Switching to a single plane intake!
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
I'm not sure I agree with that. An ignition misfire would leave unburned fuel in the cylinder and should read as a rich condition on your WBO2. Someone else mentioned an injector misfire would show as a lean condition and I agree with that also.
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Instructor
Joined: Apr 2005
Posts: 228
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From: Göteborg
To my understanding, the wb only read amount of free oxygene. If there is no combustion, the oxygene in the cylinders will not be converted into CO2. The amount of oxygene will be higher than normal and this is what the WB see and display as lean.
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Instructor
Joined: Apr 2005
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From: Göteborg
Made some new tests:
-set zero lash
-bypassed the J&S safeguard knock box
-new distributor rotor
-removed the piping between blower and TB and used the short belt (in essence running it NA)
-removed one injector clip at the time
-filled up with fresh gas
Result: nothing, it is maybe even running worse now. It took only about 5minutes before it starts missing and it completly stalled after about 20 minutes
(Had to wait at the roadside for about 20 minutes when I managed to limp home).
No change disconnecting one and in one occation two injectors, still run like crap (only tested at stand still and revving it).
-set zero lash
-bypassed the J&S safeguard knock box
-new distributor rotor
-removed the piping between blower and TB and used the short belt (in essence running it NA)
-removed one injector clip at the time
-filled up with fresh gas
Result: nothing, it is maybe even running worse now. It took only about 5minutes before it starts missing and it completly stalled after about 20 minutes
(Had to wait at the roadside for about 20 minutes when I managed to limp home).
No change disconnecting one and in one occation two injectors, still run like crap (only tested at stand still and revving it).
Last edited by bogor; Jul 20, 2014 at 06:26 AM.
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Yeah, I see your point. I guess I didn't think that one through.
Melting Slicks
Joined: Oct 2000
Posts: 2,158
Likes: 9
From: N.E. WA
Have you verified these things when it is hot and acting up?
1)fuel pressure
2)timing
3)spark (maybe you can use and inductive pickup or something
4)injector impedance
If those all check out, then maybe the ECU. Seems unlikely that it happened right when you changed to a single plane.
Just throwing some things at ya to help keep you thinking.
1)fuel pressure
2)timing
3)spark (maybe you can use and inductive pickup or something
4)injector impedance
If those all check out, then maybe the ECU. Seems unlikely that it happened right when you changed to a single plane.
Just throwing some things at ya to help keep you thinking.
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Instructor
Joined: Apr 2005
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From: Göteborg
1) fuelpressure: checked cold and warm
2) timing: verified that commanded spark advance and real advance are the same, checked with strobe light at idle
3) well, I have looked at the spark plugs but when you mention it I will check it really is spark when it runs.
4) injector resistance checked with ohmmeter hot and cold
Today I checked exhaust temp with my IR gun. It looks like there is a discrepancy for cylinder 7: at idle and directly after shutdown all header pipes reach around 400-500F. However, no 7 is only at around 150-160F.
I will get a noidlight to check the injectors really are getting power or if there is a problem with one or several of the injector drivers in the ECU.
Update: checked spark and all 8 wires "hot" and live. The noidlight showed that cyl 7 is dead (no light). Strange thing is that now also cylinder 2 is cool (same as cyl 7) but noidlight lights up-strange...guess the problem at least partly lies within the ECU
2) timing: verified that commanded spark advance and real advance are the same, checked with strobe light at idle
3) well, I have looked at the spark plugs but when you mention it I will check it really is spark when it runs.
4) injector resistance checked with ohmmeter hot and cold
Today I checked exhaust temp with my IR gun. It looks like there is a discrepancy for cylinder 7: at idle and directly after shutdown all header pipes reach around 400-500F. However, no 7 is only at around 150-160F.
I will get a noidlight to check the injectors really are getting power or if there is a problem with one or several of the injector drivers in the ECU.
Update: checked spark and all 8 wires "hot" and live. The noidlight showed that cyl 7 is dead (no light). Strange thing is that now also cylinder 2 is cool (same as cyl 7) but noidlight lights up-strange...guess the problem at least partly lies within the ECU
Last edited by bogor; Jul 21, 2014 at 02:12 PM.
Thread Starter
Instructor
Joined: Apr 2005
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From: Göteborg
Thanks! This has been a real pain but yes, it finally looks like I'm getting somewhere after stumbling around in the darkness for several weeks now.
I have located another Autronic SMC unit I most likely can borrow and test this week! If it is something in the electronics thats broke in my unit it prob will need to be sent to Australia so lets hope its just something related to internal wiring, connector etc.
I have located another Autronic SMC unit I most likely can borrow and test this week! If it is something in the electronics thats broke in my unit it prob will need to be sent to Australia so lets hope its just something related to internal wiring, connector etc.
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Thread Starter
Instructor
Joined: Apr 2005
Posts: 228
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From: Göteborg
It looks like a soldered wire close to the clips at cylinder 2 was bad. Dont know where the problem lies for cylinder 7 but when bypassing the old wiring and clip with a new wire and clip it works. Its strange, all eight injector clips measured ok (zero resistance). It seems like a soldered joint tends to brake down after some years. I will replace the whole injector harness later but for now I just replace the two clips and nearby wiring.
Thankyou everyone for support and good ideas!
Last edited by bogor; Jul 23, 2014 at 03:48 PM.
Burning Brakes
Joined: Mar 2005
Posts: 1,082
Likes: 115
From: Richmond Hill Ontario
This is my analysis and recommendations and the reasons for.
You are running in open loop and using a Wideband O2 in the exhaust just to monitor AFR so this has no relevance to symptoms. You have already checked and or replaced anything to do with ignition such as plugs, wires, distributor and coil. If it was caused by an ignition misfire this would cause raw fuel to be dumped into the exhaust which will definitely cause backfire or popping in the exhaust – which you do not mention of having.
