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Help with building your Speeduino, installing it, getting it to run etc.
By Cylinder 8
Hi All,

Thought I'd start a thread on my Volvo project, it's my first ever ECU installation and a steep learning curve but I'm enjoying it so far!

I've nearly finished the wiring in the car but I've got a really stupid question before I install any wires into the Speeduino connectors. I've got a UA4C (this one: https://diy-efi.co.uk/product/speeduino_ua4c_ecu) and the pictures show which pin is used for what. My question is which side of the connectors do I look at when following the pin numbers in the diagrams? Are they numbered as though I'm looking at the port in the ECU case or as though I'm looking at the connector with the loom coming out the other side?

User avatar
As-viewed looking into the ECM. The image below by WTMTronics should help, and while I don't know why it is not offered more clearly on the info page, the documentation for the UA4C series is here. Hope that helps.


From the GitHub site:
UA4C_Conn.jpg (246.34 KiB) Viewed 976 times
By Cylinder 8
I finally got it running today. It seems reasonably happy overall but there's one problem that's quite obvious. Even with the acceleration enrichment values all set to maximum, it will not rev quickly. The only way I can increase the revs is by pressing the throttle really slowly, any quicker than that and it just stutters and almost stalls, while the AFR gauge shows it suddenly running very lean.

The only possible cause I can think of is the TPS. Even though I've calibrated it several times, it's not showing any change near the top end of the pedal's travel. I can get the the engine up to about 1500rpm before tunerstudio shows 1% throttle position.

Would that alone upset the accel. enrichment or is there something else I should be looking at?
By Cylinder 8


I don't have a log of it yet, I'll record one tomorrow morning. What's more useful, a screenshot of it or the log file itself?
By stum
Not being familiar with your engine, But looking at your ignition table I would say it would like some more advance.

Depending the head design determines the amount of advance to start with. Normal a figure between 30-40 degs.

I normally like to have about 30 deg by 3500 rpm (at 100kpa) and leave it at that up to red line. And at idle a figure between 10-15 deg depending on Cam profile........ This will liven it up.

There are a few good old school books on ignition timing for carburetor engines on how to tune distributors, they have some good concepts and process in them. Most of it is still relevant today on EFI engines.

Good work and keep it up
By LAV1000
Cylinder 8,
Post the complete datalog.
Al the info is in there and it is more detailed then a screenshot.
By Dagaz_Psi
Here`s a stock spark table, have in mind that its for AFM.
Up to 30 is atmospheric and 100 is 0.5 bar of boost.
I usally rev them to 7500rpm, they start to valvefloat at 8000. i would say 7000 is the safe number.
And here`s a volvo on speeduino redlining at 7500
By Cylinder 8
Thanks all, I really appreciate all the advice.

I've added a bit of ignition timing at the lower end of the rev range but not as much as the standard table, I'm probably being over-cautious.

Hopefully this link works, this is the data log showing it bogging down when the throttle is opened quickly:

https://drive.google.com/file/d/19fhCKn ... sp=sharing

I've tried changing the accel. enrichment to MAP-based instead of TPS-based. No difference.

The more time I spend on it the more problems I find, it doesn't seem to be controlling the idle control valve properly and won't run when cold unless I keep the throttle open. It also won't start at all unless I have a second battery connected to it with jump leads. With just one I can hear the fuel pump and coil pack relays clicking on and off repeatedly as it turns over, preventing it from starting. With two batteries they just click on once and it works fine. With the original ECUs this car would start even when the battery was pretty low. :(
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