Mot Fail S16

[Jemehan 3 1 Cars]

I Hadnt suspected the Fuel pump as she runs fine (bar the issue previously mentioned). The pump primes as it should, runs constantly untill i turn the engine over, i have not waited for it to stop priming before trying to start the car. A whole new loom does sound quite excessive for an issue that has appeared after its been running for the last year without issue.... I have read elsewhere that TPS can break down over time.

[pug_ham 240 3 Cars]

I'm not suggesting a whole new loom, although yours does look to have been chopped about for some reason which could be a cause if two badly cut & joined wires are touching each other or one has broken & looses contact when you accelerate due to engine movement.

 

I had an issue just last week where the gearbox to chassis earth on my 306 was breaking down & I was getting random abs warning lights flashing up while driving along & the coolant temp gauge reading 10' higher.

 

g

[Jemehan 3 1 Cars]

I will probably take the tape of the wires and have a proper look inside to see the condition of the joined wire, and how they have been joined. If it is poor i may get a soldering iron out there and solder them together to give a cleaner connection. May help. Though im hoping this issue is majority caused by bad sensors.

I took the battery out and intake and all that yesterday and had a poke around at the loom to see whats what down there and it seemed ok. It just concerns me why the car laggs, just hoping this will fix it. Ideally i would like to borrow a coil pak / buy a spare and change it over to the other 3 coils that are not new to see if its them causing the issue. just in case.

[Vili 17]

Have you measured the fuel pressure? My old 306 S16 used to bog down and it took ages to crank. The fuel pressure regulator had gone. The pressure was around 2 bar at idle and it idled fine but under load the pressure dropped under 1 bar and the car lost all power.

[Jemehan 3 1 Cars]

To be fair, no have not measured the fuel pressure. Where can i get a regulator from? I dont want to pay too much as i have spent a small fortune on parts to try and ammend the issue, i dont think ill ever know for sure why its doing it even once its fixed. I will get the new parts fitted this weekend and if the issue is still there get a regulator too. Can you measure the fuel pressure from where the filter is? Surely this would not tell you how much pressure is running through the regulator though?

 

 

Also, would this cause this intimittent issue if it were the case?

[welshpug 1,623]

ebay, local parts stores, scrapyard.

 

 

pull a pipe off the rail and pressurise it, your gauge should reach 3 bar and hold it.

[Jemehan 3 1 Cars]

Right, latest update lads. Changed all the sensors for new ones now, still doesnt start any faster or run any better though. I have also tried a different fuel pressure regulator, which made no difference at all, I am low on fuel though so will try again once i have had a chance to fill up. I have a spare coil pak which i will need to try on each cylinder in turn to see if any of those are dodge. On the upside, the new fan switch works, so no more over heating for the MOT.

[Jemehan 3 1 Cars]

Taking ages to crank over to start is often a sign of lack of fuel pressure at the rail, usually from a faulty return valve in the in-tank pump.

 

Basically, you're having to crank the engine over for long enough for the fuel pump to re-pressurise the fuel rail before there's sufficient pressure to inject sufficient fuel. Usually once it's started, you can switch off and it'll start again on the button within a few minutes, but not when left for an extended period.

Right, so This (above) is the only thing left that i have not tried. I have changed the inlet, tested all the coil paks with a spare and they are all firing, i have checked for air leaks and there are none. I have changed all the inlet sensors (bar ICV - but tested and this works fine). The only thing left to change would be the fuel pump. But its hard to believe this is the issue. I did video the funny misfire but it wasnt a great video, can post the videos of the issue if people think it will help diagnose it?

 

The only thing that causes me to consider perhaps the pump is the problem is worse straight after i go all the way around a round about, you put your foot down to come off and she bogs, no accel and starts to slow down trying to stall, you let off and she pops and spits, it takes a couple seconds to clear (normally having to pull over to let it sort itself) and then it struggles to get going agian, though once it passes roughly 3k revvs there is no issue at all. Does this help? Really getting frustrated now...

 

**I have changed the fuel filter and as previsly stated, checked plugs and coils paks.

Edited January 6, 2013 by Jemehan