug leads were put back in the right order?
1. The car was running fine before?
2. Then you reset the valve clearances?
3. Did you change the spark plugs at the same time or was that before or after it started running rough?
4. Did you fix the air hose at the same time as the valve clearances? (I take it you mean the corrugated hose between the air flow meters and the throttle body?)
5. What colour are the spark plugs now? Are they all the same?
6. (Silly Q but it happens to us ALL) are you absolutely absolutely sure that the spark plug leads were put back in the right order?
haggishead said: hang on - one thing at a time, I might be simple but I need to get this straight.
1. The car was running fine before?
2. Then you reset the valve clearances?
3. Did you change the spark plugs at the same time or was that before or after it started running rough?
4. Did you fix the air hose at the same time as the valve clearances? (I take it you mean the corrugated hose between the air flow meters and the throttle body?)
5. What colour are the spark plugs now? Are they all the same?
6. (Silly Q but it happens to us ALL) are you absolutely absolutely sure that the spark plug leads were put back in the right order?
haggishead, thanks for your time
1 basically yes, occasionally off colour
2 yes, barely needed adjusting
3 no, changed them later
4 no, noticed hose afterwards, (yes, the corrugated air hose)made at ford's emmenthal factory
5 I'll have to check in the morning
6 yes, twice, old set and new, no difference
idling and gentle acceleration feel normal
since last post I have noticed the misfire occasionally improves, with that familiar surge, then it's back
It is possible that when you ran out of fuel a whole load of dregs from the tank got sucked into the system and caused a blockage, hopefully just in the filter. If dregs have found their way further into the system, then it's more complicated.
Try replacing the filter. This happened to me with a Ford 2.8 and a new filter fixed the problem.
Nothing lost by replacing the filter as a precaution, as you are supposed to do this as part of the service schedule anyway. The TVR filter is the same as the Ford one.
Try replacing the filter. This happened to me with a Ford 2.8 and a new filter fixed the problem.
Nothing lost by replacing the filter as a precaution, as you are supposed to do this as part of the service schedule anyway. The TVR filter is the same as the Ford one.
It's starting to look like dregs in the fuel system.
I had Mr engine tuner round today. He said ignition is ok, tweaked mixture, left timing as it is ok, but the fuel pressure is up and down like a bored pensioner with a new stair lift.
It is swinging between 50psi with smooth idle which is in spec., to 70 psi with rough idle, about 15psi too high. I suspect it has gone higher as it has started to push up the top of the new fuel filter(close eye being kept there!)
Mixed result because, although I didn't get charged, I didn't get fixed either. The man's best advise was get some really strong injector cleaner in your tank, and look out for a scrap capri for a warm-up regulator and air flow meter.
Any other suggestions?!
I had Mr engine tuner round today. He said ignition is ok, tweaked mixture, left timing as it is ok, but the fuel pressure is up and down like a bored pensioner with a new stair lift.
It is swinging between 50psi with smooth idle which is in spec., to 70 psi with rough idle, about 15psi too high. I suspect it has gone higher as it has started to push up the top of the new fuel filter(close eye being kept there!)
Mixed result because, although I didn't get charged, I didn't get fixed either. The man's best advise was get some really strong injector cleaner in your tank, and look out for a scrap capri for a warm-up regulator and air flow meter.
Any other suggestions?!
maxd said: There’s also a fuel filter in the tanks sump. If you remove the cover its in there. Obviously the tank needs to empty to do this.
does this mean the filter can be removed for cleaning from underneath the car?
that is to say , is this cover external on the swirl pot or inside the tank
I'm expecting to spend Sunday under the back end of the car 'shaking' bits out of the pump etc
>> Edited by Ali B on Friday 6th June 20:13
The pressure on the fuel injection rail is set by the Fuel Pressure Regulator. I'm assuming that the rail is where they took the pressure readings from. Maybe this has some crud in it and is causing the pressure variance. Also a blocked fuel return line could do it, but it's a little less likely. Try removing the regulator and blowing it through with some carb cleaner.
