4x4 YB running in a mk1 Escort - idle speed problems
10-06-2017, 10:00 PM
#43
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So the ISCV is definitely sorted, it no longer spikes, sits revving itself all the time, or sits at 2000rpm all of the time, or bounces up and down continuously, all of which of course is a big improvement.
The bad news is that idle bypass screw still doesn't appear to do anything. This is with a brand new screw and we've even tried sealing the aperature of the idle screw hole over, in case the o-ring wasn't sealing properly - no difference.
Starting from cold with the ISCV connected it will idle at around 1600-1800 rpm for a few seconds, before dropping to 1200-1400 for maybe 30 seconds, then settles in to a nice 800-900rpm idle. With the ISCV disconnected and from cold it starts at around 1200-1400rpm for a few seconds and immediately settles down to 800-900rpm. So it seems that the starting operation of the ISCV valve is pretty much spot on and working as expected.
As the car starts to warm up the idle gets more erratic, dropping down to 400-500rpm now and again (just for a split second - then back up to 800-900), accompanied by the odd flicking of the tacho needle. As it gets hotter this gets worse. On occasion it will drop so low that it will stall before the ISCV has a chance to cut in and bring the revs back up. Without the ISCV connected it will of course stall far more often, other than that, the behaviour as it starts to warm up is the same, with or without the ISCV connected.
I'm starting to think we're going to need better diagnostics than what we currently have available. I'm giving serious thought to investing in the IAW monitor software to check what the various sensors are actually reporting as it starts to warm up and exhibit this erratic behaviour.
The bad news is that idle bypass screw still doesn't appear to do anything. This is with a brand new screw and we've even tried sealing the aperature of the idle screw hole over, in case the o-ring wasn't sealing properly - no difference.
Starting from cold with the ISCV connected it will idle at around 1600-1800 rpm for a few seconds, before dropping to 1200-1400 for maybe 30 seconds, then settles in to a nice 800-900rpm idle. With the ISCV disconnected and from cold it starts at around 1200-1400rpm for a few seconds and immediately settles down to 800-900rpm. So it seems that the starting operation of the ISCV valve is pretty much spot on and working as expected.
As the car starts to warm up the idle gets more erratic, dropping down to 400-500rpm now and again (just for a split second - then back up to 800-900), accompanied by the odd flicking of the tacho needle. As it gets hotter this gets worse. On occasion it will drop so low that it will stall before the ISCV has a chance to cut in and bring the revs back up. Without the ISCV connected it will of course stall far more often, other than that, the behaviour as it starts to warm up is the same, with or without the ISCV connected.
I'm starting to think we're going to need better diagnostics than what we currently have available. I'm giving serious thought to investing in the IAW monitor software to check what the various sensors are actually reporting as it starts to warm up and exhibit this erratic behaviour.
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megatron-uk (12-06-2017)
11-06-2017, 08:29 AM
#45
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Unfortunately I don't have a green wire - in the new harness the lambda is connected with a three wire red, black and white (I think) spur. Should that whole sensor be unplugged?
11-06-2017, 08:50 AM
#46
Regular Contributor
check you have the lambda connected correctly, with signal at pin 2, I often see people think the black is ground, but on the oe lambda black is signal.
to put the car in open loop just disconnect the signal wire, but leave the heater circuit connected to keep the sensor clean.
11-06-2017, 10:07 AM
#47
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Okay, that's something I'll definitely check - there isn't a green wire in the lambda connector in this loom though.
The Bosch sensor is a white/black/red 3 wire thing, I was fairly certain the loom terminated in those colours too, but I'll check what they actually are today.
The Bosch sensor is a white/black/red 3 wire thing, I was fairly certain the loom terminated in those colours too, but I'll check what they actually are today.
12-06-2017, 06:22 PM
#48
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Well some great news - the advice to disconnect the lambda sensor was spot on. With it disconnected the car runs beautifully. The idle bypass screw now works and the idle can be adjusted up and down as normal. From cold it sits at around 1200rpm, then settles down to a newly adjusted idle of just over 900rpm.
Dad didn't have time to get the car really hot and get the fans to come in, but it got reasonably warm and didn't exhibit any of the erratic idling or rev counter behaviour that we had seen previously.
It looks like you found the problem James, much appreciated!
Now to look at the lambda wiring (didn't get dad to do that over the phone - he's not a fan of electrickery, so he's leaving that to me LOL!). Hopefully that's just a case of incorrect wiring as you suggested.
Dad didn't have time to get the car really hot and get the fans to come in, but it got reasonably warm and didn't exhibit any of the erratic idling or rev counter behaviour that we had seen previously.
