nicobel

"running rich when hot"
MAN
I would like to be rich and then be running in my shark...
I look hot in the shark, no problem ( we all do)

John Speake

I would want a sizable deposit via Paypal. But apart from that just my out of pocket expenses - i.e carriage costs.

If you want it fast (1-2 days) then it costs about 75USD to FedEx to you. Last time they got one to Canada in one day ! If you can wait 5-7 working days then it would cost about 22USD to you.

PM me if you want to go ahead.

Rich9928p

Mark,

I have a loaner LH module that I can ship later this week or early next week. I sent you an email with specifics.

I've seen that modules act different from one car to the next, so it is possible that when you did a trial by installing your module in another car that it didn't show a problem (immediately).

I'll be at the 928 Owners Club International Convention in Wichita and expect to have a few extra modules in case anyone has trouble on the way.

MBMB

TempII sensor hot is 207 ohms.

O2 sensor shows decreasing O2 as the problem arises. (I was hoping that it would show a lean condition as the problem arose, which would suggest a failing O2 sensor).

Jim @ EuroWerks

Hey guys, I've been out of town and just got back. How come we haven't talked about fuel pressure yet? Sometimes when a regulator fails fuel pressure shoots up to something stupid like 4 or 5 bar. ck that. Also I will never let go of the crappie ground problem under the air cleaner. On the engine block. I don't have my schematics at home so I don't know which ground point #s they are.

MBMB

Jim,

Would the FPR fail only when hot?

Tell me more about the crappie ground problem.

Jim @ EuroWerks

The fuel pressure can fail in all kinds of conditions. It can shoot up slow to give your condition or fast where it cuts off (the car) so fast it seems like ignition failure. The grounds are located under the air cleaner. Remove the upper section, then the lower section (ten mm head bolts). Oh by the way, this repair is a bitc(((. Under the lower half is a wheel mounted on a plate. This is to guild the throttle cable. Anyway if you remove the two ten mm head bolts holding the bracket for this to the engine block. There are grounds bolted at each bolt. You will have to pull the braket up to find the grounds. It's hard enough to get to that when I do this repair I also solder new ends on the wire. If you attemt this, do it right the 1st time, no shortcuts. Don't want to do this twice.

MBMB

Jim,

What uses the grounds to which you refer? What might they have to do with the rich condition?

If fuel pressure is too high, does it just squirt too much fuel for each injector pulse, or is there a point at which excess fuel pressure will prevent the injectors closing fully between pulses?

What could temperature have to do with excess fuel pressure? The obvious -- pv/t=k? Or something else?

A slow increase in fuel pressure might be consistent with the problem coming on more quickly in traffic (where the engine is idling more, not sucking up as much fuel) than on the freeway.

(Thinking I might be getting somewhere, and wondering why these epiphanies always come after the big 3 are closed for the weekend.)

Jim @ EuroWerks

MBMB, You are making this way to complicated. Simple, put a fuel pressure gauge on the fuel rail and see if the pressure goes up as your running problem occurs. Also remember that there needs to be a vacuum hose connected to the fuel regulator so pressure is alittle low at idle then goes up just off idle. The reg would fail just as anything else breaks down with age and heat. Make sure it's getting vacuum also. The grounds supply a number of points all within the fuel/LH/EZ system . As they break down, all kinds off weird stuff happens running wise.

MBMB

What can I say? I'm very **** ytical. I'm figuring out how I want to put in a fuel pressure gauge; I'll check those grounds too. I doubt that anything is going to happen before Tuesday.

Thanks, Jim.

Jim @ EuroWerks

The pressure gauge is easy to hook up. Pull the cover on the passenger fuel rail. Remove the 19mm fitting and the connector hooks up there. Ck that 1st since it's easiest.

Mattman928

Below, is some guidance sent to me from the "All Knowing" Wally P, when I was having the same problem.

In my car, I had three problems, (ECTS II) Temp sensor, a corroded terminal on one of the coils, and the MAF died. If you tested your LH, replaced your coils, then I think it narrow's it down to the Temp II sensor or possibly the WOT.

Below is Wally's wisdom:

Back to basics.
Either you are getting too much fuel or you are not burning the fuel that
you are correctly getting. Given the fuel mileage, the black residue, etc.,
I would guess that the "too much fuel" is the more likely scenario.

If you were losing one ignition system, the ignition monitoring system is
supposed to cut the injectors on those cylinders off. You would be way down
on power, but the engine shouldn't be running rich at all.

There are only two likely ways for fuel to get into the engine - either it
is coming in thru the injectors, or it is leaking in thru a split diaphragm
in one of the fuel dampeners or regulator.

The easiest check is to pull the small vacuum line from each of the fuel
pressure dampeners (one front, one rear) and the fuel pressure regulator
(on the rear of the engine) in turn, and check for any trace of fuel in the
vacuum line. The main problem with this possibility is that it should make
the engine very difficult to start when it is hot. Since you didn't mention
that, a split diaphragm is less likely - but it is still worth checking first.

If you are getting too much fuel injected, there are several things to
consider.
First - once the engine warms up, it should go into "closed loop" - that
is, the ECU should use the output of the oxygen sensor to adjust the pulse
width of the injectors to hold the mixture at stoichiometric, which is
pretty lean. This definitely isn't happening.

One thing that keeps this from happening is the WOT (Wide Open Throttle)
switch. This switch on the throttle body should be open unless the throttle
is more than 2/3 open or so. When the switch is closed, the ECU goes to
"open loop", running off of a pre-programmed fuel map that is set for max
power. While this is possible, it sounds as if you are running much, much
richer than that.

Another possibility is that the fuel pressure is way, way too high. Causes
for that could include a faulty fuel pressure regulator or a plugged fuel
return line. You could check that by pulling the fuel return line on top of
the fuel tank (under the hatch carpet) and see if fuel flows freely at idle.

Another possibility is a faulty ECU. Plugging in a known good one, or
plugging your ECU into someone else's car is the easiest check for that.

Hope that this helps some...

Wally Plumley
928 Specialists

MBMB

Matt --

Thanks, that's great stuff. When you say you had the same problem, did it appear the same way -- after the car had been running a while?

How did you determine that your TempII sensor was bad? Did it test bad, or did you just replace it? (Mine seems to test fine.)

Mattman928

Well, the symptoms were fun (grin). I was on my way back from SITM, with a good 8 hours ahead of me, when it all happened. The car was having a bad day.

I stomped on the gas to pas another car, and I literally blew out the oxygen sensor (It had been cross threaded). The car drove well for a while, but then I started loosing power. It would stall at idle, and lost so much power, that I could barely get it up hills (I had to keep the RPMs over 4000 just to get back to 928 Specialists)

(With Earl's Wally's, and Dave's help) We replaced the Oxygen Sensor, this didn't fix the problem. Next we checked the spark system, and found corrosion on the coil connector. After replacing the entire spark system (Coils, ist, caps, etc). We ran the Bosch Hammer, and it indicated a failed temp sensor. We replaced that. After all of the above the car ran a little better, so I was able to limp the car home. It ran slobberingly rich; I averaged 13mpg on the long highway drive home. The car would stall whenever it idled (This was definitely worse when warm).

Once I got home, I changed all the plugs (since they were now completely fouled). I tested the LH in another car, and it ran great. I then tested another Mass Flow in my car, and she fired right up. So I've ordered another one, and then I will button her back up.

MBMB

Where did the WOT switch problem come in?