No full throttle. No idea why??? Help!
Discussion
My 350i is giving me a bit of hassle. I starts and drive perfectly but will not rev past 3500/4000 rpm when you floor it and it just starts to hesitate.
I have replaced the temp sensor (faulty), plugs, H.T leads, rotor arm, coil, dissy cap, fuel pump (low fuel pressure), fuel filter and ignition module not because of this fault but because they were in need of replacement due to there condition/age. I also fitted an adjustable FPR with a gauge and the fuel pressure is approx 38psi.
Its bloody annoying not being able to floor it.
Any ideas or suggestions?
I have replaced the temp sensor (faulty), plugs, H.T leads, rotor arm, coil, dissy cap, fuel pump (low fuel pressure), fuel filter and ignition module not because of this fault but because they were in need of replacement due to there condition/age. I also fitted an adjustable FPR with a gauge and the fuel pressure is approx 38psi.
Its bloody annoying not being able to floor it.
Any ideas or suggestions?
I had the same thing happen with mine last year. Initially I put it down to the throttle pot as when I set that up properly it started to rev again. But a couple of weeks later it started doing it again and finally died completely at a set of lights after getting hot. The ignition amp and temp. sensor had failed together although I put the non-revving part down to the iginition amp. Steve.
Having another think about it --
1st - have you checked that the petrol cap's breathing ok,
2nd -- 38psi is correct wouldnt go any higher,
3rd -- check your points at ecu to your flapper [giving wrong readings?]
4th -- check fuel rail's under plenum, could be a slight blockage but still giving same psi readings,blow air through,
5th -- air flow meter receiving wrong readings from ecu, down to connections somewhere,
6th -- Good luck.
1st - have you checked that the petrol cap's breathing ok,
2nd -- 38psi is correct wouldnt go any higher,
3rd -- check your points at ecu to your flapper [giving wrong readings?]
4th -- check fuel rail's under plenum, could be a slight blockage but still giving same psi readings,blow air through,
5th -- air flow meter receiving wrong readings from ecu, down to connections somewhere,
6th -- Good luck.
1. With the engine off, bonnet open, have someone stand on the accelerator pedal and check the throttle is opening to 90 degrees (i.e. fully open). It's the first rule of tuning!
2. Assuming this is OK, another problem not suggested above is the mechanical advance weights in the dizzy. Disconnect the vacuum advance and rev the car with a timing light attached. You should see it advance quite a bit over 2500 rpm - from recollection 15-20 degrees?
I had this on the old wedge and someone had as a bodge advanced the whole timing, so it was just about OK but petered out around 4.5-5k rpm.
2. Assuming this is OK, another problem not suggested above is the mechanical advance weights in the dizzy. Disconnect the vacuum advance and rev the car with a timing light attached. You should see it advance quite a bit over 2500 rpm - from recollection 15-20 degrees?
I had this on the old wedge and someone had as a bodge advanced the whole timing, so it was just about OK but petered out around 4.5-5k rpm.
adam quantrill said:
1.
2. Assuming this is OK, another problem not suggested above is the mechanical advance weights in the dizzy. Disconnect the vacuum advance and rev the car with a timing light attached. You should see it advance quite a bit over 2500 rpm - from recollection 15-20 degrees?
I am not an expert on Wedges but the symptoms you describe as a general rule on all cars, sounds like a timing problem, and as the problem only occurs at high revs with hesitation, I agree with Adam that it could be the advance weights not functioning properly. Check as described with a strobe light.2. Assuming this is OK, another problem not suggested above is the mechanical advance weights in the dizzy. Disconnect the vacuum advance and rev the car with a timing light attached. You should see it advance quite a bit over 2500 rpm - from recollection 15-20 degrees?
Tony. TCB.
I only have a small amount of knowledge but have been doing some research and in-depth reading of RV8s and their system's as i plan to own one some day!!..I agree with adam, If your car feels good and strong at low revs but drops off as the revs rise and its all noise and no power over 4500rpm then it most certainly could be that the centrifugal advanced mechanism has seized..Apparently its not uncommon..Try as advised..Disconnect vaccum and test the ignition timing..It should be advancing as the engine speed increases..You should typically see 8 degrees BTDC at idle rising to 28 degrees BTDC at 4000rpm.
Also be aware that the timing markers were not always accurately fitted and have been observed up to 10 degrees out!
Hope this helps..Ziga
Also be aware that the timing markers were not always accurately fitted and have been observed up to 10 degrees out!
Hope this helps..Ziga
http://www.ebay.co.uk/itm/NEW-THROTTLE-POSITION-SE...
Says its for a 4.2 v8 and many other variants any good
Says its for a 4.2 v8 and many other variants any good
Im having the same problem with the revving over 2500 problem.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Im pretty sure it is the TPS but I cant find one at the moment so Im going to try and make a change piece to connect a common part to the existing.
If you do find one let me know who is doing them!
Stu
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Im pretty sure it is the TPS but I cant find one at the moment so Im going to try and make a change piece to connect a common part to the existing.
If you do find one let me know who is doing them!
Stu
hallsie said:
Im having the same problem with the revving over 2500 problem.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Im pretty sure it is the TPS but I cant find one at the moment so Im going to try and make a change piece to connect a common part to the existing.
If you do find one let me know who is doing them!
Stu
Try Rimmerbros.com , think they sell themhttp://www.pistonheads.com/gassing/topic.asp?h=0&a...
Im pretty sure it is the TPS but I cant find one at the moment so Im going to try and make a change piece to connect a common part to the existing.
If you do find one let me know who is doing them!
Stu
Jack Valiant said:
Stu, did you not get my pm email re the identifying numbers of the throttle pots fella?
Chris
I havent yet mate, but Ive been out in the garage playing...Chris
Ive taken the internals from old TPS and have fashioned the one that Rob sent me onto it so that I can use the drive from the old one through to the newer one.
All I need now is to get an alternator back on the car and Im away..... I hope!
Stu
Gassing Station | Wedges | Top of Page | What's New | My Stuff