Bimmerfest - BMW Forums

Bimmerfest - BMW Forums (http://www.bimmerfest.com/forums/index.php)
-   E30 (1982 - 1993) (http://www.bimmerfest.com/forums/forumdisplay.php?f=96)
-   -   M10 hesitating? Common problem? (http://www.bimmerfest.com/forums/showthread.php?t=657218)

First time 11-09-2012 03:22 PM

M10 hesitating? Common problem?
 
Hey guys, I again have an issue with my M10 in my '84 318i.

I thought I had it all solved until I started off down my street and there is no response from the throttle. Doesnt matter if the car is hot or cold the symptoms are the same. From idle to about 2K the car hesitates (even when floored) from 2k to 2.8k it seems to accelerate fine. Then from 2.8k + hesitates again.

I think the rev limiters on these engines are non existant (from what ive read) but when i reach almost 4k it simply will not rev any higher.

I am waiting on my bently manual to try and troubleshoot various pieces that might be related to this issue. I am thinking it is fuel related because ignition timing is purely mechanical on the earlier L-jetronic systems iirc.

I do have pretty brownish gas with only about 1/8 of a tank left. Possibly a clogged fuel filter? Was going to try and siphon out remaining gas and refill with new gas.

Also if bad gas isn't the issue maybe a bad AFM or ECU? Those two parts have been the solutions for other peoples problems in my research. I hope that the manual can help me out some but Maybe some guys here have some info that can set me on the right path?

Thanks again guys! You have all been a good help.

SWISS 11-09-2012 06:00 PM

Quote:

Originally Posted by First time (Post 7186190)
Hey guys, I again have an issue with my M10 in my '84 318i.

I thought I had it all solved until I started off down my street and there is no response from the throttle. Doesnt matter if the car is hot or cold the symptoms are the same. From idle to about 2K the car hesitates (even when floored) from 2k to 2.8k it seems to accelerate fine. Then from 2.8k + hesitates again.

I think the rev limiters on these engines are non existant (from what ive read) but when i reach almost 4k it simply will not rev any higher.

I am waiting on my bently manual to try and troubleshoot various pieces that might be related to this issue. I am thinking it is fuel related because ignition timing is purely mechanical on the earlier L-jetronic systems iirc.

I do have pretty brownish gas with only about 1/8 of a tank left. Possibly a clogged fuel filter? Was going to try and siphon out remaining gas and refill with new gas.

Also if bad gas isn't the issue maybe a bad AFM or ECU? Those two parts have been the solutions for other peoples problems in my research. I hope that the manual can help me out some but Maybe some guys here have some info that can set me on the right path?

Thanks again guys! You have all been a good help.

I bet the entire fuel system is clogged from rust in the tank.

Has the car ever sat for a long period of time?

First time 11-09-2012 06:42 PM

Well yes the car sat for at least 3 years to my knowledge. Im betting on more than that. When i had in the old M10 (this engine I have now is a used M10) it did the exact same thing that this one is doing. So im guessing it is bad fuel also. I popped of the fuel pump housing cover and the fuel was nasty and brownish looking.

downhiller 11-09-2012 08:16 PM

fuel system flush. new fuel filter and probably be worth cleaning the injectors

BMWFatherFigure 11-10-2012 04:00 AM

+1 on downhiller. Take the injectors to a shop with a cleaning and flow test/pattern test rig. Please not use 'add to the tank' cleaners.

SWISS 11-10-2012 06:09 AM

Drop the tank and use steel shot inside the tank as an abrasive and what I did was suspend it in a pick up truck bed and drove around the city sreets about 6-7 miles and then flipped over and repeat. You and a buddy can just shake it to instead though. All the crusty rust chunks came out and the inside is shiny again. Use a telescoping magnet to gat all the shot out. Vid I saw they used gravel...but that seemed like a major PITA fishing out of an E30 tank so I got steel shot from Wholesale tool cheap like $2 a bag.

Tkaczuk 11-10-2012 08:00 AM

Quote:

Originally Posted by SWISS (Post 7186948)
Drop the tank

:thumbup:

Its the only way your gonna get the fuel system clean. Do the fuel filter aswell. Also wouldn't hurt to blow air though your metal fuel lines under the car. Make sure they are disconnected on both sides, tank and engine. Could have a chunk of rust in there.

First time 11-10-2012 10:25 AM

Yes my next step was to pull out the tank. Thanks for the help guys I will let you know how it goes. I have a bead blaster so I will use that most likely.

I also have access to a compressor to blow air through the lines.

Looks like I got a little work ahead of me. Thanks again.

Nick323 11-12-2012 01:00 AM

I have seen a guy seize his 2-stroke engine this way :bawling:
Different fuels deteriotrate differently...

