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New Siemens Deka 80# high z injectors came in from www.fuelinjectionconnection.com swapped them in. No dice still same issue. Readjusted gap again on speed sensor. Same. Does anyone know how close I can get on the reference sensor before the speed sensor touches the starter ring gear? I read that there is a high spot on the ring gear which the speed sensor reads off of. I'm beginning to think I'm just chasing my tail. I'm wonder if the whole issue is the notched bell housing. Regardless of the updated sleeve. Who here has the notched bell housing? I'm hoping that an aftermarket flywheel is not the only solution. Since someone is having issues with the clewet front mount crank sensor.
Peep,
Is it possible to use a cam sensor for a trigger? Also, does vems use both speed and reference sensors?
Just curious if you're using the spacer (item 32) on the speed sensor? That spacer has the effect of pushing the reference sensor closer to the stud on the flywheel.
I updated to this bracket recently on my 85 NA racecar after notching the bell housing and did not put the spacer in. My car starts now w/o all the kickback drama but I might add the spacer and check for clearance to reference sensor just because I'd like to know.
Just curious if you're using the spacer (item 32) on the speed sensor? That spacer has the effect of pushing the reference sensor closer to the stud on the flywheel.
I updated to this bracket recently on my 85 NA racecar after notching the bell housing and did not put the spacer in. My car starts now w/o all the kickback drama but I might add the spacer and check for clearance to reference sensor just because I'd like to know.
I have the spacer. And per your experience, I removed it and regapped the sensors again. Just to be sure the reference sensor didn't hit, I found the pin and made sure it didn't hit, while I hand cranked the motor over back and forth. I also swapped my new facet sensors to my older fae sensors, same issue. Gonna probably buy bosch sensors next. I also rerouted the battery cables to starter and made them farther from sensors. The only other thing I can think of causing interference with sensors is the cable from battery to alternator. But there isn't another way to route it. There are a few here with the Nissan alternator mod and no issues. Maybe it's my ice shark cable kit? Looks like the shielding use is not for emi or rf but for heat shielding. I want to exhaust all options before going to a crank trigger route. Appreciate your input.
Req_fuel fuel is set at 9.5. Have not made alot of few WOT runs, cause of bad weather here. So I manually input alot of tables based on 2 full wot pulls.
Req_fuel fuel is set at 9.5. Have not made alot of few WOT runs, cause of bad weather here. So I manually input alot of tables based on 2 full wot pulls.
Um, how did you arrive at a Req_fuel value of 9.5? I have the same Siemens-Deka 830CC injectors that you do, and my Req_fuel is set at 5.0. I think this explains why your VE table has such strangely low values. Here's a copy-and-paste from the VEMS webpage:
Basic req_fuel calculation:
req_fuel = 6.49 * (D / N / I)
D engine displacement (cc)
N number of injectors (eg. 4 for a 4 cyl port injection)
I injector flowrate (cc/min)
This is a simplified equation, if you are interested in the reasoning behind it you can read more here: http://www.vems.hu/wiki/index.php?pa...njectorOpening
I am not convinced that this is causing your weird starting issue, but it should at least help with tuning.
Um, how did you arrive at a Req_fuel value of 9.5? I have the same Siemens-Deka 830CC injectors that you do, and my Req_fuel is set at 5.0. I think this explains why your VE table has such strangely low values. Here's a copy-and-paste from the VEMS webpage:
Basic req_fuel calculation:
req_fuel = 6.49 * (D / N / I)
D engine displacement (cc)
N number of injectors (eg. 4 for a 4 cyl port injection)
I injector flowrate (cc/min)
This is a simplified equation, if you are interested in the reasoning behind it you can read more here: http://www.vems.hu/wiki/index.php?pa...njectorOpening
I am not convinced that this is causing your weird starting issue, but it should at least help with tuning.
