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TPS is a new Ford tps on a 65mm throttle body. I calibrated it in the tps calibration screen. When I get bad start condition, it does not respond well, like lag when I press the gas and when it actually revs. On good starts it works perfectly.
Vacuum line has its own port off the intake manifold straight to vems ecu with nothing tied into it.
If there is an extreme lean running condition (large vacuum leak, etc), an engine will barely rev up and respond to throttle input----BUT the TPS reading should be the same with the same throttle opening, regardless of how the engine starts or runs. It's not the TPS reading that lags when the engine is really lean, but how the engine actually responds to the throttle input. As in, you can hold the throttle 50% open (which will read 50% on TPS), but the engine itself will barely rev up. I find it odd that your TPS reading does not go past ~6% or so in that video, even though it seems like you are snapping the throttle at the same rate as in the "good" video.
It will be incredibly easy to verify this. Shoot a "good start" and "bad start" video and in each condition hold the throttle at the same opening (say 25% or 50%) and make sure the TPS reading is the same for each. If this is consistent, you can move on.
In other news, I am happy to report that tuning VEMS to pass CA tailpipe emissions with 80# injectors is a snap! Just had to change VE table slightly at the idle, low load range due to the more restrictive "street spec" exhaust .
It pays to keep your engine bay looking stock. Find the catch can!
this is great news! I figured that it would be possible. How can it not? ..ability to tweak the fueling.
You're the first congratulations!! FYI all the others, CA smog is a PIA
this is great news! I figured that it would be possible. How can it not? ..ability to tweak the fueling.
You're the first congratulations!! FYI all the others, CA smog is a PIA
Yes, it's the visual inspection that is a killer. I was a bit worried due to the lack of an airflow meter, Laust vacuum manifold, and the elimination of the branch manifold under the intake----and the stealth catch can mounted in the A/C receiver/dryer spot. I had a co-worker take the car to a place down the street from my shop; he verified that the factory cat was installed, poked around the engine bay a bit, and deemed it OK. Luckily most don't know what they are looking at in terms of '80s German cars. And it is a happy coincidence that I do not like flashy engine bays anyway!
As for the tuning with large injectors, if you have the correct injector dead time settings and are already tuned to stoichiometric at idle/cruise range (which any engine should be), then you are 98% there. It would be a little tougher in an "enhanced" area of CA that tests on a dyno under light load and measures NOx, but if your cat is in good shape that should also be OK.
EDIT: Props to Lindsey Racing for stocking the awesome silicone hose sets for the boost/intake/J-pipe and for the breather hoses. Eliminating the hard pipes underneath the intake manifold makes everything so much tidier!
Completely off subject here but I have installed a VEMS plug/play and need a little help. This is a new N/A motor build for E Production SCCA racing.
It has 12:1 Compression, big cam, solid lifters, 951 injectors, Molnar rods, Wossner pistons, crank mods/scraper, light flywheel, oil exchanger and many other bits.
I used the VEMS last year in a "stock" motor and it worked great. Peep helped me get this motor fired up last week so it's running and getting broken in.
My problem is idle while cold and warm and throttle lift. I've set my fuel pressure to a safe level so I don't lean out OR wash down my cylinders. I've also set my cold and warm idle to 1500 and Ign. based idle is disabled.
The urgent problem is that it won't follow the 1500 all the time, especially after I rev to 4000 and lift. The RPMs drop down to dangerous levels. The danger being low oil pressure due to the larger capacity oil exchanger.
I haven't had a chance to drive the car or Dyno yet so Live VE analyzer hasn't run yet. It's not street legal.
So, my question is: For now, how can I keep my RPMs from dropping below my settings?
If there is an extreme lean running condition (large vacuum leak, etc), an engine will barely rev up and respond to throttle input----BUT the TPS reading should be the same with the same throttle opening, regardless of how the engine starts or runs. It's not the TPS reading that lags when the engine is really lean, but how the engine actually responds to the throttle input. As in, you can hold the throttle 50% open (which will read 50% on TPS), but the engine itself will barely rev up. I find it odd that your TPS reading does not go past ~6% or so in that video, even though it seems like you are snapping the throttle at the same rate as in the "good" video.
