BlowMyWhistle 0 Report post Posted October 9, 2011 Hi Y'all, I've posted this before and no one has ever been able to answer it. 1990 e30 320i, was my daughters car,but she got so sick of it she went and bought an '07 ford 4wd... So now it goes to the boy... Sometimes it is fine, always runs well, but at idle it breaks down, starts hunting, the car jerks around and will stall. As soon as you accellerate it's gone. If you hold the brake and revto 1k rpm it goes away! Idles about 700rpm. It runs fine at first, then gives a skip and starts playing up. Not really a misfire, more a surge and dip. We've taken it to a few different people, ze german, Peter the master mechanic tested everything that could be tested, no faults came up, He put the idle UP, to over 1k rpm, so it was too fast for everyday driving. I've replaced the leads the plugs the rotor the coil. I took it in to Andy at beemer motor works, thought it might be a leaky butterfly, he rebuilt the throttle body, set the idle better, sits down lower now with a nice thump thump rhythm like a #2 cam, but some times idles smooth, and then breaks down. it's been suggested by ze German zat it could be leaky injector boots, these were all serviced a year ago, or a leaky intake. But it's been tested for leaks and nothing. I can't afford to take it places for them to experiment on it, so I want to have a go at it myself. My current thinking is the cold start circuit, does the e30 have an extra injector for cold start, or how does this work? Last time Andy had it, he spent 3 or 4 hours on it, only charged us a couple hundred bucks! But the 'plate' for the cold start dint seal well and leaked. I replaced the gasket, but it was still leaking, My daughter took it to the garage next to her work and they stuffed it up even more, pulled the thread and put a self tapper in it! Anyway I fixed that properly, but meantime I clamped the line in to stop it leaking. Could this be an issue with the idling? sumhow getting the wrong temp readings and 'flooding' the engine? Now it's my sons car, and He doesn't spend all his money on clothes and hairstyles, we're guuner bilstein the suspension and put a decent exhaust on it, and some big wheels! And change it to a manual. But wtf is wrong with this car? computer's okay. far as we know cam is original, been rebuilt by P.O. but old man, hardly likely to cam it up. possibly cam from another model? Just run out of Ideas, this has been a plague with this car, since before we bought it. P replaced head, all hoses ICV etc. Don't think it has a ICM but all that's been checked. Andy's had it for 2 weeks a couple of tomes now and can't find anything else. he can tune the 'miss'out of it, but it always comes back. Not really sure if there's a difference in running hot or cold? Think it's okay cold? Like I said I've posted this before, so it's a real poser! Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted October 9, 2011 Has anybody ever checked the valve clearances ?? Quote Share this post Link to post Share on other sites
oscar90 0 Report post Posted October 9, 2011 God you've had no end of trouble with this car! you must have the patience of a saint!! I would have sold it by now! If he's keen to play with it a wee bit either sell it, and buy a better model already Manual or get a replacement 2.5 motor with gbox & loom and rip the entire old loom out with the motor and start again Sounds like the car is cursed, no joke lol Otherwise hopefully Glenn etc can chime in with a brilliant idea Quote Share this post Link to post Share on other sites
Surge 1 Report post Posted October 10, 2011 (edited) Not sure if this will be much help but it's worth checking out... There is a connector below the intake manifold on the facelift cars, it's called the C191 connector - the injectors (1-3, 4-6) and the two temperature sensors (one for the ECU and one for the temp guage on the dash) go to it. This is known to cause all sorts of intermittent issues due to the plug getting rusted up and causing poor connections. Apparently a factory fix was to cut a hole in the boot so water could not pool up in it. Bit of a guide here: http://www.r3vlimited.com/board/showthread.php?t=198461 If the ECU temperature sensor isn't getting a signal it runs the injectors every rotation which should only occur when the engine is cold resulting in increased fuel usage. That and the injector wires having poor connections can also cause all manner of driveability issues. It's worth opening it up (rotate the plug) and check the condition of it. If it's rusty as hell, try to clean up the pins or alternatively cut it out completely and hard wire it. If that's not the case, check the condition of the temperature sensors - on the thermostat housing, front of the engine one's blue, one's black (check resistance... google 'e30 temp sensor resistance' to find appropriate values). They do wear out over time. Finally, I'm guessing you've thoroughly checked for vacuum leaks or a split intake boot? They can crack rather awesomely in the middle between the ribs, meaning you can't see the damage until you pull the boot around to see between the ribs. Edited October 10, 2011 by Surge Quote Share this post Link to post Share on other sites
