Yes I've searched, but haven't found anything deffinitive, there are to many variables.
This is a new car to me, that sat for a year and has a broken odometer, so I decided a timing belt was needed.
Replaced
Timing Belt, Tensioner, started 1 tooth off
Cap/Rotor
Plugs/Wires/Coil
Water Pump
Adjusted valves (most exhaust were at .010, except 5 was at .011 or so, and 6 was less than .050, intake were all .080.)
Installed Mark D chip
Initial drive after work, car felt great, pulled really well, was night and day from before the work.
Next day topped fuel and added Fuel injector cleaner.
That night, got a minor hesitation at about 1500 rpm in 5th. Figured it was just to low to pull 5th gear. Then got a similar hesitation in 3rd and 4rth.
Next day, went on a 20 mile cruise. Started getting hesitations in 2-5 at partial throttle openings between 1500-3000. Most prevelant on the highway in 5th.
Yesterday, I checked all plug wires and plugs, didn't see anything abnormal. Drove again, now Hesitation is in all gears, 1st stutters from 1000-2000rpm, then clears up. All other gears stutter 1500-2500+.
Decided to pull Mark D chip, thinking maybe it was stressing the FPR. Drove, no change, possibly worse, could be just the power difference from Stock to Mark D chip, but feels more weighted.
Today, replaced Fuel Filter on the idea that the Injector cleaner may have loosened crap from the tank and clogged the filter. There was no change from this.
I've inspected the plugs, they all look as I would expect with only about 25-30 miles on them. There is no Fuel, oil or water on them.
I have seen anything from FPR, AFM, Coil, Injector O Rings, ECU, O2 sensor, fuel pump, Temp sensors as resolutions for this issue. As a profession I service Lab equipment and I hate throwing parts at a problem.
It feels like a fuel delivery issue, which could be a problem after new cap/rotor (better Spark) But with the injector cleaner, maybe it's slowly clearing injectors, so I'm getting intermitent spray patterns.
It is California, so it could be shitty fuel, I did use Chevron 89. Tank is full at this point, or I'd get Shell 91, which seems to be a slightly higher quality.
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Another Hesitation Problem (RESOLVED)
Another Hesitation Problem (RESOLVED)
Last edited by 325racer on Sep 16, 2010 2:05 AM, edited 1 time in total.
Verify vacuum line to fuel reg is good.
I was a true blue chevron user for decades and just recently changed to Shell 87. Car runs like crap on any Chevron and not as well with Shell 89 or higher. My experience is to stay away from any fuel injector cleaner. I assume you corrected the timing belt upper molars not matching with the lower molars?
I'm confused on your valve adjustment settings. What was your final settings?
I was a true blue chevron user for decades and just recently changed to Shell 87. Car runs like crap on any Chevron and not as well with Shell 89 or higher. My experience is to stay away from any fuel injector cleaner. I assume you corrected the timing belt upper molars not matching with the lower molars?
I'm confused on your valve adjustment settings. What was your final settings?
Pop the AFM cover and loosen the wheel (counterclockwise) by two teeth and take it for a spin if you know the fuel pressure reg is working properly. This will permit the AFM flapper to react quicker (less flapper tension against the same vacuum pull from the intake) and subsequently the wiper arm location to a higher level on the resistance band. I just did this with the eta...my symptom was once or twice accelerating cold engine from a stop...hesitation. Hesitation is now greatly reduced but a hint still present. If that doesn't help just reposition it back.
I feel like I could have written this post about my own car. I feel for ya. I've got word for word almost exactly the same problem with the M535i right now. I've swapped out the Mark D chip the same as you have and it's just made things worse. Car runs like an absolute bucket of merde. No idea what's wrong and no idea how to fix it yet. It's beyond me I'm afraid. I'm gonna have to give it to someone before it leaves me on the side of the road again when it next rains like it did 3 weeks ago.
Just wanted to pass on my commiserations. I feel your pain 100%.
Just wanted to pass on my commiserations. I feel your pain 100%.
My theory... If it is getting progressively worse and you have a Bosch rotor I would have a look at that. I've had one each fail on the 5 and 6 in the last couple years roughly and were causing weird intermittent running issues. One in only about 6k miles, the other maybe 13k. They also ruined the dist cap when they wiggled loose, so nearly $100 bill each time around. Now I only use Bremi and no problems.
My thinking is Bosch has outsourced the bolts to save $.02 and the metal now yields or stretches and the rotor comes loose. fwiw I've been working on 80's era BMW's for 20 years and this has only happened to me in the last year or so with new Bosch parts. Thus my conclusion. And I haven't had anything else fall off my cars because it was too loose.
So there's one thing you might not normally think to check.
