MPFI deadspot in throttle - blog **99% SOLVED**

SuBaRiNo · Post by **SuBaRiNo** » Mon Jun 19, 2006 12:43 am

Mines a 3 wire... and can also run without it connected at all... actually seams to run better without one than when it is running a busted one. Never seen a 4 wire one.

Dave

subanator · Post by **subanator** » Sun Jun 25, 2006 11:19 pm

Had a think about this after reading your post Dave, so I ran it without the O2 sensor connected. Did seem to run without so much of a flatspot.

I then checked for the earth path, exhaust - body. It was of a high resistance, and knowing the sensor voltage is so low, it would affect the reading heaps. I think there supposed to be an earth wire connected some where, so I ran a new one.
Ran car with new earth to exhaust and sensor connected - result very good, large improvement!

Definately a lot smoother around the boost transition, does hold back a little still, but nowhere as bad. Still might replace O2 sensor as Subarino suggested.

EDIT: Driving around today found it was basically back to usual flatspot. This prob is intermittant and makes harder to find.
Also found out today that a 3 wire sensor is basically a 1 wire with heater, both narrow band. The 4 wire is wideband and has a different output.

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Wed Jun 28, 2006 7:44 pm

I am chasing an eradic and occasional rough idle in Dads Car (EA82T) So far ive given it a upper engine clean, cleaned the bypass air controller (was really really dirty in there) and related hoses and inlet plenum, and have cleaned the AFM, the problem is still there so next its plugs and leads.

subanator · Post by **subanator** » Fri Jul 07, 2006 12:05 am

90% progress Update:
Wagon has been left a tuner/repairer this week after I exhausted my capabilities.
Briefly, it has been running ultra lean, 16-17:1 air/fuel ratio.

Now has a RX Turbo ECU, improved by a huge amount. He cant put his finger on the last bit, but he is trying to achieve 12:1 A/F, currently runs 13:1.
This has been achieved by using a higher volume pump to up the fuel pressure (test only) and clamping the regulator return line. A Malpassi adjustable reg is on order and to be fitted.

Also he sees the injector pulse width maxed out along with the air flow signal at standard 7 psi boost. This is the current hurdle, seems strange this is how this has limitations, is this an RX Turbo thing?

mAJORD · Post by **mAJORD** » Mon Jul 10, 2006 7:13 pm

odd.

Well with a malpassi rising rate reg, I can tell you the standard injectors are good for a lot more than you'll be needing at 7psi. not sure at standard fuel pressure however.

subanator · Post by **subanator** » Thu Jul 13, 2006 12:00 am

PROBLEM SOLVED - 99%

Car now back today :P , drives heaps better, pulls evenly without any flatspot. Power does tend to flatten in the top RPM, but this is the characteristic of EA82T's. Does go heaps better, verdict - keep car now.

This is good as it gets, so I will have to be happy with that, as even more money would need to be spent.

I will look into any Jaycar kits that convert or adjust the AFM signal, as this can get a little more out of the ECU to the injectors.

An intercooler will be next and a better aircleaner and a bigger dump-pipe. This is far as I can go on the stock ECU, would need an aftermarket one if I wanted to fit the Forester XT turbo I have. (will sit on that one for now)....
Roger

BlackMale · Post by **BlackMale** » Thu Jul 13, 2006 11:51 am

Mate good to hear that she is back and firing hard... AND that you are going to keep her. We'll compair if you like (hope i do not get shamed out though

)

wrx_nut · Post by **wrx_nut** » Thu Jul 13, 2006 6:47 pm

so what was wrong with it? my ea82t is playing up...

subanator · Post by **subanator** » Thu Jul 13, 2006 7:50 pm

Hey Jaffa, I would like to compare, and give you a drive too, cos I dont think it is as good as it could be, just a little short in top end? 100% better than it was

wrx_nut, just read the whole thread, too much to explain. It gives a pretty good process of my elimination and may give you a few pointers to start looking at. You may have similar or different symptoms.

wrx_nut · Post by **wrx_nut** » Thu Jul 13, 2006 7:51 pm

righto cheers

subanator · Post by **subanator** » Mon Jul 24, 2006 11:45 pm

WOO HOO - 100% SOLVED

Another post on the forum finally solved the problem.
Thanks to Suby Wan Kenobi, he mentioned a difference in injectors, being red ring ones for turbo, and grey ring ones for N/A.

Mine had 1x red and 3x grey ones. Then last w/e I got 4x red ones, fitted them today and what a difference!!!!!!!!!!

The engine now feels way different, power now stronger along the whole range, and the boost has risen to 7.5 - 8 psi. I can spin up the tyres easily now much to my surprise.

I am so glad I perservered to get to this point, cos I was close to selling it a couple of times, so on with the lift and other bits to fix (a list still a mile long)

Thanks to all replies and help on the board.
Roger

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Tue Jul 25, 2006 12:25 am

Sweet, great to hear its finally sorted, it must have run like crap with only one red injector in there.

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MPFI deadspot in throttle - blog 99% SOLVED