I would recommend that you concentrate your efforts on a faulty injector, injector connector or wiring, or possibly an intermittent injector driver when it gets hot. A misfiring injector will cause your wideband O2 to read very lean.
You can try to run the car until the symptom happens then pull over and with an Ohmmeter measure each injector’s resistance value to see if anything seems abnormal on any one of them.
Hope this gives you some direction to troubleshoot.
You are running in open loop and using a Wideband O2 in the exhaust just to monitor AFR so this has no relevance to symptoms. You have already checked and or replaced anything to do with ignition such as plugs, wires, distributor and coil. If it was caused by an ignition misfire this would cause raw fuel to be dumped into the exhaust which will definitely cause backfire or popping in the exhaust – which you do not mention of having.
I would recommend that you concentrate your efforts on a faulty injector, injector connector or wiring, or possibly an intermittent injector driver when it gets hot. A misfiring injector will cause your wideband O2 to read very lean.
You can try to run the car until the symptom happens then pull over and with an Ohmmeter measure each injector’s resistance value to see if anything seems abnormal on any one of them.
Hope this gives you some direction to troubleshoot.
Thread Starter
Instructor
Joined: Apr 2005
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From: Göteborg
FrankieD: your crystal clear assessment and recommendations were spot on and I really appreciate you steered me in the right direction!
I have changed the injector clip for cylinder 7 but it seems the problem lies somewhere in wiring that is well tucked away at the firewall. I have now made a "semi permanent" connection from the ECU connector and to a new clip and this will hopefully last the season. I will replace everything when the snow is back and car on jackstands.
Before doing some street tuning and dyno I need to have the car approved in the yearly inspection by the transport authorities so hopefully on the dyno in a week or two from now.
I have changed the injector clip for cylinder 7 but it seems the problem lies somewhere in wiring that is well tucked away at the firewall. I have now made a "semi permanent" connection from the ECU connector and to a new clip and this will hopefully last the season. I will replace everything when the snow is back and car on jackstands.
Before doing some street tuning and dyno I need to have the car approved in the yearly inspection by the transport authorities so hopefully on the dyno in a week or two from now.
Last edited by bogor; Jul 25, 2014 at 02:33 AM.
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Instructor
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From: Göteborg
Im finally back on track and looking forward to find out what this new intake will result in when I take the car to the dyno (soon).
Last edited by bogor; Jul 25, 2014 at 02:48 AM.
Thread Starter
Instructor
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From: Göteborg
I made some initial WOT runs tonight. The tune was way off when I started but Im npw at around afr 11,5 at 5000rpms. Also very conservative advance (17degrees). Maybe partly in the tune but it feels like I lost considerable amount of torques at mid rpms (vs the Superram I used before). Also feel like Im down on power at higher rpms but suspect more spark advance will change this.
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Instructor
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From: Göteborg
Today I visited the track and made some full 1/4 mile runs. My SOTP feeling was unfortunately correct, trap speed is down 3mph with the single plane intake versus the superram/tpi intake. Best trap speed today was 117 mph. Quite dissapointing outcome of all work. ET was real crappy (12,5) but I take it very gently having two broken driveshaft still fresh on my mind. Fuel was at afr12.Tried some various settings of SA and 24 degrees gave me best trap speed but lit the knock light. Less spark got rid of the knock but speed was down even more. Alot of rain so I could only make five passes but I think additional runs and tuning wont be sufficient tp get me where I want to be (close to 125 mph).
Last edited by bogor; Aug 17, 2014 at 05:05 PM.
Safety Car
Joined: Nov 2009
Posts: 3,973
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From: Adelaide South Australia
Today I visited the track and made some full 1/4 mile runs. My SOTP feeling was unfortunately correct, trap speed is down 3mph with the single plane intake versus the superram/tpi intake. Best trap speed today was 117 mph. Quite dissapointing outcome of all work. ET was real crappy (12,5) but I take it very gently having two broken driveshaft still fresh on my mind. Fuel was at afr12.Tried some various settings of SA and 24 degrees gave me best trap speed but lit the knock light. Less spark got rid of the knock but speed was down even more. Alot of rain so I could only make five passes but I think additional runs and tuning wont be sufficient tp get me where I want to be (close to 125 mph).
if a manufacturer had built that setup it would have spent millions of dollars and had an entire engineering department working on it
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Instructor
Joined: Apr 2005
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From: Göteborg
After discussing with Greg and given the facts that I now run 3mph slower on the 1/4 mile and boost is the same as before, it looks like the new intake combo is actually more restrictive than my old Superram combo!!
Since I have replaced alot of tubing with one 90 degree and an elbow and the TPI 2x52mm TB with a huge 100mm LS style TB I now suspect the single plane intake itself to be the bottleneck. Looking at it from the positive side-I have learned alot...
Last edited by bogor; Aug 19, 2014 at 10:18 AM.
Thread Starter
Instructor
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From: Göteborg
see post #47
The120mph runs was during 2013 (that was on another track but similar 60 ft time) and according to the logs I shifted at around 6000 rpms.
Since I reach max impeller speed (50000) at 5800rpms I have kept revs down a little but during this last week runs with the single plane I took it up some more (about 6400 rpms) on one of the runs but no real improvemnt in trap speed.
The120mph runs was during 2013 (that was on another track but similar 60 ft time) and according to the logs I shifted at around 6000 rpms.
Since I reach max impeller speed (50000) at 5800rpms I have kept revs down a little but during this last week runs with the single plane I took it up some more (about 6400 rpms) on one of the runs but no real improvemnt in trap speed.