It will be incredibly easy to verify this. Shoot a "good start" and "bad start" video and in each condition hold the throttle at the same opening (say 25% or 50%) and make sure the TPS reading is the same for each. If this is consistent, you can move on.
Will test tps once I get my ecu back. Gave it to another local who has a supercharged n/a with vems. Had him test it and it runs perfectly. Now we know ecu is good. Gonna replace dme temp sensor, oxygen sensor and TPS. Does anyone know what part number oxygen sensor they're using. I'm using a bosch 17014 LSU 4.2, from my old wideband setup, could possibly be the problem. Just want to know what else everyone is using. I ordered mine without an oxygen sensor ( since I had one ) afm to IAT harness, since I rewired it myself coming from a maf. And I wired in my wasted spark coil from my vitesse wasted spark setup, which again, might contribute to my issues. Gonna try and get close to what everyone has. Gonna need wideband part number, and wasted spark coil part number. Much Appreciated.
Completely off subject here but I have installed a VEMS plug/play and need a little help. This is a new N/A motor build for E Production SCCA racing.
It has 12:1 Compression, big cam, solid lifters, 951 injectors, Molnar rods, Wossner pistons, crank mods/scraper, light flywheel, oil exchanger and many other bits.
I used the VEMS last year in a "stock" motor and it worked great. Peep helped me get this motor fired up last week so it's running and getting broken in.
My problem is idle while cold and warm and throttle lift. I've set my fuel pressure to a safe level so I don't lean out OR wash down my cylinders. I've also set my cold and warm idle to 1500 and Ign. based idle is disabled.
The urgent problem is that it won't follow the 1500 all the time, especially after I rev to 4000 and lift. The RPMs drop down to dangerous levels. The danger being low oil pressure due to the larger capacity oil exchanger.
I haven't had a chance to drive the car or Dyno yet so Live VE analyzer hasn't run yet. It's not street legal.
So, my question is: For now, how can I keep my RPMs from dropping below my settings?
Possible vacuum leak? Do you have an idle control valve?
Not vacuum and I tested the ICV. I'll be getting the car to a proper dyno tuner soon. Just thought I'd try to get the idle safe before I go. Thanks anyway!
Installed new bosch 17014 LSU 4.2 wideband oxygen sensor, calibrated. Replaced new Ford 3 wire TPS, calibrated. Installed new bosch DME temp sensor. Still same issues. I can confirm that when bad start condition happens, TPS does not display properly or respond properly, like a lag when the gas is pressed to when it actually registers. This is with old tps, new tps and with factory 951 tps. Changed over a while back hoping to fix this issue.
Next would be IAT and Knock sensors, but a friend of mine pointed out my knock config retard is 0,so no effect would be noticed. And IAT would not change the way it starts.
Looked at bosch wasted spark coil offered on VEMS online shop and it's similar to what I have already. I originally had an MSD 8239 unit, bought a cross referenced similar unit from Autozone, no change when I changed over.
Rechecked wiring on O2 Sensor and everything checks out fine. ( the reason I checked was I soldered connector harness from old wideband setup to vems harness to skip on fishing new wires through firewall.)
Not vacuum and I tested the ICV. I'll be getting the car to a proper dyno tuner soon. Just thought I'd try to get the idle safe before I go. Thanks anyway!
try adjusting the idle bypass screw and throttle stop, maybe recalibrate the TPS.
MAP tuning is very tolerant of vac leaks but if the throttle sensitivity isn't right it can make weird drop-throttle situations in my experience.
also, don't worry about oil pressure.
remember a 944 pump can make 45psi at 900 rpm with hot 20W50 oil.
i ran for 7 years with 2x Setrab 13 row coolers in series and about 10 feet of -10 size lines (a LOT of added oil capacity) and never had oil pressure problems even with 110F ambient temperature.
