My '88 325iS stalls then catches at any speed..

[hairfarmer]

Greetings,

I hope this is the right forum for this:

Problem:
When driving my 1988 325iS, (at any speed) it will occasionally stall, then catch itself and resume as in nothing happenend.

Its like this: I'm driving along, then the power suddenly cuts off, (and I can feel the car lurch a bit when the power is cut off) but then (and I'm only assuming this part) the car, which is still rolling, will jump-start itself and then I have power again. All this happens in about one second.

This may happen on the average of 2-3 times every 60 miles or so.
Anyone have any ideas why my car loses power suddenly. Its not like running out of gas, which is more of a gradual loss of power. This is suddenly, and always unexpected, and at any rev.

My thoughts: Faulty Inginition coil? Test or replace it?
Primary ignition circuit shorted or open intermitedly? Its not a timing issue becasue the car runs strong generally, when its not cutting power. Vacuume?

I want to have a little bit of knowledge before I take this car to my mechanic. I hate being at his mercy regarding diagnosis. I don't trust him. BTW, any body know of a trustworthy mechanic in Long Beach, California?

Thanks,

Hairfarmer
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[jrt67ss350]

I'd be interested in knowing what others think and what you end up finding out because my car does this EXACT same thing every once in a while.

 

[epj3]

Do you mean it does it on its own? When driving the e30 cold, I would go to pull out, give it plenty of gas and it would nearly stall but then catch itself and go back to running fine.

If it's happening any time no matter what, I'd point to relays especially the fuel pump relay.

 

[ldzpstnr]

I had a 85' 318i that did the same exact thing. Be running down the road fine and then just cut out for split second or two, then start running fine. I never found out what the problem was, just ended up taking the fuel injection off the m20 engine and putting a weber carb on it.

I thought maybe it was something maybe in the AFM. I never tested it though. I know if I unplugged the AFM the car would die instantly, while unplugging the other sensors the car would not die. THIS WAS ONLY A GUESS THOUGH. I never ended up figuring it out.

Hmm maybe a problem with all e30's? My '87 325 hasnt done it yet. Knock of wood of course.

 

[jrt67ss350]

Do you mean it does it on its own? When driving the e30 cold, I would go to pull out, give it plenty of gas and it would nearly stall but then catch itself and go back to running fine.

If it's happening any time no matter what, I'd point to relays especially the fuel pump relay.

Yeah, in my car it can happen when driving down the interstate at 70 mph. It's just a 1 second or less interruption of power delivery. It definitely seems electrical - it's like turning off a switch then turning it right back on again. Fuel pump relay seems somewhat plausible, but I wonder if the power delivery would interrupt so quickly - if the fuel pump momentarily quit working, I guess I would expect more of a stumbling, not such an abrupt loss of power. Maybe it's the main relay.

 

[epj3]

Yeah, in my car it can happen when driving down the interstate at 70 mph. It's just a 1 second or less interruption of power delivery. It definitely seems electrical - it's like turning off a switch then turning it right back on again. Fuel pump relay seems somewhat plausible, but I wonder if the power delivery would interrupt so quickly - if the fuel pump momentarily quit working, I guess I would expect more of a stumbling, not such an abrupt loss of power. Maybe it's the main relay.

Does the check engine light (and the whole dashboard) pretty much light up during that 1 second? Kind of like when you stall the car and all those lights come on.

 

[hairfarmer]

More info

I've been researching this issue for about 6 hours on the internet, and it could be a bad or intermittently faulty DME (ECU).

http://member.rivernet.com.au/btaylor/BMWText/technical/DriveabilIntermittStopE28.html

http://member.rivernet.com.au/btaylor/BMWText/technical/IntermittantMissE28.html

http://member.rivernet.com.au/btaylor/BMWText/technical/EngineCutsOutIntermitE30.html

It might also be main relay.

These are the areas that I will start with. Of course, I'll go the cheapest route first, and try swapping the main relay.

