More E30 Troubleshooting

Feb 7

After reviewing the data logs from yesterday I realized the MAP signal was essentially flat lined at 100 kPa or 0.0 psi. This was quite odd considering most engines pull a decent vacuum during idle, normally I’ve seen between 15-20 inHg (33-50 kPa). This connected the dots of running extremely rich at idle, the ECU thought it was full load and giving it the corresponding amount of fuel.

Damn Dirty Rats

Thinking through it a bit more lead to realizing I probably have the MAP sensor disconnected for whatever reason. Turns out I did, but it wasn’t my fault. Rats appear to have eaten the vacuum tubing between the intake and ECU…

Replaced the vacuum line and voila purring like a rusty kitten. Let the engine get up to temp while checking everything over and topping off the water. Smooth sailing, no issues…

IR camera

Replaced the vacuum line and voila purring like a rusty kitten. Let the engine get up to temp while checking everything over and topping off the water. Smooth sailing, no issues…

Until about 15 minutes of idling, letting the fans kick on and off a hand ful of cycles o ensure nothing weird would pop up and then the engine started to bog down and struggle. My worst nightmare after a quick rebuild and two years of sitting, I feared the worst. Checked all fluids, turned over the engine by hand to see if it had seized. It appeared fine, leaving me stumped. Fuel gauge showed plenty full, spark was fine, ECU showed no issues.

Easy Access Fuel Pumps/Senders

So checked fuel pressure and found air in the lines. I suppose I could have a bad fuel gauge or sender so opened the tank and found it dry. Problem solved!
Not quite so fast. When I checked the passenger side I found it full of fuel. E30’s have a saddle tank that naturally balances itself out during driving. We are running a pair of fuel pumps on each side for fuel starvation instead of a swirl pot.
Turns out the passenger fuel pump is dead, likely from our setup and lots of slosh caused starvation. While the drivers side of the tank is dry.
Problem actually discovered.

Rats struck again?

Then I noticed the brake lights were on for some reason. Pushed on the pedal to see if maybe the sensor was stuck and it just fell off. Seems the plastic housing cracked and fell off.
Add it to the list of parts and fixes.

Final task for today was sorting through the pile of ‘spares’ and other junk in the trunk. Found lots of rotten tape, random zip ties, spray paint. Even was a some actual useful things like new rotors (front and rear!) as well as pads for all four corners. Some parts weren’t so lucky despite being new in package.

Organized into plastic tubs that should keep everything in better condition going forward.