Frustrating, Random No Start Condition. Cranks and Doesn't Fire Every 1/10 Starts 325

[RLGDiesel]

Quick and Dirty:

Already replaced...

Fuel tank
Fuel pump
Fuel pressure regulator
Fuel Filter
Ignition switch
Spark plugs

Should I replace...

Coolant temperature sensor??
Crank position sensor??
Fuel pump relay??
Fuel pump, FPR, filter AGAIN?? Defective?? Only the FPR is aftermarket from RockAuto
Injectors?? Doubtful because oil does not smell like gas

Longer

My 1990 325i (5 spd, 4 dr, 218k) does not start reliably. This car sat for about 5 years, and I'm trying to restore it to its former glory. Before it became my daily driver, I siphoned the old gas out and changed the fuel filter (in addition to oil, t belt, etc). Apparently, that wasn't good enough because the car kept losing power above 2.5K RPM and I had to replace my fuel tank, fuel pump, and fuel filter (again). Now the car does not lose power at all...it runs awesome all the way to 5K RPM...but it doesn't start on the first try about 10% of the time. I have to crank the key for a good 7 seconds sometimes (at which point I stop to prevent burning out the starter). Then the car almost immediately fires on the second or third attempt. Where should I start with this??

[blocke]

I just had this problem. Replace both the DME relay and the Fuel pump relay if they are the original ones. I had the same issues, replaced mine, and now it fires over first time, every time.

[BergerNJ]

don't you have two pumps? if so which did you replace?

are you getting good pressure? are you getting consistent spark?

[RLGDiesel]

I have a plastic-bumpered facelifted car (89, 90, 91 model years)...I think it only has one pump located beneath an access panel under the rear seat...that is the one I replaced...I am fairly sure I'm getting good spark since the car runs great and doesn't idle rough.

Thanks for the reply

[RLGDiesel]

I've got a DME and fuel pump relay on order already...great advice...hope it solves my issue!! I have a hard time believing its something mechanical since the problem is so intermittent...any additional tips would be great!

[tim88325is]

Check out the c191 connector under the intake, can cause a bunch of random problems...

Usually looks fine from outside but can be a corroded mess under the rubber boots.

[amcink]

I just had this problem. Replace both the DME relay and the Fuel pump relay if they are the original ones. I had the same issues, replaced mine, and now it fires over first time, every time.

where are these relays located???

[5Toes]

My car did this too when warm. It was flooding itself.. so fix leaks, etc.

Relays are on the driver side fender, little rectangle box with a black plastic cover

[RLGDiesel]

Solved...DME and FUEL PUMP RELAYS

[Quinthirty]

Similar experience. I'm waiting for my DME.