My thinking is Bosch has outsourced the bolts to save $.02 and the metal now yields or stretches and the rotor comes loose. fwiw I've been working on 80's era BMW's for 20 years and this has only happened to me in the last year or so with new Bosch parts. Thus my conclusion. And I haven't had anything else fall off my cars because it was too loose.
So there's one thing you might not normally think to check.
In my case it is very bad indeed when the engine is stone cold. The first couple of corners you go around and try to accelerate away from the engine just dies. As the OP said it feels for all the world like a fuel delivery problem but I've had the fuel pressure & flow checked and both are perfectly normal. As the engine warms up, the severity of the problem is not quite so obvious, but the problem never fully goes away. I just want my car back again how it was. I know full well just how much of a jet it is when running properly with the Mark D chip and it's killing me that it's running like this. 
Since the car ran great on the initial test drive, I'm pretty sure the timing belt was installed correctly and the valves were adjusted properly.
Since the problem "Seems" to have started after adding Injector cleaner and fuel, I think I may drain the tank and put in some other fuel.
I like the idea of the rotor coming loose, as it was a Bosch rotor. I ordered from Pelican Parts, thought I ordered Bremi, but got Bosch. So I'll check that.
On a Plus side, I just did the OBC LED conversion and it looks good. Next will be Odometer fix.
Since the problem "Seems" to have started after adding Injector cleaner and fuel, I think I may drain the tank and put in some other fuel.
I like the idea of the rotor coming loose, as it was a Bosch rotor. I ordered from Pelican Parts, thought I ordered Bremi, but got Bosch. So I'll check that.
On a Plus side, I just did the OBC LED conversion and it looks good. Next will be Odometer fix.
my mechanic recently cleaned all of the chassis ground points. I swear she runs and idles much smoother now.
I have been going through the exact same thing you are doing.
i did a smoke test, swap afm's replaced plugs, wires, cap rotor, coil, in tank fuel pump, fuel fitler, tested the fuel pressure.
everything was checking out.
i have some just rebuilt injectors to go on and i found my fan clutch was frozen. I have a new one to go on tonight.
good luck!
I have been going through the exact same thing you are doing.
i did a smoke test, swap afm's replaced plugs, wires, cap rotor, coil, in tank fuel pump, fuel fitler, tested the fuel pressure.
everything was checking out.
i have some just rebuilt injectors to go on and i found my fan clutch was frozen. I have a new one to go on tonight.
good luck!
Another simple test(maybe it was mentioned) is the CTS which has a big impact on driveability as engine temperature changes. It needs to be in spec cold and hot and in between. If the issues are largeley associated with engine temp changes you might look at that also.
And... if you have the wrong plugs(which is most every plug but a WR9LS or ZGR5A) it seems that fouling from rich conditions will cause problems to exagerate themselves. I've found platinums will foul easily(15 years ago) and don't use them anymore. Combine an out of spec CTS with platinum plugs and your car will go downhill fast. Been there before too.
Good luck
And... if you have the wrong plugs(which is most every plug but a WR9LS or ZGR5A) it seems that fouling from rich conditions will cause problems to exagerate themselves. I've found platinums will foul easily(15 years ago) and don't use them anymore. Combine an out of spec CTS with platinum plugs and your car will go downhill fast. Been there before too.
Good luck
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dubcraftee
- Posts: 118
- Joined: Jul 30, 2009 5:34 PM
- Location: Baltimore
Today, pulled fuel pump to inspect for clogging of the pickup or any sediment/etc in the tank. ( Problem started after injector cleaner was added and car sat for a year before I bought it) Tank and pump looked clean. Syphoned down to 4 gallons, then added fresh gas.
Found a small hole in intake boot, patched that.
Went for 8 mile drive, problem still hasn't changed.
Disconnected O2 sensor, drove around the block. No change.
Issue seems to be the same when cold or hot, so I don't think it's a Temp sensor issue.
May try to borrow and ECU tomorrow to make sure I didn't damage a joint or something swapping chips.
Found a small hole in intake boot, patched that.
Went for 8 mile drive, problem still hasn't changed.
Disconnected O2 sensor, drove around the block. No change.
Issue seems to be the same when cold or hot, so I don't think it's a Temp sensor issue.
May try to borrow and ECU tomorrow to make sure I didn't damage a joint or something swapping chips.
You've been thinking of all the same things I've been thinking of too. Please report back and let us know what you find with swapping ECUs. I can't easily do this here as I don't know where I can source another ECU from. Although I've always been extremely careful about handling the ECU when I've been swapping chips to avoid just this kind of hassle, I have swapped an awful lot of chips in and out over time. I guess it's a possibility.325racer wrote:May try to borrow and ECU tomorrow to make sure I didn't damage a joint or something swapping chips.
Swapped ECU today, drove it. Didn't seem to change anything.
Put original ECU with Mark D chip back in, felt about the same, but with more power.
