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electrical issues

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electrical issues

Postby emilcabrera » Mon Jan 14, 2019 5:38 am

Hey guys, i am writing this post because i am desperate. i bought an used bighorn 2000 lotus edition, this version come with a 4JG2 engine with electronic fuel injection, for some reason mine was downgrade to a mechanical fuel injection.
Because of that my ECU is not woring and i have not RPM reading, glow plugs are not working and the TCM is going crazy.
I had seeking in every forum and electrical drawings to make it work, but the drawings and pinouts that i found do not mach with my truck.
i am looking for somebody with the same issue solved in the past, that can give me some light about it.
i am from Dominican Republic and it is very difucult find a good mechanical over here.
My TCM is the Part#8971294440
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Re: electrical issues

Postby geeves » Mon Jan 14, 2019 2:36 pm

what are the first 5 characters in your chassis number. It will start UBS and will be either 69 or 73?
Trans will probably settle if you disconect the throttle position sensor but it will be slow to change gear. If its doing what mine did this is still a big improvement
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: electrical issues

Postby emilcabrera » Tue Jan 15, 2019 2:18 am

it is UBS 69, i was trying to find the way to find the way to disconnect the Throttle and tachometer sensors from the ECU and connect directly to the TCM (is it is possible), in that way i could just eliminate the ECU because those are the only function that is doing right now.
emilcabrera
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Re: electrical issues

Postby emilcabrera » Mon Jan 28, 2019 6:35 pm

Hay, good morning guys, nobody has an answer, I would apreciate it a lot
emilcabrera
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Re: electrical issues

Postby geeves » Tue Jan 29, 2019 4:32 pm

Are you sure its a 2000. The ubs69 was replaced in 98. It sounds an oddball and there is no easy answer for the trans
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: electrical issues

Postby emilcabrera » Fri Feb 08, 2019 11:45 am

The registration says 2000, but anything can happened in my country, so, could be 1998.
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Re: electrical issues

Postby geeves » Fri Feb 08, 2019 1:46 pm

Glow plugs are probably not an issue there. It should be warm enough to start. Rev counter could be fixed by replacing with the earlier model and rewiring to match. Rev counters are the least of your worries though.This only leaves the trans. Try unpluging the wire to the speedo sensor on the trans and see how it drives. Obviously not a fix but it might point to a way around the problem
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: electrical issues

Postby DonaldNZ » Fri Feb 08, 2019 3:48 pm

my 97 wizard ubs69 4jg2 with electronic fuel pump throws toys out with the speed input wire disconnected to the speedo within a very short time time.
at low speed it's ok,
over about 60 km/hr
check trans light on
immediately gear shift held back
no top gear or overdrive, unless already in top or overdrive.

First Id be looking at trying to find out what inputs the ECU and TCM received when it had a electronic pump. Then I'd decide if I can simulate that.

no reason you cant have the electronic pump tps hooked up to the manual pump linkage.
you may be able to make a pulse generator proportional to speed using the alternator as a trigger. This might satisfy the control units.
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Re: electrical issues

Postby emilcabrera » Thu Feb 14, 2019 12:16 am

Hi guys, thank you so much for your answers.
Geeves I will try this ideas soon I will come back with the results.
DonaldNZ I was trying to get the pinout for ECU and TCM, but it was impossible, I check one by one the cables from the ECU and have an idea where the cables are connected now, but not about the original engine, so I have nothing. I know I have 5 cables that go from the ECU to the TCM, but don't know the function of each one
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Re: electrical issues

Postby DonaldNZ » Thu Feb 14, 2019 9:42 am

re engine and trans ecu pin outs

I too would like these for my own maintenance. I am yet to find accurate data specific to the electronic pump , it is like rocking horse manure to obtain.

This is all I have on the electronic pump from a bighorn unknown year, although someone on here will probably know what model and year Isuzu had the electronic pump

Isuzu Bighorn info(1).pdf



I have a [147 pages] trans overview training manual that includes AW30-43LE as fitted to a volvo. again this is only a guide and not for specific wire locations in the trans and engine ecu connector plugs.

I do have this concept picture form a training manual on the re engine and trans ecu pinouts
this from a trans overview training manual AW30-43LE Model as fitted to a Volvo

trans in output.JPG


Re the hook up the trans directly bypassing the engine ecu ,
Probably the easiest way is measuring of a known good vehicle prior to attempting as the signal may be 'conditioned' [inverted, power level change] to make it acceptable to the trans ecu. People [not me] can make signal modifying electronic black boxes if needed.

Would you consider fitting a known good correct electronic pump? If all else is in place how easy would that be ? I would consider it a more predictable outcome.

Measuring, designing, Fabricating and installing electronic signal modifiers to 'trick' the ecu is in the region of less than 0.1% common knowledge

saying that the above concept drawing only shows 2 inputs to the trans that are speed related

anyone know where the engine and trans ecu are mounted in a 97 wizard?
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Last edited by DonaldNZ on Thu Feb 14, 2019 9:57 am, edited 3 times in total.
DonaldNZ
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Re: electrical issues

Postby DonaldNZ » Thu Feb 14, 2019 9:50 am

if you don't go for the correct pump
Glow plugs control relay could be hooked up to a aftermarket glow plug timer, Id suggest selecting one with afterglow to give a better cold idle and less smoke after cold start.

about 1-1.5 hours, about NZ$100-150 for a timer , ebay is probably 1/4 of that

I'm happy to walk you through the install and setup to prevent overheating & destroying the plugs
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Vehicle: stock wizard 4jg2t efi & 30-43le external pressure control via throttle quadrant

Re: electrical issues

Postby emilcabrera » Wed Feb 20, 2019 5:45 am

Thanks for the information DonaldNZ.
I have solved the glow plugs issue, buying a glow plug controller from an older trooper in a junky.
About the transmission, we are thinking that the issue is over temperature of the oil, we will test with an oil cooler and see what happen. i will let you guys know if that solve the issue.
We still looking for a solution for the tachometer sensor, but sounds like the better solution is replace with the newer model, as Geeves recommend, i still looking for it.
emilcabrera
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Re: electrical issues

Postby DonaldNZ » Wed Feb 20, 2019 6:34 am

Trans Over temp happens at around 140°c
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