DanaT

I am perplexed and cant figure out what is going on.

I had the car dyno'd and the car is running lean when on boost. I have started to go back and check everything that could be causing this.

I have checked TPS to make sure it works right. Per the factory manual testing at the KLR it reads 571Ohms at throttle closed and then was in the correct range at WOT.

I have checked al vacuum lines (new) to the FPR.

Fuel pressure regulator (3.0 bar) I am assuming is woking as it is basically a new unit that has been sitting around for a while.

What I have started to think is that maybe I have a "bad" fuel pump. It is possible that a stock fuel pump (it could be the original one that came on the car from the factory, I dont know) would work enough to make the car run, but not be working well enough to feed the system properly?

My thoughts are to get a fuel pressure gauge kit and look at. But, one under the hood doesn't do a lot to tell me if the FP comes up under boost. It hard to have someone drive the car with the hood open, and me holding onto the front of the car. This leads me to an electric gauge. These are about $250. By the time I have the electric gauge, I could basically have bought a new fuel pump.

My other thought is to buy a Wideband kit to try and get the AFR dispalyed and a new fuel pump. Hopefully the new fuel pump would give me some more fuel and then everything would be OK. But, if it didnt fix it, I wouldnt have any data to know where to look.

Here is some more interesting information.

The car was dyno'd in October with a completely different turbo and MAF system. I was running a 2.5 bar pressure regulator. The dyno did not have an AFR probe at the time.

The car was run on the same dyno yesterday but now they have a AFR probe. The car has a new turbo, injectors, MAF kit, everything. Now a 3.0 bar FPR. It should be spot on. The dyno graph from the old setup and the new setup were almost exactly the same shape and power. Almost exactly teh same. The car FEELS totally different now. I doubt the dyno could make multiple duplicate pulls if it was not correct. But my AFR yesterday were constant 13-14 across the entire RPM band even with boost.

With some phone support, I was suspecting a TPS but it seems fine (yes, even when hot) and the car was running a non-WOT map. It was also suspected that the was a vacuum/boost leak to FPR. I can't see anything and all the line is new. This is why I want to see FP under boost. It should rise with boost.

I am now thinking maybe its the fuel pump. If I have a fuel pump that works, but not optimum, maybe my power, and the reason why the two completely different setup have the same power curves, is that my limit is the fuel supply coming from the fuel pump. Does this make any sense?

Anyone have any other strange, wacky ideas to check out?

Being that is a saturday, there is not much opportunity for me to get fuel pressure adaptors or anything. Really, it will take the week to get a fuel pressure gauge or a wideband.

Any even off the wall things that I could check would be helpful.

Thanks
-Dana

CPR

If your readings were a solid 13-14 across ALL ranges, then I would suspect the AFR the shop was using is in incorrect or malfunctioning, or maybe not hooked up correctly.

DanaT

CPR,

I should also mention that when I run the car on a 4th gear roll and was logging my factory Narrow band, the car shows consistent 14 AFR.

-Dana

docwyte

Add fuel with the SMT6. We're at altitude and you'll find that does funny things to the maps. On my old 951 S with the Vitesse MAF I had to add fuel with the FQS (I didn't have an SMT6 on that car) as it was running too lean once cold enrichment ended.

LS1951

Have you tried testing for codes with a blink tester?

I had a bad TPS even though the impedence checked out ok. Every other time I drove the car it would go into low boost mode(still running the cycling valve) and when it would run at full boost it would lean out bad enough to ping at WOT. I suspect the best test would be to check the voltage out of the TPS to the DME. The input side is 5v but I was unsure of what range the output voltage to the DME should be.

I wired up an LED from the diag. port and ran it under my windshield wiper so I could monitor the codes while driving. 4 out of 5 times I would get 4-1 for a bad TPS, once in a while it would give me 3-3 for a KLR problem. I must have tested that TPS 3 or 4 times and even though it ohmed out fine I just replaced it anyways and my problem went away.

joeytoad83

whens the last time your fuel filter was replaced. my afrs were fine part throttle, but wot would lean out changed out the fuel filter and good to go.

fast951

Dana, In addition to what we discussed. How old is the fuel filter? A clogged filter would restrict flow, the same as a fuel pump on its way out.
You can always set the FQS on the DME to +10% and see if the AFRs change. Of course, make sure you are not pulling fuel out via the FQS causing the current lean condition.
Turn boost down as far as you can, before testing. Lean mixture will cause serious problems. So keep your runs as short as possible!

As far as measuring the fuel pressure, it might be possible to get a pressure sensor and log it via the PB. It will run less than a $100, and you can remove it after the test.

BTW. the TPS WOT and Idle should be checked at the DME. (IDLE pin#2 and WOT DME pin#3).

fast951

Adding fuel via the PB is fine as long as there is no mechanical problem with the car. Dana is also experiencing VERY rich cold start which is not normal.
That's 2 red flags! I would investigate first!

CPR

Hey John,

What would cause, or potentially cause, rich cold starts?

fast951

Eng temp sensor, O2 sensor, TPS...

Of course, there is the ground problem, which you know of very well.

Some of these sensors also attribute to rich running conditions even under normal operating temps.

Cold start enrichment is normal, it takes a a few seconds (30-60). Should start rich (the colder the richer it'll run) and get leaner as the engine warms up and the O2 sensor kicks in triggering the DME to operate in closed loop.

CPR

Thanks for the insight John.

And yes, I unfortunately was one that found out all too,too, too well what bad grounds can do

Thankfully, those gremlins have been put to rest

DanaT

Fuel filter is brand new. Was changed when everything else was updated.

To add fuel, I cheated. I ran the E85 map +25% fuel. That should really richen things up. Well, that it did. It is so rich that at idle it kills the engine when warm. Strange, but I logged the run with the piggy back and even under mild boost, the piggy back was showing 14.7:1.

I think right now, I am basically shooting in the dark. I probably need to get a wideband. I will go check the DME #2 and #3.

-Dana

fast951

Oh yes, I remember the ground issues on your car too well! Who can forget the countless hours spent diagnosing a ground problem?

BTW. my response to the Cold Start is for the Motronic system. Which, based on your signature, you are no longer running. My response may or may not apply to your system.

DanaT

DME Pin #2 to ground = continuity when pedal is not pushed / open when pushed

DME PIn #3 to ground = open under all throttle conditions.

However, I am not sure that I am testing this right. The DME pin says "Full load signal from K/CP control". I am thinking this is not a simple continuity check?

-Dana

DanaT

I am hoping my grounds are all OK. The wiring harness was all rebuilt with new Lindsey wiring looms and an iceshark battery/ground kit was installed.

-Dana