Cold Start Issues, Cranks & stumbles but wont fire..

[DmcL]

right.. have this posted on another forum also so this will be a bit of a cut & paste but this is really starting to annoy me given the amount of time/effort/money i have put into the car.

first of all.. does the M20 have a cold start valve?

ok heres the problem.. sometimes it will start ok, other times it just doesnt want to start point blank.. only seems to happen when its cold. evne when it does start ok it will turn on the key for a few seconds before the engine
kicks into life. when its acting up it will turn on the key and the engine will kick once but not fire up, it will do this untill the battery runs flat. usually by this stage i put jump leads on it or plug the battery in on a fast charge for 5 mins and try again and it usually fires up after a few tries and then runs a bit lumpy for the first 5-10 seconds then back to normal. only happens when the car has sat over 13 hours in the cold but doesnt happen every time.

the only things i havent already replaced for other reasons is the AFM, ICV, fuel filter and the brown top coolant temp sensor. prettymuch everything else has been replaced, plugs, leads, distributor, fuel pump, FPR was changed but both the old and new to me one work fine.

i was thinking it may be the injectors seeping fuel and essentially flooding the engine as when i bought it one of the things wrong with it was the intake manifold gasket was toast on a couple cylinders, possibly from fuel saturating the gasket over time? cant really think of much else unless there is a cold start valve or something i missed..

i have also tried various chips including standard, its not chip/tune related.

also FWIW i have tried starting it with the battery on a charger and also with the battery on said charger set for 12v engine start which will crank it plenty but it just doesnt fire. it will kick and stumble but just doesnt want to fire.. even today when i finally got it started it wanted to die so i had to give it some gas for the first 10-20 secs, runs very lumpy when its doing that also. last but not least i have even tried using some of that easy start type aerosol that u spray into the intake but again no effect.

[DmcL]

late 88 build, 89 on paper/89+ spec 325i running motronic 1.3 (173 ECU)

[325zimmer]

After cranking can you smell fuel out of the exhaust?
Cos mine used to to this but i guess not as bad as yours. Mine used to crank over for a while before catching. It took me years to figure it out. I eventually took my injectors to get ultrasonicly cleaned, they also changed the filters, nozzles & o-rings. Now it starts on the button, and my economy has gone up!!
It's definately worth doing, especially if your car has done over 100,000 miles.
It cost me about £90 for 6 injectors, at a place near Feltham, called boxer motor works i think.
They will do it by postage as well.

[Brianmoooore]

http://www.e30zone.net/modules.php?name ... c&t=152878
No 'cold start valve' on your car, as such. The cold start enrichment is done by the engine ECU widening the injector pulses in response to temperature information from the 'blue' temperature sensor on the thermostat outlet elbow.

[H35-24]

I have similar problem with my 1988 320i, it comes to life everytime, but 90% of the time I have to sit for about 10 seconds cranking it on the starter while pressing the throttle, somethimes I find a sweetspot on the throttle and it kicks into life instantly, but mostly I end up just giving it WOT until it fires.

Temparture dependancy is not really an issue, it's all the time.

I have checked the coldstart temperature sensor and it works fine.

This summer I had a reaccurring failure readout stating that the ECU didn't have contact with injector number 6. But after having the injector part of the wiring loom out and refitted it stopped with this failure. But the starting issue hasn't changed.

I suspect the plug that connects the injector wiring to the main engine loom to be the problem. One of my friends has had some difficulties with his 325i engine due to this plug. And in the end his mechanic soldered all the wires together and binned the plug. Since then no problems.

[Brianmoooore]

Problems with the C192 connector are common and well documented on 6 pot E30's, but, again, don't normally give the exact symptoms you describe.
Always worth checking out this connector though (and under the rubber boot of the lower half), as it may cure the next problem you have, even if it doesn't cure this one!

[DmcL]

dont thing its the injector loom plug. im wondering it it may be just a weak battery and the engine getting flooded because it cranks faster on the charger or on jump leads so ill try that first. got a heavy duty battery that will start a diesel easy so should soon see if its the battery or not.

[DmcL]

new heavy duty batter did the trick. turned on the key in freezing weather for like 5-10 secs then fired right up.

[H35-24]

Nice to see ou got yours fixed. I put in at new batery about 6 months ago, no difference on the starting problem thou.

[H35-24]

Nice to see ou got yours fixed. I put in at new batery about 6 months ago, no difference on the starting problem thou.

Got mine fixed now. found a complete fuelrail with injectors, pressureregulator and wiring on ebay only done 40.000 miles. It's the late model were the wiring is in a plastic enclosure like the HT leads.

Fitted it, and now the cars works perfect. Maximum 3 seconds on the starter and it fires up.