I was driving my GTI the other day and noticed the engine was bucking/surging at low RPM. It was fairly intermittent, however the idle was smooth. The next day the check engine light went off, a quick scan of the OBD-II port revealed at P0100 code “Mass Air Flow or Volume Air Flow Sensor Circuit”. I was initially going to clean the MAF sensor, but after reading the VW forums I thought I should check the harness first.
I peeled away the split loom and sure enough there was a break in the ground (brown) and one of the DC voltage lines (yellow).
The break occurred right where the harness makes a sharp 90 degree bend.
I cut and soldered the wires back together (note to self: buy a cordless soldering iron). Being that this is an under hood repair it will be exposed to a good amount of moisture and needs to be sealed. Since I didn’t have any adhesive lined heat shrink on hand I covered the repair in RTV and slipped a piece of heat shrink over it before hitting it with the heat gun.
After mending the wires I also routed the harness sightly different than factory. Instead of going over the hardpipe and making a sharp bend, I ran the wire under the hardpipe allowing for a larger radius bend.
This project involved designing a device to regulate the flow of chilled water through a heat exchanger based on the coolant temperature of an internal combustion engine. It’s made up of three parts: A controller, a motorized valve, and a temperature sensor.
The controller consists of an arduino, a LM298 based motor driver, resettable fuse, LCD and misc. buttons/connectors.
The motorized valve is a standard ball valve with a bracket to support a gear motor and a encoder for position feedback.
The operator inputs a desired coolant temperature which is maintained by adjusting the flow through the heat exchanger. During this project I learned about driving inductive loads with a micro controller, PID tuning, and closed loop feedback control.
I finished the installation of sub-frame connectors on my 69 Camaro. While I installed them I also put in some new sub frame bushings. Both came from Detroit Speed & Engineering. Installing these SFC’s is a lot more involved then your standard SFC install on a late model Camaro. The way these are design they are virtually invisible when looking at the side of the car, unlike bolt in ones which hang about 5 inches from the bottom of the car, these follow the contour of the floor pan allowing them to be very low profile. Here’s the write up:
The first item I installed was the sub frame bushings. As some of you may know the first and second generation f-body’s came with a removable front sub frame. The car was a sort of hybrid uni-body. The front sub frame is held in with four body mounts and two that attach to the radiator core support. Here’s the kit from DS&E.
The bushing in the center is for the radiator core support the other two are the body mounts. The new ones are made of aluminum and are hard coated. They came with stainless steel washers.
If you recall, work stopped on the 383 due to push rod length issues. Because of different valve stem lengths we had to use non stock length push rods. We had ordered them over a year ago, but never really got around to checking how well they worked. The basis for all this is they fact that we were using roller tip rocker arms. An oft overlooked part of engine building is checking where the roller tip contacts the valve stem over the duration of the cam’s lift. When using standard stamped rocker arms this is really a non-issue. The large radius of the contact pad is very forgiving of push rod length issue. However roller tip rockers have a very narrow contact patch. While this reduce horsepower robbing friction, it also puts enormous pressure on a very small area of the valve stem. If this contact patch does not fall on the correct part of the valve stem it can lead to mushrooming (deforming) of the valve stem tip. This picture from Comp Cams illustrates the proper location of the contact patch at various points of a cam’s lift.
This engine has been a long time in the making. I believe talk of building this engine began around 2002-2003. We had a spare 4 bolt main block out of truck that had massive oil consumption issues due to broken piston rings and bad valve stem seals. Being that it was a 4 bolt main block, we wanted to build something a little more special than a run of the mill 350. We decided a 383 would be a fun engine to build and we began to gather parts. It took almost all of 2004 to get the parts together and have all the machining done. The block was boiled, then painted with Chevy orange on the outside and Glyptal in the lifter valley. Glyptal is a paint that is normally used to coat the windings in an electric motor, however engine builders use it to make the oil flow down the lifter valley quicker. A local machine shop bored and honed the cylinders, and line honed the mains. By December 2004 we had all the parts we needed and were ready to assembly it. We added the heads and a partial valve train around 2006 and it has sat in silence since then. Below are some of the details of the assembly of the short block.
It’s based on a 4 bolt main truck block that was pulled from a 3/4 ton ’86 pick up. The rotating assembly consists of an Eagle 5140 steel crankshaft, Eagle H-beam rods, and Speed Pro hypereutectic pistons. The Block was bored, honed and painted. The mains were line honed with an ARP main stud kit installed. The bottom end is very stout, and should handle pretty much any cam/head combo we could dream of.
The bare block with bearing halves installed
The battery in my 1987 325is has been losing its charge recently. It left me stranded at work a few weeks ago. It problem was diagnosed as a bad alternator. with the car on the battery was not being charged. This meant the car was basically running off the battery. Eventually the battery gets so low that the car cannot run properly . Dim lights, rough running, and no accerosires are common symptoms, The alternator had been replaced once before several years ago by my brother, luckily the alternator had a lifetime warranty through AutoZone so it cost me nothing.
First gather your tools: