Pinging w/Dinan chip

[ratphoto]

1987 325iS; K&N filter; high-flow cat and Magniflow exhaust, new uprated fuel injectors.

I put a Dinan chip in the original DME (-153) and had nothing but problems with it pinging between 4500-5500 rpm and losing power on the top end. Below 4000 rpm the car did not ping at all, even under heavy load. It only pinged in the high rpm range at 3/4 to full throttle.

Running Chevron premium (91 octane).

Here's what's been done trying to solve the problem:

New: airflow meter, O2 sensor, plugs, cap, rotor, wires, intake boot, fuel transfer pump, main fuel pump, fuel regulator, fuel injectors; tested all sensors for proper operation.

De-carboned the cylinders numerous times with BG-44k directly into the intake, as well as two cans of BG-44k through the gas tank, and then two cans of Redline intake system cleaner.

Still pings.

Installed a wide-band O2 sensor in a second O2 bung and ran diagnostics to check air/fuel mixture. It's right where it should be throughout the rpm range, so it's not running lean.

Hooked up remote diagnostics to the car's diagnostic port to check timing advance while driving. With the Dinan chip there was 44 degrees of total advance in the 4500-5500 rpm range where the pinging was occuring. Way too much!

With the stock chip in the DME, the air/fuel ratio was actually a bit lower (richer) on the top end, and the timing peaked at around 34 degrees total advance.

Just for grins, we pulled a Dinan chipped DME out of a '91 325iC and put it in the car and ran the diagnostics again. The car ran great, with no pinging, and had around 34-35 degrees of total advance.

I ordered up a later DME (-525) and a correct Dinan chip for the box. The first chip Dinan sent was bad--it wouldn't even start the car--so we had to send it back and get another one.

Once the second chip arrived we installed it in the 525 DME and put it in the car . . . and it still pings like a mother between 4500-5500 rpm! My guess is the advance curve is again way too high in the top end, but we haven't put the scope back on the car yet.

Anyone know if Dinan changed their advance curve?

Right now I've pulled the chip out and the car runs great, but I'd really like the extra hp of the chip.

Has anyone else had these problems with a Dinan chip? How about the JC chip? Any suggestions?

Any help will be greatly appreciated.

Scott

 

[Big Daddy]

I used the JC chip in my 91 318is and liked it better than the Dinan.

 

[Custom 3]

Honestly...it sounds like you may have a bad chip. Have you linked up with anyone else in your area that may have a JC or Dinan chip for the same 153 DME? Also, are you sure that the Dinan chip you have is the correct one for your DME?

 

[ratphoto]

Yes, I'm sure it was the correct chip for both the 153 box (the first attempt), and the 525 box (the second attempt). I do know the first chip Dinan sent for the 525 box was indeed bad--it wouldn't even start the car. The second chip for the 525 worked, but had the same pinging problem as the chip in the 153.

If the pinging is because the chip is bad, then I've gotten three bad chips in a row for two different DMEs. If that's the case, then Dinan has a serious quality control problem. From my discussions with them, my car just can't handle the "agressive advance curve" their chip has. In my opinion, and the opinion of the Dinan distributor that's doing the work on the car, the chip's 44-46 degrees of total advance between 4500-5500 rpm is way too much.

Dinan has offered to burn a "custom" chip with less advance (they've had this problem with other E30s before), but only for the "stock" DME. After spending $300 for a 525 DME, which solves several of the driveability issues I had with the 153, I'm not about to go back to the stock box.

Plus, we contacted Dinan before buying the 525 DME to see if there would be any problem putting it in an earlier car, and their tech said "it wouldn't be a bad thing to upgrade to the later DME."

At this point, I've given up on Dinan and am trying to find out what the advance curve looks like for the Conforti chip. If it's more reasonable, I'll try one of those. Plus, they've got a 30-day, no questions asked, guarantee.

For what it's worth, after all my problems, I definitely would NOT recommend a Dinan chip to anyone.

 

[xLibelle]

whooop. thanks for the review then.

 

[rjp325i]

When I had my 1989 325i w/Conforti chip I would get some pinging in the summer heat (100+ deg) here in Las Vegas. The octane requirements of an engine increases as the temperatures head skyward as we experience temps in the 105-115 range daily during the summer. The M20 engine as in the E30s does not have knock sensors. As a result I used a 25% mix of unleaded 100 octane with the 91 octane gas. Such a combo yields an octane number of about 93. That eliminated the pinginging for me. In the cooler months the 91 would run fine. The unleaded 100 octane gas is available at Unocal 76 stations. At the recommendation of the local BMW dealer motorsport director I still use that ratio with my 04 w/ZHP even though that engine has knock sensors. It keeps the power from dropping off due the the sensors kicking in and retarding the timing and reducing power.