3RZ using fuel and lacking power?

[2JZXL]

Hi I've done an engine conversion fitted a 3RZ twin coil engine to an RN110 hilux extra cab 4x4 in place of the 22R. engines standard done 305000kms or so stock ECU, injectors, intake etc just has a 2 1/4 mandrel bent exhaust. Problem with it is I'm averaging around 28L per 100km mixed highway bush driving. It has 4.56 diff gears and roughly 32 inch tyres, alloy tray unloaded no air con etc.

I've changed plugs and leads, changed oils, cleaned filters etc has new fuel pumps, cleaned MAF sensor, cleaned injectors, cleaned throttle body. Motor doesn't seem to make the power it should and noticabley gutless and reluctant to pull on highway speeds not so noticable in low range with less load on engine so I'm thinking maybe its a coil issue?

Anyone had similar issues with the 3RZ any help would be appreciated?

cheers

[Dazza]

I would try another oxygen sensor.

[allencr]

What's the compression?
How is the ignition timing being set & wadda the plugs look like?
Coil Issue, Does it miss/run ruff at high RPM or steady speeds?
Nothing with a 4.56, 305k's & bush driving is going to win an kilometerage awards.

[Daddio]

Could be ECU temp sender fail, which causes it to run rich, thus high consumption and lack of power?

[2JZXL]

This model has no oxygen sensor, will change temp sensor and coils and do a compression test this afternoon. Not sure about timing will check it too. I don't expect it to be as economical as a Prius but it should be a lot better than it is I've read forums where people get around 13-15l per 100km.

Cheers guys

[Dazza]

I would have expected it to use around 14L per 100 Km. I agree that the temp sensor could be the problem.

[allencr]

Close up the plug gap by 30-50% & see how it goes. If there's an actual coil problem, it'll run much better & only a slight bit worse if there isn't.

[litldv8]

what did you use to clean the maf?

[2JZXL]

Cleaned the MAF sensor with the proper aerosol spray. Am getting it plugged in to a computer by a Toyota technician so will see what that shows before I buy new sensors and coils etc. I didn't realise the coolant sensor for ECU was at back of head so it probably copped some punishment against firewall lifting motor in and out doing conversion.

[2JZXL]

Well over weekend did compression test all cylinders were between 210-220psi not bad considering it's 310000km engine. Fuel pressure at 50psi. Hooked scan tool up to DLC3 plug and coolant sensor, MAF sensor, TPS all working fine. Timing is around 8 degrees, injector pulse is normal so all fingers pointing at dodgy coils. Tacho goes crazy most times when revving out apparently another sign of faulty coils. Will get 2 different coils clean up all the earthing points and mounts and hopefully will fix it.

[4th surf]

I would also check the ECU wiring as there are differences depending on if the original car that the engine came out of was Thai built or Jap built. It will be down to one wire but which one escapes me ATM. Had the same problem once before and it was down to one voltage to the ECU, once that was sorted hot damn did it go. The same problem was also had wiring a 1UZ into a Hilux that a 3RZ came out of as no wiring schematics for the Hilux were correct

[2JZXL]

Ok thanks mate, was thinking it may have been a voltage issue as the tachometer was going mental but it's constantly got 15 volts at ECU right through rev range until rev limiter even when the tachometer is playing up. Not sure where original vehicle was made its a 2000 model 2WD ute RZN149r

[neal]

Isnt 22r single coil dizzy setup and 3rz has no dissy and wasted spark coil packs? If so you may need a tacho booster for your taco to work properly.

[2JZXL]

Yeah mate I've done the 10ohm resistor mod to tachometer so it reads the signal properly from 3rz.

[2JZXL]

Well I changed the coils which fixed the issue with tachometer being erratic so there must have been a dodgy earth or something. I sorted out the issue with fuel consumption and lack of power theres a VSV type switch mounted to the charcoal canister, wiring from this goes directly to ECU. As an experiment I unplugged the switch and blocked up the vacuum line running from throttle body and problem solved.