Here's some useful information too:

http://member.rivernet.com.au/btaylor/technical.html

BTW, whats the best cway to pinpoint an oil leak. My 88 325iS drinks about a quart every 400-500 miles.



Thanks,

Hairfarmer

 

[hairfarmer]

Oh, here's another good artical on the DME (ECU) swap:

http://www.pelicanparts.com/BMW/techarticles/E36-DME-Repair/E36-DME-Repair.htm

Hairfarmer

 

[epj3]

I doubt it's the ECU - but its definitely something to check.

Quart every 400-500 miles? That doesnt sound like burning - you have to be leaking some to lose that much. I used to do about 1 quart for every 1500-2000 miles on my 88 325is (165k miles when I bought it, 182k when the audi ran into me. I drove the piss out of that thing, too.)

 

[jjporter]

Hi everybody and forgive my plugging in in a 3-Series thread with a 5-Series issue, but the analogies are too many for me to refrain.

My 1991 Euro 525i (M50 engine without Vanos) started having exactly the same jerk Hairfarmer described when it had 100.000 km (~60.000 miles) on the clock. Back then, it only occured two-three times a year but now that the car has run more than 340.000 km (~212.000 miles) that sort of unsolicited cut-off does occur once every 30-35 km (~20 miles).

It always happens at low revs, tipically in the range from idle to 2000 rpm, and when the engine has reached the normal operating temperature. All the warning lights in the dashboard [oil pressure, battery charge, (P) brake, (!) brake, (ABS) brake] come on just to extinguish few moments later. On some occasions the lights stayed on and the car would refuse to pick up speed even when flooring the gas pedal. However turning the engine off and back on would reset the condition.

Over the years the dealer replaced the ignition coils and cables, the big fuse near the suspension turret, the injectors and any sort of parts related to the air intake system. Lots of $$$ thrown away and all to no avail.

Still, I suspect the fault has to do with one or more signals the ECU gathers (crankshaft position sensor? Revolution sensor? You name them) but at the end, fed up with these awkard jerks that made the car truly undriveable (the joys of manual transmission...), I decided to put my old 525i at rest and get a 2001 535i V8.

Having always regretted that decision (the 525i was a great car and a perfect ride for commuting to/from work) I would really love if someone could come up with words of wisdom and help my 525i return back to service.

Cheers,

JJ

 

[epj3]

hairfarmer and justin - just curious, if you were to press in the clutch while it did this, would it actually stall?

 

[ldzpstnr]

Yea the firs time my 318i did this issue with me was when I was on a road trip in canada. You want to talk about getting my heart racing.

There is another guy in my city that has a 325ic with the same problem too. I think its like a 1990 or something. I am good friends with his mechanic and he was asking me about it... since I have owned a few E30's. Of course the problem never happened while the mechanic was driving. That E30 is in prime shape, and probably has only around 150k miles on it or less.

It is EXACTLY like a swtich being turned off and back on. I dont think its a fuel issue, if the fuel was cutting out wouldnt the injectors just lose pressure and the engine slowly die? As I said I never figured it out. To hard to trace.

I wonder if it may be a solder point inside either the AFM or DME. Maybe an important wire inside them is coming loose for a split second.

 

[epj3]

Yea the firs time my 318i did this issue with me was when I was on a road trip in canada. You want to talk about getting my heart racing.

There is another guy in my city that has a 325ic with the same problem too. I think its like a 1990 or something. I am good friends with his mechanic and he was asking me about it... since I have owned a few E30's. Of course the problem never happened while the mechanic was driving. That E30 is in prime shape, and probably has only around 150k miles on it or less.

It is EXACTLY like a swtich being turned off and back on. I dont think its a fuel issue, if the fuel was cutting out wouldnt the injectors just lose pressure and the engine slowly die? As I said I never figured it out. To hard to trace.

I wonder if it may be a solder point inside either the AFM or DME. Maybe an important wire inside them is coming loose for a split second.

