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Isuzu pickup space cab TDI swap wiring harness

41K views 314 replies 7 participants last post by  superhl 
#1 ·
I'm in the process of swapping a salvage 2002 New Beetle 1.9l TDI ALH engine into a 1992 Isuzu space cab. I'm waiting for my adapter to arrive from Matt Whitbread. He also is tuning my ECU. This totally new but will see it through. Just bought a Chevrolet S10 V6 4.3L GM NV3500 NV 3500 Transmission 5 Speed. I am looking a for a Chevy 153 tooth flywheel for an "internally balanced" or 2 piece rear. It came out of a 1995 chevrolet s10 4.3 v6 truck. I can find plenty of 153 tooth flywheels 16 lbs but Randy - tdconversion recommended a heavier flywheel. The heavier flywheels are not cheap. Anyone know of good deal on a heavier flywheel let me know.

While I'm waiting for the adapter to arrive, I have removed most of the wiring from the VW. To complete the wiring removal, I need to remove the connection to the fuse box inside the car. How do I do that? Cut the wire? Would it be better if possible to mount the internal fuse box from the VW in the Isuzu? Or cut the wire then determine which wires are need and connect to the Isuzu fuse box. Matt says there will only be a few wires needed once the IMMO is deleted.
 
#2 ·
In the short rows...need some help

I have the engine mounted, tryanny and drive shaft connected. Now I am wiring. I need a little help with wiring. I have already labeled all the wiring and connected using the beetle fuse box and relay panel very bulky. What I would like to do is power the ECU from the Isuzu ECM relay. How is the best way to test this without frying the ECM.
 
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#4 ·
Where did you get your flywheel? Years ago i found cheap steel or maybe cast iron flywheels in the 25 lbs range, they were dirt cheap because everyone wanted lighter flyweel for quicker revs, i also think the epa prefers the lighter flyweel.

So the only guys wanting heavy flyweels are 4x4 guys wanting that heavy mass down low and the conversion guys. The price has quadrupled.
 
#11 ·
I deleted all that stuff. To bulky and also the relays are expensive. I got a 6 pack of 5pin 40amp relays with pigtale harness for like $20. Used one for the 109 relay and used one to run my cruise and one for glowplugs (Manual bypassed ecu) I grabbed the under dash relay holder (holds 12 relays) and cut it so its only 4 holders wide and slide my relays in that. there is also a spot to hook several blade fuses to the same holder and you only need 2 fuses minimum. one for the 109 and one for the power sensors (MAP, N75 valve...)

Look on my thread at TDi club you will see how I wired mine.
 
#16 ·
I have someone looking at the wiring schematics ensuring all is correct. Once the relays arrive, we are going to re-organize. Hopefully I will have this puppy running soon.
View attachment 110674

I need to replace this box
View attachment 110682
Yea that box can go. The big terminal end wires are great to use though. I used that fat 10 gauge wire to run a hot buss for the 2 relays I needed. If you keep the VW glowplug relay to run off the ecu it only needs 14 gauge at a max of 40amps its plenty of wire to run that current. I ended up just running thee GP manually though.
Is your donor car a automatic? if so the alternator is only 90amp. The stick is 120amp.
 
#185 · (Edited)
I I completed the transmission install. Really line how smooth the gears change. Drove to beach over weekend. After leaving work today it was running great but suddenly cut off. I notices a hose was leaking fuel. Cut end off and re-attached. Hard to prime but got is running and make it to clients house. One hour later, tried to crank and no start. We determined lift pump is not working. After bleeding, finally it started. Drove fine all the way home. Arrived home, shut off and tried to start again but would not start. I remember you saying you installed a 2004 Cummings lift pump. I want to replace the Isuzu gas lift pump with a diesel lift pump. How did you modify your neck so the lift pump would fit? Any suggestions? Thanks!
 
#24 · (Edited)
Motohead1,
Can you explain to me how exactly the Direct fuel injection works from the time the switch is turned to on? The guy helping me with wiring is little confused by the schematic in the Bentley. ..... Also, I believe I read you did not use the VW fans but a fan from a Thunderbird? The vW fan system is little complicated. The fans are bulky and I don't have much room and would like a thin fan.
Not sure I am answering your question but this motor is controlled just like a VE pumped 4bt except the ECU controls throttle rack electronically and timing is achieved the same as a 4bt but timing control is based on several maps and the 3rd injector needle lift sensor. Shutown is accomplished by solenoid just above the delivery valves on the pump just like alot of VE pump cummins.