BlowMyWhistle 0 Report post Posted October 13, 2011 Cheers y'all. far as I know no ones ever checked the valve clearances, it's got a new timing belt and tensioner... had the injectors serviced... Will check that connector and the temp gauges. Keeping the car as is, for the boy now, we spent enough on it already, just a 2l is fine as it is... It is pretty hungry on gas, and my guess is something to do with the cold start, feels like it's flooding? It's only the idle, and then only some of the time, it'll be fine, then gives a lurch and starts the hunting. Now next question, new post... Not sure if this will be much help but it's worth checking out... There is a connector below the intake manifold on the facelift cars, it's called the C191 connector - the injectors (1-3, 4-6) and the two temperature sensors (one for the ECU and one for the temp guage on the dash) go to it. This is known to cause all sorts of intermittent issues due to the plug getting rusted up and causing poor connections. Apparently a factory fix was to cut a hole in the boot so water could not pool up in it. Bit of a guide here: http://www.r3vlimited.com/board/showthread.php?t=198461 If the ECU temperature sensor isn't getting a signal it runs the injectors every rotation which should only occur when the engine is cold resulting in increased fuel usage. That and the injector wires having poor connections can also cause all manner of driveability issues. It's worth opening it up (rotate the plug) and check the condition of it. If it's rusty as hell, try to clean up the pins or alternatively cut it out completely and hard wire it. If that's not the case, check the condition of the temperature sensors - on the thermostat housing, front of the engine one's blue, one's black (check resistance... google 'e30 temp sensor resistance' to find appropriate values). They do wear out over time. Finally, I'm guessing you've thoroughly checked for vacuum leaks or a split intake boot? They can crack rather awesomely in the middle between the ribs, meaning you can't see the damage until you pull the boot around to see between the ribs. Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted October 22, 2011 i have basically the same problem in my m20b25 525 all the leads etc check out compression test is all even i fixed a split in the intake boot which to be fair i think i made it while taking it off car has been sitting for a while so new fuel and injector cleaner has helped quite abit will look at the C191 connector tomorrow or Monday hopefully that fixes it otherwise ill be taking a good look the the O2, distributor and AFM will let you know how it goes Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted October 23, 2011 c191 connection was fine i took it for a decent drive with fresh fuel today seems to be equally bad through the whole rev range so im guessing distributor over the afm public holidays were made for people with broken euros Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted October 26, 2011 sorry for hijacking this thread but hopefully this helps others i tested the fuel pressure and the return line had no pressure so all was good there the high pressure line is running at 34 psi the regulator is rated at 3.0 bar / 45 psi im not sure if this is the root of my problem but ill replace it anyway got a new one coming tomorrow from mosens if that doesnt work i will spend the weekend removing the intake and replacing the c191 plug and re gasketing everything on the intake side im suspicious of the ignition rotor as it had carbon build up on about 3/4 of the surface and only the end was shiny cleaning didnt help though im guessing 1/4 of the spark time would hurt its power and idle Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted October 30, 2011 ok quick update got it running sweet turns out it was the C191 plug under the intake first inspection it looked fine but after cutting the plug ends off there was abit of green powder around replaced with bullet terminals and the car runs alot better now hopefully it will get even better after a few days driving to retune the ecu i tested the plug by removing the intake reinstalling the fuel rail and tunring the car over rear three injectors squirted fuel 6 feet into the air front three only about 1 foot there are separate power feeds for the front and rear three so that meant bad power feed connection on the plus side i found inside the intake ports to be spotlessly clean like a brand new engine still shiny alloy and the same under the rocker cover seems this engine has been taken care of in the past Quote Share this post Link to post Share on other sites
