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x-rad · Post by **x-rad** » Sun Nov 25, 2007 12:28 pm

yep, took her on the road for a good hour ride through the hills...

engine is strong! no smoke. ran at 150 the whole time. Hood vents really keep temps down!!

BUT STILL HAVE INTERMITTENT POWER LOSS????? must be wiring but i don't know where to look. Fuel pump wiring appears OK, I will change it oit next weekend..

It only ocurrs sometime when stepping on the gas. If i step all the way for full throttle, no problems..

Mats · Post by **Mats** » Mon Nov 26, 2007 12:59 am

Is it possible that it's expecting a lambda signal?

Post by **Zamani** » Mon Nov 26, 2007 9:27 am

Hey Mats,

You could be right. Maybe the Lambda circuit or wiring of the ECU is flaky. Or maybe the lambda (O2) sensor itself is broken. The tell tale sign is, WOT is OK but part throttle there is some oscillation in power delivery.

x-rad · Post by **x-rad** » Mon Nov 26, 2007 3:54 pm

Thahnks guys, but there is a Brand new sensor and wiring (O2) ....checked w/ air fuel mixture guage and it was dead on center stochiometric...

I need to get a fuel pressure guage on the fuel system as well so that I can see it while driving around..not just reving in the garage..

Anyway..met this Italian at my local bar tonight...he runs an engine emissions consulting company and one of his employees is this guy who is really versed in Italian and German electronincs from the 80's(Ferrari, Alfa, fiat. etc.....)

I will meet with him and see what he thinks...

x-rad · Post by **x-rad** » Sun Dec 09, 2007 3:49 pm

OK..Bosch guy had no clue

.I am considering keeping both cars now that the wife has settled down a little...unless my price is met

In any case, played around some more with Alfa today....

Noticed that my hesitation problem only occurs once engine is warm...when cold, no problems.

Thermotime switch is unhooked

...will definately wire up fuel pump on its own tomorrow...

MR2 Zig · Post by **MR2 Zig** » Mon Dec 10, 2007 6:29 am

Iv'e seen crank position sensors (on motorcycles) fail with heat...once warm...but be ok when cold.

an idea.....maybe a crappy one, but I hope it helps.

Scott

x-rad · Post by **x-rad** » Mon Dec 10, 2007 10:22 am

No crank pos sensor on L-jet...

crappy weather...did not get to work on car today

Mats · Post by **Mats** » Mon Dec 10, 2007 11:30 am

x-rad wrote:No crank pos sensor on L-jet...

crappy weather...did not get to work on car today

Check your distributor.

x-rad · Post by **x-rad** » Mon Dec 10, 2007 12:24 pm

Mats: I looke d closely at the dizzy...still don't see a crank position sensor

I do see a hall sensor which loosely relates to crank position....

but since I put in an entirely different dizzy sensor (optical) and and entirely different injection control (Haltech)...and an entirely different engine...and the hesitation still persisted:

the problem must be with fuel supply loop (not inlcuding fuel pressure regulator or injector control) or fuel pump power...

Mats · Post by **Mats** » Mon Dec 10, 2007 12:36 pm

I would seriously look at the mout to that optical sensor.

For the record, I would never fit an optical sensor on my car for something as critical as that. They are very sensitive and cannot be trusted. What was wrong with the std Hall sensor?

kevin · Post by **kevin** » Mon Dec 10, 2007 12:46 pm

x-rad, as mentioned early I had a simmiliar problem with the hesitation on friends car and it actualy occured mainly when the stearing wheel was turned. It was the power supply to the fuel relay, which was catching on some other wire. Try a new cable direct to the pump and no innertia switches to test.
Cheers

x-rad · Post by **x-rad** » Mon Dec 10, 2007 2:50 pm

THANKS GUYS for your input..I do appreciate it!!

MAts: I converted back to hall sensor (stock dizzy, on the car now)

Kevin: today i directly wired the fuel pump to the battery. Man that pump was humming like never before. And then I went for a ride...

Well, the problem was much much less prominent!!!! BUT, there is still some slight hesitation (rare, but I would say it happens 1 out of 10 times when stepping on the gas--stepping slow or fast does not make a difference)

cruising at 50-60..absoulutely no problems..unlike before

Then I disconnected the fuel pressur regulator and blocked the hollow intake pin...still very slight hesitation (but maybe a hair better)

It feels like the engine is trying to catch up as in "not enough fuel"

Maybe there is a leak in the fuel line and a small amount of air is enetering the system near the pump. I have put all new lines in from front to back except the line from tank to pump...this one is old line from tank to pump and it has some small cracks in outer casing..

I feel strongly now that this is a fuel pressure problem as several of you have already stated. If I end up not selling the car, I will wire up a whole new pump w/separate relay and lines and pressure regulator....

Anyone ever have trouble with the aluminum one way valve located on the fuel line high pressure side??? MAybe I should remove this????

sira · Post by **sira** » Mon Dec 10, 2007 4:19 pm

x-rad wrote:
It feels like the engine is trying to catch up as in "not enough fuel"

Maybe there is a leak in the fuel line and a small amount of air is enetering the system near the pump. I have put all new lines in from front to back except the line from tank to pump...this one is old line from tank to pump and it has some small cracks in outer casing..

????[/b]

hmmm i had similar problem with this, clamp on fuel hose from tank to pump was bad and air was entering. It was on 2.0 TS and I can't start the car with that problem.

x-rad · Post by **x-rad** » Tue Dec 11, 2007 2:10 pm

yep Sira...this could definately be the problem...

and maybe when i turn, the hose gets stretched just a little but enough to crack open and let air in...no fuel leak though...

someone coming to look at car tonight for possible sale, if not sold, I will repair this weekend...

Mats · Post by **Mats** » Tue Dec 11, 2007 10:51 pm

Wouldn't that lead to fuel leaking out? Or is the in-tank pump broken too?