S50B32 not running clean

[Larsen-Racing]

Hi!

Got trouble with my S50B32 not running clean. I have new spark plugs on it's way.

Engine has been sitting for about 6 months before I got her fired up in the E30M3. Cheating can only be felt when I floor it in first and second.

Does the fault codes on the DME delete it self when the battery is disconnected?

You can clearly hear it in this movie here:

[DanThe]

Does the fault codes on the DME delete it self when the battery is disconnected?

Nope, they will stay on until cleared off with a scanner/fault code reader etc

[Larsen-Racing]

Ok, and that will be Car Soft or something?

[Larsen-Racing]

Have been to BMW and they could not find any fault codes that should interfere with the engine not running clean.

I have also changed the spark plugs, of course I used the stock "in"expensive NKG plugs. And it is still not running clean in first. I assume don't have all the HP eather.

You who got S50B32 in E30, if you start off rolling slow in first and put the pedal to the metal. Does the tires start to spin before you hit the rev limiter? Mine don't with 225/35 Toyo T1-R....
Even in WET it don't!

Going to the dyno on Saturday, so if I don't find out anything before that time I will probably see it on the dyno sheets. With no speedometer signal the curve drops drastic at about 5-6000 to rev limit. It just dives down.

The hesitation is felt best at first gear. Some say that it is programmed in DME to put aside torque in first. But DME does not know what gear I have it in. The gear shift switch is soldered together so DME thinks the car is in gear all the time. That includes the clutch line switch as well.

[Larsen-Racing]

No one that can help??

I have dynoed the car as well. No miss shaped curves at all. Did a pull in second gear, and then I got an uneven curve. Pulled 280 at the wheels.

I can also "fool" it. If I rev it up to 4-5000rpm rolling with not much throttle before I floor it, it is almost running clean the rest of the way.
But if I floor it from 1500rpm it is just cheating all the way...

Can it be the O2 sensors?

[UweM3]

No one that can help??


I have dynoed the car as well. No miss shaped curves at all. Did a pull in second gear, and then I got an uneven curve. Pulled 280 at the wheels.

I can also "fool" it. If I rev it up to 4-5000rpm rolling with not much throttle before I floor it, it is almost running clean the rest of the way.
But if I floor it from 1500rpm it is just cheating all the way...

Can it be the O2 sensors?

what do you expect? Somebody pulling a rabbit out of the hat and solve you problem in 5mins?
With an engine conversion like yours there are many factors to be considered.
Just imagine you have got something minor wrong with the wiring for example, it will be impossible to trace your problem over the internet IMHO

And by "cheating" I guess you mean missing/misfires?

[Larsen-Racing]

No.

By cheating I mean that if I get it to high rev with less throttle, like old people do...

[BAZE30]

Hi Larsen,

I had similar issues, hesitiation from 1500 to 5000 revs. I found a few things wrong when fault finding, idle control hoses where bad. A couple of other vacuum leaks. However, 2 of the biggest changes I notice where

1. Oxygen sensors where replace. 90% performance difference.
2. Cam sensors replaced (both intake & exhaust) - really felt the car improve from this.

Hope this helps!

[Larsen-Racing]

Ok! Thanks! I have changed all idle control hoses and vacuum hoses before fitting the engine.

Oxygen sensors are expensive or?

[blue30]

You mentioned you weren't sure how the DME might be torque limiting the engine in 1st. Well, don't know if this applies to the S50 but on some of the Fords that do torque limiting in the lower gears it's done by a road speed vs engine speed calc, rather than any kind of sensor on the gearbox and it retards the spark when it thinks you're in the bottom gear.
Anyway don't know if this is useful at all but more info never hurts

[BAZE30]

Ok! Thanks! I have changed all idle control hoses and vacuum hoses before fitting the engine.

Oxygen sensors are expensive or?

They can be expensive, yes. I paid around €700 Euro for 2 on mine. 1994 B30.

[UweM3]

Ok! Thanks! I have changed all idle control hoses and vacuum hoses before fitting the engine.

Oxygen sensors are expensive or?

They can be expensive, yes. I paid around €700 Euro for 2 on mine. 1994 B30.

you paid what? SEVENHUNDRED Euro for two oxygen sensors??

[Larsen-Racing]

Thinking of the gear shift indicator switch and it's function, does anyone know how it works?

And, the gap between the crank sensor and the trigger wheel. How big is that?

[Larsen-Racing]

Just had to try something not healthy today....
On cold engine I did floor it in first and the rear tires started to spin and it pulled like hell!
That means that it works when it is cold...

Does not that cook it down to the O2 sensors?

[toby]

Or maybe something else which is temperature dependant?

[HenryM3]

surely it not something as simple as the temp sender, giving the ecu the wrong info. Mine will spin the rear wheels in first with 245 tyres.

[Larsen-Racing]

I also thought about the temp sensor... I will try to plug it out and see.

It was sick how much faster it was when it was cold. Pulls like stock S14 on first when it cheats. I just got kicked back in the seats and the rear tires spin.
It will also mean that I will have more on all the other gears as well.

[Larsen-Racing]

Or maybe something else which is temperature dependant?

Yes, but what?

