350i starting issue
Discussion
Don't know if anyone could offer any advice but having trouble starting the beast. So the other day decided to go for a spin, car started as per normal drove out of garage onto drive, got out to shut garage door and the cars idle slowly reduced and conked out. So went to restart and car totally dead, turns over ok but does not fire.
So seem to get pretty good spark, plugs seemed wetttish.
Checked the resistance of various sensors, ie coolant temp, thermotine, and all seemed ok.
Checked for air leaks, replaced a couple of hoses which looked slightly perished but all seemed ok.
If I put igniton on and blip throttle, injectors all click.
Fuel pump runs if I operate the AFM vane.
I have a foxguard alarm which looks like its disabled, although not entirely sure.
So at this point I gave up and decided to buy a pressure gauge to check fuel pressure. So having left the car for a week, I thought turn the key and see what happens and car fired up first time, drove car out onto drive left it running for a bit, got out to shut garage door and it conked out never to restart again.....sigh!
There does appear to be some sign of life now, like it thinks about starting but doesn't.
So checked fuel pressure and I'm guessing there's something not quite right here but can't believe this isn't why it doesn't fire up. So attached gauge to 9th injector, (have to say didn't purge air out of the line) and when you run fuel pump it reaches a max 45psi, but when you turn off fuel pump it immediately drops to about 38psi and then over the course of a minute drops to about 25psi. If I start to pinch the fuel line back to tank, I can get more than 45psi.
So I'm at a bit of a loss, I'm a bit conscious that I don't want to go tearing too much apart and causing other issues, but just wondered whether anybody had any ideas as I'm wondering whether I'm missing the obvious here.
Any help obviously greatly appreciated as I'm suffering with wedge withdrawal symptoms.
So seem to get pretty good spark, plugs seemed wetttish.
Checked the resistance of various sensors, ie coolant temp, thermotine, and all seemed ok.
Checked for air leaks, replaced a couple of hoses which looked slightly perished but all seemed ok.
If I put igniton on and blip throttle, injectors all click.
Fuel pump runs if I operate the AFM vane.
I have a foxguard alarm which looks like its disabled, although not entirely sure.
So at this point I gave up and decided to buy a pressure gauge to check fuel pressure. So having left the car for a week, I thought turn the key and see what happens and car fired up first time, drove car out onto drive left it running for a bit, got out to shut garage door and it conked out never to restart again.....sigh!
There does appear to be some sign of life now, like it thinks about starting but doesn't.
So checked fuel pressure and I'm guessing there's something not quite right here but can't believe this isn't why it doesn't fire up. So attached gauge to 9th injector, (have to say didn't purge air out of the line) and when you run fuel pump it reaches a max 45psi, but when you turn off fuel pump it immediately drops to about 38psi and then over the course of a minute drops to about 25psi. If I start to pinch the fuel line back to tank, I can get more than 45psi.
So I'm at a bit of a loss, I'm a bit conscious that I don't want to go tearing too much apart and causing other issues, but just wondered whether anybody had any ideas as I'm wondering whether I'm missing the obvious here.
Any help obviously greatly appreciated as I'm suffering with wedge withdrawal symptoms.
Hi, thanks for the replies.
In answer to questions:
1. No giving throttle doesn’t help starting.
2. On the regulator front, I hadn’t realised there were different ones, i’ll have to do some investigation there once I get it running again. As for fuel pressure I get loads, I ran up fuel pump and started to pinch fuel hose returning to tank and it went up to 60psi. It probably would have gone further but I started to get worried about whether I’d done the jubilee clip on the pressure gauge up properly and didn’t want the fire it into oblivion. But thanks for the info on pressure regs.
3.adam, yes the car started on those 2 occasions and looking back I’m slightly annoyed that I let it conk out but at the moment I can’t get it started at all.
I’ll have another look Saturday, having done lots of reading can’t help but think it’s a fuel issue as mark said. I’m thinking next step is to attack the aux air valve at the front and measure sensors from the ecu connector. I’ll keep you posted, any bright ideas and please let me know as I’d prefer to be out driving it than fixing it.
Cheers Pete
In answer to questions:
1. No giving throttle doesn’t help starting.
2. On the regulator front, I hadn’t realised there were different ones, i’ll have to do some investigation there once I get it running again. As for fuel pressure I get loads, I ran up fuel pump and started to pinch fuel hose returning to tank and it went up to 60psi. It probably would have gone further but I started to get worried about whether I’d done the jubilee clip on the pressure gauge up properly and didn’t want the fire it into oblivion. But thanks for the info on pressure regs.
3.adam, yes the car started on those 2 occasions and looking back I’m slightly annoyed that I let it conk out but at the moment I can’t get it started at all.
I’ll have another look Saturday, having done lots of reading can’t help but think it’s a fuel issue as mark said. I’m thinking next step is to attack the aux air valve at the front and measure sensors from the ecu connector. I’ll keep you posted, any bright ideas and please let me know as I’d prefer to be out driving it than fixing it.
Cheers Pete
Hi, thought I’d just add some closure to this one but after a lot of sodding around I finally discovered that my throttle potentiometer had been adjusted right to the end stop, so I was getting 0v as opposed to the 325mv as expected. I’ve never adjusted this so I don’t know what that’s all about, but I’m guessing the cars going to fail on emissions at the next mot. Does anyone know if there’s a reason why you’d adjust this potentiometer like this?
On the plus side car now goes like a beast and starts instantly as opposed to the 4 second delay before. I’m slightly confused as they say in the manuals that the throttle pot makes little difference to ecu and that people often disconnect them.
Need to sort out the slight fuel pressure seepage now, my fuel pressure reg looks old so might replace anyway. Any suggestions for pressure regs, are the rising rate the ones to go for?
I noticed in the manual it says if you fit a rising rate reg you need to adjust the extra air valve at the back of the plenum.
Anyway off to drown out the ford tuner boys that seem to have invaded the place this weekend.
On the plus side car now goes like a beast and starts instantly as opposed to the 4 second delay before. I’m slightly confused as they say in the manuals that the throttle pot makes little difference to ecu and that people often disconnect them.
Need to sort out the slight fuel pressure seepage now, my fuel pressure reg looks old so might replace anyway. Any suggestions for pressure regs, are the rising rate the ones to go for?
I noticed in the manual it says if you fit a rising rate reg you need to adjust the extra air valve at the back of the plenum.
Anyway off to drown out the ford tuner boys that seem to have invaded the place this weekend.
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