I initially did that method, using formula, but was later instructed by Peep to adjust Req_fuel until I have spot on lamba at idle. My req fuel is high, be table values are low, I see that everyones req fuel is low, and table values are high. Main point that lamba values are achieved, I think it's ok. I might have a lead on solving this issue. After adjusting and swapping out brackets and sensors, I began to look at pin height of the reference sensor. I noticed it to be too far in. Going to try and get the reference gap as close as possible. So I removed the Allen screw, bought a new one and reset the height with red threadlocker. I might go and find a longer screw for good measure, stock is m6x12, maybe go m6x16. Tried a cap head bolt but it hits the bell housing. I believe the critical sensor is the reference compared to the speed sensor. As it determines TDC.
I initially did that method, using formula, but was later instructed by Peep to adjust Req_fuel until I have spot on lamba at idle. My req fuel is high, be table values are low, I see that everyones req fuel is low, and table values are high. Main point that lamba values are achieved, I think it's ok. I might have a lead on solving this issue. After adjusting and swapping out brackets and sensors, I began to look at pin height of the reference sensor. I noticed it to be too far in. Going to try and get the reference gap as close as possible. So I removed the Allen screw, bought a new one and reset the height with red threadlocker. I might go and find a longer screw for good measure, stock is m6x12, maybe go m6x16. Tried a cap head bolt but it hits the bell housing. I believe the critical sensor is the reference compared to the speed sensor. As it determines TDC.
Hey, you might be onto something here (though I think that several of us have asked if speed AND reference mark sensor gaps were good). The reference mark signal is really only used during cranking to determine when TDC #1 is approaching (at least on the original Motronic system) to enable engine startup. After that, the DME is capable of calculating engine position by counting engine revolutions via the engine speed sensor, thus rendering the reference mark signal redundant while the engine is running. This would explain why your engine runs well and continues to do so if it starts well, or runs crappy and continues to do so until the next "good" start.
Let's hope that is it before you replace any more parts!
Hey, you might be onto something here (though I think that several of us have asked if speed AND reference mark sensor gaps were good). The reference mark signal is really only used during cranking to determine when TDC #1 is approaching (at least on the original Motronic system) to enable engine startup. After that, the DME is capable of calculating engine position by counting engine revolutions via the engine speed sensor, thus rendering the reference mark signal redundant while the engine is running. This would explain why your engine runs well and continues to do so if it starts well, or runs crappy and continues to do so until the next "good" start.
Let's hope that is it before you replace any more parts!
Nope, just put her back together and same issue. Speed and reference sensor gaps are very close now, both at 0.8mm or closer. As much as I want to send in my ecu for evaluation, I've had this problem since installing it new. Got a new set of bosch sensors coming in. Swap out Nissan Quest alternator? For a new or stock?Replace my Ice Shark Battery / Alternator / Starter cables? Idk, thoughs?
Nope, just put her back together and same issue. Speed and reference sensor gaps are very close now, both at 0.8mm or closer. As much as I want to send in my ecu for evaluation, I've had this problem since installing it new. Got a new set of bosch sensors coming in. Swap out Nissan Quest alternator? For a new or stock?Replace my Ice Shark Battery / Alternator / Starter cables? Idk, thoughs?
Have you ever used a timing light to check the timing values at various RPMs and compared values after "good" and "bad" starts, and compared it to what the VEMS thinks it is? If the values are different between the two modes at the same RPM, that would confirm some sort of trigger issue, though it seems like you've tried everything related to that . . . . .
If there is some trigger issue (missing trigger events, noise etc) then it should throw trigger error flag with information which type of trigger error there was. And would be useful to record triggerlog (Tools -> Record triggerlog) for both good and bad starts, that would help to eliminate trigger issues and wasting time if there is no problems.
Also regarding req_fuel, it doesn't matter what it is as it is just a multiplier for VE table and you cannot compare VE table values directly anyway unless engines are identical. You can compare VE table shape but that is also affected by injector dead times etc.
02-09-2019, 01:27 AM
