Lack of power 1994 850 SE

juggernaught_666 · Post by **juggernaught_666** » 12 Feb 2017, 19:56

Id like to thank the many years of silent help everyone on this site has done for me.

Vehicle:
1994 850 Sedan 2.5 SE
10 valve [edited from 20 to 10]
B5252S
276K km
owned the best part of 11 years

So there is a lot of a back story to get here but to summarise:

car would stall on idle at stops randomly for the last year.
been in and out of various mechanics replacing:
MAP, finding out I don't have a MAF, Distributor cap and rotor button, cleaned plugs, replace 1 damaged lead.

After all the mechs gave up, I left it stranded at my parents house and over a few weeks, my tinkering dad thankfully found the culprit, a jammed idle air valve, cleaned it out and lubricated it with silicone.

Now it idles and stays running perfectly.

The problem now is that it revs fine and kicks down fine, but has underwhelming power, I can barely make it up a hill (70km/hr zone) I use to easily get above 90, now I'm lucky to stay above 60.

The throttle if I floor it and wont change up (might be a kickdown issue) but if I back it off just a little it will change fine.

I did a ECU reset on the weekend reading all the wonderful outcomes, have only had 2 key starts during its test phase, but still no luck getting up similar hills.

Read codes before and after, ones that remain (but may not have been cleared correctly)
A1
223 Throttle position (TPS) sensor signal too low
143 Kickdown switch faulty or short to ground
A2
cleared successfully

I also opened up the throttle body and cleaned the small amount of residual soot.

Its also worthy to note that the fuel consumption has gone up, but this may be because I'm revving it high but getting no response after 2500 rpm, it literally feels like that's the peak of it power.

the only things left that I can think of is:
a clogged catalytic convertor
low compression (one mechanic did test this 6 months ago and said it was good for its age)

Has anyone got any other suggestions?

Post by **abscate** » 13 Feb 2017, 03:36

How old are spark plugs! Let's have a look at them with a picture, in order.

Test your fuel pressure at the rail with a gauge. Your car has a fuel pressure regulator with a vacuum house that can go bad, which I believe makes your car run rich, usually. No power and bad economy,

Post by **misha** » 13 Feb 2017, 08:08

juggernaught_666 wrote: 20 valve
B5252S

That's not gonna happen.B5252 is a 10 valve car and since they have completely different engine management than 20v cars....this data is VERY important.

10 valve cars are not have enough power for the chasis like 20v cars especially with auto transmission.2.0 engines are even more underpowered.
Kickdown button not working certainly contributes underpowering situation.
Tps also must be replaced because it is important here.It is saying ecu how much fuel to inject depending on throttle position.
Map & tps are playing in the team in this MAFless versions(10v cars don't have MAF sensor) and they are very important.

Jaguar xjs · Post by **Jaguar xjs** » 13 Feb 2017, 16:10

Any idea when the fuel filter was changed?

Gordon

juggernaught_666 · Post by **juggernaught_666** » 11 Apr 2017, 18:43

I now have some time coming up to address these issues. so im going to start answering and asking more.
Replys now will be short, but accurate.

abscate wrote: How old are spark plugs! Let's have a look at them with a picture, in order.

Test your fuel pressure at the rail with a gauge. Your car has a fuel pressure regulator with a vacuum house that can go bad, which I believe makes your car run rich, usually. No power and bad economy,

photos not currently available, on dads phone, plugs have been cleaned since.
Will see if the mechanic has these pressure values on record, i doubt he wants to see it again to test the compression.
Fuel pressure regulator vacume hose, is ths around 1.5cm OD? goes brittle? leads to vaccuum tree from behind/underneath the alloy rail?
what value am i looking for in terms of pressure?

misha wrote: Kickdown button not working certainly contributes underpowering situation.

button? isnt it a switch or a sensor?

Jaguar xjs wrote:Any idea when the fuel filter was changed?

a few years ago (less than 10000km, probably less than 6000km) last time i changed it when we thought there was a problem, the old one looked relatively good for a 5 year old++ filter

I need some help finding a replacement kickdown switch, none on eBay and none at my 3 regular parts sites, it has had one replaced before at my old mechanic somewhere between 4 and 7 years ago. I’m fairly confident I know physically where it is (against the fire wall on the throttle cable), is there another name for the kickdown switch?

thanks again everyone

juggernaught_666 · Post by **juggernaught_666** » 03 Dec 2017, 22:05

An update for those who may have wanted to know.

It had been a lawn orniment for the last 8 months.
I found a genuin mechanic who thanked me for giving him the opportuinity to play with it.
Today i got the call saying it was ready to be picked up.
Still yet to pick it up and confirm his findings.

After all that it was a clogged Cat.