Help Me Decode LH 2.2 WSM Test Results - 84 Euro
#1
Rennlist Member
Thread Starter
Trying to Resolve 84 Euro Hestitation, Bucking, Surging Issue
OK - I have an 84 Euro that is surging at idle and upon acceleration is choppy and feels under powered. (Its starts up warm or cold no problem.) I'd dare say a lean feeling condition. I went through the WSM and ran multiple LH tests. Here are the results. I would appreciate any help in deciphering and other recommendations. Thanks!!
Testing done @ Multiple Pin Plug at LH air flow sensor
skipping to...
TP#3 - LH Air Flow Sensor
3. Pins 4 & 2 - 12.3v @ spec
4. Pins 6 & 3 idle mixture position (spec. 0-1000 ohms) =411
c. Pins 5 & 3 (3.6-4.1) =4.3
TP#4 - Temp Sensor II
1. Prong 1 @ temp sensor = 648 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
2. Prong 2 @ temp sensor = 657 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
Spec:
TP#7 - Auxillary Air valve
2. Voltage = 12.7v in spec
3. 26.1 Ohms @ plug (specification 10-45 Ohms)
TP#10 - Fuel Pressure
3. Fuel Pressure @ idle = 2bar (spec 2 bar)
4. Fuel Pressure with vacuum hose removed = 2.5bar (spec 2.3-2.7 bar)
Thanks!
Testing done @ Multiple Pin Plug at LH air flow sensor
skipping to...
TP#3 - LH Air Flow Sensor
3. Pins 4 & 2 - 12.3v @ spec
4. Pins 6 & 3 idle mixture position (spec. 0-1000 ohms) =411
c. Pins 5 & 3 (3.6-4.1) =4.3
TP#4 - Temp Sensor II
1. Prong 1 @ temp sensor = 648 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
2. Prong 2 @ temp sensor = 657 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
Spec:
- 0 C / 32 F: 4.4k to 6.0k Ohms
- 15 - 30 C / 59 - 86 F: 1.4k to 3.6k Ohms
- 40 C / 104 F: 0.9 to 1.3k Ohm
- 60 C / 140 F: 480 to 720 Ohms
- 80 C / 176 F: 250 to 390 Ohm
TP#7 - Auxillary Air valve
2. Voltage = 12.7v in spec
3. 26.1 Ohms @ plug (specification 10-45 Ohms)
TP#10 - Fuel Pressure
3. Fuel Pressure @ idle = 2bar (spec 2 bar)
4. Fuel Pressure with vacuum hose removed = 2.5bar (spec 2.3-2.7 bar)
Thanks!
Last edited by checkmate1996; 10-02-2017 at 06:32 PM. Reason: incorrect readings - updated
#2
Addict
Rennlist Member
Rennlist Member
LH Tests
The 1984 - 1985 Euro 928s require air/fuel mixture to be manually set at the MAF. The CO spec is 0.5 to 1.5% with intake at 59 -95 F and oil temp at 80C (176F). The CO% is measure pre-catalytic converter if in stalled.
The EURO 928s are sensitive to an out of calibrated MAF.
Rich
928 OC Membership Chairman
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue cover girl too
1979 928 Euro 5-liter track beast
The EURO 928s are sensitive to an out of calibrated MAF.
Rich
928 OC Membership Chairman
1993 928 GTS Cover Girl
1987 928 S4
1979 928 5-speed rescue cover girl too
1979 928 Euro 5-liter track beast
#3
Rennlist Member
Thread Starter
The 1984 - 1985 Euro 928s require air/fuel mixture to be manually set at the MAF. The CO spec is 0.5 to 1.5% with intake at 59 -95 F and oil temp at 80C (176F). The CO% is measure pre-catalytic converter if in stalled.
The EURO 928s are sensitive to an out of calibrated MAF.
The EURO 928s are sensitive to an out of calibrated MAF.
Rich - I sent you an email. Thanks!
#4
Rennlist Member
Thread Starter
OK - I have an 84 Euro that is surging at idle and upon acceleration is choppy and feels under powered. (Its starts up warm or cold no problem.) I'd dare say a lean feeling condition. I went through the WSM and ran multiple LH tests. Here are the results. I would appreciate any help in deciphering and other recommendations. Thanks!!
Testing done @ Multiple Pin Plug at LH air flow sensor
skipping to...
