88 528e curious stumbling problem

Alright all ye who are strong in BMW-fu

98.4 percent of the time this car runs absolutely fantastic. The other times it acts as though it is overheating then stumbles and runs quite poorly. The temp needle climbs, it stumbles, won't accelerate, then a few minutes later it clears up and again...runs great. I have replaced the thermostat. I have, but have not yet replaced, the coolant temp sensor. I have replaced the airflow meter, on the advice of a mechanic. Fortunately, it was cheap...(EBAY) but it made no difference. I love the car...It's in great shape...but HELP!
Reply to
zamboni30000
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  1. Get the Bentley manual and test the coolent-related senders/sensors.
  2. Change the thermostat if it's over 2 years old.
  3. Check the fuel pump relay. it may be affected when it gets hot under the hood.
  4. Get back to the group with your findings.

Bill in Omaha '86 535i

Reply to
Bill

My sad tale thus far:

I have the Haynes, easier to find, though I might look for all the manuals I can get! I had already bought a coolant temp sensor, which turned out to be a good thing, because the old one crumbled when I removed it. It didn't help though. I unplugged the temp switch so the gauge read 0 (they didn't have the part in stock) No difference.

I did replace it with a good quality one. We have a parts store in town that specializes in european import car parts. I don't mind paying a little more even if I just "think" I'm getting a better part. I'm a sucker like that. No, actually they are a good bunch and they carry the real stuff. Bosch etc. Thermostat also didn't help.

I want to try this one. Haven't yet I was just going to replace it. Seems like there are three different possibilities. I'm going to try to locate it and get some numbers to match it up.

Oh I will!

Bill, thanks for your input...I'm Mike in Mobile AL

It's really strange. All the obvious things haven't helped. The gauge climbs and it starts stumbling.When it happens it's revving up and down and the temp needle does likewise. I was wondering if there might be a grounding problem...or a computer problem? It's hard to tell what's happening first. There's no particular reason that it should overheat...and so quickly...especially since I replaced the thermostat. It's full of coolant, the water pump's spinning, fan clutch seems to be pulling air through the radiator, the color of the coolant looks good, it runs great until the stumbling starts, so I don't think its a cracked head or head gasket. Then, just as soon as it starts...it's fine again. But I don't trust it right now. I zip through the neighborhood...but I don't want to take it out on the open road! As long as the temp needle is in the middle, it runs fine. If it goes above 3/4 then it starts doing its thing.

TIA Mike

Reply to
zamboni30000

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I moved to Omaha after Katrina. I'm from Biloxi, MS! If you like, I can send the CD I've built that covers a lot of troubleshooting for the e30, e28, and a few others. I even have the Haynes in pdf. The ECU may be reading a gap/bubble in the coolant system, if the gauge fluctuates. I checked mine with the engine running and the reservoir open (cap off). I also squeezed the hoses until it warmed up good and thermostat opened. I added until it near overflowed and capped it. Be careful on revving the engine when warm, it will overflow with the cap off. This technique has been flawless for me since 1988. I also have a few relays I can send. I get them from the parts yards and test them on the meter. I got them parts! Let me know what's up. The CD is free. It could also be fuel injectors. I have a set of those too, good and inexpensive.

Bill in Omaha '86 535i

Reply to
Bill

If the ECU is bad, I may have one. What's the number? BMW number from 3/87 is 12141730793. Off-hand, I don't know the Bosch number. Check here:

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under the archive section for e28.

Bill in Omaha '86 535i

Reply to
Bill

Interesting. Actually, I'm originally from Pass Christian. A small town, which I know you're familiar with, who's only clam to fame is getting wiped off the face of the planet from time to time by hurricanes. We all thought Camille '69 was bad...she had nuthin. Katrina was a monster. Even in Mobile I didn't have power for a week. Downtown flooded, trees down everywhere...(I didn't think there were any left after our near-miss with Ivan in 94,) and that was about 80+ miles from where she hit.

I might have to take you up on that...but I'm really hoping to find something so easy/obvious I slap my head. I'm kinda new to this car. It belongs to an ex-girlfriend sooo I've worked on it from time to time but she's giving it to me and it's frustrating a bit. It runs so good, just when it starts acting up I want to thrash it with a tree branch.

Do you know where the fuel pump relay is, you mentioned that as a possible problem? The fuse/relay box on the driver's side fenderwell only has three relays in it and they don't seem to be marked as anything involving a fuel pump.

Are you planning on returning to Biloxi when things settle down? They've reopened one span of the Bay Saint Louis Bridge, and there is supposed to be one span of the bridge over Biloxi Bay by the end of the year. Some of he beaches are finally opened, and of course the casinos are opening. The Hard Rock is supposed to open any time now. Remember it was originally scheduled to open 2 days after Katrina! It's still pretty depressing driving down HWY 90. I used to really enjoy that drive. Well, maybe someday in my fully armed and operational BMW. Sunroof open. Windows down. Buffet on the radio.

Mike

Reply to
zamboni30000

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We stayed during the hurricane... STOOPID US! We were about 1/4 mile from Edgewater Mall, to the northeast, just north of the RR tracks. We saw no standing water and the trees saved our bldg. The rest of the apartment complex was virtually destroyed. We got water in 7 days and electricity in

  1. It was like extended camping for me. The wife hated it. The worst was the heat. Luckily the bugs all blew away. The RR tracks were like a dam and stopped all the surge to the south. Most other areas weren't so lucky. I may be tripping home for a few days around September, but probably won't move back. Housing/apartments cost WAY too much due to price-gouging. Our apartment was undamaged and rented the next week after we left for 0.00 more per month than we were paying! Yikes! My mom still lives in Gulfport just a few blocks from the beach and her house took about 00 in roof repairs. Not bad at all.