Hard to say for sure, but I think it may be starting to get better, which would point to bad fuel.
On a side note, I'm pissed at myself, as I broke the Speedo needle after completeing Odometer repair. Happened when accdentally dropped cluster while screwing back together, I think.
Put original ECU with Mark D chip back in, felt about the same, but with more power.
Hard to say for sure, but I think it may be starting to get better, which would point to bad fuel.
On a side note, I'm pissed at myself, as I broke the Speedo needle after completeing Odometer repair. Happened when accdentally dropped cluster while screwing back together, I think.
Update: Still not fixed.
I've since swapped the Thermo Time switch and Coolant Temp Switch, both of which deal with cold start stuff. Neither of these affected anything.
Pulled injectors to inspect and clean as good as possible with carb cleaner, this didn't get in them, but cleaned the nozzles and filters. During this I found 1 bad o-ring on an injector and the FPR. Changed those O-Rings, Cold start and idle improved dramatically.
Started it up and pumped a bunch of blew smoke one day. Went to swap AFM found a lot of oil in the intake. Seems to be coming through the Idle control valve, not the valve cover tube, which is ODD. Cleaned everything up, and that seems to be going away.
Swapped AFM, but it was questionable and the car wouldn't even start.
Swapped FPR, no change.
Removed cover on my AFM, cleaned contact with a pencil erasor, no change.
Ran a higher consentration of Injector cleaner, it seemed to make it better for about 10 miles.
At this point my theory is that I have 1 or more bad injectors that are either running rich or lean once they warm up within a certain load requirement.
I've since swapped the Thermo Time switch and Coolant Temp Switch, both of which deal with cold start stuff. Neither of these affected anything.
Pulled injectors to inspect and clean as good as possible with carb cleaner, this didn't get in them, but cleaned the nozzles and filters. During this I found 1 bad o-ring on an injector and the FPR. Changed those O-Rings, Cold start and idle improved dramatically.
Started it up and pumped a bunch of blew smoke one day. Went to swap AFM found a lot of oil in the intake. Seems to be coming through the Idle control valve, not the valve cover tube, which is ODD. Cleaned everything up, and that seems to be going away.
Swapped AFM, but it was questionable and the car wouldn't even start.
Swapped FPR, no change.
Removed cover on my AFM, cleaned contact with a pencil erasor, no change.
Ran a higher consentration of Injector cleaner, it seemed to make it better for about 10 miles.
At this point my theory is that I have 1 or more bad injectors that are either running rich or lean once they warm up within a certain load requirement.
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Rich Euro M5
- Posts: 6098
- Joined: Mar 10, 2006 6:20 AM
- Location: Klein, Texas
WRONG325racer wrote:
I've since swapped the Thermo Time switch and Coolant Temp Switch, both of which deal with cold start stuff. Neither of these affected anything.
The CTS provides coolant temperature feedback to the ECU at all times, not just at cold start. As tn535 said, the CTS has to be within tolerance at both end points and the resistance change must be linear between the end point values.
Rich
Maybe the next course of action should be to have the injectors cleaned and flow tested? Re-reading it does seem like the injector cleaner was the start of some of these troubles.
Another idea... Have you ever done a hot soak, where you add something like Seafoam or Ventil Sauber to the intake when the engine is hot. If your problems are related to deposits and buildup on intake runners and valves, etc...the injector cleaner may have unsettled this condition and now it needs a good cleaning.
BMW had a lot of issues with cars of this vintage that were driven too gently. As I recall they would remove the intake and blast the intake side of the head with walnut shells to improve idle and eliminate hesitation.
Regular doses of injector and valve cleaner are actually prescribed for these cars. I don't think you did anything wrong. There are some cleaners that work better than others though depending on the type of injector. Chevron Techron was considered best for the injector and Ventil Sauber for the valves. Or so I've understood.
Another idea... Have you ever done a hot soak, where you add something like Seafoam or Ventil Sauber to the intake when the engine is hot. If your problems are related to deposits and buildup on intake runners and valves, etc...the injector cleaner may have unsettled this condition and now it needs a good cleaning.
BMW had a lot of issues with cars of this vintage that were driven too gently. As I recall they would remove the intake and blast the intake side of the head with walnut shells to improve idle and eliminate hesitation.
Regular doses of injector and valve cleaner are actually prescribed for these cars. I don't think you did anything wrong. There are some cleaners that work better than others though depending on the type of injector. Chevron Techron was considered best for the injector and Ventil Sauber for the valves. Or so I've understood.
One more thing to add, if you have a lot of oil on the intake side it's a sign that other things are wrong, most notably a large vacuum leak letting too much airflow through the CCV. So maybe another thing suggested is to check all the vacuum hoses and o-rings carefully. If they are old and brittle I would just replace them for good measure. This condition will also contribute to more deposits on the backside of intake valves, etc.