TP#3 - LH Air Flow Sensor
3. Pins 4 & 2 - 12.3v @ spec
4. Pins 6 & 3 idle mixture position (spec. 0-1000 ohms) =411
c. Pins 5 & 3 (3.6-4.1) =4.3
TP#4 - Temp Sensor II
1. Prong 1 @ temp sensor = 648 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
2. Prong 2 @ temp sensor = 657 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
Spec:
TP#7 - Auxillary Air valve
2. Voltage = 12.7v in spec
3. 26.1 Ohms @ plug (specification 10-45 Ohms)
TP#10 - Fuel Pressure
3. Fuel Pressure @ idle = 2bar (spec 2 bar)
4. Fuel Pressure with vacuum hose removed = 2.5bar (spec 2.3-2.7 bar)
Thanks!
Testing done @ Multiple Pin Plug at LH air flow sensor
skipping to...
TP#3 - LH Air Flow Sensor
3. Pins 4 & 2 - 12.3v @ spec
4. Pins 6 & 3 idle mixture position (spec. 0-1000 ohms) =411
c. Pins 5 & 3 (3.6-4.1) =4.3
TP#4 - Temp Sensor II
1. Prong 1 @ temp sensor = 648 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
2. Prong 2 @ temp sensor = 657 - Engine Temp = 44C/111F degrees // Ambient temp is 83 degrees F
Spec:
- 0 C / 32 F: 4.4k to 6.0k Ohms
- 15 - 30 C / 59 - 86 F: 1.4k to 3.6k Ohms
- 40 C / 104 F: 0.9 to 1.3k Ohm
- 60 C / 140 F: 480 to 720 Ohms
- 80 C / 176 F: 250 to 390 Ohm
TP#7 - Auxillary Air valve
2. Voltage = 12.7v in spec
3. 26.1 Ohms @ plug (specification 10-45 Ohms)
TP#10 - Fuel Pressure
3. Fuel Pressure @ idle = 2bar (spec 2 bar)
4. Fuel Pressure with vacuum hose removed = 2.5bar (spec 2.3-2.7 bar)
Thanks!
#5
Rennlist Member
The 84-86 Euros were always on the lean side from the factory. I had a lean condition (bucking sometimes) even with a new MAF and sorted engine. Back in the day, we would swap in an adjustable fuel reg and the S3 damper in order to richen it up. That worked pretty good. This was before John Speake offered his S2 Euro performance chips several years ago. These things worked flawless for my Dad's '84. It has never ran as good as it does with those chips. You will have to swap out the '84 LH for the '85 or newer one. The S3 LH will also work. That is what my Dad's 84 is using with John's chips.
#6
Rennlist Member
Thread Starter
Replaced Temp 2 sensor. Atleast that is reading correctly now. It helped my idle as well.
#7
Rennlist Member
Thread Starter
To follow up - I started checking all things vacuum. Please correct me, but from the WSM the vacuum line coming off the spider goes to the ignition control unit in the car next to the CE Panel. (The other vacuum on spider goes to AC idle valve).
1) There is only one vacuum line from spider entering the firewall to goto the ignition unit, correct?
I ask because I found something strange. The vacuum line coming off the spider as intended (small hard vacuum hose with the rubber curved connector), it wrapped down under some wires and then back up near the air tube to connect to a slightly larger vacuum hose. That hose looks to run down the fender area and I presume goes to the ignition unit in the ce panel. The part that has me scratching my head is where the hose enters the larger hose somebody previously put a screw in the hard tube which seems to me effectively cutting off vacuum to controller. Is there a reason why somebody would have done this? This can't be right.
Thoughts??
1) There is only one vacuum line from spider entering the firewall to goto the ignition unit, correct?
I ask because I found something strange. The vacuum line coming off the spider as intended (small hard vacuum hose with the rubber curved connector), it wrapped down under some wires and then back up near the air tube to connect to a slightly larger vacuum hose. That hose looks to run down the fender area and I presume goes to the ignition unit in the ce panel. The part that has me scratching my head is where the hose enters the larger hose somebody previously put a screw in the hard tube which seems to me effectively cutting off vacuum to controller. Is there a reason why somebody would have done this? This can't be right.
Thoughts??
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#8
Rennlist Member
This thread has a copy of the vacuum diagram that comes with Roger's replacement kit. It is good for the 85-86 US and 84-86 Euro according to the pic. Maybe this will help...
https://rennlist.com/forums/928-foru...uum-lines.html
https://rennlist.com/forums/928-foru...uum-lines.html
#9
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To follow up - I started checking all things vacuum. Please correct me, but from the WSM the vacuum line coming off the spider goes to the ignition control unit in the car next to the CE Panel. (The other vacuum on spider goes to AC idle valve).
