1991 325i m20 help, madison
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idle is fine until it's warm. it starting surging real bad while driving. i limped it back to the garage, put in neutral and it would still surge badly. i shut it down then and came on here.
been doing lots of searching online. Does the fuel pressure regulator make any sense that it'd fail when engine is warm? I gotta find some westsiders that I can swap parts with.
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i think that's OK. nothing milky in oil. i've popped the cap and looked good when i did the valve cover gasket before changing the oil
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Surging when warm can be caused by the ecu coolant temp sensor. My e30 would surge once warmed up randomly until I cleaned the connector that plugs into it. It can be a misleading problem because the dashboard gauge is a separate sensor. It will cause a too rich condition because it thinks the engine is still cold. I would check this to rule it out. Do you have a multimeter?
Here is a detailed testing procedure. http://www.e30zone.net/e30zonewiki/index.php/Blue_Plug
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This is very similar to what I have going on with my e30 except mine doesn't surge at idle when up to temp, it high idles instead.
As a side not when I was looking for sensors online shopping via ECS and BluntTech they both had the ecu and dash sensors listed as "water temp sensor". I'm replacing both just cause.
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I picked up an ECU coolant temp sensor cause it was $16, figured i'd just try that and I'm not out much if it isn't it. Probably on its way out anyways if I have the original. I'll get that in tomorrow and let you know. Badger game to watch tonight!
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Yes
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well, the ecu coolant temp didn't do anything. next guess is fuel pressure regulator i think unless someone else has another idea. Anyone know if I could take one off of a e28 5 series?
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Ran to the junk yard and got a fuel pump regulator used. It didn't work. Tried o2 sensor idea and no difference. I have no idea. Could a bad catalytic converter do something like this? Would that just suddenly go? I'm out of ideas for cheap parts.
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If disconnecting the 02 sensor made no difference in the surging then perhaps there is a problem with the O2 sensor. An O2 sensor on its way out would cause idle problems once the engine is warm.
I don't remember reading in the thread but are you throwing any CELs?
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i have above a 1/4 tank left. i had to fill it up on my way back from IL when i bought it end of Nov. I did start it throughout the winter and i did just yesterday throw some fuel injector cleaner in. Unfortunately it won't make it to a gas station to top her off:( Did the stomp test and didn't get any codes.
So, you think o2 is the next cheapest thing to try? no other way of testing that I assume?
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Cheap: Since the car won't make it to the gas station go to Wally world or where ever and pick up a 5 gallon plastic gas container and a bottle of HEET gas line dryer. The injector cleaner you added needs to get mixed in with the gas, so maybe adding some will help.
Cheap: 1/4 tank maybe your fuel pump pickup is clogged (rust flakes etc)? Pump is under the rear seat passenger side. Pull the pump and see if the screen/sock is clogged.
Cheap: metal elbows on the throttle body. Are these tight?
O2 sensor: not so cheap. There are ways to test (folks will weigh in here, or if you have an Bentley handy; maybe this http://www.verrill.com/car/idle/e30_o2test.shtml), but I replaced mine on both e30s since very high mileage and I had no idea when it was done last. Just a heads up that they were a pain to remove. A fouled O2 sensor could be the issue and would not necessarily show up in the stomp test/code read.
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thanks Boris3. I might just do the o2 sensor. Car has 100k on it and i dont know when it was ever done. I'd be surprised if the filter gets clogged as it take the car running for about 5 mins of running before it starts to bogg down. If it got clogged do you think that would happen quicker? I'll check it eitherway though. Cant hurt!
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You haven't put gas in since last November? Get some fresh stuff asap. Try to find it without ethanol, ethanol deteriorates quickly and is not friendly to older cars. If the cat was plugged the vacuum would drop as you revved the engine higher. And typically idle will be ok but power will be poor to terrible when trying to drive.
Sent from my potato phone
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yes same tank, car has been in and out of storage for the winter. it does fire right up and drives fine for a bit, so it doesn't seem like the gas is bad? Does smell like she's running a bit rich though. But yes, some fresh gas is on the list. Was going to try to get some today but didn't make it out of the subdivision.
Here's what she looks like today. Figured I'd give you all some eye candy so you can see the cause you're working on
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