For fan I used the stock Dakota AC electric puller fan in the stock location. Its all thats needed. I paralleled a manual adjustable temp bulb zip tyed to the outlet pipe of the radiator. It never comes on unless in stop and go traffic with AC on. Stock V8 radiator is plenty for this motor. You might be thinking of Jimbotes Tacoma with ford fans on it. Any factory fan that pulls good CFM should be fine as I think you will find it will not come on as much as you think. Mine is set to pop on around 185F on the outlet pipe on a stock 192 thermostat. That tells you just how cool these motors run.

Ill add the bently is a little weird at first but once you understand how it jumps to the next page it makes sense.
 
#31 · (Edited)
I wired pin 121/37 into the Isuzu 12v wire that is hot when switched on. Looking at the Bentley wire 121/88. goes to a light switch? Does it need to be wired in? I noticed some others have it wired in as if powers the ECU. I'm not seeing in the Bentley. All the wiring should now be completed for the truck to run. Now need to connect the fuel lines and master cylinder line to slave cylinder. I am wonder if the Isuzu master cylinder is big enough for the NV3500 tranny. The NV3500 is larger then Isuzu manual tranny. I guess I will find out.
Do you see any issues with mounting intercooler near the battery under the flatbed. It will be about 7 feet away.
 
#32 ·
yea pin 88 needs 12 volts same power as the ecu 12v. I never really found out why it was going to a light circuit but its not anything other than a switched on 12v.

Intercooler is best out front of course but as you see I mounted a tiny intercooler sideways with a scoop and its adequate at best till a 100 degree day. your truck is much lighter than mine so you might be ok. i have plans to change to a big front mount as soon as I finish my bumper.
 
#33 · (Edited)
I connected the fuel lines. Getting fuel to the IP. Not starting. Not getting power to the big blue on the relay. As far as voltage, what should I be seeing from pin 121/18 coming from the ECU to the relay or does this wire ground the relay. How can I test to ensure it is working properly
 
#34 · (Edited)
121/18 grounds the relay.

Also Minimal interface pins posted by Jimbote on TDiclub.

121 ecm interface pin/wire chart:
component:...........pin color
CEL:…...................24 ws/bl
tach:.....................27 gn/br
glow:.....................40 bl/gn
vss:.......................20 bl/ws
k line:....................16 gr/ws
clutch cancel:..........66 ws/ro
BS n/o:...................32 ro/sw
BS n/c:...................65 ws/ge
"wake up"
(key O/S):...............37 sw/li
 
#35 · (Edited)
She is running! What a great sound! I had a wire missing in my relay panel. It took a while to get it to start. I'm assuming air was in the lines...Thanks for your help Motohead1. I still have few more wires that go to the cluster. Is there any part of the electrical that runs the high/low fans on the radiator that I need to keep. I would love to delete the unneeded wires. I purchased an electric fan with relay and temp control. Thanks God the hard part is over! I knew nothing about wiring! I have simplified schematics that I will post along with pictures once all is completed. Hopefully these will help someone else. Engine Auto part Electrical wiring Technology Electrical supply
 
#37 ·
intercooler and cold air filter

I don't have enough room the engine compartment for the intercooler and air filter.
Any recommendations. I see tons of them on ebay. Also, I would like to move the air filter outside of the engine compartment. Any recommendations?
 
#38 ·
Got any pics of your truck? Im trying to imagine room wise what your working with. Is it 4X4? If you have room you could do the sideways sitting intercooler with a scoop like I did. see pics on Tdiclub. It amazingly works great until the temp outside gets in the upper 90s and the truck is loaded down. Its a rare occurrence but I am working on building a bumper with a massive cooler to fix that issue. I also need the bumper for some tire clearance.

Airbox I used the stocker v8 one and piped the intake to the inner fender. You might could fit the small donaldson filter setup but thats not free. You could grab one of the universal snorkels and cut a hole in the fender but looks a little goofy unless your crossing rivers every weekend.
 
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