can anyone shed some light, im at the end of my teather!!!

[no1tosh]

hey
i still have this problem that with my rica 304 in when you let off the throttle it bucks.

i have eluminated that its not the ecu as i have tryed other remaps and it does the same. Now it does not do it with the standard ecu in.
And for some reason scanners will only reconise abs and wont read fault codes. Ive made a flash reader and that came up clear 1-1-1.

ive check fuel preasure with 35 psi at idle and 43 when i open the throttle, i have a volvo document that says it should be 43 psi at idle.

is this right?


so far i have changed:

fuel regulator and rail
plugs
top engine mount
removed DV and put on standard recurculation valve
boost control selloniod
flywheel sensor
changed all my vac lines again even though they were mint
checked for boost leaks
cleaned all my earths
cleaned idle valve
cleaned throttle body

can anyone please help, im on limited funds at the minute so i can't keep buying parts in the hope it fixes it.

cheers

[merc85]

fuel pump getting week??

[M-R-P]

Air leak between maf and turo? Dodgy maf?

[no1tosh]

would a weak pump not have effects on the accelaration as well? i have noticed it has a very faint whine to it not long after i fitted an MBC ages ago. its not been on though sice i got the rica.

is there any way for testing an air mass sensor with a volt meter?

[Volvostorm]

Yup, you connect to pins 2 & 4


https://www.youtube.com/watch?v=NdGPuerxuvU

Just use something better than nails!

[no1tosh]

ahh sweet ill give that a go tomorow night :)

[no1tosh]

right i had a go at the maf test and got 0.90v at idle.
i dont know what this means but it had a steady rise and fall when i revved it.

in the vid above his sits at 0.60 at idle.

ive checked for air leaks between the turbo and maf and there are non.

ive done some more tests which i will post later as im on my way out

[no1tosh]

compression: 175 psi on all cylinders with a steady rise

plug gaps: 0.28

MAF idle: 0.87-0.90

fuel preasure at rail: idle 32-35 psi, with a little throttle it rises to 40-42 psi

can anyone make anything of this? im going to do a voltage test on the TPS tommorow

cheers

[merc85]

175psi is good compression bud :)

[stribo]

When you say let off the throttle do you mean from full throttle to closing it, or part throttle to a bit less throttle?

[no1tosh]

it seems to happen as the butterfly closes, the more rev's the more violent.

it doesnt seem to do it mid rev's.

[siamblue]

Have you checked the TB for any gumming up?

[jdavis]

Actuator?

[stribo]

Have you checked the TB for any gumming up?

Yeah, it does sound like a TB problem, or even the TPS.

[jdavis]

Could the actuator/dump valve be sticking causing air not to be vented away from the throttle intake on releasing the throttle?

[no1tosh]

cheers guys the throttle body has been stripped and cleaned as has the idle valve.

im just going to go and do a multimetre test on the tps now.

the dump valve has been disconected until i can find a replacment intercooler pipe as the last owner chopped mine in half to fit the DV.

[theflyingbrick]

erm I might be wrong but that plug gap seems a little small?? I thought it was supposed to be 7 thou? maybe its not getting a big enough spark and causing it to jerk after a full throttle burst as in slightly stalling caused by flooding the chambers?? but as always I could be well off lol

[no1tosh]

i think i used imperial gap gauges but converted it to metric.

the problem is it does it at any revs and speed, as soon at the throttle shuts it bucks.

ive just done the tps multi- meter test and at idle it is 0.60 and has a steady climb and fall.
the vid on youtube shows his sitting at 0.59 at idle.

can anyone tell me what the fuel preasure at the rail is suposed to be at idle?

mine is 35 psi and as soon as you turn the igition off it drops to 10 psi.
If you rev it a little bit it climbs to 40 psi.

ive read it is suposed to be 43 psi at idle or 3 BAR can anyone conferm this please.

thanks again

[stribo]

Yeah, pre ME7 engines run 3 bar fuel pressure.

[no1tosh]

so could maybe that be the problem?

could it be the fact that there isnt enough fuel preasure in the line when i let off so it could be leaning out a bit?

seems strange though that it doesnt do it with the standard map in