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GQ 2.8TD ECU Repairs?

4413 Views 6 Replies 4 Participants Last post by  Spargo
Have just had to replace the ECU, which is just a glorified Glow Plug Timer. Nissan wanted $1200, got one at the wreckers for $300. Went down this path as didn't really want to put in a manual glow switch. Does anyone know of a company that repairs them? They're a basic unit, exposed passive components, not set in epoxy so should be relatively easy to repair. Have had no luck in finding anyone.
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Just wondering what problems you've been experiencing with your ECU, cause after reading your post alarm bells started ringing. I've had a problem with my '97 GQ 2.8TD cold starting. I've found that by warming the glow plugs, cancelling with the stop button on my turbo-timer and re-warming them the vehicle starts better (obviously not the ideal way to start the car). However, once the motor is warm it will start straight away, first time.
Have you been experiencing something similar? I was hoping it wasn't going to be an expensive fix, but having already replaced glow plugs and having the starter motor rebuilt, this may be the route i might have to go down too.
Symptoms were:
1. Tacho stopped working.
2. Glow indicator on the dash no longer illumunated when ignition switched to on.
3. Couldn't hear the glow relays clicking as usual.
4. First start was a dog, heaps of black smoke and rough running till warm.

The reason the tacho stopped working is because the ECU monitors the revs before pushing the signal out to the dash dial.

There are a few ways to determine whether the glowies are getting volts, the easiest is the run a volt meter between the lower bus-bar next to glow plug 6 (just near the cable connection) and earth, switch on the ignition and as long as water temp is below approx 75C should get full battery voltage for 10 seconds and half battery voltage for 30 seconds.

Be aware that glow plugs 1,2,3 are different to 4,5,6. A lot of people, mechanics included, have misdiagnosed glow plugs being faulty because of the minor difference between the first and second banks.

See how you go with the test, if you're still having trubs I can get some drawings and diagnostic tips to you maybe.

Regards, Bone
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Thanks for the info. My tacho and glow plug indicator work fine. But what you describe about cold starting certainly sounds familiar. I knew about the two different types of glow plugs (at least the mechanic got that much right). It's been to three mechanics, and non have had any idea (including a truck workshop). I'll try the test, but if this doesn't work i think an auto-elec will be the next port of call. Thanks again for the info.
Roger that, don't hesitate to give us a yell if you keep having trubs.

Go the 2.8

Its a very simple problem people are having and only takes 5 mins to fix, there is a blown transistor on the ECU/Glow control unit/what ever you want to call it. Transistors cost about 20c from Jaycar electronics just gotta un-solder the old one off the board and solder the new one back on. The reason it runs rough is because only 3 of the glow plugs are operating because they're activated directly after the ignition and dont go through the glow control unit.

either that or the timer doesn't turn off and just burns out the plugs and leaves the 6.5v after burns on, still fixing this is just the transistor

But still test all the sensors, engine revolution, engine temperature etc.
pics/diagrams of the transistor that blows??
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