1) There is only one vacuum line from spider entering the firewall to goto the ignition unit, correct?
I ask because I found something strange. The vacuum line coming off the spider as intended (small hard vacuum hose with the rubber curved connector), it wrapped down under some wires and then back up near the air tube to connect to a slightly larger vacuum hose. That hose looks to run down the fender area and I presume goes to the ignition unit in the ce panel. The part that has me scratching my head is where the hose enters the larger hose somebody previously put a screw in the hard tube which seems to me effectively cutting off vacuum to controller. Is there a reason why somebody would have done this? This can't be right.
Thoughts??
1) There is only one vacuum line from spider entering the firewall to goto the ignition unit, correct?
I ask because I found something strange. The vacuum line coming off the spider as intended (small hard vacuum hose with the rubber curved connector), it wrapped down under some wires and then back up near the air tube to connect to a slightly larger vacuum hose. That hose looks to run down the fender area and I presume goes to the ignition unit in the ce panel. The part that has me scratching my head is where the hose enters the larger hose somebody previously put a screw in the hard tube which seems to me effectively cutting off vacuum to controller. Is there a reason why somebody would have done this? This can't be right.
Thoughts??
#10
Rennlist Member
Thread Starter
Great to see you again at SIH!
#11
Rennlist Member
Thread Starter
This thread has a copy of the vacuum diagram that comes with Roger's replacement kit. It is good for the 85-86 US and 84-86 Euro according to the pic. Maybe this will help...
https://rennlist.com/forums/928-foru...uum-lines.html
https://rennlist.com/forums/928-foru...uum-lines.html
Thanks!
#12
Rennlist Member
Thread Starter
Very helpful. Thanks. Here's a thread you posted along time ago. https://rennlist.com/forums/928-foru...ting-help.html Does that euro wiring diagram hold true. Also, did you mean ignition control unit for LH?
Thanks!
Thanks!
Black vacuum line coming off spider. In wsm this is suppose to go to Ecu.
A smoke test revealed false air leakin out of the screwed in end . I have no idea why it's capped off.
The hose runnin down the fender of which the black hose was connected too.
#13
Rennlist Member
Thread Starter
Case closed
Case closed. The 84 euro does have a vacuum hose that connects from the front of the spider to the ecu. I had found the "other half" of the vacuum hose tucked under the wires near the t14 connector just sucking in unmetered air. I reconnected the two hose and voila air was passing through as expected. I put vacuum on the line and it held perfectly. I started the car and the hesitation, choppiness, lean feeling between 0-2000 rpms was gone. Why someone capped this hose will probably be forever a mystery.
Thanks for for all the responses.
Thanks for for all the responses.
#14
Rennlist Member
Thread Starter
Case closed. The 84 euro does have a vacuum hose that connects from the front of the spider to the ecu. I had found the "other half" of the vacuum hose tucked under the wires near the t14 connector just sucking in unmetered air. I reconnected the two hose and voila air was passing through as expected. I put vacuum on the line and it held perfectly. I started the car and the hesitation, choppiness, lean feeling between 0-2000 rpms was gone. Why someone capped this hose will probably be forever a mystery.
Thanks for for all the responses.
Thanks for for all the responses.
Possible theory??: LH Computer is getting signal from MAF, signal is downgraded at the fuel injectors more than normal and running leaner due to corroded grounds making MAF work harder by having to increase AF mixture causing faster MAF burnout??
Anyways, here's to adding to the list of items to fix 84-86 Euro hesitation, stumbling, surging, bucking:
- Verify all vacuums lines, elbows, hoses are not leaking.
- Verify fuel regulators and dampers hold vacuum and fuel pressure
- Verify timing belt on twin dizzy is in good shape and rotors are aligned to notches
- Verify spark plugs are in good shape
- Verify spark plug wires measure 3k OHM (resistance) from end to end.
- Verify current MAF resistance
- Verify Rotors and Caps are good condition.
- CLEAN all Grounds as mentioned above!
Potential solutions if that doesn't work
- S3 damper and Adjustable fuel regulator
- Update LH with new S3 and get Johns chips
- Roger Tyson also suggested getting Greg's adaptors and running higher powered injectors e.g. 24 lb Type IIs...
- Test and or replace MAF after having exhaust analyzed and making sure itis' in spec and all the other things above have checked out
Please add to this list! After reading a lot of rennlist posts on this subject it would be nice to have definitive place for resolving this issue.