Mazda Rotary Club

General => General Technical => Topic started by: dubber91 on March 31, 2006, 12:18:46 PM

Title: Cant floor it!
Post by: dubber91 on March 31, 2006, 12:18:46 PM
Right i have a 1988 13b 6 port in my beetle that when i stamp my foot to the floor seems to limit itself........and wont rev. If i am gentle with the throttle application it will rev up to the redline no worries. The point at which it starts \'limiting\' is, i would estimate, at around the point at which the throttle spindle comes off the throttle position sensor. Any ideas as to what this might be?

Cheers in advance guys

Steve
Title: Cant floor it!
Post by: dubber91 on March 31, 2006, 11:35:35 PM
anybody? please help!
Title: Cant floor it!
Post by: MikeLMR on April 01, 2006, 08:30:22 AM
could be somthing starving the engine for fuel ?
Title: Cant floor it!
Post by: dubber91 on April 01, 2006, 12:41:13 PM
Possibly, but its fine up to that point.....its the same relativ throttle position regarless of rpm...so even at 2000RPM and i nail it (go past this point on the accelerator pedal) it will seem to limit itself, likewise at 4000RPM...

STeve
Title: Cant floor it!
Post by: jon haines on April 02, 2006, 04:40:45 PM
had the same problem a few days ago. have a 1990 n/a that i got a little while ago and gave it a first real run after doing some work and found if i floored it it would limit and pull very badly at mid revs but drive at very gentle throttle, turned out that it was running very rich and flooding itself at full throttle, put it on four gas and turned the fueling down and it know runs a treat.  could be lucky if youve never tuned it, jon
Title: Cant floor it!
Post by: dubber91 on April 02, 2006, 04:44:06 PM
how can you turn down the fueling?
Title: Cant floor it!
Post by: jon haines on April 02, 2006, 04:51:37 PM
on the seven theres a resistor that adjusts the fuelling. its a round black tube slightly smaller than a penny in diamiter and about 15-20mm long you remove the top cap and inside theres a round spindall that youre supposed to use a mazda tool on but you can get it with a pair of long nosed pliers and twist it anti clockwise to turn down the fuelling and vise versa. on the seven it was located on the left of the engine bay just infront of the suspension strut, i am not great with a computer but could poss manage a picture to your email if it would help
Title: Cant floor it!
Post by: dubber91 on April 02, 2006, 05:05:55 PM
hmmm a pic would be really helpfull....cheers :) But is the phenomenon you speak off like the engine is still spinning but does not want to rev any higher? It actually sticks at whatever RPM you choose to floor it at?

Cheers for all your help
Steve
Title: Cant floor it!
Post by: jon haines on April 02, 2006, 05:14:47 PM
no, it didnt stick. the car would yuck for want of a better word. the car would loose power for a second then pick again for a second and keep repeating until i let off ther pedal.
Title: Cant floor it!
Post by: dubber91 on April 02, 2006, 05:17:05 PM
i dont think this is the same problem then....it feels more electrical than fuel orientated as well. It really is like the engine hits a wall and wont rev any higher unless you let off, and the rev it
Title: Cant floor it!
Post by: jon haines on April 02, 2006, 05:23:44 PM
fair doos, but dont write of fuelling, mine felt more like the coils or plugs breaking down or arching than fuelling. have you tried getting any fault codes, if its a sensor problem it might show. on more modern cars you would probably suspuct the air mass meter and unpug it and try running it to see if it improved.cavaliers had a simular problem on their air flow meters. jon
Title: Cant floor it!
Post by: dubber91 on April 02, 2006, 05:28:08 PM
ohhhh i might try the airflow meter...got another one of them to try :)
Title: Cant floor it!
Post by: dubber91 on April 04, 2006, 05:39:33 PM
right, AFM changed, no change.....Changed the fuel filter.....No change.....Really starting to get to me now!
Title: Cant floor it!
Post by: jon haines on April 04, 2006, 09:19:45 PM
would still consider over fuelling/air intake restrictions or even air leaks causing fuelling problems.does it rev freely when stood or is it happening regardless of load conditions. under load might suggest the ignition is breaking down under pressure but i am crap at diagnoseing without having a play myself but i have some friends at bosch tech help line and will pick thier brains tomorrow just in case were missing anything obvious.
Title: Cant floor it!
Post by: dubber91 on April 04, 2006, 09:37:04 PM
ok....im impedence checking the injectors now
:D

it revs freely when stood yes
Title: Cant floor it!
Post by: jon haines on April 04, 2006, 10:41:04 PM
i think you will check the injectors ok, you might strike lucky on an asnu but i doubt that as well. jon
Title: Cant floor it!
Post by: dubber91 on April 04, 2006, 11:49:24 PM
asnu???

Steve
Title: Cant floor it!
Post by: dubber91 on April 05, 2006, 03:50:24 PM
ive changed TPS now, and the injectors have 3 ohms accross em, any other ideas?
Changed AFm too now, no change
Title: Cant floor it!
Post by: jon haines on April 05, 2006, 07:00:34 PM
lucas asnu - it means as new, its what they call thier test rig, it also does a flow test, ultrasonic clean then retests flow and pattern to see if they are any better. you need a fuel specialist or lucas dealer for it. should cost around £20- 25 + vat for up to four injectors. jon