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Well this morning I had to use my 951 to get to work on a cold snowy day because a brake line on my truck broke. Anyways I noticed my 951 has trouble cranking over when its in freezing temperatures as it has done this for years, its fine in regular temps. The battery and starter are known to be good it just seems like it struggles to crank when its in freezing temps. The cranking slows and fluctuates fast and slow. The only thing I can think of is that the 20 /50 oil is too thick when its that cold and causes the crank to struggle turning or the battery cables need swapped. Any input on this would be helpful, I don't drive my car in the winter but in a jam I'd like it to crank without issue. This causes a no start issue because the starter struggles to turn even with a fresh battery and starter (only on a cold start on a cold day.) Warm starts are always fine regardless of weather temp and on normal to hot days, always fine.
Well I jumped the battery and it turns over more but still no fire up. Whats weird is it only happens on days like today 20 to 30 degrees on complete cold startup. Ive tried changing the DME coolant temp sensor and DME relay. No difference. I get fuel and air filter and vac lines are all good no leaks. I didn't check spark but it Runs perfect any other time but when its this cold outside so I can't see that being an issue. Plugs wires cap and rotor are all good. And by fresh battery I mean a new one. I typically charge my batteries if they get low but just to be sure the cranking amps were good I tried a new one. Same effect
I tried a new one a few months ago with the same effect. Like I said this only happens on days where its in bitter cold temps on a completely cold start. Warm starts on these days are fine. And everything is normal on normal to hot temp days.
I'm looking for some not common out of the box reasons/ solutions at this point. I tried grounding the motor with jumper cables and this didn't help. It almost seems like something is just frozen. Because when it gets into 35 degrees and warmer the issue is gone
Low possibility, but it may be binding because the whole assembly shrinks too much when it gets down to freezing.
Not too long ago, some starters actually had to be shimmed to get them into the perfect position to properly engage the teeth. It might just be that it's cold enough to shrink everything just a little too much, making everything a bit too tight. Is there anything non-stock about your pressure plate (just asking since this is where the ring gear is mounted)? If everything is OEM, I wouldn't think it's possible to have binding at those temps (since those aren't uncommon in Germany) but you never know.
You can try two things, but not at the same time:
1) Shimming the starter out just a little bit - maybe start with very thin washers (equally on both bolts, between the starter and the bellhousing) and see if there's any improvement. This will back it out just a slight bit, and that may be all it needs. However, if the starter is not solidly mounted when you do this, don't try to turn it over or you will probably break a tooth on the ring gear, and maybe break the starter as well. If the washers don't work, the only way to safely shim it out is to use thin round metal rings that fit perfectly on the face of the starter.
2) You might also need to shim it so that the gear on the starter just slightly tips away from the ring gear - there's no good way to do that because of the way the starter is mounted since it only uses two bolts and they're tangential to the ring gear, but as a test, you might sandwich a piece of a feeler gauge between the bellhousing and the starter on the bottom edge of the bellhousing (equidistant between the bolts) so that the bottom edge of the starter is slightly pushed away. See the attached picture.
You don't have to fully remove the starter to try either of these two things. Loosen both bolts to give you just enough space between the starter and the bellhousing.
If slow even with new battery and starter, then I'd take a close look at the battery and alternator cables and consider something like the Iceshark replacements.
I'm probably going to replace my cables from the battery to starter just to clear that. But I'm cranking now with no fire. I got a space heater with the car now. Hoping to thaw it out. I got the battery on the trickle charger so I'll let that go for awhile
When you have this cold start problem, do you get any tach bounce? Have the speed and reference sensors ever been replaced? If so, I wonder if the gap was set a bit too big - a gap that works when it's warm, but not when it's cold and the flywheel shrinks?
Also, until you get your new cables, try removing the starter and warming it up inside, then reinstall it and try to start the car. It would help to try to begin isolating which part of the car is not working at cold temps.
Haven't got new cables yet but had another frozen car morning. I ran it all over yesterday and last night in cold weather. the initial start of the day seemed like it cranked slower but it fired up. The warm starts later were perfect as could be. This morning it just wouldn't fire though it sounded liked it tried to fire with a few pops while cranking. Something is definitely weather temp sensitive and needs addressed. Just can't figure it out. Also to reply to the post above, I do get TAC bounce.
A quick over view of my cars setup:
2.5 block
Lr Super 65 turbo with p trim hot housing
Lr 4 in big flow exhaust, no cat, WG dumped
Dry turbo setup
New ignition wires
Engine recently serviced, seals and timing
X3 lr oil cooler
Dual port wastgate
Mbc, venturri delete
Simplified vac system to bare minimum, charcoal canister system removal
All new vac lines and seal
Stock AFM with large round k&n filter
Full clutch overhall last summer
New fpr
New ignition coil
Lr one piece headers
2 piece crossover
Nissan alt mod
The list could go forever. Just about new everything. And professional restorations on what could be done.
I'm thinking maybe the car has something that's freezing literally at these temps. Haven't been able to isolate anything besides that bitter cold causes it to happen. No issues in, say 40 and above temps
Some tests today, pulled the DME relay and jumped the fuel pump, acted completely normal, my injectors are maybe 2 years old and don't suspect any fueling issues. Its rich if anything. I can't imagine an air issue so spark is my variable I want to look into more. Its hard when the issue is only affected by temp outside. It runs perfect on chilly to hot days. And on warm starts on even the coldest day
Last edited by mahoney944; 01-27-2015 at 06:26 PM.
The only solution I've found for this is to place a heater in front of it overnight. There's got to be something, maybe not so obvious, occurring. Anyone have some bypass / test ideas I can try tomorrow? Like I said. I have TAC bounce and jumping the fuel pump sounds normal too.
I would go with lighter weight oil. Had this same problem in northern Maine at 35 deg F below. Go with synthetic 10-40 or 15-xx..
Oil is the cheap solution.
Yeah I just looked at the oil chart in the owners Manuel and it looks like 10-30 and 10-40 have the best range for weather. I'll trickle charge the battery and give it an oil change. Thanks
You might bundle up and try turning the motor by hand when it's cold (24mm socket on a breaker bar on the front pulley) to see if the motor is particularly hard to turn when cold? The balance shaft bearings like to bind up in the front if not aligned just right -- so maybe something like that is tightening up when very cold..?
01-08-2015, 04:07 PM
