no power at low revs, HELP!!!

[sexa]

I need your help guys!!! ive been having problems with my 88 exa for bout 4 months now, when the cars in low revs(1000-3500) i have no power, thats untill it kicks in at about 4000rpm and the car starts jolting back and forwards then bang it takes off!!! untill i change gears and it drops off again untill 4000, its been doing this for a while now and i know its gotta be hurting my car, also since that ive been losing about 100 k's or so per tank in petrol meaning more fill ups and more $$$. Ive been to 2 mechanincs now and they have no idea whats causing it, i really need some help, could anyone point me in the right direction?? thanks!
oh yeah and when its in low revs now it almost sounds like a rotor making that bubbling sound:hitwall:

[Blood]

TPS & CAS need correct adjusting ....

[sexa]

what do tps & cas stand for? can i adjust them myself and if so how? and where are they? i have no clue

[bogan]

TPS = throttle position sensor
CAS = crank angle sensor

and yes u can adjust them yourself....
ill let silvexa or someone else explain how to.. :)

[turbo18exa]

I would suggest the tps isnt adjusted right as this happend to me but i actually got more km to the tank cause it was tellin computer that i was offf the gas for the first 1/2 of acleration
To adjust it u need a multi meter
set it to ohms
Put it across th top 2 terminals on tps switch
it should read 0 ohms and if u just move the butterfly it should go to infinity it it does its ok
if not loosen off the bolts which hold it on and move it until it does the above it will take a bit of mucking around

[DEVILsEXA]

cheers turbo18exa... now i just need a multi metre...

where are these switches that u talk about?

cheers,
Craig.

[TTriX]

devils...
the switch he speaks of...
the TPS is basically a switch on it's own...(for sexa it's the black box mounted oposite to the throttle spring/cable assembly)...
disconnect the plug to this unit...you will see the pins he speaks of.
connect the multi-meter and follow his instructions.
T

[TTriX]

sexa...
the CAS is the crank angle sensor...it is mounted on the pully side of the motor(round silver unit with three 10mm bolt holding it on-with a plug at the bottom)...this may be giving you your problem as if it is out of adjustment it will be a total dog in the bottom revs and then pull like a bastard after 4g's plus...
loosen off the three bolts, move it forward or back wards, tighten one bolt...go for a test drive and see how it feels...if it is worse, then go back the other way till it feels close to what you want...but be carefull and listen for "pinging".
i have two marks on mine(that i put there)...one for everyday driving which gives decent all round acceleration...and the other for high revving and racing...this does work as it basically moves the power band(peak rpm curve) to where you want it.
T

[Howie]

Could be either a TPS/CAS as mentioned. But it's also worth running a diagnostic on your ecu to find out if your detonation sensor is faulty (Error code 34 on Mode II)... if this is the case the detonation sensor will retard timing under 3500rpm... after this point the motor no longer relies on the det sensor.

[matara]

Had exactly the same symptoms, and its down to the detonation sensor. Its a pig to swap as you need a 24mm pipe spanner to get it off, and its right at the back of the engine, so you need to jack it up, put it on stands and crawl underneath.

Do a diagnostic on your ECU in mode 3 to see if you are getting Code 34.

I've found that you can cheat the ECU (and have it advance the timing to normal) by putting a 5 or 6 kilo ohm resistor in place of the det sensor. A temporary fix costing all of 20 cents.

Steve

[Howie]

although.. if you've got small arms you could try to get to it from the back of the motor. But in the end you'll probably end up having to jack up the car.

I've done what you have matara.. by using a 1mega ohm resistor (wouldn't work with anything less than 1mega ohm) and shorting the plug to the detonation sensor.. works a treat as a temporary fix.

[sexa]

so how much will it cost to run a diagnostic on the ecu? expensive im guessing, could i do it myself? what would i need and how would i do it?otherwise would i have to get a mechanic in??

[Howie]

do it at home man. Underneath the passenger seat is your ECU... remove the covers to gain access to it. On the back of your ECU you'll see two lights and a place to put your flathead screw driver in.

Turn your key to Ignition.. then using the flathead screw driver place in the plug (remember roughly where it was initially .. as you'll need to get back to this point) and turn fully clockwise.

The two lights green and red will blink to indicate what mode you're in... wait till it blinks three times.. this means it's in mode three.. then using your flathead turn completely anti-clockwise.

