Daf
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| posted on 27/4/15 at 02:16 PM |
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Engine won't rev
A dilemma for you all to consider on a sunny Monday afternoon….!
The problem is quite simple – the car starts and idles perfectly but the instant the throttle is opened the revs drop and starts to cut out unless I
close the throttle. I can sometimes squeeze the revs up to 2k. It’s an ST170 engine running(!?) on bike throttle bodies and an Emerald ECU – all the
readings from TPS etc. look good when the laptop is plugged in. You can put it in gear and happily pull away no problem.
With a normal car I’d be thinking along the lines of vacuum leak or low fuel pressure etc, but as this is the first time I’ve converted an engine to
run on throttle bodies I thought there may be something fundamental I’ve overlooked! Plus I’m in work right now and can’t go and play with it – so I
thought I’d post on here as someone is bound to think of something I haven’t! 
If someone comes up with the solution there's a cake in it for you in Stonleigh!
[Edited on 27/4/15 by Daf]
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HowardB
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| posted on 27/4/15 at 02:23 PM |
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fuel delivery,.... pressure too low?
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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Daf
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| posted on 27/4/15 at 02:48 PM |
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quote:
Originally posted by HowardB
fuel delivery,.... pressure too low?
Is there a way I can test this without spending £70+ on a tester? I'm using the ford fuel rail with the schrader valve on one end of it.
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HowardB
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| posted on 27/4/15 at 02:53 PM |
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I guess that the easiest way is to check the return line, and see how much fuel makes it back.... otherwise I am not sure. Short of your ecu map being
way out, it's where I would start.
Have you got a base map?
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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Daf
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| posted on 27/4/15 at 02:56 PM |
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quote:
Originally posted by HowardB
I guess that the easiest way is to check the return line, and see how much fuel makes it back.... otherwise I am not sure. Short of your ecu map being
way out, it's where I would start.
Have you got a base map?
Yep a couple of base maps were supplied by emeral themselves, plenty of fuel is coming back along the return line so the fuel is making it's way
around.
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Jenko
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| posted on 27/4/15 at 03:27 PM |
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Do you have a wide band lambda you can use to monitor AFR. Sounds like there is either a lack of fuel (or too much). What do the plugs look like after
it has stalled (are they wet?.)
MY BLOG - http://westfieldv8.blogspot.co.uk/
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adithorp
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| posted on 27/4/15 at 03:53 PM |
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What was the old set-up and what is the new one?
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Daf
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| posted on 27/4/15 at 04:39 PM |
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quote:
Originally posted by adithorp
What was the old set-up and what is the new one?
It's all new! it's a new build - I dont have access to a wide band lambda, might be a worthwhile investment?
Does anyone have a standard zetec map for an emerald that I could try? If I can get some sort of revs from that it could point me in either the
direction of the map being out or a physical issue.
.
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owelly
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| posted on 27/4/15 at 05:14 PM |
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Is there a pressure regulator in the system?
http://www.ppcmag.co.uk
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rusty nuts
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| posted on 27/4/15 at 05:28 PM |
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Retarded ignition timing could possibly cause lack of revs , especially if the exhaust manifold gets very hot (glowing) Are you using the ST flywheel
and crank sensor ? I
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Daf
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| posted on 27/4/15 at 05:52 PM |
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quote:
Originally posted by rusty nuts
Retarded ignition timing could possibly cause lack of revs , especially if the exhaust manifold gets very hot (glowing) Are you using the ST flywheel
and crank sensor ? I
Ah yes now we're talking - the manifold does heat up alarmingly quickly. I've never had it running long enough to get it glowing but the
rate at which it heats up I would imagine it would do.
I'm not using the ST flywheel - I was under the impression that it was the same as the standard zetec one, am I wrong???
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obfripper
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| posted on 27/4/15 at 06:26 PM |
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Check the polarity of your crank sensor, if the 2 wires are swapped it will have an incorrect position for tdc as rising edges are seen as falling
edges, iirc the missing tooth in the flywheel is at 90°btdc, and all ford i4 manual flywheels have the same pattern and missing tooth position.
I don't know how the emerald unit deals with an inverted crank signal, but the ford edis unit gives a limited rpm range.
Does the emerald allow you to set the missing tooth offset, as v6 and v8's have the same pattern but differing positions for the missing
tooth.
Dave
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Daf
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| posted on 27/4/15 at 09:38 PM |
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quote:
Originally posted by obfripper
Check the polarity of your crank sensor, if the 2 wires are swapped it will have an incorrect position for tdc as rising edges are seen as falling
edges, iirc the missing tooth in the flywheel is at 90°btdc, and all ford i4 manual flywheels have the same pattern and missing tooth position.
I don't know how the emerald unit deals with an inverted crank signal, but the ford edis unit gives a limited rpm range.
Does the emerald allow you to set the missing tooth offset, as v6 and v8's have the same pattern but differing positions for the missing
tooth.
Dave
After a bit of research the crank set up is correct - the trigger pattern is the same for all inline 4 fords. someone has kindly sent me a zetec map
which I'll have a whirl with tomorrow, it's too late now I risk waking the child!
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Daf
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| posted on 28/4/15 at 10:05 AM |
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I put a standard zetec base map on it today and it revs as free as a bird! I'll have to get in touch with emerald to see if they can supply a
different map until it's time to get it on the RR
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Ugg10
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| posted on 28/4/15 at 10:36 AM |
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Out of interest how are you controlling the VCT with the Emerald and I think that this ECU can only do the off/on/off VTEC method and not a fully
controlled VCT ? May be worth a read of JENKO's build blog (1.7 puma) as he show how his engine is mapped for VCT using the VTEC method, pretty
successfully.
(Interested as I have a 1.7 Puma with VCT).
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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Daf
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| posted on 28/4/15 at 11:02 AM |
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At the moment I'm just triggering it on/off, however I think long term I will probably remove the VVT altogether and fit verniers - I think this
would be the best solution for my set up
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Ugg10
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| posted on 28/4/15 at 11:18 AM |
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Sounds like you have a plan, Jenko found on the puma engine that he go t a load more performance by turning the VCT off at higher revs, he has graphs
of VCT on and off on his blog which shows the cross over points. I think he also turned his off at low load conditions as well. he was using an Omex
600 though.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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mcerd1
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| posted on 28/4/15 at 03:39 PM |
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Have you read this old thread ?
http://www.locostbuilders.co.uk/viewthread.php?tid=165372
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