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I( can'r win.. Starting issues
1 year 2 months ago #22920
by aardvark
Replied by aardvark on topic I( can'r win.. Starting issues
It must be the choke (or in this case cold start) is staying on. The rich burn smell never goes away..
Thanks for the input.
Thanks for the input.
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1 year 2 months ago #22922
by Rich928
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
Replied by Rich928 on topic I( can'r win.. Starting issues
There is no choke on a fuel injected engine. This 1985 - 1986 generation 928 uses the first generation of digital fuel (LH) and spark control (EZF). The air/fuel ratio are managed by:
1. A presumed fuel pressure. The system requires a precise fuel pressure to operate. Also, the fuel pressure regulator and/or damper can leak unmetered fuel into the intake manifold causing an over-rich air/fuel ratio.
2. Coolant Temperate sensor (AKA Temp II sensor). Both the LH and EZF modules obtain engine temperature from this single sensor. If it reports the wrong temperature (it has a reverse coefficient of resistance), The fuel injection system may inject the wrong amount of fuel for the existing engine temperature.
3. Mass Airflow Sensor (MAF). This system uses a hot wire heat and control to provide an accurate representation of the mass of air flowing into the engine. The LH injection module uses this measurement to calculate how much fuel to inject. A failing MAF can result in too little or too much fuel to be injected. The hot wire glows red after each driving cycle to clean off contaminants. After a few decades of use, the resistance of the hot wire changes and the MAF drifts out of calibration. Replacing the MAF is a normal service item and should be tested every 60,000 to 80,000 miles to verify proper operation.
4. Fuel injector flow: A leaking or improper spray pattern can result in improper running. The fix is to clean them and have them flow tested and replace if necessary.
5. LH Fuel Injection module: this computer takes in all the inputs and calculated the exact fuel necessary for the engine temperature range and power demands. If it fails, it normally doesn't work at all or injects the improper amount of fuel.
A qualified mechanic can diagnose failure in these items. The operation of the LH and MAF modules can be tested and repaired as needed.
1. A presumed fuel pressure. The system requires a precise fuel pressure to operate. Also, the fuel pressure regulator and/or damper can leak unmetered fuel into the intake manifold causing an over-rich air/fuel ratio.
2. Coolant Temperate sensor (AKA Temp II sensor). Both the LH and EZF modules obtain engine temperature from this single sensor. If it reports the wrong temperature (it has a reverse coefficient of resistance), The fuel injection system may inject the wrong amount of fuel for the existing engine temperature.
3. Mass Airflow Sensor (MAF). This system uses a hot wire heat and control to provide an accurate representation of the mass of air flowing into the engine. The LH injection module uses this measurement to calculate how much fuel to inject. A failing MAF can result in too little or too much fuel to be injected. The hot wire glows red after each driving cycle to clean off contaminants. After a few decades of use, the resistance of the hot wire changes and the MAF drifts out of calibration. Replacing the MAF is a normal service item and should be tested every 60,000 to 80,000 miles to verify proper operation.
4. Fuel injector flow: A leaking or improper spray pattern can result in improper running. The fix is to clean them and have them flow tested and replace if necessary.
5. LH Fuel Injection module: this computer takes in all the inputs and calculated the exact fuel necessary for the engine temperature range and power demands. If it fails, it normally doesn't work at all or injects the improper amount of fuel.
A qualified mechanic can diagnose failure in these items. The operation of the LH and MAF modules can be tested and repaired as needed.
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
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1 year 2 months ago #22923
by aardvark
Replied by aardvark on topic I( can'r win.. Starting issues
Rich.
Your last sentence is an issue here.
I haven't found a "Qualified Mechanic'' ' in this general area.
Your last sentence is an issue here.
I haven't found a "Qualified Mechanic'' ' in this general area.
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1 year 2 months ago - 1 year 2 months ago #22924
by Rich928
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
Replied by Rich928 on topic I( can'r win.. Starting issues
Where are you located? Someone may be able to suggest one. I can imagine a mechanic familiar with mid 1980s European cars may understand this generation of Bosch engine control systems. Volvo and Saab used similar systems.
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
Last edit: 1 year 2 months ago by Rich928.
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1 year 2 months ago #22925
by aardvark
Replied by aardvark on topic I( can'r win.. Starting issues
Thanks and I appreciate it, but I've got to move fast on this.
I'm west of Asheville N.C..by about an hour.
There is a shop in Asheville but the distance is cause for concern. There is also a shop in Waynesville but they have a 3 month waiting list.
I just can' wait 3 months for an appointment,
At this time, I'm trying to get the car up "For Sale" . I can't wait 3 months and am willing to reduce the price so the next Owner can address this issue.
I'm always open with Buyers on issues. Maybe too honest for my own good, but it's the right thing.
I hate having to sell it, but personal finances are entering into the mix, and She's gotta go.
Feels like a bad divorce to me, She's fighting me every step of the way.
The Car only has 46,000 miles on Her and She's definitely a looker.
I'm west of Asheville N.C..by about an hour.
There is a shop in Asheville but the distance is cause for concern. There is also a shop in Waynesville but they have a 3 month waiting list.
I just can' wait 3 months for an appointment,
At this time, I'm trying to get the car up "For Sale" . I can't wait 3 months and am willing to reduce the price so the next Owner can address this issue.
I'm always open with Buyers on issues. Maybe too honest for my own good, but it's the right thing.
I hate having to sell it, but personal finances are entering into the mix, and She's gotta go.
Feels like a bad divorce to me, She's fighting me every step of the way.
The Car only has 46,000 miles on Her and She's definitely a looker.
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1 year 2 months ago #22926
by Rich928
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
Replied by Rich928 on topic I( can'r win.. Starting issues
The closest shop to you that I've interfaced with is Top Auto located SW of Charlotte in Indian Trail. There are very good shops Digital Chassis in Durham, NC and Howard Wright in Atlanta, GA.
These may be too distant. So I suggest that you call local independent shops that work on older Volvos or Saabs and ask if they'd take a look at your 928.
These may be too distant. So I suggest that you call local independent shops that work on older Volvos or Saabs and ask if they'd take a look at your 928.
Rich
Membership Chairman
Charter Member
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue
1979 928 5-liter track beast
Please Log in or Create an account to join the conversation.