Mazda Rotary Club

General => General Technical => Anything Engine/Performance/Tuning related => Topic started by: adib on October 20, 2008, 07:08:02 PM

Title: help needed please
Post by: adib on October 20, 2008, 07:08:02 PM
when my m8 revs his car it try to cut out and pops and bangs and when you drive it you cant accelerate past 3000 revs as it just trys to cut out,you can drive along at 30 in 4th gear no problem but as soon as you try and give it some beans it do want to no.:xconfused
it has a rebuilt street ported engine in it and a straight throw mid exuast and running standard twins
Title: help needed please
Post by: g11ary on October 20, 2008, 07:34:22 PM
there is a water temp sensor, 1 of 2. The one you might want controls the ECU, basically it tells the ECU the cars warmed up and to allow full beans, if the ECU thinks the car has just started and is cold it restricts the car.
Cant say this is your problem but very similar to what I had and that cured it
Title: help needed please
Post by: clive on October 20, 2008, 07:51:51 PM
Quote from: adib;546249when my m8 revs his car it try to cut out and pops and bangs and when you drive it you cant accelerate past 3000 revs as it just trys to cut out,you can drive along at 30 in 4th gear no problem but as soon as you try and give it some beans it do want to no.:xconfused
it has a rebuilt street ported engine in it and a straight throw mid exuast and running standard twins

This may need lots more info to work out the problem, but lets start here,

If this engine has just been put back in the car, check that the primary injector plugs are not plugged onto the secondary injectors.

The secondaries come in at 2800 revs and it sounds like they are not injecting .

Next up is has he fitted big 1600 injectors but is still on a stock ECU if so it will cut the engine at the revs you describe,

Next is has the pipe fallen off the Map sensor which is the small black box on the bulkhead behind the throttle body,

This could be soooo many things so we will all need more info and even then it may need to be physically looked at.
Title: help needed please
Post by: adib on October 20, 2008, 08:05:02 PM
hi clive
checked the map sensor and thats ok and he has got standard injectors on it and when we first put engine in, it was reving ok did find a hole in 1 off the pipes but replaced that but did not make much difference, did notice it seens to smoke a bit on tick over
Title: help needed please
Post by: adib on October 20, 2008, 09:19:00 PM
g11ary thanks for that ill check it
Title: help needed please
Post by: bin liner on October 20, 2008, 09:32:15 PM
try an ecu reset, disconnect battery and keep foot on footbrake for 30 sec then reconnect...could be so may things but start there first..
Title: help needed please
Post by: CraigWWW on October 20, 2008, 11:03:11 PM
I had this same problem a year or so back, i never found the solution as I ended up fitting a new engine but I will look out the thread or you can search under my name to try and find it. There was some helpful posts if i remember correctly.

Check all earthing points in the car, Pip reckoned this could have been the issue. There is one just near the from bumper somewhere that he says can cause all sorts of issues when it has a bad connection.

Check the ECU isnt comprimised, the passenger footwell is notorious for letting water in and this can mess with the ECU causing \'Limp Home\' mode but to be honest the car should still rev passed 3000 if this was the case but only on light throttle.

Thats all i can remember just now.

Craig

http://mazdarotaryclub.com/forums/showthread.php?p=324368#post324368
Title: help needed please
Post by: Laeeq on October 21, 2008, 11:09:23 AM
I think its your TPS not connected....did you take the plenum off at any stage and forgot to plug it back in.
Title: help needed please
Post by: Prof on October 21, 2008, 11:39:07 AM
Check tightness of alternator belt as well - a lose belt will give similar symptoms, as it slips at higher revs.
Title: help needed please
Post by: adib on October 21, 2008, 07:32:54 PM
thanks guys, car was running ok, and then he phoned me saying it had gone wrong checked it sunday but still the same i was thinking ecu will try that saturday when he brings it over.
when you reset the ecu do you have to a learning thing like put ac on then back screen heater ect or is that just with pfc
Title: help needed please
Post by: CraigWWW on October 21, 2008, 08:35:22 PM
No learning required just disconnect, depress brake pedal for about 30secs then reconnect.
Title: help needed please
Post by: adib on October 21, 2008, 08:41:43 PM
ok thanks craig :Thumbsup!
Title: help needed please
Post by: JayDee on October 21, 2008, 08:54:57 PM
i would also check the charge control solenoid, to do this start the car and see if the little actuator on top of the y pipe is sucked in.
J
Title: help needed please
Post by: adib on October 21, 2008, 09:13:21 PM
jaydee- checked that and looks ok :Thumbsup! .
told him to reset the ecu, because i did find a split in a pipe that has the pill in it so could have gone in limp mode. will let you no what happens tomorrow :2Rolleyes
Title: help needed please
Post by: adib on October 22, 2008, 09:05:07 PM
ok guys, he reset the ecu and now cant start the car at all :eek:
Title: help needed please
Post by: CraigWWW on October 23, 2008, 12:22:25 AM
Has he flooded it?

If so tell him to follow the procedure for starting a flooded car...always worked wonders for me. Do a search for the threads.
Title: help needed please
Post by: K1HKS arse on October 23, 2008, 08:10:11 AM
Stock ecu????

If so sounds like engine running in default which fixes timing and fuelling and doesnt allow any hard driving as you have described.This default can be caused by many things,all of which are electrically connected like - rats nest solenoids,metering pump,crank angle sensors,water and pressure sensors.All of these things could be reading wrong due to getting wrong or no signal like - solenoid on rats nest which has a split pipe

Ideally get a diagnostic check on it. Try an ecu reset as said before as this might clear an old ecu fault that is causing default, maybe from the split pipe you changed.If not the quickest way is plugged into a diagnostic machine that can read mazda ecu.If you cant do that then its a process of elimination with swapping out parts.

Good luck.
Title: help needed please
Post by: adib on October 23, 2008, 07:39:19 PM
dont no if he has flooded it going over saturday to have a look at it so hopfully ill find the problem