Final persistant issues.

Me again, and apologies. In an effort to get the car running 100% I have a couple of queries remaining after getting the car on the road this week.

First off is coolant temperature. The gauge will get to around 1/3 or slightly more when idling but when driving around it drops to almost nothing, on the motorway it indicates stone cold.

I have replaced the thermostat in case it was stuck open or weak, I have tested the gauge by shorting the feed, it pegged out so it works fine, I have a new gauge sensor coming in the post to try. Anything else I should be considering? I'm pretty sure the system is bled properly.

Next up could someone experienced with the cars have a quick look at my plugs, last set were black with soot due to det sensor being knackered, this new set has done around 90 miles of normal driving, not a lot of boosting, I would say they maybe look like it's running a bit lean? But I'm no expert at reading plugs They are BCR8ES, I am a bit paranoid about running lean I have to admit.


I'm keen to get a wideband afr gauge but need a neat solution for the cabin as I hate extra gauges around.

Thanks in advance

Have you checked for any air locks in the radiator, run it with rad cap off and see if theres any bubbles, id also be tempted to flush the system

White tips normaly mean its running lean black sooty colour means its running rich .... can you post up a closer look on one of the plugs please mate ...

Loads plugs looks likes it's running lean, if you think you have an issue with your det sensor and it's retarding the ignition then those plugs might make sense

Thats what i mean the tips look quite white ....have you cleaned them since you done the det sensor ???

Coolant system has been drained, filled and properly bled about 3 times in the last couple of weeks, it will get done again when I do the sensor if there's nothing else to check. Might flush it too while I'm at it but it's pretty clean in there.

I have just changed the det sensor to a good one, but no I havnt cleaned them since that. Might be an idea to do that then give it a proper thrash and check the plugs.

They were proper black before when the det sensor was knackered as it retards it and richens the mixture, must have been running like that for ages.

Too lean graham
You need to buy a wideband to monitor afr's for sure as there's a prob there somewhere

Getting a bit tired of it all now. Fix it from being too rich and now too lean!

Have ordered an AEM wideband but further to that I'm out of cash for a while as the house needs some attention so hopefully it's something simple.

Will turn the boost down for now and start to check out fuel supply. Plenty of possible culprits there.

How the car feel now grim ??? Yeah lots of possibilties on fueling .... what boost are you running ???

Car feels fine, on and off boost, drives better at low revs after changing knock sensor.

Currently running 1.35bar

Previous owner told me that when the car was mapped they went for 1.6bar but it was running too lean at high revs due to fuel pump wiring not being able to cope so settled at 1.35bar

Different shell but wiring could be worse...

I had the same issue on the dyno when being mapped, with standard wiring loom to fuel pump. Remember the wireing on GTiR's are 20+ years old & don't hold enough current now!

So I did the direct feed mod on the fuel pump... Then you will know its getting a good power feed then & that's 1 issue out of the way!

http://www.gtir-motorsport-club.com/t1373-direct-power-feed-from-battery-to-fuel-pump

Thanks gaz that is one of the things on my list to do, boy I share my unit with is a bit of an whizz with all that and we've been discussing the best way to do it.

The how to isn't that great but I appreciate it's just copied from the oc.

Ok so fuel pump wiring mod done, new fuel filter and Wideband gauge installed.

Seems to be running a bit rich now although plugs look ok to me.

At idle start at around 12.5 dropping to high 11's then stays there.

Cruise around town 2.5k revs it sticks around stoich, going up and down with input.

Cruise at higher revs mid 12/13.

WOT it will go right down to 10.

Don't think I have an air leak as have about -0.5bar of vacuum.

It is maybe possible that now the fuel pump is delivering fuel as it should the fuel map is off? Time to start looking for boost leaks too. Maybe fuel pressure too high now and weak fpr?

Something else of note is that most of the time the car does require a little blip of throttle on start up or it will stall, might be related, IACV issue?

Could it be butterflies not shutting properly or sticking ????

I don't think so but that wouldn't contribute to being over rich at wot?

No i guess not @wot it wouldnt .... like you say check for boost leaks...

Leak tested today, at least until the tester gave way,

The turbo outlet hose had a hole in it, so changed that, made no difference. Still mid 10, low 11 afr on idle.

No significant leaks elsewhere, I'm sure there will be some tiny ones about.

Fuel pressure is 3.2 - 3.4bar at idle, a little high, enough to cause it to be this rich? rises to about 3.7 when revved. Standard FPR.

Not sure what to try now or if the next logical step is to have it mapped