On another note, when you have all clean & new filters etc. etc. put a binding agent in your first 20L of fuel and run that through your motor until about 10L remain, which you will drain & susequently donate to your neighbour (yeah, the one who has a kid with a LOUD scooter) :)

First time 11-14-2012 07:41 PM

Ok well I recieved my Bently manual in the mail. This is a nice piece of information to have. I have had others before and this one is no short of excellent!

Got around to testing my pumps (lift and in-line) and both seem to be operating correctly. I also checked resistance on all injectors and all are within spec. I checked the fuel pump relay and that was fine. And I also did bently's fuel supply test which also netted a passing mark.

On that last note the gas that is being pumped out of the tank is some of the nastiest "gas" I have ever seen. It is brownish and very very dirty. It's no wonder the car accelerates poorly, is hard to start at times. Im betting the fuel filter is clooged like no other and possibly the other hard lines too.

I dont want to drop the tank, however I think i will need to. I have a siphon pump that I will use to suck out the 1/4 tank of gas and try and clean out the remaining crap somehow. Then I will be getting a new fuel filter (maybe 2 or 3 seeing as it probably will clog again) and filling up with new gas. Hopefully my issues go away. Wish me luck. Thanks again for the help.

First time 11-14-2012 09:49 PM

Here is the old gas (left) vs. new gas (right)
This is what is siting in my tank.

http://i708.photobucket.com/albums/w...DCEF14E823.jpg

hornhospital 11-14-2012 10:18 PM

The old stuff looks more like gasoline than the new! :confused::dunno:

First time 11-15-2012 10:56 AM

Quote:

Originally Posted by hornhospital (Post 7195977)
The old stuff looks more like gasoline than the new! :confused::dunno:

Lol

downhiller 11-15-2012 05:36 PM

siphoning wont get the gunk out. but if you siphon out all the gas, then let it dry out for a while (with the gas cap out and intank pump) then shove a shop vac down and get the big stuff out. but there will still stuff in there

First time 11-15-2012 06:30 PM

Yes i know it wont get all the gunk out. I probably will have to drop the tank. I was going to do just what you said. Siphon then vacuum. However the fuel pump housing is small. So i wont be able to get all the big stuff out.

BMWFatherFigure 11-15-2012 06:56 PM

If you have debris in the tank bigger than the pump flange hole throw the tank away... Get brave and do it properly. Then there is no doubt, no being stranded on the freway, no unhappy pleasure trips. Also if you miss a gathering of her family - no more sex - ever.

First time 11-15-2012 10:52 PM

Yes i want to do it properly. Really i want to buy another tank but that isnt going to happen at $700+ right now.

Still i need to find time to remove the tank. Doing work is no problem for me. Time constraints is more my issue. But soon enough i will be able to tackle this small hurdle.

Having the know how isnt my issue. I suppose I am trying to find the easy route out as all try and some fail while others are victorious.

Nick323 11-16-2012 01:57 AM

Vacuuming out fuel tanks
 
I agree with Downhiller that it is part of the solution is to finally[QUOTE]then shove a shop vac down and get the big stuff out[/QUOTE
But, then I have a funny story to tell :)

In the bloom of my youth I held a most stressfull job at Cobbs ski factory in Corona SoCal. I had to take these jet skis down to a dam near Elsinore for testing & final tuning.
Naturaly this "work" culminated in washing these jet ski's after thoroughly putting them through their paces. The hulls always had water in them, so instead of stooping so low as to sponge it up with a shop rag, I used my superior intelligence and made use of R2D2- the dry/wet shop vac ;)
What I did not think about was that part of the hull liquid was gasoline & that the motor of R2D2 produced some sparks :yikes:
I think i need not to go into detail about the top (that houses the motor) of this shop vac going into orbit with all attending cowering :rofl:

So maybe make sure the tank is BONE DRY before you start sucking away :bigpimp:

SWISS 11-16-2012 05:39 AM

Shop vac+ gasoline= I hope someone takes pictures lol

hornhospital 11-16-2012 09:35 AM

....and gets the name of the next of kin. :yikes:

I don't care if that tank has sat open for a year, there can and most likely WILL still be enough volatile fumes in it to go BOOM! DO NOT USE A SHOP VAC ON IT! I can't believe someone actually suggested that. :tsk:

Have it boiled out by a radiator shop. Costs little and will be cleaner than you could ever get it at home.

First time 11-16-2012 02:45 PM

Ok guys i will scratch the vacuum portion of the "easy" solution. The tank will probably come out today if the rain ever stops.

downhiller 11-16-2012 07:40 PM

Quote:

Originally Posted by hornhospital (Post 7198418)
I don't care if that tank has sat open for a year, there can and most likely WILL still be enough volatile fumes in it to go BOOM! DO NOT USE A SHOP VAC ON IT! I can't believe someone actually suggested that. :tsk:

ive done worse. but i was also drinking last night. shoulda made a note on that:doh:


All times are GMT -7. The time now is 11:41 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms