Mystery problem - Help needed -

[RyanC]

Can you rig up the fuel pressure gauge and take it for a spin, get it to "bogg down" and see what the pressure is and if it drops?

[z3i]

I wouldn't have thought it's fuel otherwise it would pinging it's tits off! And running mega lean, temperature gauge would rocket, possibly melty time?

[hangman]

RyanC , I've done that and the pressure was fine even when the car "boggs down" . when I press the gas the pressure rises a little, with the car bogging or not.

About the temperature, the car always seems to run at normal temperature, however I had a problem with one of my exhaust valves (befoe this problem started) could this be related ? (I've already replace the exhaust valves )

about disconnecting the lambda, the lambda that I have it's like... 2 years old or something. When I disconnect it the car "boggs" exactly the same. the behaviour is the same when I disconnect knock sensor or the  co pot.

The only sensor that seems to change the behaviour of the car is the blue temp. when I disconnect this sensor, the car dosen't "bogg dow" but also dosen't rev up like a "good" car (and I've already replaced the blue temp, the behaviour is the same with both new and old sensor)


let me just ask a "silly" question (just to be sure ): the co2 pot resistance is mesured between wires 1 and 3, and this process is done with the car running or not ?

[samg40]

Check your knock sensor out. That can cause sudden losses of power/jolting if there is an issue with it.

[hangman]

but, if I disconnect the knock sensor the ECU will ignore it, or am I wrong ?

[kwijibo_coupe]

Because you've been disconnecting sensors here there and everywhere have you hooked it up to a code reader to see if it is throwing up any fault codes?

Might be an idea to get them deleted and see what happens, if it still is bogging down after that then see if the code reader can shed any light on the case. I know these ECUs are a bit primative but it is worth a try.

[GR40]

but, if I disconnect the knock sensor the ECU will ignore it, or am I wrong ?

No it doesn't ignore them. It adjusts as if reading 0 to their values. Example: for Lambda missing the car would still work but your fuel efficiency would go out of the window! Plus when u disconnect blue sensor the ecu goes into safe more. If with the blue sensor disconnected the car doesn't bog I would suggest another blue one, your new one could had been faulty to begin with.

[RyanC]

Okay so u have pressure at the rail and you have changed the ecu so The map sensor should be okay but have you checked the vacuum line to the map sensor?

I'm guessing they are very short journeys that u are doing in it to test? Is it temperature related? Eg worse when it's hot or cold or just the same?

What dose it behave like at idle? And dose it bogg down if you rev it on the spot?

[hangman]

Well, think solved it (but really don't know what have I done )

Aparently the Co2 pot wasn't working right and the boost was very low ... I cleaned the co pot and re set it to 550. I've also replaced the v-belts,(they where old and worn out)... And the car seems perfectly fine now.

It's kind of odd, how this 2 small things can make such a difference in how the engine runs... my bet is that the engine was working super rich and causing it to "bogg"...

I'm going to use the car a little more in this next week and I will post here if anything changed