Andy
Andy
current symptoms...
replaced warm up reg with s/h capri unit and the car behaves like the pressure has stabilised (hasn't been measured but-) tickover is now stable rather than cycling 500-900 rpm and noticeably smoother.. progess is being made! checked cold start injector and wiring all working perfectly
but
still have misfire, even after 3 tanks worth of redex injector cleaner although I now get more acceleration before it kicks in.
warm starts are fine.
cold starts first time then usually dies.
may take 2-5 attempts to persuade it to stay started!
slow gentle application of throttle gives 4000+ rpm before slight faltering misfire is apparent
sudden throttle movement at any speed induces spitting kangarooing embarrassment so I avoid it.
misfire cannot be driven through..once misfiring further throttle just makes it worse and no extra pwer develops. rpm may increase but number of cylinders firing seems to decrease. I aviod this too!
current plan of attack
start at tank
-clean swirl filter (if I can work out how to remove it)
-clean pump internals
-accumulator too
-check main fuel line for blockages
-check if new filter is now blocked
-take banjos off fuel distributor and spray carb cleaner down the holes.
am I barking up the wrong tree here (am I just barking)
thanks for all the input so far. hope for more of the same as I'm driving around with a diminished grin. not an absent grin, it is an S after all!
replaced warm up reg with s/h capri unit and the car behaves like the pressure has stabilised (hasn't been measured but-) tickover is now stable rather than cycling 500-900 rpm and noticeably smoother.. progess is being made! checked cold start injector and wiring all working perfectly
but
still have misfire, even after 3 tanks worth of redex injector cleaner although I now get more acceleration before it kicks in.
warm starts are fine.
cold starts first time then usually dies.
may take 2-5 attempts to persuade it to stay started!
slow gentle application of throttle gives 4000+ rpm before slight faltering misfire is apparent
sudden throttle movement at any speed induces spitting kangarooing embarrassment so I avoid it.
misfire cannot be driven through..once misfiring further throttle just makes it worse and no extra pwer develops. rpm may increase but number of cylinders firing seems to decrease. I aviod this too!
current plan of attack
start at tank
-clean swirl filter (if I can work out how to remove it)
-clean pump internals
-accumulator too
-check main fuel line for blockages
-check if new filter is now blocked
-take banjos off fuel distributor and spray carb cleaner down the holes.
am I barking up the wrong tree here (am I just barking)
thanks for all the input so far. hope for more of the same as I'm driving around with a diminished grin. not an absent grin, it is an S after all!
Ali B
I know you're thinking of fuel delivery being the problem, but I'm not sure you've not cured any pressure regulation or dirt in the system problems you might have had following your tank-emptying.
I'm no mechanic, and might easily be wrong, but I was always 'brought up', as it were, with the assumption that if you have a misfire under load but otherwise OK, first suspect the HT system (plugs, leads, dizzy etc). Just because a mobile mechanic says it's OK doesn't guarantee it - been there, done that, done the head scratching.
It need only be a tiny fault for it to fail, it being under such a load. I once had a Dagenham Dustbin which misbehaved so persistently my local garage had to resort to spraying water over the HT system in the dark to find the arcing. A bit drastic perhaps, but found an otherwise tiny fault with a new HT lead - might equally apply to the plugs, unlikely, but it does happen.
Have you had a good look at the dizzy cap too? Again, a tiny fault is all that's needed, so look closely. If you chose to replace it, do the rotor arm at the same time, even if it looks OK. Not a lot of dosh for either.
Your "sudden throttle movement at any speed induces spitting kangarooing" might easily be the potentiometer and could, I suppose, contribute to your cold starting problems. But there should be a temp sensor for the injection system (separate from the cooling system I think) which regulates fuel enrichment during warm up and this, or it's connection, could be at fault. My guess is this screwed into the block, looks a bit like an oil pressure sensor and the wiring goes to the ECU. Replacement is the only real way of checking this, and that's only for the cold start. Make sure you get the right one though!