Confirmation of tn535i:tn535i wrote: BMW had a lot of issues with cars of this vintage that were driven too gently. As I recall they would remove the intake and blast the intake side of the head with walnut shells to improve idle and eliminate hesitation.
Regular doses of injector and valve cleaner are actually prescribed for these cars. I don't think you did anything wrong. There are some cleaners that work better than others though depending on the type of injector. Chevron Techron was considered best for the injector and Ventil Sauber for the valves. Or so I've understood.
Absolutely correct! I had an 86 535 in 88 with 28k on it. One of the 30k inspection 1 items was to clean the intake with walnut shell pieces.They were giving me a bottle of injection cleaner every oil change (Chevron techron I believe) but in a BMW wrapper.
Finally Resolved
Resolution UPDATE:
After Much troubleshooting, including purchasing the Bosch Motronic Bentley manual I was not able to find the problem and ended up bringing it to a VERY qualified shop.
What I personally checked or replaced in the entire process.
AFM
All coolant sensors/switches, the one for ECU I bought New
Plugs Again
Ohmed out plug wires
swapped coil to original and back to new
changed fuel pump
changed FPR
swapped speed reference and crank reference sensors
double checked timing
swapped injectors
Ohmed TPS
checked Cold Start for leaks
Ran LubriMoly engine flush
Checked everything above a couple more times.
Ohmed all sensor at ECU connector
Well, bottom line none of this did anything, I realized I haven't taken a car to a shop other than for Welding in over 15 years but I couldn't deal with it anymore.
Verdict from the shop was the following.
TPS while in motion was actually shorting from open to closed, not sure how they tested it different from me to find that, but I'm not suprised at this finding. They reported that made it better, but still had hesitation.
They then swapped Bremi Cap and Bosch Rotor (which I just replaced) for both new Bosch Parts. That seems to have cured the problem. They report that they only use Bosch and have seen issues with the Bremi parts. Based on what the Original Cap/Rotor looked like I NEVER would have suspected the new parts could perform worse than the ones I removed. I will inspect the parts they removed tomorrow for any signs of issue, but I've had them off and saw nothing noteworthy that would hint at a problem.
In Summary:
Check/Change your TPS and only use Bosch Cap and Rotor, or at least try Like Brand parts, I think I had miss matched Cap/Rotor. Maybe a Bremi rotor would have worked better with Bremi Cap, but saving $18 on the Cap, cost me probably 40+ hours of my own time and nearly $500 in new parts and labor.
After Much troubleshooting, including purchasing the Bosch Motronic Bentley manual I was not able to find the problem and ended up bringing it to a VERY qualified shop.
What I personally checked or replaced in the entire process.
AFM
All coolant sensors/switches, the one for ECU I bought New
Plugs Again
Ohmed out plug wires
swapped coil to original and back to new
changed fuel pump
changed FPR
swapped speed reference and crank reference sensors
double checked timing
swapped injectors
Ohmed TPS
checked Cold Start for leaks
Ran LubriMoly engine flush
Checked everything above a couple more times.
Ohmed all sensor at ECU connector
Well, bottom line none of this did anything, I realized I haven't taken a car to a shop other than for Welding in over 15 years but I couldn't deal with it anymore.
Verdict from the shop was the following.
TPS while in motion was actually shorting from open to closed, not sure how they tested it different from me to find that, but I'm not suprised at this finding. They reported that made it better, but still had hesitation.
They then swapped Bremi Cap and Bosch Rotor (which I just replaced) for both new Bosch Parts. That seems to have cured the problem. They report that they only use Bosch and have seen issues with the Bremi parts. Based on what the Original Cap/Rotor looked like I NEVER would have suspected the new parts could perform worse than the ones I removed. I will inspect the parts they removed tomorrow for any signs of issue, but I've had them off and saw nothing noteworthy that would hint at a problem.
In Summary:
Check/Change your TPS and only use Bosch Cap and Rotor, or at least try Like Brand parts, I think I had miss matched Cap/Rotor. Maybe a Bremi rotor would have worked better with Bremi Cap, but saving $18 on the Cap, cost me probably 40+ hours of my own time and nearly $500 in new parts and labor.
Do your self a favor and find a car in the wrecking yard and remove everything from the engine. Cap,rotor,wires,plugs,sensors,relays,coil,ecu,ref sensors ... Since we don't have a diagnostic port on these cars it just easier to swap in parts when troubleshooting. You can verify the parts by now installing on your known good engine,take these parts and store them for next time you have an issue.I think in the long run this will save time and money.
That's pretty much what I did in this whole process, the problem was the NEW cap and rotor were the biggest issue. Never would have suspected them, because it ran fine with old very worn and pitted parts. I assumed nothing could be worse than those and was surprised it ran at all with how they and the old plugs looked.