85 318i won't start, no spark on #4?

thebutterson · 02-04-2012, 02:13 PM

So I've finally made my way to e30 ownership 2 years after my eta got wrecked, and the 85 318i that started and drove fine (aside from rough and high idle) the day I bought it hasn't ran since. Here's what I've done so far after searching through other people's problems:

Tested the fuel pump relay with 12v, seems to be operating fine, applying 12v from terminals 15-31, and then applying 12v at 50 allows continuity between 30 and 87/87b.

Jumpered 30-87/87b and heard at least one fuel pump (seemed to be the one under the car) buzzing along with something inside the engine bay buzzing.

Hooked up a multimeter to the starter positive lead and ground in the bay, showed 10-10.5 volts while cranking, 12.5-13 static

Used a timing light to verify #1-3 are firing, however, I get nothing from #4, even when swapping plugs and wires.

Cap and rotor look new

The AFM was supposedy replaced, and also looks new.

Pulled the valve cover off to make sure there weren't any broken compontents in there, and everything looked right, but there was a vapor coming out of the oil drain holes. ???

Throttle Position Switch Checked good for both closed and WOT switches

I removed the injectors and rail from the manifold along with the cold start valve and jumpered the fuel pump, nothing was stuck open or started leaking.

Removed vacuum line from FPR and jumpered fuel pump, no leak from vacuum line hookup

Injectors have been swapped with some spares I have, I think they're 325i injectors. I compared the flow rates of the part numbers installed in the car and my spares, and it's a difference of .5 lb per hour. Resistance was the same across the injectors.

With a fuel pressure guage installed before the rail, it holds 45psi while cranking.

Wire brushed the ground wire from valve cover to body, and attaching points.

To me it seems like there's too much fuel given the fact that it cranks better with the throttle wide open, but it seems like all the fuel components are checking out.After cranking for a few seconds, if I hold the throttle open, it almost starts, it did start once right after changing the plugs, but died as soon as I let off the throttle.

I don't understand what would cause #4 not to fire if the plug and wire aren't related and the cap and rotor look good. I'm gonna change plugs and the fuel filter just in case. The #4 plug had some kind of dirt all over it, although it could have just scraped against the outside of the engine on it's way out. I have't checked it again since replacing injectors, but I was thinking it could have just been related to too much fuel being in the cylinder.

I haven't checked compression yet, but can't think of how this would change from one start to another, at least in terms of not causing the engine to start at all.

bmwm42 · 02-04-2012, 04:13 PM

Timing is probably off this cars problems sound familiar though

thebutterson · 02-04-2012, 07:53 PM

I lined up the crank and cam marks, and set the rotor to the mark on the distributor. It still hasn't started but I do have spark on #4. At least I don't have to chase that problem down.

Hey_You · 02-06-2012, 08:20 PM

Coolant temp sensor?

thebutterson · 02-06-2012, 11:32 PM

How powerful is that sensor? Do you happen to know any resistance values I can use to try and test it? It's my understanding that the coolant temp sensor only affects the cold start injector. When I try to start the car, unplugging the cold start injector makes no difference.

I'm hoping I have time in the next few days to go mess with it some more. But engineering classes and college apps are taking all my time.

bmwm42 · 02-07-2012, 07:11 PM

http://www.r3vlimited.com/board/showthread.php?t=215948

dude did you buy your car from this guy i seriously think your car and this one are the same

thebutterson · 02-08-2012, 09:51 PM

I bought it from some people who flip cars in Oakville, WA. I bought from an older guy who said it was his son's hobby to buy nonrunning cars, and flip them. He only had the car for about a week, and the title said Onalaska. Both towns are quite a bit south from where that guy claims to be, so I don't think it's that car.

They said when they bought it, it wouldn't start. They put a new exhaust, negative cable, and afm on it. It didn't idle, or take off from a start well when I bought it, but I did start it several times between testing it and making stops on the way home, and I never had a problem. Then it sat for 4 days while I waited to register it and hasn't started since.

Just searched that guys post, his car is a different color.

thebutterson · 02-19-2012, 03:49 PM

It's been a while since I had time to mess with the e30, but to today I went out with the intentions of doing a compression test, and realized that the starter just doesn't seem to be cranking to fast. This was with a fully charged battery. It's been cranking like this the entire time and I just never thought much about it.

So I followed this great youtube video:

http://www.youtube.com/watch?v=XhRPLgH6uZg

The one problem with performing the test, is that I'm pretty sure the starter uses the transmission and the engine as a ground instead of having it's own ground cable. But when going from positive starter post to grounding on the engine, I get 9V. This video points to the starter positive lead, so I'm gonna give that a shot and see what I get. It'll have to wait till tomorrow though.

Clark954 · 02-19-2012, 03:54 PM

I have a motor forsale if ur interested, ill make it worth your wild

thebutterson · 02-19-2012, 04:26 PM

The shipping cost alone would put it over what I could get one for up here. Thanks for the offer though.

thebutterson · 02-24-2012, 06:44 PM

After swapping the positive lead, still no luck. Swap the starter from my 2002tii, yet again, no start. the main ground from the engine has already been replaced also. But...

While messing around I unplugged the icv and decided to just feather the throttle a little bit while cranking and I got a few back fires. One was quite loud! It scared me a bit and echoed through the neighborhood. There were one or two more, but not as loud.

I have also pulled all the plugs our and varified they fire.

I guess I'll check timing again, but I lined up the rotor with the notch in the distributor that's near the vacuum hookup, which points towards a little bit in front of my fuse box. Any ideas?

Jaxx_ · 02-26-2012, 09:33 AM

timing. For sure. Make sure your firing order is in the correct direction, too.

thebutterson · 03-16-2012, 04:43 PM

Which coolant temp sensor is it that will mess everything up? Today I stuck the sensors in pot of water and checked resistance across terminals as I heated them up.

Closest to drivers side with external prongs (coolant temp switch?)-no continuity anywhere.

Brown connector (thermo time switch?)
Very low resistance, slightly more above 140 degrees.

Whitish standard bosch connector(coolant temp sensor?) - checked out all good.

thebutterson · 03-23-2012, 12:49 PM

Got the coolant switch/sender replaced and the car went from not firing at all to to firing but not starting. At the suggestion of a local bmw shop I did a compression test.

I knew something was up as soon as I pulled the plugs and #1 was black and the rest looked untouched.

#1 was the only cylinder with decent compression, the others were around 20 psi. The guy from the shop suggested that all the start attempts may have washed the cylinder walls and caused the compression to drop, so I added oil and it got better, but still sucked. #2 came up to 80, 3 to 60, and 4 maxed out around 40. What a bummer.

I picked up a rebuilt head and gasket set locally and I'm gonna pull the head off next weekend. Some day I'll have a running e30.

Jaxx_ · 03-23-2012, 01:59 PM

uhhh... you're pulling the head why? you probably scored the cyl walls from having the fuel wash them, and the rings rub against them. your block will need to be honed.

02-08-2012, 09:51 PM	#7
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	I bought it from some people who flip cars in Oakville, WA. I bought from an older guy who said it was his son's hobby to buy nonrunning cars, and flip them. He only had the car for about a week, and the title said Onalaska. Both towns are quite a bit south from where that guy claims to be, so I don't think it's that car. They said when they bought it, it wouldn't start. They put a new exhaust, negative cable, and afm on it. It didn't idle, or take off from a start well when I bought it, but I did start it several times between testing it and making stops on the way home, and I never had a problem. Then it sat for 4 days while I waited to register it and hasn't started since. Just searched that guys post, his car is a different color. Last edited by thebutterson; 02-08-2012 at 10:03 PM..

02-26-2012, 09:33 AM	#12
Jaxx_ E30 Fanatic Join Date: Dec 2009 Location: Heilbronn, Germany Posts: 1,355	timing. For sure. Make sure your firing order is in the correct direction, too. __________________ '84 318i M10B18 - 147 - Safari Beige - MS2E w/ 2-step

03-23-2012, 01:59 PM	#15
Jaxx_ E30 Fanatic Join Date: Dec 2009 Location: Heilbronn, Germany Posts: 1,355	uhhh... you're pulling the head why? you probably scored the cyl walls from having the fuel wash them, and the rings rub against them. your block will need to be honed. __________________ '84 318i M10B18 - 147 - Safari Beige - MS2E w/ 2-step