But I keep thinking that this happened after you adjusted the valve clearances and so I would think they're worth checking again, if only to eliminate something unusual, and what haggishead said about the leads being back in the right order. Sorry, not being rude, but it's easy to do - in fact I'm the bloke who once grabbed a HT lead of a very old Viva with a wet hand. Yes, while it was running. eek! No, I haven't done it since.
If all this sounds like complete tosh, sorry for wasting your time but I'm doing it from memory and assuming it's mostly similar to a S2.
But good luck with it.
I know you're thinking of fuel delivery being the problem, but I'm not sure you've not cured any pressure regulation or dirt in the system problems you might have had following your tank-emptying.
I'm no mechanic, and might easily be wrong, but I was always 'brought up', as it were, with the assumption that if you have a misfire under load but otherwise OK, first suspect the HT system (plugs, leads, dizzy etc). Just because a mobile mechanic says it's OK doesn't guarantee it - been there, done that, done the head scratching.
It need only be a tiny fault for it to fail, it being under such a load. I once had a Dagenham Dustbin which misbehaved so persistently my local garage had to resort to spraying water over the HT system in the dark to find the arcing. A bit drastic perhaps, but found an otherwise tiny fault with a new HT lead - might equally apply to the plugs, unlikely, but it does happen. Have you had a good look at the dizzy cap too? Again, a tiny fault is all that's needed, so look closely. If you chose to replace it, do the rotor arm at the same time, even if it looks OK. Not a lot of dosh for either.
Your "sudden throttle movement at any speed induces spitting kangarooing" might easily be the potentiometer and could, I suppose, contribute to your cold starting problems. But there should be a temp sensor for the injection system (separate from the cooling system I think) which regulates fuel enrichment during warm up and this, or it's connection, could be at fault. My guess is this screwed into the block, looks a bit like an oil pressure sensor and the wiring goes to the ECU. Replacement is the only real way of checking this, and that's only for the cold start. Make sure you get the right one though!
But I keep thinking that this happened after you adjusted the valve clearances and so I would think they're worth checking again, if only to eliminate something unusual, and what haggishead said about the leads being back in the right order. Sorry, not being rude, but it's easy to do - in fact I'm the bloke who once grabbed a HT lead of a very old Viva with a wet hand. Yes, while it was running. eek! No, I haven't done it since.
If all this sounds like complete tosh, sorry for wasting your time but I'm doing it from memory and assuming it's mostly similar to a S2.
But good luck with it.
i know its not the throttle pot as there isn't one on the 2.8
plugs are new but didn't make any difference
leads, dizzy, dizzy cap and coil only a few months old and problem is the same with the old leads anyway.
i think an ht breakdown would show up on the sillyscope trace.
however your advice is sound. I rechecked the valve clearances last weekend and found them wanting, so I shall recheck the electricals to be certain.
plugs are new but didn't make any difference
leads, dizzy, dizzy cap and coil only a few months old and problem is the same with the old leads anyway.
i think an ht breakdown would show up on the sillyscope trace.
however your advice is sound. I rechecked the valve clearances last weekend and found them wanting, so I shall recheck the electricals to be certain.
weekend update filter in tank swirl pot is as clean as a whistle. I was expecting gunge and bits. found about thirteen flakes of metal and two stainless pins.. optional extra?
also, to be certain about the ht side
have also change distributor cap (halfords hdc567 )and ht leads motorcraft ewr9 (ewr9 5 030 306) for 2.9 engine also fit my 2.8 (standard leads are ewr12)
still not found the cause of the misfire
Prior to the nisfire have you had any water running down the windscreen. A design weakness in the S1 results in water runnining of the windscreen will go staight to the coil and electrics and will cause misfire esecially ove 3k revs. I is not omly caused by heavy rain buy washinig the winscreen liberally.
One sign of this will be the Tacho suddenly dropping back to zero when you get to 3k rpm and nisfire will begin.
Wd40 will immediately cure this and for long term waterproofing to redirect the water flow from the windscreen to avoid the coil. I stuck on draught proofing strip.
