Rebuilt Hartge H26 Engine Idle Issues
Moderator: martauto
Hello all,
I've been restoring a Hartge H26.
The engine has been fully rebuilt all new vacuum lines, all ignition components are new, injectors are new (EV6), new coolant sensors too.
Only parts not to be changed are TPS, ICV, AFM and Pulse sensor.
Now I'm pretty sure when I first started the rebuilt motor the engine was running good at idle, I say pretty sure as when I did it I didn't have the exhaust system connected so you can imagine it was very loud.
I've reconnected the exhaust system and the engine is running around 500 rpm at idle. Engine seems sweet above this idle but when you release the throttle and it goes back down and it almost stalls but then recovers to around 500 rpm.
I removed the ICV and ran all the tests the valve does operate under a 12V load, cleaned it out with Carb cleaner (which I had already done) and still its not idling right. TPS seems fine.
Even though the ICV passed all the tests I am suspecting it might still be an ICV. The reason I say this is I had a similar issue with my E36 M3 when I cleaned the ICV out the valve became a lot of flexible i.e. it would move much more quickly when you'd rotate the ICV around.
With the H26 even after cleaning with ICV with carb cleaner it still feels pretty stiff when rotating it moves but a lot more effort is required to get it to move.
Anyone on her have any advice, I don't really fancy forking out £200 for an ICV so hoping someone on here has some other ideas or even validate my theory, if so then so be it i'll have to get a new ICV.
Thanks in advance.
By the way you can see the idle problem on my instagram page as well as follow my progress @azmontana1
I've been restoring a Hartge H26.
The engine has been fully rebuilt all new vacuum lines, all ignition components are new, injectors are new (EV6), new coolant sensors too.
Only parts not to be changed are TPS, ICV, AFM and Pulse sensor.
Now I'm pretty sure when I first started the rebuilt motor the engine was running good at idle, I say pretty sure as when I did it I didn't have the exhaust system connected so you can imagine it was very loud.
I've reconnected the exhaust system and the engine is running around 500 rpm at idle. Engine seems sweet above this idle but when you release the throttle and it goes back down and it almost stalls but then recovers to around 500 rpm.
I removed the ICV and ran all the tests the valve does operate under a 12V load, cleaned it out with Carb cleaner (which I had already done) and still its not idling right. TPS seems fine.
Even though the ICV passed all the tests I am suspecting it might still be an ICV. The reason I say this is I had a similar issue with my E36 M3 when I cleaned the ICV out the valve became a lot of flexible i.e. it would move much more quickly when you'd rotate the ICV around.
With the H26 even after cleaning with ICV with carb cleaner it still feels pretty stiff when rotating it moves but a lot more effort is required to get it to move.
Anyone on her have any advice, I don't really fancy forking out £200 for an ICV so hoping someone on here has some other ideas or even validate my theory, if so then so be it i'll have to get a new ICV.
Thanks in advance.
By the way you can see the idle problem on my instagram page as well as follow my progress @azmontana1
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Speedtouch
- Old Skooler

- Posts: 14060
- Joined: Tue Feb 14, 2006 11:00 pm
- Location: Canterbury
Reset the ECU by disconnecting it or the battery for an hour or so. Reconnect then leave it idling for at least 10 minutes to enable base idle settings to be learnt.
Then switch off and take it (ideally for a drive) throughout the rev range.
This ensures full data transfer from the EPROM chip to the ECU processor.
Also, do you have the correct H26 ECU and chip, or are you using a standard 325i or similar ECU to run it?
Then switch off and take it (ideally for a drive) throughout the rev range.
This ensures full data transfer from the EPROM chip to the ECU processor.
Also, do you have the correct H26 ECU and chip, or are you using a standard 325i or similar ECU to run it?
///M aurice
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
I've not looked to see what ECU chip is installed. I've been thinking about getting the chip from the guy selling on here seems to have good reviews.Speedtouch wrote:Reset the ECU by disconnecting it or the battery for an hour or so. Reconnect then leave it idling for at least 10 minutes to enable base idle settings to be learnt.
Then switch off and take it (ideally for a drive) throughout the rev range.
This ensures full data transfer from the EPROM chip to the ECU processor.
Also, do you have the correct H26 ECU and chip, or are you using a standard 325i or similar ECU to run it?
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Speedtouch
- Old Skooler

- Posts: 14060
- Joined: Tue Feb 14, 2006 11:00 pm
- Location: Canterbury
I would advise opening up the ECU to check which chip you have - a standard BMW one will have a silver label with a part number on, e.g., 1 267 356 378, whereas a Hartge one will probably have one of their labels on.
It could be that if yours is a standard 325i chip (or worse, 320i), it won't give the correct idle control required by an H26 engine.
It could be that if yours is a standard 325i chip (or worse, 320i), it won't give the correct idle control required by an H26 engine.
///M aurice
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
It's not that as the engine was running nicely before I decided to rebuild the motor.Speedtouch wrote:I would advise opening up the ECU to check which chip you have - a standard BMW one will have a silver label with a part number on, e.g., 1 267 356 378, whereas a Hartge one will probably have one of their labels on.
It could be that if yours is a standard 325i chip (or worse, 320i), it won't give the correct idle control required by an H26 engine.
- aimlessrock
- E30 Zone Squatter

- Posts: 1821
- Joined: Sun Dec 06, 2009 11:00 pm
- Location: Manchester
I'm in Manchester and have at least one Icv from a B20 in my stash.. pm me if you still need it.
E30 320i Convertible (1989)
190 Mercedes (1988)
"there is nothing more expensive than a cheap E30"
190 Mercedes (1988)
"there is nothing more expensive than a cheap E30"
Anyone heard of Löwe Automobil? Are the parts of good quality? Seen this on the bay.
https://www.ebay.co.uk/itm/262427798960
https://www.ebay.co.uk/itm/262427798960
Ok so took it for a drive today. Its not just idling rough it drives like shit, won't accelerate. I'm now thinking its either a fuelling issue or it could be a tooth out on the timing. Any other suggestions welcome. Will test the fuel pressure today to rule that out.
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jimbom30cab
- Tech 1 freak
- Posts: 7634
- Joined: Mon Oct 12, 2009 11:00 pm
- Location: in the garage
glad you got it sorted
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steve_k
- E30 Zone Team Member

- Posts: 8044
- Joined: Fri May 23, 2008 11:00 pm
- Location: in the vale of mansfield
- Contact:
Any pictures of the car??
if it's got t*ts or wheels it's bound to be trouble...............prove me wrong.
getting oral sex off an ugly person is like rock climbing.....don't look down ;)
getting oral sex off an ugly person is like rock climbing.....don't look down ;)
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steve_k
- E30 Zone Team Member

- Posts: 8044
- Joined: Fri May 23, 2008 11:00 pm
- Location: in the vale of mansfield
- Contact:
no worries, looking forward to the pic's.Azmontana wrote:Not finished with her yet, needs a respray and some finishing touches. Once she's done I will post some pictures.steve_k wrote:Any pictures of the car??
if it's got t*ts or wheels it's bound to be trouble...............prove me wrong.
getting oral sex off an ugly person is like rock climbing.....don't look down ;)
getting oral sex off an ugly person is like rock climbing.....don't look down ;)