[Larsen-Racing]

I have now tested more. Disconnected these individually and it still cheats: water temp, air intake temp and MAF.

Going to do the O2 sensors as well

[BAZE30]

When the engine is cold the O2 sensors and a few other sensors are ignored. The temp sensor indicates to the engine when to start reading signals from the O2 when the car is up to temperature. It then 'listens' to the readings from the O2 sensor. A bad o2 sensor(s) may be your problem.

[Larsen-Racing]

Ok, thanks! If a O2 sensor is disconnected, there shall be a difference in how the engine runs?

The MAF cant be healthy eater, I have read that if the MAF is disconnected the engine will act funny at normal driving. And I can't say I noticed any difference at all.

At the dyno I got 2hp less with the MAF disconnected.

[BAZE30]

With an O2 disconnected, voltage returned on the O2 will be zero. The ECU might throw an error. The car will run very rich. If you have a bad o2 then with it diconnected it should run better but will be annoying to drive.

Have a read of this link
http://www.aa1car.com/library/o2sensor.htm

To quote -- "When no signal is received from the O2 sensor, as is the case when a cold engine is first started (or the 02 sensor fails), the computer orders a fixed (unchanging) rich fuel mixture. This is referred to as "open loop" operation because no input is used from the O2 sensor to regulate the fuel mixture."

[DanThe]

With MAF and O2 sensors disconnected the engine will be eating away at the cylinder bores

I also suspect the dyno you are using is way out

[Larsen-Racing]

These engines runs fine without MAF at WOT i have heard. Heard that if the MAF fails, they are just plugged out so the engine will work fine.

The dyno is recently calibrated, and on a 300hp car there was a difference of 10hp in that dyno and a Dynapack. And, you don't need a accurate dyno to see that there is a drop of 2hp when MAF is disconnected.

[DanThe]

Ok sorry should have read the thread properly, I was thinking you had 319hp on the printout or something

[Larsen-Racing]

Did more testing yesterday! There is a change on idle when I unplug and plug the MAF.
-Disconnected one and one O2 sensor, no difference. But I can hear a change in idle when I plug it in a few seconds before it is adjusting back in.
-Disconnected the TPS sensor and there was no cheating at all, I did only one run i 1.st gear on all tests to not harm the engine. When TPS was disconnected the engine lost some power but it run clean.

Took off the TPS and twisted it with a screwdriver when the engine was running. There was change in the mixture when I did this.

Also got some other tip from a Opel guy. He told me that some have mixed the plug for the idle control valve and the knock sensor. When that was done the engine was cheating like mine. But I marked all the plugs before removing them. So I'm pretty sure that all are in the right place.

TPS are prone to fail on these engines. Mine was marked with BMW so it has probably never been changed.

I also thought of one other thing. I think the engine is running clean when the automatic choke is on. Going to check the fuel pressure, but the spark plugs tells me that there is no lean condition of the engine.

Then there is the coils.....Never have been changed eater. But cant think of why there shall be a change on them when the engine is warm.

[Gunni]

There is no automatic choke.

The TPS has 3 wires, the knock sensor 2 wires,

when you unplug the maf the ecu defaults to a alpha-n safe mode.

, you need to measure the resistance across the TPS from one end to the other and notice if the resistance is not linear . i.e there maybe a point where there is an issue on the trace and the resistance changes the ecu´s understanding of where the TPS is, this can result in non vanos activation which will seriously limit power.

[Larsen-Racing]

How can I measure the output signal of the TPS?

[Gunni]

with a multimeter

[Larsen-Racing]

Yes, but what values am I looking for? Just that it is not linear or should it be a specific value at WOT?

I was also wondering, at a stock S50B32. There is a hose going into the air filter box, when you buy a induction kit you will get a filter that sits on the hose.
Where does that hose go to, I cant remember it and suspect that I have done something wrong there maybe.

Cheers

[ross_jsy]

I don't know anything of real value about this engine swap but I am led to believe the b32 runs a higher pressure fuel system that the b30 (something like 5bar instead of 3). Might be wrong but thought I would throw that one out there.

[Larsen-Racing]

You are right about that, I have a Bosch 044 in line pump as well as stock E30M3 in tank feed pump. So it shall deliver enough fuel for the engine. 044 pump can do 500-600hp.


And as I stated above, on cold engine it runs like hell! Kicks the tail out on dry asphalt.

[penton08]

I was also wondering, at a stock S50B32. There is a hose going into the air filter box, when you buy a induction kit you will get a filter that sits on the hose.
Where does that hose go to, I cant remember it and suspect that I have done something wrong there maybe.

Cheers

i think that pipe runs to the auxilary air pump, did you remove the pump? there are other pipes that would of needed blocking off if you did

[Larsen-Racing]

Removed the AC-pump yes! Have blended pipe at thhe exhaust side, vacuum at the rear of the TB's and vacuum on the hose that goes from the vacuum rail to the idle control valve.

[Larsen-Racing]

Double checked the fuel pressure yesterday, it was 5 bar fine.

I also had a wideband lambda and it was fine as well. It was around 12-12.3 at WOT.
I the disconnected the MAF, and then it was leaning out to an unstable 13-15.