over fueling problem

New poster! (less than 10 posts)

Hello,
Ive got a really bad fueling problem, when im cruising the AFM goes as low as 9.9:1:crap:, but on idle its stays in the mid 14s and on WOT in the low 12s.

Its a 5 gtx with a b18ft, heres the spec - stock engine, standard T2 turbo (13psi), 5 GTX N/A camshaft, Scoff mod , r5 pace intercooler, 2" straight through, BMC air filter with ram pipe, air flow meter set to 700k for more fuel on boost.

At first i set the boost to 13psi and turned the airflow meter to 700k to be on the safe side as i didnt have a AFM guage. Ive now got a LM1 and 9.9:1 reading is insane, plus is bad for the engine. Ive been runnig it like this for a while, but now abit worried.

Has any one had similar problems, or have any suggestions to what i might be able to do?

So far ive messed around with the air flow meter setting and the bypass but no luck at all.

What bypass method are you using?

New poster! (less than 10 posts)

Its got the original bypass pipe , the one right by the turbo. With the original bypass it used to idle with afm in the high 12s; so i removed one of the bungs on the rubber pipe between the turbo and air flow meter. This helped the idling, it runs pretty much bang on 14.7:1 but didnt make any difference when cruising, still super rich.

Have you tried putting them bung back in, then adjusting the airflow meter screw accordingly to around 14.1 then see how your fueling reacts?

New poster! (less than 10 posts)

yes ive already tried that, no luck. Its proper weird.

up the boost:D

New poster! (less than 10 posts)

Ive tried all sort of combinations to fix the problem, even turning the boost up and down with different air flow meter settings. To save fuel i end up flooring it everywhere, it runs less rich on boost than cruising:dearme:.

the system should have NO airleaks between the opening of the afm, through to the engine its self. as mentioned via pm. also the afm should only be set to 650 for increased boost to a bar, std 4-7psi is about 380 ohms. also as mentioned via pm, sort any leaks by doin a boost test with a compressor then try adjusting the afm. it shouldn't need to be that high as the reg will increase fuel as boost increases. uness its sticky which is where the prob could be?

New poster! (less than 10 posts)

Ive leak tested upto 25psi and there are no leaks. This is when everything was bunged up on the pipe between the turbo afm but still was super rich when cruising, ive only recently removed the bung to see if it will help but its exactly the same, but less rich on idle. I will check out the fuel pressure regulator.

sorry for the thread jump:D but how do you adjust the air flow meter? Also dose this need to be done if using standard injectors but running 18psi? (which i hope to do) Just a thought but could an exhaust leak cause the bad readings?:confused:

25psi is good enough for testing, and any bypasspipe is to trick the afm to seeing less air. the bigger the hole is the less air it sees, so the ecu puts less fuel in. could be worth tryin a std volvo lambda probe if its on later ecu's. ahh just thought, are you still running std fuel tank and lifter pump? is the lifter inlet and outlet pipes the same size? on a campus the return is smaller, i forget on monaco's, so could be causing a restriction, could be worth plumbing gauges in to see feed and return pressures if they are the same. you could also test while running the engine and give the reg some boost from the airfline to see how it increases.

on side of afm is a small plastic, or metal disc pushed into it so its set from the factory, it needs drilling out. then there's a brass adjustment screw below. remember to check what its at before you start to adjust tho. this needs to be upped from around 350-400ohms std to about 650ohms for a bar of boost.
for 18psi you'll need green 740t injectors with matching resistor pack or they'll blow the ecu outputs, and a small bypass pipe.

The tank is the standard 5gtx item but i plumbed in 8mm feed and return fuel pipes with a high pressure bosch fuel pump, ive never had the b18ft lambdahooked up though. Ill check the pressures as soon as the gtx is on road, changing the clutch at the moment.

will using a rising rate regulator (1.7:1) make the std injectors fuel for 18psi?