krystar

yea but even antifreeze freezes. but at the point that ethylene glycol freezes, u'd have bigger concerns than the car not starting.

ExitWound

I knew the car took over 6 quarts. I put nearly 6 in and was nearly a full quart low after the trip around the block. It's bigger than it looks for a 4cyl engine.

As for the thick oil, I was hoping it wasn't related. The engine turns fine. The antifreeze is new as well, mixed 50/50 with water. And again, the reason I went with thicker oil was to hopefully bring the pressure up at idle while warm while I investigate the low idle pressure, possibly the OPRV or pump. I have pressure, it' s just lower than it should be. And for the record, no-start scenarios are incredibly frustrating, espeically when you don't have a garage to work on and it's 29F out.

Edit: Took off the speed and reference sensors to check if there was anything obviously wrong with them, and to reseat them. The one closest to the firewall was fine. The other has some wear on the casing. The wires look to be intact, but the insolation is shot. Picture attached:



Bought a spark tester to see if I had spark and I do. I have spark from the ignition coil to the distributor, and i have spark on all four wires beyond the distributor on each plug wire.

After reseating the speed and reference sensors, I still have a no-start, but with some sputtering.

I've bypassed the DME relay and jumpered with the 3-prong attack, and the fuel pump runs, and fuel can be heard in the fuel rail. How do I test the injectors to see if they're firing properly?

Air flow sensor was working last I checked, as we cleaned the swing arm inside. Could something have gone wrong with this?

ExitWound

Took off the distributor cap, cleaned all of the contacts. Everything in there seems to be working properly.

jpk

I'd bet money on the refrence sensor being bad; especially with those frayed wires. Order one for a Bimmer M3 circa 1988 from bavauto.com; it'll only set you back about $60.

Mike C.

Cold temperatures and heavyweight oil can certainly slow down the cranking speed when starting cold. But unless you notice it turning over much slower I doubt that's the problem.

ExitWound

It doesn't appear to be slowing down the crank at all, at least not anything noticably slower. Perhaps it IS just beyond tolerance for a fire to take hold.

Tested the TPS and it triggers fine in all three states (closed, open, and WOT).

Tested the AFM. Smooth voltage increases as the air door is opened. Perfect readings (compared to clarks) at idle.

jpk

On the other forum, you mentioned that you've read that the tach bounce indicates the DME and both sensors are good - that's not true. The tach bounce only confirms two things:

1) the DME is getting power.
2) the engine speed sensor (the one closest to the firewall) is generating a pulse that the DME is reading and using to drive the tachometer.

It tells you nothing about the condition of the refrence sensor since it has nothing to do with the tachometer circuit. Your picture, says a lot about the condition of the refrence sensor.

You've mentioned that you do have spark. You cannot confirm is that the spark timing is correct though. The DME uses the refrence signal to figgure out where the engine is in the cycle (where is TDC). Without the refence sensor signal, the timing is set neutral; 0 degrees advance. Thats about right if the engine is at 4000 rpm or so. The timing needs to be retarded quite a bit at slower speeds, and advanced for higher speeds.

To do a proper check of the sensor, you need to have an oscilliscope and look at the waveform and magnitude of the pulse. You can do a cursory check of the sensors by checking resistance at the three pins in the connector; it should be something like 1000 ohms between the center pin and one of the outer pins, infinite between the center and other outer.

As I mentioned previously, I'd bet money that the sensor is bad.

ExitWound

By 'the sensor', you are referring to the sensor ... lets call it a plug... and the wire attached to it back to the connector, correct? You are not *only* referring to the plug that houses in the bell housing.

Tested both sensors. One reads 915 Ohms and Infinite Ohms, the other 938 Ohms and Infinite Ohms.

theykallmekem

sorry to back track, but why use 20W50 in the winter?? im sure its cold over there in PA, why not switch back to 10W30??

reguarding your "low oil pressure", where does it idle at when cold, and where does it idle at when hot?? as long as it doesnt go below "1", i thought that was ideal or normal.

theykallmekem

BTW your oil cap is very yellow lol niice.

ExitWound

HA. I know. That's one of my upgrades. Added 5 horsepower! The old cap had a broken ring on the inside, so I ordered a new one from Pelican. It's pretty!

When cold: 4bars.
When warm: .5bars

Less than 1 bar, which is why I'm investigating the OPRV and pump. The thicker oil was to keep the pressure over 1 bar at warm idle, long enough that I could drive the car more than 3 miles without fear of no pressure.

theykallmekem

really ??!! WHEN WARM= POINT FIVE BARS (.5) ??!!

according to 9xauto.com, they say anything below 3 is considered camshaft barring wear........but mine idles at 2 when hot and 3-4 when driving.

clarks garage says anything below 1 is NOT GOOD.

so idk which is accurate. but i do understand why you know had to switch it to thicker oil. there is a difference IMO from the thinner to thicker oil, ive experimented with different oils, and im surprised my oil pump hasnt blown up lol

theykallmekem

https://rennlist.com/forums/showthre...w+oil+pressure

https://rennlist.com/forums/showthre...w+oil+pressure


found those old topics about my low oil pressure woes.

Rock

LOL! I was hoping someone would say that. I got through the first few posts and about shat a brick.

ExitWound

How about helping this no-start Porsche owner instead of criticizing others who have tried.

Any other ideas for me?