02-04-2012, 02:13 PM	#1
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	85 318i won't start, no spark on #4? So I've finally made my way to e30 ownership 2 years after my eta got wrecked, and the 85 318i that started and drove fine (aside from rough and high idle) the day I bought it hasn't ran since. Here's what I've done so far after searching through other people's problems: Tested the fuel pump relay with 12v, seems to be operating fine, applying 12v from terminals 15-31, and then applying 12v at 50 allows continuity between 30 and 87/87b. Jumpered 30-87/87b and heard at least one fuel pump (seemed to be the one under the car) buzzing along with something inside the engine bay buzzing. Hooked up a multimeter to the starter positive lead and ground in the bay, showed 10-10.5 volts while cranking, 12.5-13 static Used a timing light to verify #1-3 are firing, however, I get nothing from #4, even when swapping plugs and wires. Cap and rotor look new The AFM was supposedy replaced, and also looks new. Pulled the valve cover off to make sure there weren't any broken compontents in there, and everything looked right, but there was a vapor coming out of the oil drain holes. ??? Throttle Position Switch Checked good for both closed and WOT switches I removed the injectors and rail from the manifold along with the cold start valve and jumpered the fuel pump, nothing was stuck open or started leaking. Removed vacuum line from FPR and jumpered fuel pump, no leak from vacuum line hookup Injectors have been swapped with some spares I have, I think they're 325i injectors. I compared the flow rates of the part numbers installed in the car and my spares, and it's a difference of .5 lb per hour. Resistance was the same across the injectors. With a fuel pressure guage installed before the rail, it holds 45psi while cranking. Wire brushed the ground wire from valve cover to body, and attaching points. To me it seems like there's too much fuel given the fact that it cranks better with the throttle wide open, but it seems like all the fuel components are checking out.After cranking for a few seconds, if I hold the throttle open, it almost starts, it did start once right after changing the plugs, but died as soon as I let off the throttle. I don't understand what would cause #4 not to fire if the plug and wire aren't related and the cap and rotor look good. I'm gonna change plugs and the fuel filter just in case. The #4 plug had some kind of dirt all over it, although it could have just scraped against the outside of the engine on it's way out. I have't checked it again since replacing injectors, but I was thinking it could have just been related to too much fuel being in the cylinder. I haven't checked compression yet, but can't think of how this would change from one start to another, at least in terms of not causing the engine to start at all.

02-04-2012, 07:53 PM	#3
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	I lined up the crank and cam marks, and set the rotor to the mark on the distributor. It still hasn't started but I do have spark on #4. At least I don't have to chase that problem down.

02-06-2012, 08:20 PM	#4
Hey_You E30 Modder Join Date: Nov 2009 Location: The 209 Posts: 963	Coolant temp sensor? __________________ 85' 318i ~The Bronze Bomber (FrankenM10 with a Forced Future )

02-06-2012, 11:32 PM	#5
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	How powerful is that sensor? Do you happen to know any resistance values I can use to try and test it? It's my understanding that the coolant temp sensor only affects the cold start injector. When I try to start the car, unplugging the cold start injector makes no difference. I'm hoping I have time in the next few days to go mess with it some more. But engineering classes and college apps are taking all my time.

02-19-2012, 03:49 PM	#8
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	It's been a while since I had time to mess with the e30, but to today I went out with the intentions of doing a compression test, and realized that the starter just doesn't seem to be cranking to fast. This was with a fully charged battery. It's been cranking like this the entire time and I just never thought much about it. So I followed this great youtube video: http://www.youtube.com/watch?v=XhRPLgH6uZg The one problem with performing the test, is that I'm pretty sure the starter uses the transmission and the engine as a ground instead of having it's own ground cable. But when going from positive starter post to grounding on the engine, I get 9V. This video points to the starter positive lead, so I'm gonna give that a shot and see what I get. It'll have to wait till tomorrow though.

02-19-2012, 03:54 PM	#9
Clark954 Member Join Date: Jun 2011 Location: South Florida Posts: 84	I have a motor forsale if ur interested, ill make it worth your wild

02-19-2012, 04:26 PM	#10
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	The shipping cost alone would put it over what I could get one for up here. Thanks for the offer though.

02-24-2012, 06:44 PM	#11
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	After swapping the positive lead, still no luck. Swap the starter from my 2002tii, yet again, no start. the main ground from the engine has already been replaced also. But... While messing around I unplugged the icv and decided to just feather the throttle a little bit while cranking and I got a few back fires. One was quite loud! It scared me a bit and echoed through the neighborhood. There were one or two more, but not as loud. I have also pulled all the plugs our and varified they fire. I guess I'll check timing again, but I lined up the rotor with the notch in the distributor that's near the vacuum hookup, which points towards a little bit in front of my fuse box. Any ideas?

03-16-2012, 04:43 PM	#13
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	Which coolant temp sensor is it that will mess everything up? Today I stuck the sensors in pot of water and checked resistance across terminals as I heated them up. Closest to drivers side with external prongs (coolant temp switch?)-no continuity anywhere. Brown connector (thermo time switch?) Very low resistance, slightly more above 140 degrees. Whitish standard bosch connector(coolant temp sensor?) - checked out all good.

03-23-2012, 12:49 PM	#14
thebutterson Wrencher Join Date: Jan 2012 Location: Seattle, WA Posts: 215	Got the coolant switch/sender replaced and the car went from not firing at all to to firing but not starting. At the suggestion of a local bmw shop I did a compression test. I knew something was up as soon as I pulled the plugs and #1 was black and the rest looked untouched. #1 was the only cylinder with decent compression, the others were around 20 psi. The guy from the shop suggested that all the start attempts may have washed the cylinder walls and caused the compression to drop, so I added oil and it got better, but still sucked. #2 came up to 80, 3 to 60, and 4 maxed out around 40. What a bummer. I picked up a rebuilt head and gasket set locally and I'm gonna pull the head off next weekend. Some day I'll have a running e30.