223 replies to this topic

[DaveyC]

A bit of an update -

 

I took the car to Vocky to take a look at the wiring. He stripped out the engine bay loom, tested it and re soldered all the extended wiring used for the supercharger conversion. He also tried a known good coil pack and some other spark plugs. No real difference noticed.

 

He then tried a different coolant temp sensor and there was a slight improvement so he installed a new one. I used the journey home to re-learn the base fuel table, which was about an hour and half of solid driving at varied speeds, loads and gears, mostly trying to focus on the problem areas wherever I could. The stuttering is considerably better, but certainly still there, particularly when gently trying to increase speed from around 2k rpm and is still there when the engine is under no load at all i.e. in neutral just holding the revs at 2k.

 

In total, the car has had replaced:

coil pack

spark plugs

ignition condenser/suppressor

ECU

complete bottom end

head gasket

valves

valve stem seals

cams

inlet/exhaust gaskets

complete exhaust system (3" tullett + HSJ cat)

injectors

fuel pump

throttle body

Both OEM O2 sensors

2 wideband O2 sensors

crank sensor

coolant temp sensor

knock sensor

two timing chains (most recently timing set by Vocky)

 

During the stuttering the fuel pressure reads constant and normal and the lambda reads constant and normal.

 

[siztenboots]

map sensor leak?

[DaveyC]

Do people typically pop some rtv or something on there?

[CHILL Gone DUTCH]

I removed the rubber boot and put some ptfe tape around it and put boot back on until it was a good fit As it is a little lose on its own

[DaveyC]

Pretty sure that's what I did when I installed the tmap. Snug as a bug.

[siztenboots]

spray brake cleaner around the intake manifold, there must be a vacuum leak somewhere for low load to be affected

[Hopegreen]

Hello from Barcelona,

 

We are a group of three speedster in the same garage (at this moment 4). All of them with OBD tuner and supercharged stage 2. (some little differences between them).

One of us is having the same issues, he finally changed the engine due to other problems (the engine splits in two parts due to a bad mapping) and now with another engine the misfires are still there.

 

We have done a lot of tests swapping parts from the other two speedsters but it doesn't work. We only improved it when we added fuel manually.

 

Right now we are having some problems with the coolant, it looks like it doesn't flow properly...

 

Kind regards,

Francesc

[DaveyC]

Interesting. Have you swapped the thermostat or anything like that? Mine had a new water pump but the same thermostat.

[Hopegreen]

We swapped thermostat and last week we replaced the water pump.

Edited by Hopegreen, 26 January 2016 - 01:44 PM.

[DaveyC]

Well let me know if you ever fix it.

[Hopegreen]

Of course, I will post here our progresses.

[CHILL Gone DUTCH]

could this be down to the fuel pressure regulator,

do you have the pipe from the regulator on to the inlet manifold ??

[DaveyC]

Yeah I do. Changed the pipe just to be sure. Also had a fuel pressure gauge hooked up and the pressure remains constant during the misfiring.

[CHILL Gone DUTCH]

have you still got your issue davey 

[DaveyC]

Yeah I do.

[CHILL Gone DUTCH]

did it get any better in the summer months 

 

[DaveyC]

Hard to say really, it has had such little use!

[CHILL Gone DUTCH]

my thinking was that you could be running the wrong temp plugs 

or the fuel regulator/ or fuel regulator to manifold pipe 

 

have you checked the pressure from the inlet manifold to regulator pipe 

 

[DaveyC]

Should be the same pressure picked up by the map sensor, right? As for the plugs, I've tried a few different styles and temps but nothing has made a difference. You can notice the misfire at a fast idle when there is next to no load on the engine as well as whilst driving along.

[CHILL Gone DUTCH]

ah have you tried a known working fuel rail