LFA951

I see that the 3 bar fpr by Bosch are black, is this something new? I have a Bosch 3 bar but it is the same color as the stock 2.5 bar and the part number is 280 160 294, is this the correct one for our cars or should I get the black one?

KuHL 951

I've seen them in both colors and have both. Vitesse sells the gold one which is probably more 'smog ****' proof but then again my 'test only' smog place here passed a friends S2 w/ a supercharger on visual Most shops just don't see many 944's and 951's and don't know what to look for anyway. I'm sure both parts will have the same spec even though the part numbers might vary.

Acetylene

Not to be a smart aleck, but when the paint starts to flake on the black ones they are the typical gold anodized look underneath.

Jusii

Same part, the black one is originally for BMW E30

LFA951

So how can you tell if it's good? Since I put in the 951 Max chips, I am running really rich, when I accelerate slowly in 4th or 5th, it stumbles/ bucks/cuts out, also when I am in 5th and I let go of the gas to decelerate.

fast951

The Black and the Zinc 3bar FPR function the same, just a different color. The sure way to test the FPR is by checking the fuel pressure, 43-44psi at idle, vacuum line off. A simple (but not 100% accurate) test is to remove the vacuum line and inspect it for any sign of fuel. Based on your description, I doubt your FPR is the problem. When the FPR fails, you get bad AFR all over not just under certain conditions.

LFA951

I put the 951 MAX chips in a week ago and I've noticed my gas mileage drop and the car is running rich as well. When I floor it in first thru third it feels responsive but when I shift you'll hear backfiring and when I am on the highway in 4th or 5th and I accelerate, the car will stumble slightly or buck as they call it. Before with my Autothority chips, it didn't accelerate as nicely, but it didn't stumble in 4th or 5th gears, felt smoother...

KuHL 951

You might try putting the old chip back in and see if it does the same thing. Then go back to the 2.5 FPR with the old chip. At least that might rule out one part or another and get you pointed in the right direction.

TRACKIN951

Mine is black!

LFA951

With the previous Autothority chips I was running lean, that's why I blew up hg in 5th gear doing 150 mph, so these MAX chips are the opposite, they are rich, a lot of backfiring when shifting and letting go of gas, if I go back to the old chips with the 2.5 it would be way to lean, maybe I should use the 2.5 with the Max chips, perhaps it would balance out?

2bridges

Are you running supporting mods to run with the max chips?
Cleaned and flowed injectors, 3" exhaust wo cat, method of boost control?
If not, better regroup and refer to vendor provided recomendations

KuHL 951

The reason I ask is yours is the first real complaint I've heard about that chip so I'm wondering if it could maybe be something else. Have you run the car since the HG repair with the old chip/FPR or is this a new set-up directly after HG repairs? Was the FQS switch on the DME set on any special value for the APE chip? Is there any chance the new chip isn't completely seated? Maybe you can call Russell and see if he has some insight in case it is the chip. There are so many things that can make the car stumble under load and a vac leak is a very common one. I hope you find the problem.

I know my Vitesse AFM K26/8 chip still gets me 25mpg on the highway and never runs rich at all, even on cold starts.

LFA951

I have the 3" exhaust with no cat and MBC

Acetylene

Agreed, call Russell and see if he can help. i have yet to hear anything bad about the 951MAX chips, but you never know.

LFA951

There is no vaccuum leak and the FQS has not been touched, if you read some other threads, a lot of people say they have the same experience but that it's better to be rich than lean. I did run the car with the old chips, then changed to these a few days later, it ran smoother with the old chips in 4th and 5th gear, no sutmbling, but it accelerates nicer with the Max chips in 1st - 3rd gears