E30 M20 No Start w/ Fuel & Spark + Advanced Diagnostics Completed

[E30Bastard]

Hi Guys,

'88 325iS here.

I recently needed to replace my heater core so while I was waiting for that part to show up I did some other maintenance on the car I'd been avoiding (intake manifold gaskets, fuel return line, harness tape on starter and alternator wires, a fresh set of green top injectors and O-rings, and a vacuum manifold for the intake, 3 port catch can routed the jlevie way - valvecover to IN 1, OUT to dipstick, IN 2 is a vent overboard and, yes, I capped off the throttle body vacuum ports!). Long story short I got everything buttoned back up and couldn't fire up the car. Did some back and forth diagnostics and realized that the CPS and Tach were swapped, once I did that the car fired up for a few seconds and then died.

I cranked on it some more and then fuel started gushing out of the inlet pipe of the FPR!! I don't remember doing this but at some point I must have swapped the fuel lines at the junction when I was replacing the return line by the firewall. Anyway, I got back under the car and traced the hardline from the fuel filter and made sure that the FPR is getting the correct fuel line. I cranked the motor and sure enough fuel started gushing out of the FPR hose. Buttoned everything back up and still no start.

Before posting I wanted to make sure I crossed all my t's so I went ahead did some research on here, found some great diagnostics by jlev and Dan - here are my results:



As you can see everything checks out perfectly. I also physically verified 12 volts at the coil and that spark is happening at the coil and at the spark plugs. The CPS sensor reads 507 at the connector. During the diagnostic phase I physically verified that all 6 injectors are firing. I have pulled the plugs, blown compressed air in there, cranked the motor to get any flooding out. I have also double-checked the timing marks (recently changed tb, wp, etc., but have put a couple thousand miles on it since that work) and opened up the oil filler cap to make sure the cam is turning. Lastly, I swapped the FPR with one I had in storage but no change in behavior so I put the old one back.

I have a few questions as electrical is more my thing with cars:

1. Did I damage something by having the fuel lines swapped (I swear to GOD I only changed that return line 1:1)?
2. Did I flood the motor with an insane amount of fuel?
3. Is the FPR screwed up now? When I removed the FPR the brand new o-ring was expanded and way bigger than the fpr nipple itself. I think this happened from the reverse flow. I did swap out the fpr with another one but I'm not sure it's the correct FPR even though it fits and says 3.0 bar on it.
4. When cranking - is fuel supposed to gush out of the firewall side or does that only happen after it starts if at all?
5. Just to fully confirm - IN is at the FPR and OUT is at the firewall?

[E30Bastard]

Bad intel on the in and out. I had it right to begin with. Definitively in goes to the firewall and out is the fpr side. Swapping the fuel lines back got it to start!!!

But...It idled perfectly for about 20 seconds before making a soft popping sound, like a misfire or a backfire, then a fluctuating in revs between 700 and 1500 like someone was in the car messing with the pedal. It also started billowing white smoke. Eventually the revs evened out to 1k, like a cold start, and I let it run until the first temp notch then shut it down; thought it might be excess fuel but the smoke didn't stop. What could be causing this smoke? The car pulled into the garage running perfectly. Is it the catchcan setup? Cheap aftermarket FPR I bought for diagnostics not doing its job? Injectors? Head gasket (how?!)?



The smoke isn't crazy thick like a head gasket, check out the pic! I did do a lot of cranking with the spark plugs removed thinking it was a flooding issue but you'd think 10 minutes or so of idling would clear it out.

[E30Bastard]

Should be noted that I vacuum tested the coolant system after heater core replacement for 20 seconds at 25psi with my nifty venturi tool, so the possibility of spontaneous head gasket death on cold start is negligible.

Stomp showed a 1223. Hit the cts and had 2800 ohms at "garage cold". 0 ohms at dme pins 24 and 45(*EDIT from 44). Unplugged the cts and got 1440 ohms. It's a short. What happened last night i theorize was the cold start relay for the first 20 seconds and then the faulty shorted CTS took over and started running insanely rich and threw the code.

Time to readdress C191 situation. Will update.

[roguetoaster]

CTS probably still ignored at the 20s mark.

Is the smoke oily, fuely, or sweet smelling? If uncertain, pull a plug or two to check for overheat conditions or anything else that might cause poor ignition/combustion.

[ForcedFirebird]

Smoke is probably just condensation, drive it a bit to clear it. I had done a HG jobber for a client a couple years ago and he was worried when picking up since there was a ton of smoke (probably from coolant getting in the exhaust system), cleared out by the next commute.

[E30Bastard]

Rogue and Firebird, thanks for the responses. I cleaned up C191 and was able to match the ohmage of the CTS pins at DME pins 24 and 45. Haven't thrown a code since and it is now idling and running better than it ever has since I bought it.

The smoke still continues at cold start and I am seeing oil streaming out of the exhaust side of the bottom right corner where cylinder head bolt #14 would be and coolant streaming out where cylinder 1 intake manifold runner is. The tstat housing is dry as a bone, the coolant is coming out directly under the intake. Guessing it's an HG about to go.