Help!

[BG1.8sp]

hi guys,
as some of you may have already seen, i have posted in the "random question thread" with no response,
so i thought i might start my own thread here.
anyway,
my car (1991 BG astina sp 1.8 DOCH), is having some 'flat spot' issues.
between 3500 and 4500 it is lacking in power (not too badly),
so i was going to check out a few things.
i have already cleaned and checked the AFM and all electrical connectors within the engine bay, all is good there.
it has a new air and fuel filter.
next i am going to check the TPS (throttle position sensor) and the timing.
however, i have done a search on here and google, but have found nothing on either.
so what voltage should the TPS be set to,
and is adjusting the timing on the 1.6 the same as the 1.8,
described in the link below
http://autorepair.about.com/library/a/1i/bl438i.htm

also if it still persists, the next thing will be to check for any vacuum leaks,
using my home made boost leak tester and the compressor.

after that, if it is still having the same issue, i will be replacing the O2 sensor.

IF it still has the same flat spot, i will have to pull out the injectors, and have then cleaned and flow tested.

if anyone can help please do,
also, any suggestions, or things that i should check, or have missed???
cheers,
AzzA

[maztech]

Mate i would be changing the o2 sensor first then getting injectors cleaned

[BG1.8sp]

yea, that's what i said. they are all in order/ steps. O2 comes before the injectors in my list.

[Old Grey]

I would be checking the ignition first, always change plugs first

[BG1.8sp]

forgot to mention,
the plugs have also been changed and are brand new, gaps also checked.

[BG1.8sp]

can anyone at all confirm that this method;

http://autorepair.about.com/library/a/1i/bl438i.htm

for timing the 1.6L is the same method for timing the 1.8 DOCH,
i assume that the dizzie's are exactly the same so therefore the method of timing should also be the same.

i will try it by this method on the weekend if no reply.


also, thanks to those who have made suggestions already.

[maztech]

No not right .
Ground the TEN terminal in the diagnostic box then set base idle and timing

[BG1.8sp]

thanks mate,
that was my initial question (the reason for starting this thread)
thanks for answering.
also, still wanting to know, what should the TPS voltage be at??

[maztech]

I will try to dig up the BG sp workshop manual and have a look at voltages

[BG1.8sp]

just wondering if you managed to find those voltages for me?
cheers

[maztech]

Yeh had a look at it the other day 2 pages in manual about continuity checks with feeler gauges and resistance checks then in PCM voltages 2 different pins with throttle closed and fully open , so what exactly do you want to check , do you think the resistor is broken in the sweep , the only way of checking this is with a analoge multimeter.Have you replaced the O2 sensor yet as the BGs were prone to these fouling.

[BG1.8sp]

cheers mate,
i just wanted to ensure that the ECU is getting the right message from the TPS.
as in, when throttle is fully open, the ecu doesn't think that it is only 3/4 open.

so i need to check and adjust the TPS on both closed and open throttle.
also, make sure that the resistor is working correctly, as you said.

and no, i have not yet replaced the O2 as i haven't been able to go to the parts shop yet. hopefully i will soon.

[BG1.8sp]

also, is it also a possibility that the fuel pump could not be working properly??,
as the car was sitting under a cover never driven for 3 years.

[maztech]

Dont think it would be the fuel pump if it was it would be a huge flat spot and take a while to clear or you would have to back off tottally - there is alot of things that it could be - have the injectors been cleaned off the car and is the fuel fresh - does it do it when the tank is low. Is it worse hot or cold ?

[BG1.8sp]

the flat spot does take a while to clear...
when i am driving along it will be going fine... then all of a sudden a loss in power and it takes a bit to recover.
and yep, its got fresh fuel.
no, the injectors have not been cleaned off the car.
and it is no different whether its hot or cold, or, if the tank if full or running low

[maztech]

Clamp fuel pressure return line then take it for a drive

[BG1.8sp]

yep sure,
wont be able to do that until next weekend tho, as i only drive on the weekends and i will be in Canberra this weekend.
also, by clamping off the FP return line what are you hoping to achieve/ what should happen??
should it get better or worse.
also, if it does get better or worse, what does this mean?? faulty FPR??

[maztech]

If it gets better the injectors are getting blocked -- more pressure forces bit more fuel through pintles = runs better , you can sometimes tell the change at idle by doing this ( use something like brake hose clamps plastic ones. Worthwhile to put a fuel pressure gauge on it as well - idle then take it for a drive ( no clamp) see if it is dropping pressure when it dies

You have checked the cam timing and it is right hey

[BG1.8sp]

alright,
i set the timing... seems to be much better than before.
however, i am not 100% sure that it is set right, as i am unsure of the timing marks.
is the largest tooth closest to the front of the car 0 DBTDC, and does each tooth increase by 5. ????
i assumed this as that is the way most cars are.

Also, regarding another issue.... which just arose 30 mins. ago...
firstly my dad drove my car to work today (about 1.5 hours)

on the way back home the car made a beeping noise the whole entire way.
almost like the lights were on when the car is off.
My question is... what can cause this beeping noise???

the Temp was perfect, the fuel was sitting on 1/4, brake fluid is fine, pwr steer fluid all good, the oil is fine, Rad is fine.
so what could be the cause of this beeping??????

Also, i might just add that once the car was turned off, and turned back on again... Straight away with a 3 sec break between on, off and on again... the beeping did not occur.



Your help is appreciated,
cheers,
AzzA

[BG1.8sp]

can anyone answer these questions above??