OK here's a few ideas. How quickly do you move the key to 'start' position? I recommend that you pause in the 'on' position and give the ecu a second to boot up.
Have you used a timing light to verify actual timing? There's nothing like actual data and info to help you make an informed decision.
Do a 'wire wiggle' test. This is done when the engine is running normally at idle, just go around the entire engine bay, wire loom, and dme and gently wiggle the wires, sensors and plugs. If there's a bad connection the engine should sputter or cut out or do something odd. Don't forget to tap on the ecu case in different directions.
Did alot of searching on here and Google. How do I check timing? I've got the speed sensors out and I'm gonna paint the scribe mark on the flywheel. Do I just clamp #1 spark plug wire, point the strobe at the timing mark and verify what I'm reading at idle is the same as vems is reading? Would a incorrect set timing cause the issues I'm having?
In short, yes. The best practice is to set the ignition timing to a fixed level, say 10 or 15 deg BTDC. Then clamp around the #1 plug wire and check your timing. Should match your fixed value. If it's wrong you will need to adjust the tooth #1 offset (or whatever it's called in VEMS) until it's correct.
It's pissing in the wind to use a non-fixed timing value, as minor engine fluctuations will cause the commanded spark timing to change per the map.
Referring back to post 378, why would you not assume your issues relate to the fried motherboard? I didn't follow the back story, but you clearly had a serious overload on the ECU, enough to fry parts and melt solder. There's just no telling what else got damaged. You could have cold solder joints all over just from the heat they experienced; semiconductor parts could be fried or nearly so; hidden traced on a multilayer board could be burned out inside; etc. That the car occasionally runs great, and other times has readings that are all our of whack, is also consistent with these kinds of faults -- much like when a Motronic DME has bad solder joints. No guarantees obviously, and maybe I missed what you did to confirm the ECU is good, but if it were me I'd want to test that board on another car, or test another board on your car, before spending money on all those other parts...
What else melted? Did it cool poorly and create bad joints? Very hard to know if you patched all bad traces and what parts may not have survived... Some boards have multiple trace layers you wouldn't see to fix...
In short, yes. The best practice is to set the ignition timing to a fixed level, say 10 or 15 deg BTDC. Then clamp around the #1 plug wire and check your timing. Should match your fixed value. If it's wrong you will need to adjust the tooth #1 offset (or whatever it's called in VEMS) until it's correct.
It's pissing in the wind to use a non-fixed timing value, as minor engine fluctuations will cause the commanded spark timing to change per the map.
OK, thanks will try this and report back.
Originally Posted by Tom M'Guinn
Referring back to post 378, why would you not assume your issues relate to the fried motherboard? I didn't follow the back story, but you clearly had a serious overload on the ECU, enough to fry parts and melt solder. There's just no telling what else got damaged. You could have cold solder joints all over just from the heat they experienced; semiconductor parts could be fried or nearly so; hidden traced on a multilayer board could be burned out inside; etc. That the car occasionally runs great, and other times has readings that are all our of whack, is also consistent with these kinds of faults -- much like when a Motronic DME has bad solder joints. No guarantees obviously, and maybe I missed what you did to confirm the ECU is good, but if it were me I'd want to test that board on another car, or test another board on your car, before spending money on all those other parts...
What else melted? Did it cool poorly and create bad joints? Very hard to know if you patched all bad traces and what parts may not have survived... Some boards have multiple trace layers you wouldn't see to fix...
I had friend the ignition driver transistors due to changing some settings in vems, which I wasn't suppose to do. Replaced them and had same issues. In my recent post and testing I had a local guy run my ecu in his 944 who also has vems, with his config and it ran perfectly. He restarted it multiple times and not a single hick up according to him.
I wish I could go back to dme / Klr easily but I've swapped out tps and permanently soldered in IAT sensor plug where maf used to be.
Was advised by Peep to add more time on ignition dwell. Gonna take small steps with this as it could fry my coil or board again.
02-19-2019, 01:05 AM
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