Now count the number of red flashes followed by green flashes... this indicates the error code.. (3xred 4xgreen = code 34 = detonation sensor)... or (5xred 5xgreen = code 55 = all okay).

When you're finished.. using the flat head again turn until you get to the initial position.


This could also help if you've got a CAS problem or TPS problem.. when you've done this come back and tell us what code you have.

[sexa]

ok thanks, thats great, i'll do it tommorow rest assured you'll know by tommorow night(canberra time) hopefully it will all go ok. If it turns out that it is my detonation sensor, how do i fix it? im guessing its just a matter of replacing it which couldnt cost to much... could it?
Thanks again everyone!!

[sexa]

ok guys i did it 1st thing this morning and heres what i got, after the full turn back clockwise to find out the reading heres what happened....
after the anti clockwise turn i got,
1red flash then two seconds later 1green flash.
about 5 seconds later i then got 3red flashes and after about another5 seconds, 3 green flashes.
i guess i am supposed to take the last set of readings which gives me a code of 33!!!(3+3=33)
now i need to find out what the code means!! i dont have a service manual(are all exa owners issued with one? if so its gone a long time ago) so can anyone tell me what code 33 means, and if possible how to fix it as well??
Thanks again for everyones help,
appreciate it!!

[TTriX]

sexa...
code 33 is transistor/coil pack, it is the primary ignition code.
odds are one of your coils is stuffed...
are you familiar with how to check these???
T
they are under the plastic pice that says "twin cam blah blah blah" in white writing.

[sexa]

i had one coil replaced about 6months ago, im guessing that the problem has just gone to its next weak link, therefore another coil. i have no idea on how to check them so your knowledge here would help
by the way how would i go about getting a service manual? are they worth getting?

thanks again

[TTriX]

sevice manual...good idea.
as for the coils...
if you have one bad coil and no spares...that is a little harder to figure out especially if it is not totally stuffed yet.
but you can remove the covers and see if one has a crack in it or someone knows the specs with a meter. and check them all.
to get the covers off...
throttle intake clamp, middle intake pipe clamp(by the air box),two bolts under the pipe,
hoses going to the pipe-remove or loosen.
then eight 10mm bolts on top by the writing on the top of the motor.-then remove cover.
check wire harness for breaks before removal.
then remove coil packs...you will see when you get there.
it's pretty much straight forward...this is also the way to change/get at your plugs.
T
hopefully someone here has the specs on the coil packs.
but yes the service manual is a good idea...or just pic up one of those and do the job then.
some people on here have the manual on file or converted to cd-rom...was an old topic on here, i'd like one for my self someday-hehe
last thing...does it only do it when the engine is hot???

[sexa]

ok yeah im gonna have to get the manual - its shit if it is a coil, the last one cost me $500 to replace.... and no its not only when its hot basically as soon as you start the car till when you turn it off, even if your say sitting at lights in idle it picks up and drops of ( like 1000rpm-300 then straight up again. bubbling sound to from exhaust when the revs really drop)
um im not sure who i could get to help me fix it.. mechanics cost!!!
where would i get a manual from autobarn or something?

[Howie]

Originally posted by sexa
ok yeah im gonna have to get the manual - its shit if it is a coil, the last one cost me $500 to replace.... and no its not only when its hot basically as soon as you start the car till when you turn it off, even if your say sitting at lights in idle it picks up and drops of ( like 1000rpm-300 then straight up again. bubbling sound to from exhaust when the revs really drop)
um im not sure who i could get to help me fix it.. mechanics cost!!!
where would i get a manual from autobarn or something?


$500 to replace a coil?? Where did you get that done?? Sounds you took it to Nissan and had them install a brand new one or something.

You can pick up good coils second hand for around $75 each. If you're confident with a screw driver .... you can diagnose a faulty coil pack and swap it at home.

I have a feeling its your power transistor rather than a coil pack though. Does anyone remember how to test if a transistor pack with a multimeter? If i'll check my manual tonight.