The relays are on the engine side of the fuse box, I believe. The Haynes you have should be pretty accurate. I have a small picture I can send via e-mail. I shows the common 3-relay set and defines each relay based on model and year. BMW actually changed them around... can you believe that???

Bill in Omaha

Reply to
Bill

My mom is in Biloxi, on Popps Ferry. Just north of the Coliseum She did OK. She used to live on Reginault in extreme west Gulfport...that would've been bad...vey bad. Near the beach, south of the tracks...several feet of water. I'd say she sold her house just in time!

my proper email is snipped-for-privacy@comcastpant.net

remove my pants to email... thanks for all of your help. And it's good to meet you! I'll send along pics of my alpinweiß beast once I get her rolling...maybe pics of the car too. LOL.

Mike

Reply to
zamboni30000

Okay, okay, okay, I think I got it!

I did replace several things...all of which needed a good replacing.

At first, on the advice of a mechanic I replaced the air flow meter. Nothing

Coolant temp sensor: needed it!!!! Old one disintegrated. Nothing

Thermostat, original!!!! Needed it! Nothing

While I was there, several vacuum lines, one of which went to the fuel pressure regulator...'cos it was all crumbly. I was thinking...low fuel pressure?

I had already recently replaced fuel filter and plugs.

Cap and rotor...might have been original :-< pins nearly cut in half! Pitted, horrible Nothing

Rearranged various relays (fuel pump relay) if appropriate. Nothing

It was still overheating from time to time... which corresponded to its poor behavior.

At first glance it looked like the fan clutch was ok. But one time, I looked at it, it didn't seem quite right. So in one of my southern "Hey yall! Watch this!" moments, yet without any "y'all "to watch it or apply a tourniquet if I was wrong...I stopped the fan blade with my bare hand while it was overheating. Excellent, said I!. Well, only after noting what a dumb ass thing that just was. I put a new clutch on it.

The temp needle is absolutely rock steady. It never goes above medium. and it runs great! Better than before. I zipped around the neighborhood, frightened the children, scared the pets, stunned the farm animals. It wouldn't act up. I almost wouldn't have believed it. I'm not disappointed. Everything I put on, it needed. Even the previous air flow meter was the wrong part number. At least now it was one from the same model!

Thanks to Bill for your input. I'll let you know if it continues to be a lady or a b***h! LOL

(posted and emailed)

mike a new regular?!

88 528e
Reply to
zamboni30000

A new car would be cheaper than this!

Reply to
Oscar

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But the satisfaction would be less and you'd gain a car payment and higher insurance. New is nice, but comes with a price.

Bill in Omaha '86 535i

Reply to
Bill

$50 on EBAY

$14

$20 including gasket

$2 and I have extra

$30

$77

Free!

$92...ouch!

The car was actually given to me. Thus far I've spent $285 on it...err recently, that is (ex-girlfriend's car) and now runs like it has a rocket up it's a**. We used to drive it on road trips...good on gas too! If you can provide me with a new car, that does what it does for that price I will certainly subscribe to your newsletter.

Yeah, I know you were kidding...I think. Seriously though. It's a small engine and everything but it really goes. And as my dad used to say, smooth as snot on a doorknob...I'm glad we finally put dad in that home for his long deserved rest. He was a weirdo. Barking mad, I tell you. Woof!

mike

88 528e
Reply to
zamboni30000

I was just wondering how much longer I was going to have to wait for more of your superior wit. Too bad you actually quoted 70 lines of text to add this to...

Reply to
Psycho

Tough shit - you didn't have to read it!

Intelligence is knowing when to quit - so why don't you?

Reply to
Oscar

Okay, it did fine, fine for days...then it did something similar, though not as severe, I think. When it does it, the temp needle had usually climbed...cloom...clum...whatever...but not into the overheat range. EVERY other car I have ever owned didn't have a problem at this point. Then it does this weird surging thing. It has an economy meter from 0 to 40 mpg and that needle swings back and forth. Still it seems like as long as the temp needle stays in the proper area it runs ok. I don't mind replacing parts, the car was free, but I'd like to do something that might work. I've done everything mentioned above.

I have a new temp gauge sender(not installed yet)...only because I'd like to know if it's actually overheating. But reading other forums...fora...whatever, I saw a suggestion for a throttle position sensor. Sometimes they get grumpy when the engine bay heats up. Coil? Bad gas? Anything?

mike

88 528e...the tramp!
Reply to
zamboni30000

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Here's a few things (and they could be redundant, but) -

  1. The instrument cluster may be faulty (I have some spares!)
  2. Are you SURE it's getting that hot? (if there's air in the coolant system, the gauge jumps when the air bubble hits the sensor)
  3. If the radiator has a blockage (but then it wouldn't cool for days then act up)
  4. The coolant/water ratio needs adjustment
  5. It's just too damn hot and humid (my sister in Biloxi says it is)
  6. There's some added resistance somewhere creating an artificial reading
  7. Pull the cluster and check the 3 rear connectors for fit

Let us know. And can you send me a pic or two of the engine bay? Bill in Omaha '86 535i

Reply to
Bill

A better place to hang out would help more.

Zamboni, you need to hook up the E28 intelligentsia. We are at

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and no one there is going to tell you to buy a new car instead of fixing the one you have. Even if this persistent moron follows you there, he won't last long because we won't tolerate those who have nothing but abuse to contribute.

As for the service manual, I cannot tell you emphatically enough that the Haynes manual you have is crap. BUY THE BENTLEY! It will be the best $40 you ever spend on this car. Trust me; I've had four of these (E28s) so far and I'm buying my fifth.

-- C.R. Krieger Been there; done that

Reply to
E28 Guy©

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