This only applies to the S1 and is mentioned in the bible(a must)
best of luck
Bill
One sign of this will be the Tacho suddenly dropping back to zero when you get to 3k rpm and nisfire will begin.
Wd40 will immediately cure this and for long term waterproofing to redirect the water flow from the windscreen to avoid the coil. I stuck on draught proofing strip.
This only applies to the S1 and is mentioned in the bible(a must)
best of luck
Bill
I had a similar misfire with mine. Did all the same checks and eventually starting pulling the wiring loom apart. Discovered that the connectors to the ballast resistor had that powdery white non-conductive finish.
Replaced them and suddenly all was well.
(The ballast resistor looks like a coil of 6mm thick blue wire either on the n/s wheel arch or taped to the chassis under the rad depending on age)
Replaced them and suddenly all was well.
(The ballast resistor looks like a coil of 6mm thick blue wire either on the n/s wheel arch or taped to the chassis under the rad depending on age)
I think I have located the ballast resistor
Is it called cold start resistor on the cicuit diagram p304 of bible?
it is light gray, 5mm diameter, folded flat and taped into loom on n/s near ignition module and exhaust.
insulation seems to have melted at some time but it is not shorting out.
it only measures 1.5 ohm.
voltage between coil +ve wire and earth is 11.67v, battery is 11.81v. (0v if resistor is removed)
between coil -ve wire and earth is 0.64v
according to the ford 2.8 injection(capri)workshop manual I should be seeing "8 volts compared with the usual 7 volts"
I cannot find any mention of ballast resistor or cold start resistor in haynes book of lies for capri or sierra, or even the bible.
What voltages should I expect?
Are there any 'consequences' to the voltages I have?
Is this causing my bl@@dy misfire?
Is it called cold start resistor on the cicuit diagram p304 of bible?
it is light gray, 5mm diameter, folded flat and taped into loom on n/s near ignition module and exhaust.
insulation seems to have melted at some time but it is not shorting out.
it only measures 1.5 ohm.
voltage between coil +ve wire and earth is 11.67v, battery is 11.81v. (0v if resistor is removed)
between coil -ve wire and earth is 0.64v
according to the ford 2.8 injection(capri)workshop manual I should be seeing "8 volts compared with the usual 7 volts"
I cannot find any mention of ballast resistor or cold start resistor in haynes book of lies for capri or sierra, or even the bible.
What voltages should I expect?
Are there any 'consequences' to the voltages I have?
Is this causing my bl@@dy misfire?
Sounds like the right part. Mine measures 1.3 ohms. Make sure the connections (bullets?) are good and clean.
Dont bother about the voltage readings, the reading depends on your meter (analogue/digital)and RPM. The higher the RPM the more power dissipated by the resistor and the more likely a misfire if connections are not perfect.
Cold start is always OK because the resistor is shorted out by the starter solenoid.
ps: Dont pay too much attention to the colours on the ignition wiring diagram... mine must have been made up by a colour blind
and that cost me a new ignition module.
Dont bother about the voltage readings, the reading depends on your meter (analogue/digital)and RPM. The higher the RPM the more power dissipated by the resistor and the more likely a misfire if connections are not perfect.
Cold start is always OK because the resistor is shorted out by the starter solenoid.
ps: Dont pay too much attention to the colours on the ignition wiring diagram... mine must have been made up by a colour blind
and that cost me a new ignition module.I think I may have found my misfire!
number 4 cylinder exhaust valve lifter is 2.5mm shorter than the others, and worn very concave.
Its cam lobe looks less lobey than the other lobes, viewed peering down the lifter bores.
I see a cam kit in my near future...
Any pitfalls I should be aware of?
number 4 cylinder exhaust valve lifter is 2.5mm shorter than the others, and worn very concave.
Its cam lobe looks less lobey than the other lobes, viewed peering down the lifter bores.
I see a cam kit in my near future...
Any pitfalls I should be aware of?
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