Loss of power under acceleration?!
Discussion
Any ideas chaps? Since I owned the 'little blue shouty one' I have had a loss of power under acceleration. Not all the time (that is what is so frustrating!) but enough to make me wary of giving it some welly and I am conscious of losing power when overtaking or being overtaken which could lead to a nasty accident. Any gear, hot or cold but not all the time. Sometimes she is just a smooth as silk but other times she can run like a dog. We have just given her a 12k service and she drives like a different car, except for this loss of power thing. At a constant speed (any speed, any gear), she is perfect with no misfiring at all. The problem starts when one applies the 'go' pedal, even when being gentle. So, the stuff that has been done to try to deal with it...
1) New ignition, arm dizzy cap and magnecor leads.
2) New vacuum unit
3) New ignition module
4) New coil
5) New ignition amplifier
6) All the above on top of a 12k service.
Still the problem persists and I could use the help of the PH massive before I spunk my whole profit share for 2007! Thanks guys for any suggestions
1) New ignition, arm dizzy cap and magnecor leads.
2) New vacuum unit
3) New ignition module
4) New coil
5) New ignition amplifier
6) All the above on top of a 12k service.
Still the problem persists and I could use the help of the PH massive before I spunk my whole profit share for 2007! Thanks guys for any suggestions
There's a section in 'the bible' about checking the engine sensors with a multimeter. I'd look especially at the throttle potentiometer and the airflow meter.
Beware that they're not exhaustive checks and that they could even appear ok when they're not, but it's an inexpensive start. Even better, if you have (or have access to) a fault code reader, problems in this area may have been logged by the injection ECU.
Beware that they're not exhaustive checks and that they could even appear ok when they're not, but it's an inexpensive start. Even better, if you have (or have access to) a fault code reader, problems in this area may have been logged by the injection ECU.
Johnniem,
You might have already see it but there is a thread (link below) where a few of us are having the same or similar problems.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
G
You might have already see it but there is a thread (link below) where a few of us are having the same or similar problems.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
G
I suffered a problem with identical symptoms.
What it turned out to be was a HT lead. It would work loose and, under acceleration, be pulled away from the top of the spark plug. Cue much misfiring and loss of power.
It took a while to spot what was wrong - eventually the damn thing came completely off and that gave it away. For a few weeks I used to pop the bonnet of a morning and push it down hard - but it would work loose in a day or so. Eventually we replaced the HT leads with a new set - problem solved.
What it turned out to be was a HT lead. It would work loose and, under acceleration, be pulled away from the top of the spark plug. Cue much misfiring and loss of power.
It took a while to spot what was wrong - eventually the damn thing came completely off and that gave it away. For a few weeks I used to pop the bonnet of a morning and push it down hard - but it would work loose in a day or so. Eventually we replaced the HT leads with a new set - problem solved.
So, in to Hoods Galore for spanking new hood (woo hoo! the round to my mechincs tonight for lots of engine goodies and a go at this "loss of power under acceleration" thing. Dropped into him this morning and showed him exactly what was happening (overtaking is getting a bit scary!) and it will be there till it's sorted. Will let you all know what the result is in the next day or two hopefully. I just hope its not too expensive.
Good luck with it John! In your '12,000 mile service' can you be sure the air filter was changed?
Did anyone check the black corrugated trunking that brings the air from the air filter at the front of the car all the way back, through the airflow meter to the throttle? The standard trunking has an inner and outer layer and between them is a steel spiral that gives the trunking it's shape. The two layers with the steel spiral between them are glued together, but if through age/heat the glue hardens and fails the inner layer can collapse under the vacum created by heavy throttle loads so starving the engine of air and this would lead to the symptoms you describe.
Worth checking after the things you've already done without improvement. Nick.
Did anyone check the black corrugated trunking that brings the air from the air filter at the front of the car all the way back, through the airflow meter to the throttle? The standard trunking has an inner and outer layer and between them is a steel spiral that gives the trunking it's shape. The two layers with the steel spiral between them are glued together, but if through age/heat the glue hardens and fails the inner layer can collapse under the vacum created by heavy throttle loads so starving the engine of air and this would lead to the symptoms you describe.
Worth checking after the things you've already done without improvement. Nick.
nikman said:
Good luck with it John! In your '12,000 mile service' can you be sure the air filter was changed?
Did anyone check the black corrugated trunking that brings the air from the air filter at the front of the car all the way back, through the airflow meter to the throttle? The standard trunking has an inner and outer layer and between them is a steel spiral that gives the trunking it's shape. The two layers with the steel spiral between them are glued together, but if through age/heat the glue hardens and fails the inner layer can collapse under the vacum created by heavy throttle loads so starving the engine of air and this would lead to the symptoms you describe.
Worth checking after the things you've already done without improvement. Nick.
Cheers Nick. it is a suggestion I have made to the mechanic, which is where she now rests. An early morning blast and in to the office to stare at the phone willing it to ring to confirm that the problem has been found. It's so frustrating as the 12K service left her running superbly but for this issue. I am treating her to a new ali radiator, stainless steel fuel pipes, silicon hoses and other "stuff". That's keep me going for a few years I hope, unless the Christmas fairy brings me a voucher for a supercharge upgrade! Did anyone check the black corrugated trunking that brings the air from the air filter at the front of the car all the way back, through the airflow meter to the throttle? The standard trunking has an inner and outer layer and between them is a steel spiral that gives the trunking it's shape. The two layers with the steel spiral between them are glued together, but if through age/heat the glue hardens and fails the inner layer can collapse under the vacum created by heavy throttle loads so starving the engine of air and this would lead to the symptoms you describe.
Worth checking after the things you've already done without improvement. Nick.
Well chaps, I picked up the car from LEVENS yesterday (shameless plug!) and the results are amazing. I am now driving a completely different car and it seems so fast and incredibly smooth! The power loss was probably a mixture of ECU issues and air leakage. The thing is that Simon and Dan worked tirelessly to eliminate possible issues and finally to sort it out. The loss of power was just one thing that I had done but let me tell you those guys at LEVENS are amazing. They are aware of costs, knowledgeable and passionate. Their garage is spotless at all time (much like the McLaren factory in Woking but without carpets!) and they make you incredibly welcome. Thanks Levens, for everything!
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