It looks like you found the problem James, much appreciated!
Now to look at the lambda wiring (didn't get dad to do that over the phone - he's not a fan of electrickery, so he's leaving that to me LOL!). Hopefully that's just a case of incorrect wiring as you suggested.
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Loomer (13-06-2017)
25-06-2017, 07:18 PM
#51
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Thought I'd update on recent progress - I do still have a problem with the idle but it only now surfaces once the engine gets hot.
From cold and as it's warming up it has a rock solid idle, it runs beautifully. I did find that I had a problem with my temperature sender and my aftermarket Stack gauges, so I've had to order a new stack sender to replace the standard Cossie one, so at the moment I don't know exactly at what temperature the problem arises.
I decided that the only way to know for sure what was going on was to buy a copy of the IAW software from MSD, so I can log what is going on, and at what exact point the idle gets rough once more (revs dip, engine starts to hunt, etc, all the things I mentioned before).
I'll do some data logging when it arrives and see what is actually happening; up until the point that the engine is hot though, it's spot on, a completely different engine to what it was like when I first started the thread.
From cold and as it's warming up it has a rock solid idle, it runs beautifully. I did find that I had a problem with my temperature sender and my aftermarket Stack gauges, so I've had to order a new stack sender to replace the standard Cossie one, so at the moment I don't know exactly at what temperature the problem arises.
I decided that the only way to know for sure what was going on was to buy a copy of the IAW software from MSD, so I can log what is going on, and at what exact point the idle gets rough once more (revs dip, engine starts to hunt, etc, all the things I mentioned before).
I'll do some data logging when it arrives and see what is actually happening; up until the point that the engine is hot though, it's spot on, a completely different engine to what it was like when I first started the thread.
25-06-2017, 10:02 PM
#53
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Can't remember what the plugs are - would need to take them back out to check.
It definitely runs far, far better with the lambda disconnected. I'm leaving it unplugged for now until I get to the bottom of the other problem. But whether it's connected or not, it starts to run rough when up to temperature. I don't know what's causing it, so that's why I thought that logging all of the sensors and seeing what changes as it warms up would be the way forward now.
It definitely runs far, far better with the lambda disconnected. I'm leaving it unplugged for now until I get to the bottom of the other problem. But whether it's connected or not, it starts to run rough when up to temperature. I don't know what's causing it, so that's why I thought that logging all of the sensors and seeing what changes as it warms up would be the way forward now.
25-06-2017, 10:08 PM
#54
Regular Contributor
Some plugs are not great if the mixture is lean, so try richening the co up towards 3% and see if it stabilises.
It would make sense being mixture related if it's ok cold due to the cold start temperature multiplication tables, which tail off leaner as the car warms up towards around 75degres
if your going to buy the iaw, the pro version is the one to get so you can add and subract fuel and spark on a semi Permianant basis,
It would make sense being mixture related if it's ok cold due to the cold start temperature multiplication tables, which tail off leaner as the car warms up towards around 75degres
if your going to buy the iaw, the pro version is the one to get so you can add and subract fuel and spark on a semi Permianant basis,
Last edited by Loomer; 25-06-2017 at 10:11 PM.
06-07-2017, 06:28 PM
#57
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Only just received the IAW monitor software (just the normal version I'm afraid) and am waiting on the diagnostic cable from MSD. With a bit of luck this will help track things down.
It's definitely 100x better than it was though.
In regards to the inlet cam - it's set to standard; it's a non-adjustable pulley and the two marks were aligned when the engine was rebuilt and the belt fitted.
Lambda sensor could be faulty and/or the wrong type. I'm perfectly willing to accept that - and it could well be why it doesn't work properly when plugged in. I'll have to try a new unit (anyone have the part number of the lambda sensor as used with the MSD closed loop system?) Doesn't explain the hot/cold running issue though - I think that's fuelling as James suggests; pretty much everything else has been checked or replaced now.
I'm really hoping that the cable arrived before the weekend - been waiting a while now - and that we can get to the bottom of this.
It's definitely 100x better than it was though.
In regards to the inlet cam - it's set to standard; it's a non-adjustable pulley and the two marks were aligned when the engine was rebuilt and the belt fitted.
Lambda sensor could be faulty and/or the wrong type. I'm perfectly willing to accept that - and it could well be why it doesn't work properly when plugged in. I'll have to try a new unit (anyone have the part number of the lambda sensor as used with the MSD closed loop system?) Doesn't explain the hot/cold running issue though - I think that's fuelling as James suggests; pretty much everything else has been checked or replaced now.
I'm really hoping that the cable arrived before the weekend - been waiting a while now - and that we can get to the bottom of this.
