1992 Hilux Surf 7MGE mod

You can ask your Surf and 4Runner related questions here. Also feel free to show us the modifications you did on your vehicle.
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hannesnel
Newbie
Posts: 2
Joined: Mon Oct 07, 2019 8:49 am
Town: Grahamstown
Vehicle: 1992 Hilux Surf 7MGE
Real Name: Hannes

Mon Oct 07, 2019 10:25 am

Hi Everyone

I just want to say this forum has already helped me stacks - THANKS! :thumbup:

I recently bought a 1992 Hilux Surf LN130 with 7MGE engine modification. Even though the vehicle was in an accident somewhere in the past, the body is in very good condition. The previous owner blew head gasket and broke rings, so I got it for a very good price and it came with two 7M engines.
And this is where the "fun and games" started. :o:

The one engine was partially redone (re-sleeved), but I had the whole thing redone from scratch. After I put it back in the vehicle, I encountered a couple of problems.
I hope somebody on here can help me with at least some if it? :beg: :beg: :beg:

1. The Throttle Position Sensor is disconnected. When it is connected, the idling goes up and down continuously when it warms up. I checked the Ohms on the TPS according to the Toyota repair manual and everything is withing spec.
I'm not exactly sure of the RPM as my rev counter's needle is way below the zero when off, but it seems to idle at around 1500 to 2000 rpm.
Would these 2 symptoms be related?
And how does it even idle without the TPS connected?

2. There seems to be a sort of "misfire" / rough idling and even when accelerating, it is as if there is a miss - almost like a dead plug. I did replace the plugs, HT leads, rotor & distributor cap with new ones.
Can this possibly be caused by an injector or might it have something to do with the TPS?

3. And then there is the vacuum tubing
Has anyone got pics of where which hose must go? I can't seem to find an exact diagram even in the repair manual.
Could this also cause some of the problems mentioned above?
Please remember this 7MGE is in a Surf. The front diff is an Automatic Disconnecting Diff which also works with vacuum. This comes from 2 VSV's located close to the brake booster. See here

4. Also, my brakes seem excessively hard. Maybe I have rerouted all the vacuum hoses wrong?

5. The radiator fan switch was buggered and might have been part of the previous owner's problems with BHG. So I went and bought one at Autozone in Port Elizabeth that opens at 90*C and closes at 85*C. However, when I installed it, the fan came on immediately when I turned the key.
At first I thought it was faulty, but when I researched the part, I found that it is a normally closed circuit, i.e. continuity between the terminal and the body.
As I really needed to get this vehicle going by yesterday, and because PE is a bit far to just drive for a another switch, I searched for a wiring diagram for this type of switch. I also wasn't very sure about the existing relays and wiring so thought it simply be easier to lay down new wires and relays as I had this in my spares box.

Attached is the diagram I used;

This solved the problem - or at least part of it. The fan comes on at 90*C, but then doesn't switch off again at 85*C. When the temp goes below 85, the fans still keep running - that is until I switch the vehicle off completely and back on. Note I didn't connect to the ECU.

Can anyone please give me any pointers here? I made double sure that my installation is exactly as per the diagram, but who knows, anything is possible hey?
fan_trigger_wiring_idle-up2.png
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FIRSTGEER
LR4WD, Lockers, Crawler Gears
LR4WD, Lockers, Crawler Gears
Posts: 1514
Joined: Thu Sep 30, 2010 6:00 am
Town: King WilliamsTown
Vehicle: 2,5 D4D Singlr Cab 4X4 Full OME suspension. snorkel.GMA aftermarket bullbar.
Real Name: Tony Geer
Club VHF Licence: HC 109

Wed Oct 09, 2019 6:58 am

Hannes where have you installed the aftermarket thermostat switch and what radiator is installed in your surf.
The reason for asking these two questions is that we have recently completed a conversion to my sons sfa.We installed a merc 602
5 cylinder diesel to the hilux and I found that by installing the thermostat onto the bottom pipe of the radiator,it was more effective .
Also the radiator size for that six cylinder engine needs to be fairly big
.I fitted the 7mge into a hilux about 25 years ago so this really brings back the past.
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hannesnel
Newbie
Posts: 2
Joined: Mon Oct 07, 2019 8:49 am
Town: Grahamstown
Vehicle: 1992 Hilux Surf 7MGE
Real Name: Hannes

Thu Oct 10, 2019 7:01 am

Hi Tony

If by "aftermarket thermostat switch" you mean the switch that controls the electric fan, it is installed in the thermostat housing on the radiator side of the thermostat.
The radiator is the original Surf radiator for the 2.4 diesel turbo engine. For now it seems to be working fine. I've driven the vehicle on long uphills and as long as I'm driving at speed (enough airflow), the temperature stays at about 85*C.
However, i did notice the double electric fans don't seem to be pushing enough air through the radiator when stationary. So I'm looking into sourcing a single 16" fan with airflow of minimum 2000cfm. This, however, seems to be a hard-to-find item in SA. Or maybe the people I've approached just are not putting enough effort into it?
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FIRSTGEER
LR4WD, Lockers, Crawler Gears
LR4WD, Lockers, Crawler Gears
Posts: 1514
Joined: Thu Sep 30, 2010 6:00 am
Town: King WilliamsTown
Vehicle: 2,5 D4D Singlr Cab 4X4 Full OME suspension. snorkel.GMA aftermarket bullbar.
Real Name: Tony Geer
Club VHF Licence: HC 109

Sun Oct 13, 2019 9:39 pm

I used a radiator from an old Nissan laurel which was available those years and and the dimensions where the best I could find to fit. I used double fans in front of the radiator. And yes I was referring to the fan switch. Also how clean is your radiator
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