T5M bogs when getting off the gas

Post by **Clemens** » 28 Sep 2018, 03:54

after getting a new rotor, distributor (bosch) and volvo spark plugs for my 94 T5M that annoying problem persist: when i get off the gas at lower or mid rpms and speeds the motor bogs once or twice. it is smooth under boost and mid throttle, quite smooth while cruising.
i thought it was spark related. but maybe it is fuel (fuel filter?) or vacum. the only thing i noticed is that the intercooler hose running to the intercooler was duct taped by the previous owner. it seems to hold pressure under boost, though.

any ideas?

Post by **Clemens** » 28 Sep 2018, 11:49

anyone?

Post by **abscate** » 28 Sep 2018, 14:30

he only thing i noticed is that the intercooler hose running to the intercooler was duct taped by the previous owner.

a tiny leak here will kill you..I would replace that hose ASAP.

Post by **Clemens** » 28 Sep 2018, 15:16

thanks. i'll give it a try. sure cheaper than throwing other parts at it.

Post by **Clemens** » 10 Oct 2018, 13:11

got my new turbo to intercooler hose today and yes, even though the inner layer of the old hose appears not to be cracked, replacing it made a huge difference. seems like the damaged structural integrity of the old hose caused it to collapse and expand more than it should. it is still not silky smooth, so I will tackle the vacum hoses next.

Post by **abscate** » 10 Oct 2018, 13:50

Whose got the Volvo Horns? I can claim them for a day...or until the 2004 I worked on - her owner figures out I foxtrotted her car...

Post by **misha** » 10 Oct 2018, 16:23

Clemens wrote: ↑10 Oct 2018, 13:11 got my new turbo to intercooler hose today and yes, even though the inner layer of the old hose appears not to be cracked, replacing it made a huge difference....it is still not silky smooth, so I will tackle the vacum hoses next.

Reset ecu by removing negative battery cable for 10-15min in order to reset fuel trims.
Perform re-learn procedure and see is there any difference.

Post by **Clemens** » 11 Oct 2018, 12:52

i will give it a try and report back

Post by **Clemens** » 12 Oct 2018, 10:08

i cleaned the maf and reset the computer. that did improve dribeability. then i swapped the ignition coil with the known good one out of my 96 R and that further improved things. I'm feeling sassy and might order the last pricey item, a set of bourgicord wires. might just be a cumulated tuneup issue.

edit: what's left feels basically like small misfires at steady rpms between 2 and 3k. Snooth under boost, alright when getting off the gas

Post by **misha** » 12 Oct 2018, 10:55

I had never seen them failed.
I bought the car new and still have original wires...not a hiccup...never.
Drive it a bit allowing an ecu to fine tune itself.After reset it needs a good few hundred kms to set new fuel trims and to re-learn new inputs from all sensors.