[KAMELEON]

if all else fails with all of the above think about this
our cars have wat is called a dual length runner system
and this switches over at the exact rpm u r talking about
(3800 but ud feel it at 4000)
it is common for otehr nissans with nics or eccs to have this problem wat happens is the car is stuck in short runner mode thereby making the runner lengths shorter thus turbing the car into a pig to drive and explains why u have crappy fuel economy
of course it may not be this but if all otehr efforts and avenues have been exhasuted then id be banking on this little one
cas and tps would show signs of problems at idle and such not so much at a specific rev point
then id check the thermostat(turn the heater to full and the a/c on then drive on the freeway and if its laggy to come to half or if it falls when u get on the freeway and doesnt go to all the weay the thermostat is dead
then u have airflow meters and lamda probe(o2 sensor,oxygen sensor however u want to pronounce it)things like that
hope that helped
Trav

[TTriX]

sorry howie, the code 33 is the primary ignition which covers both coil packs and what i call the ignition module(little computer on side)
so it would be one of those...but i would check the packs first...
anyone with specs???
sexa...as for the cost of the last repair...go somewhere else or ask someone on here to help you out(in your area) and at least offer some cash plus beverages-hehe
one thing about exa/pulsar owners...we have to stick together-hehe
T

[sexa]

shit, theres seemingly endless possibilities!!! i guess its just a matter of trial and error, i think im gonna need to buy a manual, cause i dont know heaps about the tech side of things yet, i think once i get one though i should be able to get all the stuff under way, im in canberra so does anyone of a place i can get one, but if i need to i'll order one from sydney( by the way is anyone else in canberra a member here?? if so you be interested in helping me out with the mechanical side of things? i have a feeling that im not the only one with an exa with this problem> If we can sort it out this could save exa owners country wide heaps of time and money- anyways keep coming with ideas

thanx to everyone whos helped so far!!!

[DEVILsEXA]

ok guyz... just something else to add to tha list of problems/causes!!!

I have the same problem as SEXA, i got a mech to have a listen see what he thought... he recons i should start with tha fuel filter then work ma way back up tha fuel line to tha engine, if it's still playing up go from engine back to the air box/ air filter!!!

THEN and only then start thinking worse! (ie. what u guyz are talking about)

Craig.

:hippy:

[Nugget]

one more you you exa nuts out there, my 87 exa Idles at 1000 the drops down to 500 and then back up to 1000 then back down to 500 well you get the point. Any ideas guys.

[Howie]

Originally posted by TTriX
sorry howie, the code 33 is the primary ignition which covers both coil packs and what i call the ignition module(little computer on side)
so it would be one of those...but i would check the packs first...
anyone with specs???
sexa...as for the cost of the last repair...go somewhere else or ask someone on here to help you out(in your area) and at least offer some cash plus beverages-hehe
one thing about exa/pulsar owners...we have to stick together-hehe
T

Umm.. either or. It still could well likely be the transistor pack I'd say. Coil pack problems usually make your car surge and buck vigorously and that hasn't been reported. Dead transistor packs have less obviously symptoms. The fact that it is lacking power under 3500rpm is a symptom of the ecu putting it into safe mode (retarding timing). But yeah.. i'm wrong to assume it's just the tranny pack. It could then again be the wiring to the ecu.. manual tells us to check this as it will trigger a sensor is the circuit is broken.

[TTriX]

Originally posted by 16 rmc
one more you you exa nuts out there, my 87 exa Idles at 1000 the drops down to 500 and then back up to 1000 then back down to 500 well you get the point. Any ideas guys.


16mrc...
there is a small plug on the back/top of the motor, between the thermostat and the top end...right beside the fuel injector furthest from the tranni side...
this plug can become corroded or broken off an give you such a problem...it looks just like one of the electrical plugs that go to the injector.
i believe it has two wires going to it...
try that first as i had a similar problem and it was due to this and my clips on the plug were broken and it would loosen off giving me the fluctuation in idle...faily drastic one too.
hope it helps.
T

[oldskool]

Hey Sexa,
Im in canberra, I have a manual and I am also having your problem but to a lesser degree. My email is archies_1000@yahoo.com send me your details and I will organise some way of getting you the manual.
Oldskool

[][BsW][]

hmm sounds like iv got the same problem...ill do the ecu cheak and get bak to u,as i dont have a manual could some one tell me the code 4 how eva many times my ecu blinks....hmmm and my car somtimes runs good azzzz and then runs like u described it...bad idiol and so on....doz ur car eva temperally fix its self?even its it 4 a few hours or is it full time?...email mr_turbo_@hotmail.com

[chrisexa]

i've got the exact same symptoms... as this... mechanic had to put in a new second hand crank angle sensor the other day coz the old one died. i'm guessing it just needs playing with...... grrrr hate having a fun car that's running like shit!