BMW's fuel system is a fairly high pressure system, especially for being from the late 80's. The injectors require this high pressure input, or else nothing will happpen. Try this - find the fuel pump relay, and while the car is running pull it out (Or pull the fuse to the fuel pump, either way). It'll burble then die after about a second.

It almost has to be a main relay or fuel pump relay. Sounds like the injectors and everything are completely shutting off. Definitely start off replacing the two relays and go from there.

 

[ldzpstnr]

Now to depressurize the fuel system I remove the fuel pump relay and then start the car. It takes a few seconds for the car to start missing then die. I do this whenever I change the fuel filter, just to make things a little less messy. Dont the injectors use around 60psi?

The problem I have had was the car shutting off instantly for half a second then fire back up back up as if nothing was wrong, no popping or missing like if it ran out of fuel or got low of fuel pressure.

Granted start with the relay first, its cheaper and easier to get at.

 

[jrt67ss350]

hairfarmer and justin - just curious, if you were to press in the clutch while it did this, would it actually stall?

There isn't enough time to react and press the clutch in. By the time you would move your foot to the clutch pedal, the car would again be running normally.

When this happens in my car, none of the warning lights come on like when the car stalls. There's no indication that anything is wrong.

Mine does this VERY infrequently - it has done it maybe 6-7 times since I've owned the car. However, when it does happen, it'll usually do it 2-3 more times in the next 5 minutes, so it isn't a fluke thing. Thankfully, it doesn't do it anywhere near frequently enough for me to try to figure out what the problem is at this point. However, if someone else figures it out, I'd definitely love to know what the culprit was.

 

[ldzpstnr]

Yep my 318i did the same as yours Justin. And it did seem to happen once... then again within 10 miuntes or so. But then it would be gone for a while.

Hmm.... its been a while but if I remember correctly it happen to me more then 6 times. It was getting more and more frequent, like maybe once a week. I got scared and pulled the injection off.... did not think I was going to be able to track down the problem.

My '87 325 hasnt started doing it yet, knock on wood again. I hope it doesnt start hapening, but if it does I WILL figure it out. I have a few extra AFM's to try, and the ECU's for my car are cheap on ebay. Thats where I will start if this dilemma happens.

 

[Cecil]

I think you should start wih the main relay it could be the relay itself or the wiring associated with this the best way to eliminate if you are getting power interruptions is to wire a light bulb to the coil positive and then to the ground and then temporarily stick it were you can see it while driving in the cab preferably and see if the light flickers when the engine stalls it might sound wierd but i tell you it worked for me.

 

[Kether]

The same exact thing JUST started happening to my '89 325is.. except a little different.
I installed a "Dinan" chip (ebay special, yeah I know I know...) and it was working fine. Difference here is, with this chip my problem only occurs at WOT and at around 5,000rpm.

I think it might be the ECU, but seeing as how I have a parts car, I'll replace the relays and if those fix it, I'll buy new parts. Either way I'll let you all know how it goes.

 

[mjbst111]

This temporary "stall" happened to me fairly often when i first bought my 91 325i. Usually when i was flooring it. It sucked so bad. It was such a power loss your passengers can break thier neck! We would get thrown around like i was flooring letting go flooring letting go etc.. It was embarassing. I'm exagerating a little but it was pretty bad.

I was using 93 or 89 octane when it would do it though and i pretty much told myself that was the problem. I started putting in 87 and i don't think i ever had the problem again. What kind of fuel are you guys using?

Then about a half a year later i put a really cheap ebay performance knockoff chip. I know for a fact it never happened after i put that thing in. The chip was 25 dollars or 30... i think its worth a try. too bad i didn't save the ebay chip for one of you to use when i wrecked my car...

Anyone is certainly welcome to try the stock chip that i still have. It went a half a year with out the problem on 87 octane.....

 

[epj3]

Guys it really could be something as easy as water in the distributor, or bad spark plug wires. I would be willing to bet some of you still have the 16+ year old rotting wires. The wire for the coil to the distritubor alone could cause problems.