Picked up a 91 M5 recently and car will not start. This happened once before but after the tow home it started right up and has been good for 3 months. Any approximate ideas before I start ripping and tearing at this car again?
Thanks
Yes-Turns over fine, spark appears to be fine, Fuel pump relay tested and ok,
CPS read 511ohms (I read into the middle plug of the 3 plugs beside the distributor), Fuel pump moves fuel (Disconnected lines at the pump and cranked) but plugs appear to be dry. Did not pressure test.
Not sure what else to check-any advice is greatly appreciated
forgot to mention that the car ran great before not starting......Doesn't appear to be getting any fuel. Will check fuel filter and injectors next.
Been a while since I've dealt with a distributor. Shot in the dark here, but I was having problems with my first car not starting and it turned out the distributor had a crack in it. Every time we had an even remotely moist day, the water would find its way in and prevent the spark from distributing appropriately.
Seems to me like you're on the right track and have probably troubleshot shit like this before. I don't really have any further direction from what you've been doing; you just have to be diligent when you're working your way up the fuel line to be sure what you're looking at isn't causing the problem.
You've confirmed you have spark and you say there is fuel. Did you check for fuel pressure with a gauge on the feed line? If you've got both of those present then you'll need to figure out if the injectors are being fed a signal to fire. I'm assuming not. Check the crank position sensor and it's wiring on the front of the engine. It's a common fault to look for.
Mine: 1988 635CSi Euro in Diamantschwarz Metallic, 1989 ALPINA B10 3.5 in Alpineweiss II, 1981 528i in Kastanienrot-Metallic, 1958 Isetta 300 currently in rust repair
In the family: 1958 Isetta 300 in Federweiss/Pastellblau, 1987 635CSi, 2000 M5
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Hi Guys-Thanks for the help.CPS read ok with a multimeter (approx 511ohms). Upon inspection of the spark plugs I did not like the gap (.05). Picked up a set of NGK3481 (unable to get the Bosch Y6DC quickly), gapped these plugs to spec of about .028 and the car started great. Haven't had a chance to test drive but am hoping this is the problem. Possibly could be that the old plugs were just burn't too far down and the DME didn't like that. Only other thing I did was tap the fuel line splitter connection at the firewall. Either that or I have a mystery Gremlin...
These cars are very finicky on ignition parts. rotor, cap, plugs all have to be in good condition. I would dump in the proper Bosch plugs when you get a chance. A few too many stories of the wrong plug causing engine failures out there on the M5board
Thanks for the advice. Will do as soon as I can order some in. Was a little hesitant about putting in the NGK's but they are suppose to be a direct replacment (I even found a spark plug chart some where that showed these as a factory replacement) That said It's probably better to be safe then sorry. Thanks again all forum members for the advice. Regards-John
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