Engine randomly just dies

[Escaport]

So I got a new second E30 this weekend. Had a 1,400 mile trip back home. Drove fantastic nearly the entire way. Then, during the last 200 miles the engine kept dying.

The engine is as follows. 2.7 IE stroker kit. WAR chip with MAF conversion. 19 lb injectors. My first stroker or WAR chip for that matter.

The issue. I was cruising at about 75 MPH on the Interstate using cruise control. Then all of a sudden it felt like my throttle disappeared and the car started to slow. When I disengaged the clutch, the car died. Ended up on the side of the road. I opened the hood and did two things. Checked all the fuses ( all original except for two which I pulled to check) none were blown. Unplugged the MAF sensor and then plugged again. Got in, attempted to start up, and it fired. Seemed back to normal.

About 10 miles down the road, it happens again. Unplugged MAF, waited 5 minutes, car started and off again. Repeat this ten more times before I reached home.

When it fires up, it’s back to normal. No hiccups, full power. Drives great until it quits again.

After thinking for it a bit I determined the way that it felt I either lost fuel or spark. The last few times I tried to pay attention to smells. I’m fairly certain I smelled extra fuel, so I’m thinking spark. Anyone have an idea of how I should test or common things to look for?

[Escaport]

Oh, further info. It seems there was no external factors adding to it. It didn’t happen in turns, acceleration, deceleration, bumps, etc. Every time it was just straight steady cruise.

The last time I was city driving and at about 25 mph on a city street. It felt a bit different. It felt like there were three or four 1 second drop-outs in the throttle before it cut out.

[laidback93]

Welcome to the random stall out club. I've been experiencing this intermittently during the 4 years I've owned my 90 325is. Usually starts right up and no problems until about 20 minutes into the drive. It especially does not like when I turn on the AC. After replacing almost every sensor related to the DME (CPS, TPS, AFM, CTS) and all ignition related items the car still stalls randomly. Matter of fact my buddy just dropped in a 70K M20b25 because the old engine had a crack in the block. Still the issue persists because it's definitely electrical.

So, last weekend we replaced the ignition switch. Needed replacing anyways due to age and we thought that would solve the stalling, but nope.

Now I've ordered a new set of the three main relays (DME, Fuel Pump and O2 sensor warmer) in hopes it might fix it. All three of my current relays are very old with corroded pins.

Question - when the engine stalls or begins to stall, does the tach drop to zero? That's what mine does along with the check engine light popping on for a second. Usually a sign that's electric and not fuel related.

Keep us posted!

[Escaport]

Let me know if those relays do the trick.

No, I didn't see the tach drop. The only way I can explain it is if some little gnome under the hood cut the throttle cable. Cruising, then straight deceleration. No lights, nothing changes I can see from inside. Push in the clutch and all the lights pop up because the engine is no longer running, but outside of that, it's just the complete missing of throttle that indicates that it's happening.

I did change the ground straps. I have a CPS coming (those are ridiculously priced for what they are). The TPS I thought about and it's also pretty silly costwise, but it appears that SAAB used the same TPS sensor and it's less than half the cost of the BMW one.