09-07-2017, 06:06 PM
#59
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Thread Starter
Thanks for that.
Got the datalogger connected up this weekend and, after a bit of hassle getting it set up (software running in a Windows 8.1 vm, on Linux, with a usb to serial convertor) I managed to get all of the supported data out.
Unfortunately it doesn't seem to reveal anything unexpected.
It does confirm that my gauges are reading correctly - in terms of temperatures and rpm, but not much else is apparent when the engine starts to 'hiccup'; it's just logged as a drop in the rpm, an increase in the injector pulse width and a drop of the timing (is 16 deg BTC standard advance at idle speed?).
The only faults I got during the entire day was lambda sensor (when I unplugged it) and I also got one "distributor phase sensor fault or bad signal" at one point when revving, but it only occurred once during the day; it's possible the dizzy base may not be exactly aligned.
The dropped revs definitely only occur once the engine has warmed up. For the first 10 minutes or so this morning the datalogger recorded absolutely perfect running. Not single problem. However once it had got up to temperature - 90 degrees or so, the occasional blip would start; sometimes every few minutes, sometimes only 10 or 20 seconds between.
I made a video of it running this afternoon - it's mile better than it was, but it's clear to see that the rev counter needle dances about when it happens. During this the software logs that the revs drop to ~450rpm momentarily:
Also found that it hesitates and stumbles now and again after revving it. A couple of times it stalled a few seconds after revving it, as the revs died down to 400rpm or so and didn't come back up again. The video below shows it almost, but not quite, stalling:
The ISCV doesn't seem to be connected to the problems being seen now, as it has no effect to these problems after it has warmed up, or if disconnected
Running without the lambda connected is definitely better, and less problematic, so I think I've got a sensor that doesn't work with the MSD software..
Got the datalogger connected up this weekend and, after a bit of hassle getting it set up (software running in a Windows 8.1 vm, on Linux, with a usb to serial convertor) I managed to get all of the supported data out.
Unfortunately it doesn't seem to reveal anything unexpected.
It does confirm that my gauges are reading correctly - in terms of temperatures and rpm, but not much else is apparent when the engine starts to 'hiccup'; it's just logged as a drop in the rpm, an increase in the injector pulse width and a drop of the timing (is 16 deg BTC standard advance at idle speed?).
The only faults I got during the entire day was lambda sensor (when I unplugged it) and I also got one "distributor phase sensor fault or bad signal" at one point when revving, but it only occurred once during the day; it's possible the dizzy base may not be exactly aligned.
The dropped revs definitely only occur once the engine has warmed up. For the first 10 minutes or so this morning the datalogger recorded absolutely perfect running. Not single problem. However once it had got up to temperature - 90 degrees or so, the occasional blip would start; sometimes every few minutes, sometimes only 10 or 20 seconds between.
I made a video of it running this afternoon - it's mile better than it was, but it's clear to see that the rev counter needle dances about when it happens. During this the software logs that the revs drop to ~450rpm momentarily:
Also found that it hesitates and stumbles now and again after revving it. A couple of times it stalled a few seconds after revving it, as the revs died down to 400rpm or so and didn't come back up again. The video below shows it almost, but not quite, stalling:
The ISCV doesn't seem to be connected to the problems being seen now, as it has no effect to these problems after it has warmed up, or if disconnected
Running without the lambda connected is definitely better, and less problematic, so I think I've got a sensor that doesn't work with the MSD software..
Last edited by megatron-uk; 09-07-2017 at 06:09 PM.
20-08-2017, 06:13 PM
#60
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Thread Starter
I thought I'd update with the latest progress on the car - it's now moving under its own power, it's finished in terms of mechanical work and bodywork, but still tracking down various gremlins such as the running problems I've mentioned.
The plan is to get all the other issues sorted (brakes, clutch, check all the lights, etc) and get it booked in for an MOT and temporarily set the car to run open loop and set the CO accordingly. Hopefully that gets it good enough to get a few miles under its belt and then take it somewhere that can properly sort it once and for all.
Still, the fact it now idles well enough (though still not perfectly; it's really eager to stall and still has that annoying miss/rev drop) to drive it in and out of the garage and up and down the street is a big improvement.
The plan is to get all the other issues sorted (brakes, clutch, check all the lights, etc) and get it booked in for an MOT and temporarily set the car to run open loop and set the CO accordingly. Hopefully that gets it good enough to get a few miles under its belt and then take it somewhere that can properly sort it once and for all.
Still, the fact it now idles well enough (though still not perfectly; it's really eager to stall and still has that annoying miss/rev drop) to drive it in and out of the garage and up and down the street is a big improvement.