V40 T4 (1.9) Misfire / backfire - running rich

[mikeyskona]

Hi guys (and gals).

2 days ago i became the prowd owner of a 98 Volvo V40 t4. Test drove the car and it was absolutely on the money, so handed over my cash, then drove it 50 miles home without missing a beat.

Next day, at anything over quarter throttle it'd misfire, bog down and sometimes die altogether. I checked the HT leads and Coil packs and they were shot, so replaced them (spark plugs looked ok). This made it better, but the problem was sill there.

Then the wierdest problem cropped up. After turning the engine off, the cooling fan would start spinning for about 15 mins then shutting off (yet wouldn't when it's running). I had it plugged in to the diagnostics today, and they didn't give me the fault code, but told me that It reported "L1 Bank Fuel running rich" or something like that.. Basically the car is running rich.
I completely disconnected the MAF, and it improved things a bit yet it's still misfiring (and backfiring) quite Alot.. and now the MAF is disconnected it stalls on idle, but i was expecting that, sometimes it's almost undrivable.

Is it likely the MAF is the cause of all my woes? or am i looking at something a bit more severe... I am on a very limited budget after buying the car, so i have to be as systematic as i can on repairs. I can't just replace bits Just in case (not yet anyways).

Thanks in advance guys

[btsam]

the duff maf thing you mentioned makes a bit of sense,

i and gmain have accidently left the maf unplugged on our cars and as well as throwing an engine light until plugged bsck in one mine the rad fan wouldalso stay on after i switched off the ignition

s

[mikeyskona]

Ideal. Thanks.. Well i'll try and get hold of another MAF tommorrow and see if that cures

[gmain1967]

As btsam said, we had issues when the MAF was (accidently), left disconnected.

I decided to remove the MAF and. contrary to some advice, got electrical contact cleaner and gave it a spray. I also sprayed the connector on the top of the MAF unit itself, and poked dead flies off the gauze itself (still not a clue how those got there, but they were)!

Touch wood, things have been fine since. If you are considering a new MAF, worth a go with this - nothing to lose really? Just make sure that it is electrical contact cleaner you use, if you do try this.

Best of luck

[mikeyskona]

Thanks.... The MAF is definately screwed.... One of the 2 elements is missing (the clip is there but no wire in between them) so it's definately had it.

I'll try another one and see if that cures the problems. I'll let you know how i get on.

[Terminator]

Assuming its not the MAF or just the MAF, have you checked the condition of your air filter?

[T4Rick]

Replace your plugs and you should be fine,I had the same problems as you.I bought the car test drove it and was fine got it home and the car wanted to die.I got the iscv from the scrappers from a non turbo model whacked it on after i changed the plugs to platinums a few weeks back and the car got better but i still had a miss fire.I stripped the coil packs down to find my coil packs had split from the top to the bottom of the stem.So i sorted it out and has been mint.I also did replace the fuel pump for a hrc one and did the filter.But for the love of god bin those plugs or take them back please.

[mikeyskona]

thanks for your message andy.. i can't respond tho cause i havent sent enough posts.

Rick. They will be going back tommorrow!...

Just in case they aren't the whole problem, i'll mention this whilst i remember.

I've been driving the car about all day, and i've tuned the throttle right down so full bore is actually quarter throttle (because i kept o-ver throttling it and causing a misfire etc)... anyways.. it's been ok-ish... left it for 3-4 hours and just driven home now. Very cold night here in plymouth... and even warm, the car is running like absolute crap again.. worse than it's been all day.

So, it doesn't seem to like a nice clean crisp night?... i thought it would have preferred that :\.

Anyways..... the plugs might be the whole remainder of the problem...... but if this flags any other issues up to you, i'd like to know.. Best to be prepared.

Also..... Remembering i am just about skint... I want to do a fuel pump as well, as i have no idea how many miles this one has done!... What would you suggest?... I'm not after higher performance, or even something guarenteed to last forever at the moment, I just want to get everything right for the moment until the money starts to flow again and i can look at upgrades

Thanks again guys

Mike.

[Baffler]

Originally Posted by mikeyskona

I've been driving the car about all day, and i've tuned the throttle right down so full bore is actually quarter throttle (because i kept o-ver throttling it and causing a misfire etc)... anyways.. it's been ok-ish... left it for 3-4 hours and just driven home now. Very cold night here in plymouth... and even warm, the car is running like absolute crap again.. worse than it's been all day.

Not quite sure what you mean by "tuned the throttle right down"? I'm guessing you've adjusted the throttle cable? There's no need to meddle with any of the factory set screws on the throttle housing!!!

That misfire must be affiliated with the lambda sensors or unburnt fuel due to the incorrect plugs?

Originally Posted by mikeyskona

So, it doesn't seem to like a nice clean crisp night?... i thought it would have preferred that :\.

Yes, turbo charged engines much prefer dense cold air. A lot could ride on the correct plugs so, as a first step, I strongly suggest you get a set of genuine Volvo ones. They are tried and tested and good for 30k miles. Try Angliavolvo on eBay or our resident main dealer FRF Volvo Swansea (Rufe)

Originally Posted by mikeyskona

I want to do a fuel pump as well, as i have no idea how many miles this one has done!... What would you suggest?... I'm not after higher performance, or even something guarenteed to last forever at the moment, I just want to get everything right for the moment until the money starts to flow again and i can look at upgrades

As a temporary measure you could remove the in-tank fuel pump and clean the nylon filters at the bottom of the swirl chamber. After removing the fuel pump remember to replace the sealing ring and plastic retainer ring back onto the tank, whilst you're cleaning, as they WILL shrink and prove impossible to replace when you come to replace the pump. I would also advise you to replace the fuel filter (if it hasn't already been done?) just to the front of the fuel tank.

[mikeyskona]

Yeah... I adjusted the throttle cable in slack, so i couldn't do more than quarter throttle as anything over that kills it

the fuel filter was on my list of things to do next actually, gonna whack a bit of injector cleaner through my next load of fuel as well just to make sure they're nice and clean, two of the first things i do on any new motor. It will also be having an Oil and filter change very soon (what's the best oil to use on these, Castrol GTX? grade?)

Ta

Mike.