andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Trying to get a American throttle body injection system to work on a Rover V8. And failing!
Anyway, I'm getting a 11.5 volt reading when cranking on the ECU display, I'm waiting to hear from support if that is enough to get the system to run while cranking. At the moment, the RPMs aren't registering, so the injectors won't fire. But when I stop cranking and in the second before the engine actually stops, the RPM does show, I've seen 150 RPM on the display.
This indicates to me that the wiring is OK and it's the fact that I'm not getting full 12v for the ecu or coil that's stopping it running.
So I need either a way to wire the starter and ecu/coil to each get a full fat 12v or perhaps put a standalone system for ecu/coil.
I could charge the standalone via a split charger. The only issue I have with this is the earth for the distributor, it earths via the engine and through it's body. So even though the coil is standalone on the live circuit, the earths will be combined. The ecu get's it RPM signal from the neg side of the coil.
Clear as mud? So, suggestions, ideas and thoughts please.
Thanks
P.S. To remove a possible problem, it's now got a clockwork distributor with points!
|
|
|
|
|
jimi
Club Retro Rides Member
Posts: 2,058
|
|
|
What's the battery voltage before you start cranking ? what capacity is the battery ? what condition/age is it ?
|
|
Black is not a colour ! .... Its the absence of colour![](https://jlawson.co.uk/images/Jimisig04.jpg)
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
My first thoughts, so now it's got a new Exide that's at least 50% larger cold start than the original carb battery, showing 12.7 at the moment.
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Forgot to say the ECU has a main for injectors/pump and a 12v control to the ECU. The 12v control to the ECU is now running direct to the ECU via a relay.
The wiring loom is supplied with the system, not something I've knocked up, so I'm inclined to believe it works!
|
|
|
|
jimi
Club Retro Rides Member
Posts: 2,058
|
|
|
12.7v should be OK, a resting voltage of 12.6 or above is normal on a healthy battery. How is it wired ? i.e battery->solenoid-> starter and battery-> fuses->ignition switch->ECU If the main feed to the solenoid & starter and/or the engine earth are too small or in poor condition it will pull the voltage down when cranking. Have you tried running a temp feed to the ECU direct from the battery (just as a test) ?
|
|
Black is not a colour ! .... Its the absence of colour![](https://jlawson.co.uk/images/Jimisig04.jpg)
|
|
mk2cossie
Club Retro Rides Member
Posts: 3,022
Club RR Member Number: 77
|
ECU voltage drop.mk2cossie
@mk2cossie
Club Retro Rides Member 77
|
|
Also check the ECU trigger rpm. A lot of stuff won't fire unless cranking rpm is over 250-300rpm
|
|
|
|
|
|
|
Sounds to me as a wiring fault, when cranking are you sure a supply from the ignition is supplying the ECU?
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
12.7v should be OK, a resting voltage of 12.6 or above is normal on a healthy battery. How is it wired ? i.e battery->solenoid-> starter and battery-> fuses->ignition switch->ECU If the main feed to the solenoid & starter and/or the engine earth are too small or in poor condition it will pull the voltage down when cranking. Have you tried running a temp feed to the ECU direct from the battery (just as a test) ? I have tried running a 12v direct to the ECU, no difference. I up-specced the live cable to the starter solenoid when I re-wired and did the same with the smaller live to ignition switch, I have earth straps for the engine and the chassis. The + terminals were new, the earth straps will get cleaned tomorrow! On the USA Buick site, 11.8 volts was the minimum needed to get the ECU to work. Battery is on charge now! It's only a little 4 amper though. I've got a little jump start battery pack, I'll chuck that on too, when I try tomorrow! I've got no idea about age or condition of the starter, it looks OK when I climb under........I guess that could pull it down too. I'd like it to fire at least once, I'll know it's not the ECU and I'll have a better idea of what to fix
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Sounds to me as a wiring fault, when cranking are you sure a supply from the ignition is supplying the ECU? It's a got a hand held monitor, which shows the parameters of everything, both while just switched on, while cranking and while running. !2.6v while on, 11.5v while cranking. Pretty sure it's just slightly too low while cranking to read the rpm from the coil. Found someone else who had the same problem, down to a bad starter.
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Also check the ECU trigger rpm. A lot of stuff won't fire unless cranking rpm is over 250-300rpm I will, but it comes with a basic start map, so I reckon it's fine. But you never know!
|
|
|
|
|
|
|
|
Are ALL parts of the engine management system and peripherals like injectors, coil pack etc supplied by wire that remain live while cranking (ie not being cut while cranking by a relief relay?
Do you know whether the crank position sensor is a hall sensor (typically 3 wire) or VR sensor (typically 2 wire)? Hall sensor might be somewhat sensitive to supply voltage but relatively insensitive to air gap and cranking speed. VR sensor won’t be affected by supply voltage but is more sensitive to air gap and cranking speed as it generates its own voltage.
|
|
1967 Triumph Vitesse convertible (old friend) 1996 Audi A6 2.5 TDI Avant (still durability testing) 1972 GT6 Mk3 (Restored after loong rest & getting the hang of being a car again)
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Hall, VR sensor. What is this strange language you're speaking? It's a good old country boy system with clockwork points!
It can do timing and it can use a crank sensor or a locked distributor. however it's recommended that the fueling is sorted first, before having mapped timing.
The only part that seems to not work is the ignition signal from the coil, read from the neg coil point. So the ecu's unaware that the engine is rotating.
It's 2 barrel batch fired, so doesn't need to know which cylinder is on induction. Basically an electronic carb!
Anyway, the finger of shame may be pointing at me, I thought I'd unrated the battery cables, but I only did the alternator one! And it's got braided earth straps, which surprisingly, don't carry much amps. No good if the electric can get in, but not out!
|
|
|
|
jimi
Club Retro Rides Member
Posts: 2,058
|
|
|
You could use jump leads for testing purposes ![;)](//storage.proboards.com/forum/images/smiley/wink.png)
|
|
Black is not a colour ! .... Its the absence of colour![](https://jlawson.co.uk/images/Jimisig04.jpg)
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
You could use jump leads for testing purposes ![;)](//storage.proboards.com/forum/images/smiley/wink.png) Ahead of you and no, I can't! I think because it's the ecu needing to read the neg side of the coil and the distributor always being earthed to the battery via the engine, trying to get the ecu and it's connections to "stand alone" is impossible. Tried this morning to separate the starter to a second battery to avoid voltage drop to the ecu/coil while starting, didn't work. Or did you mean using jump leads as the battery cables, again tried this too. Although the jump leads may handle less amps the battery cables. Anyway, new 300 amp battery leads, (starter, and 2 earths) ordered. Added a higher amp alternator lead too with new clamps. I will win or return the stuff and go back to carbs!
|
|
|
|
jimi
Club Retro Rides Member
Posts: 2,058
|
|
|
Or did you mean using jump leads as the battery cables, again tried this too. Although the jump leads may handle less amps the battery cables. I meant using jump leads to double up on the existing leads, looks like you tried that
|
|
Black is not a colour ! .... Its the absence of colour![](https://jlawson.co.uk/images/Jimisig04.jpg)
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
Yup, tried it. Though I'm not sure if it'll do anything, will the amps pulled by the starter take the different routes, especially when one of the routes is via clamps and a much longer cable.....?
But, yeah tried it! Tried it with and without an extra battery, even tried it with a jump start pack added.
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
It's only .3 of an amp, I've got 11.5 amps showing and 11.8 amps is the minimum that the ECU needs to work.....or so the internet says!
|
|
|
|
|
|
|
i think that its showing a rev speed when the engine is stopping could be part of 2 things. It cant read the toothed wheel as maybe the sensor is incorrectly positioned, and when the engine is slowing down i can register what it sees.
What is the sensor, what is the ecu? what is the air gap?
Ive had it on my microsquirt where it didnt like the signal, and i had to fit a 1k resistor inline to quieten the signal noise.
what is the throttle body system? if its like the lada niva/renualt clio/ rover mini type idea, it may run on 1 bar fuel system not 3 bar.
|
|
|
|
andyborris
Posted a lot
![*](//storage.proboards.com/forum/images/stars/star.png) ![*](//storage.proboards.com/forum/images/stars/star.png)
Freedom is just another word for nothing left to lose.
Posts: 2,212
|
|
|
I think I should explain the system a bit.
It's American and designed to replace a big Holley carb without too much fuss, so apart from a RPM signal taken from the coil, it's self contained with all the sensors it needs in the throttle body.
The throttle body looks like a carb and fits to the same carb manifolds.
It can do mapped ignition or it can run with the points in a distributor, which how I'm trying it. It only runs on MAP/TPS, so it doesn't need to know the cam timing.
I purchased the complete kit, EFI, matched in tank pump conversion and PTFE fuel lines. The only extra item I've needed to buy is a barbed connector for the tank vent. I've needed a little bit of auto wire and some crimps/heatshrink.
It was half the price of a comparable MS install, even with shipping and tax!
And if I could get it to work, it's a no brainer!
I'm hoping that's it just voltage drop stopping the ecu working with 120 amp cable to the starter and 90 amp on the engine earth strap. Internet knowledge says that 1 amp for each cube is a good margin and I've got 240 cubic inches. So the 300 amp cables should kill or cure!
Some previous installers have had issues getting it to work because of tired starters or poor battery cables drawing too many amps, the most noteworthy of these being a guy with a 1954 Buck Nailhead and it's original starter motor! A new factory starter cured it, testament to 1950's USA engineering quality and support!
Because the manufacturer advised that the Lucas distributor provided a RPM signal input which is very "noisy", I swapped to re-manufactured Delco one from the USA.
Night and day in design and engineering quality, I especially like the little slide up window you can put a screwdriver through to adjust dwell while the engine is running.
|
|
|
|
jimi
Club Retro Rides Member
Posts: 2,058
|
|
|
It's only .3 of an amp, I've got 11.5 amps showing and 11.8 amps is the minimum that the ECU needs to work.....or so the internet says! Volts not Amps ![;)](//storage.proboards.com/forum/images/smiley/wink.png) Re the jump leads, the amount of current in each cable will carry depends on the resistance of each cable i.e if they are the same resistance the current would be shared equally. I have my doubts that voltage is the problem at 11.5v, not usual for a battery to drop to 11.5 while cranking
|
|
Black is not a colour ! .... Its the absence of colour![](https://jlawson.co.uk/images/Jimisig04.jpg)
|
|
|